pan-gondwanaland detrital zircons from ... - gemoc.mq.edu.augemoc.mq.edu.au/terranechronpds/417...

Pan-Gondwanaland detrital zircons from Australia analysedfor Hf-isotopes and trace elements reflect an ice-covered

Antarctic provenance of 700ndash500 Ma ageTDM of 20ndash10 Ga and alkaline affinity

JJ Veevers a EA Belousova a A Saeed a K Sircombe b1 AF Cooper c SE Read c

a GEMOC ARC National Key Centre Department of Earth and Planetary Sciences Macquarie University Sydney NSW 2109 Australiab TSRC School of Earth and Geographical Sciences University of Western Australia Crawley WA 6009 Australia

c Geology Department University of Otago PO Box 56 Dunedin New Zealand

Received 19 April 2005 accepted 16 November 2005Available online 23 January 2006

Abstract

Eastern Australian sediments of Cambrian Ordovician SilurianndashDevonian Triassic and Neogene ages are known to bedominated by zircons dated 700ndash500 Ma (ldquoSouthwest PacificndashGondwana igneous componentrdquo) by the UndashPb SHRIMP methodand thought to be derived from Antarctica as suggested also by paleogeographical evidence To extend the characteristics of theprovenance we subjected SHRIMPed zircons from the Middle Triassic Hawkesbury Sandstone and four Neogene beach sands toLAMndashICPMS analysis for rock type and Hf-isotope TDM model ages These data confirm the demonstration (from ages alone) thatthe beach sands were recycled from the Hawkesbury Sandstone All five samples have a substantial fraction of 700ndash500 Mazircons derived from alkaline rocks with TDM of 20ndash10 Ga We analysed zircons from the nearest exposed alkaline rock ofappropriate age in Antarctica the 550ndash500 Ma Koettlitz Glacier Alkaline Province of the Ross orogen of the TransantarcticMountains emplaced during contemporary transtension The rock types and TDM of the Koettlitz Glacier Alkaline Province zirconsmatch those of the eastern Australian samples but only over the restricted range of 550ndash500 Ma Rocks of 700ndash550 Ma age andalkaline type are unknown in Antarctic exposures

Rocks of this age and type however abound in the Pan-Gondwanaland orogens The nearest of these is the Leeuwin Complexof the Pinjarra orogen of southwestern Australia which connects through the PrydzndashLeeuwin Belt with the Mozambique OrogenicBelt In turn the Leeuwin Complex is dominated by 700ndash500 Ma alkaline rocks generated by contemporary transtension We findthat zircons from a beach sand at Eneabba 450 km north of the Leeuwin Complex are dominated by alkaline types so confirmingdemonstration by age alone that the sand came from the Leeuwin Complex An important inference is that Pan-Gondwanalandterranes are potential provenances of sediment with zircons of ages 700ndash500 Ma model ages 20ndash10 Ga and alkaline affinity

We compiled the age spectra of our samples with others of the Southwest PacificndashGondwana igneous component in southernAustralia and reviewed their paleogeographical data The Early Cambrian turbidites of the Kanmantoo Group were deposited froman axial northward paleocurrent that flowed across adjacent Antarctica in Wilkes Land The Ordovician turbidite was deposited infore-arc and abyssal fans likewise from a northward paleocurrent that flowed parallel to the uplifted RossndashDelamerian orogen TheOrdovicianndashSilurianndashDevonian Mathinna Supergroup was deposited in a submarine fan system that prograded to the east-northeast

Earth-Science Reviews 76 (2006) 135ndash174wwwelseviercomlocateearscirev

Supplementary data associated with this article can be found in the online version at doi101016jearscirev200511001 Corresponding author Tel +61 2 9850 8355 fax +61 2 9850 8943E-mail address johnveeversmqeduau (JJ Veevers)

1 Present address Geoscience Australia GPO Box 378 Canberra ACT 2601 Australia

0012-8252$ - see front matter copy 2005 Elsevier BV All rights reserveddoi101016jearscirev200511001

from high ground in Antarctica The Hawkesbury Sandstone was deposited in a braided-river system on a surface that sloped to thenorth-northeast from high ground in Antarctica Together with the zircon data the paleogeographical evidence in the CambrianOrdovician OrdovicianndashSilurianndashDevonian and Triassic all point to a provenance in Wilkes Land Antarctica of Pan-Gondwanaland (700ndash500 Ma) terranes with alkaline rockscopy 2005 Elsevier BV All rights reserved

Keywords Australia Antarctica detrital zircons 700ndash500 Ma Pan-Gondwanaland Hf-isotopes trace elements TDM paleogeography alkalineprovenance

1 Introduction

As a sequel to Sircombes (1999) UndashPb SHRIMPdating of zircons from eastern Australian sands andsandstone we analyse the same grains by LAMndashICPMSto ascertain the rock type and Hf model age of theigneous host

Detrital or inherited zircons of late NeoproterozoicndashEarly Cambrian (700ndash500 Ma) age ldquothe SouthwestPacificndashGondwana igneous componentrdquo (Ireland et al1994) are the dominant grouping in many Paleozoicgranites greywackes and gneisses of the Delamerianand Lachlan orogens (Ireland et al 1998 Williams1992) and in Triassic sandstone and Neogene littoralsands in eastern Australia (Sircombe 1999) summed upin Veevers (2000a p 110ndash130) chapter calledldquoAntarcticndashBeardmorendashRoss and Mirny provenancessaturate PaleozoicndashMesozoic East Gondwanaland with06ndash05 Ga zirconsrdquo (Fig 1) According to Sircombe(1999) ldquoAlthough the 480ndash520 Ma RossndashDelamerianOrogeny may explain some of the Southwest PacificndashGondwana age grouping the bulk of these provenanceages occur between 550ndash650 Ma and require furtherexplanation hellip Neoproterozoic convergence of theBeardmore Microcontinent in the Central TransantarcticMountains may have been more widespread than iscurrently exposed in Antarctica In particular thebasement of the Wilkes Subglacial Basin is unknownbut lies in a location that palaeodirection studies andtectonic history suggest could have been the source ofthe Lachlan Orogen and the Hawkesbury Sandstone of

the Sydney Basin hellip beaches [on the eastern Australianmargin] are dominated by Neoproterozoic zirconsprobably derived from a source that now lies over7000 km [away] due to a favourable pathway through anintermediate sediment repository in the Sydney Basinrdquo

In Western Australia the Eneabba sand (Sircombeand Freeman 1999) was derived from the Perth Basin orLeeuwin Complex or both and the Perth BasinOrdovician (490ndash450 Ma) and Permian (300ndash250 Ma)sandstones were derived from the Leeuwin Complex(Cawood and Nemchin 2000 Veevers et al 2005)

In the Adelaide region the Early Cambrian Kanman-too turbidite with 700ndash500 Ma zircons (Ireland et al1998) was deposited from paleocurrents that came fromAntarctica (Veevers 2000a p 200 206) before theintrusion of the Delamerian granites The presumedprovenance of the Kanmantoo is an ice-covered part ofEast Antarctica Following Sircombe (1999) Veevers(2000a p 114 121) regarded an unexposed Beard-morendashRoss orogen resulting from the collision of aBeardmore microcontinent with Antarctica (Borg andDePaulo 1991) as a potential source of the 600ndash550 Mazircons in the Kanmantoo and other sediments in easternAustralia Subsequent work in Antarctica (eg Goodgeet al 2002 2004) and our recognition of the older (700ndash600 Ma) part of the Southwest PacificndashGondwanaigneous component (Ireland et al 1994 Sircombe1999) seem to invalidate the concept of the Beardmoreorogen The 650ndash500 Ma interval saw Gondwanalandassembled by oblique convergence that drove internalrotation and counter-rotation of cratons (cogs) embedded

Fig 1 East Gondwanaland (Veevers 2000a fig 127) including the Mozambique Orogenic Belt and the PrydzndashLeeuwin Belt (Veevers 2003)showing bedrock of ages (Ma) and TDM model ages (Ga) represented in detrital zircons Archean of India (34ndash29 25 Ga) fromMojzsis et al (2003)and of Dronning Maud Land (30 Ga Grunehogna province) from Groenewald et al (1995) The beach sands are shown by open circlessedimentary rocks by filled circles East Antarctic data from Fitzsimons (2003) Transantarctic Mountains from Goodge et al (2004) Read et al(2002) TDM (Ga in bold) from Borg et al (1990) Borg and DePaulo (1991 1994) and Storey et al (1988 1994) The 550ndash520Ma Koettlitz GlacierAlkaline Province (KGAP) has a TDM of 142 and 125 Ga (Mellish et al 2002) within the range 17ndash09 Ga as described below marks the 175 Magranite in the Whitmore Mountains (Storey et al 1988) and the 1000 Ma gneiss in the Haag Nunataks (Storey et al 1994) The mildly deformedAdelaide Fold Belt is paralleled by the 520ndash500 Ma Delamerian granites and intensely deformed Kanmantoo Fold Belt (K)(Veevers 2000a)continuous through the 505 and 487 Ma granites (dated below) of the Oates Coast with the Ross orogen Younger fold belts are the 450ndash310 MaLachlan Fold Belt and 300ndash200 Ma New England Fold Belt (NEFB) B = Bowers Terrane HRS = Holyoake Range KGAP = Koettlitz GlacierAlkaline Province NHR = Hannah Ridge Formation NPA = Patuxent Formation Neptune Range RB = Robertson Bay Terrane TAndashKGVL = TerreAdeacuteliendashKing George V Land

136 JJ Veevers et al Earth-Science Reviews 76 (2006) 135ndash174

in fold belts (Veevers 2003) A 650ndash570 Ma stress-fieldchanged to a different set of azimuths at 570 Ma anddeformationplutonism terminated at 500 Ma with theRoss and Delamerian subduction events along the paleo-Pacific margin Characteristic of the 650ndash500 Mainterval in the interior are anorogenic magmas that

include A-type (alkaline) magma drawn into pull-apartsby extensional jogs along the strike-slip system

It is a terrane of this kind in ice-covered East Antarcticathat we suspect to have provided the 700ndash550Ma zirconsin eastern Australia as well as the 550ndash500 Ma zirconswhich could have come also from the Ross orogen

137JJ Veevers et al Earth-Science Reviews 76 (2006) 135ndash174

The Hawkesbury Sandstone contains only rarezircons from the 450ndash300 Ma granites of the LachlanFold Belt (Veevers 2000a p 122) so we rule out anysubstantial contribution from the Lachlan Fold Beltincluding the Ordovician turbidite with detrital 700ndash500 Ma zircons The Lachlan Fold Belt was presumablyburied beneath an aggrading fluvial plain in the TriassicThe NNE-ward cross-dip azimuth of the Hawkesburyindicates the paleoslope (Veevers 2000a p 122) andthe reciprocal bearing indicates the potential provenanceof a Pan-Gondwanaland terrane in East Antarctica

Of the eastern Australian sediments treated here theHawkesbury is the last to have been deposited directlyfrom the provenance The modern beach sands of north-eastern Australia were recycled from the Hawkesburyand the Pliocene beach sand in the Murray Basin atRobinvale was recycled from the Ordovician turbiditethe Hawkesbury Sandstone or both

These hypotheses from paleogeography and zirconages are now constrained further by trace-elementanalysis that indicates the rock type and by Hf-isotopeanalysis that indicates the model age of the provenanceThe new kind of evidence allows us to confirm or rejectthe provenances indicated by paleogeography and ageand to detail the provenance further by rock type andmodel age

2 Analysis of SHRIMPed zircons by LAMndashICPMS

21 Methods of analysis

Age data alone give a one-dimensional picture ofprovenance and cannot distinguish between twoprovenances of similar age but different geologicalhistory Recent developments in microanalytical tech-nology now make it possible to obtain UndashPb ages trace-element data and Hf-isotope measurements from singlegrains of zircon (Knudsen et al 2001 Belousova et al2001 2002 Griffin et al 2000 2002)

According to Belousova et al (2002) trace-elementabundances in igneous zircons as determined byelectron microprobe and laser-ablation microprobeICPMS analysis are shown to be sensitive to source-rock type and crystallization environment The concen-trations of 26 trace elements in zircons from a widerange of different rock types reveal distinctive elementalabundances and chondrite-normalised trace-elementpatterns for specific rock types Trace-element abun-dance in zircons increases from ultramafic throughmafic to granitic rocks Average content of REE istypically less than 50 ppm in kimberlitic zircons up to600ndash700 ppm in carbonatitic and lamproitic zircons

and 2000 ppm in zircons from mafic rocks and canreach per cent levels in zircons from granitoids andpegmatities Relatively flat chondrite-normalised REEpatterns with chondrite-normalised YbSm ratios from3 to 30 characterise zircons from kimberlites andcarbonatites but YbSm is commonly over 100 inzircons from pegmatites ThU ratios typically rangefrom 01 to 1 but can be 100ndash1000 in zircons fromsome carbonatites and nepheline syenite pegmatitesThe geochemical signatures characteristic of zirconfrom some rock types can be recognised in bivariatediscriminant diagrams but multivariate statistical anal-ysis is essential for the discrimination of zircons frommost rock types

This combination of techniques makes it possible todetermine for each grain not only the age but the natureand source of the host magma whether crustal orjuvenile mantle and model age (TDM) The integratedanalysis applied to suites of detrital zircon gives a moredistinctive and more easily interpreted picture ofcrustal evolution in the provenance area than age dataalone TDM model ages are expressed in Ga (eg 20ndash18 Ga) and the implicit 01 Ga signifies the level ofprecision UndashPb zircon ages are given in Ma (eg 1068Ma) except where space considerations as in somefigures require abbreviation (eg 107 Ga)

We applied this kind of analysis to the mounted070ndash050 Ga zircons from the eastern AustralianTriassic Hawkesbury Sandstone and four beach sandsthat had been dated by the UndashPb SHRIMP method(Sircombe 1999) and from another sample of aWesternAustralian beach sand dated by the UndashPb SHRIMPmethod (Sircombe and Freeman 1999) Hf-isotopeswere analysed on a laser ablation microprobe multi-collector inductively coupled plasma mass spectrometer(LAMndashMCndashICPMS) and trace elements on an electronmicroprobe (EMP) and LAMndashICPMS

The electron microprobe was used for preciseanalysis of Hf and Y in individual grains The Hf dataallow YbHf and LuHf ratios collected during Hf-isotope analysis to be converted to concentrationsThese elements together with U data collected duringthe SHRIMP UndashPb analysis provide discriminants thatcan be used to recognise broad categories of magmaticrocks from which the zircons crystallised The viabilityof such discriminants debated by Hoskin and Ireland(2000) has been demonstrated by statistical analysis oflarger databases (Belousova et al 2002)

In situ Hf-isotope analyses were carried out by a NewWave Research 213 nm LAM attached to a Nu Plasmamulticollector (MC) inductively coupled plasma massspectrometer (ICPMS) techniques are described by


Griffin et al (2000 2002) Interferences of 176Yb and176Lu on 176Hf are corrected using 176Yb172Yb and176Lu 175Lu ratios determined by analysis of mixedYbndashHf and LundashHf solutions The technique providesindividual analyses of spots 50ndash80 m across withprecision and accuracy equivalent to conventional mass-spectrometric analysis of zircon composites

In the plot of Hf vs age (eg Fig 4) with theChondritic Unfractionated Reservoir (CHUR) referenceline at zero zircons that plot below the line had hostmagmas derived in part from older recycled crustalmaterial and those above the line from juvenile mantlesources The same relations apply in the plot of 176Hf177Hf vs age with the higher reference line of theDepleted Mantle (DM)

For the calculation of Hf values which give thedifference between the sample and a chondritic reservoirin parts 104 we have adopted the chondritic values ofBlichert-Toft et al (1997) To calculate model ages(TDM) based on a depleted-mantle source we haveadopted a model with (176Hf 177Hf)i=0279718 and176Lu 177Hf=00384 to produce a value of 176Hf 177Hf(028325) similar to that of average MORB over 456Ga There are currently three proposed values of thedecay constant for 176Lu Hf values and model agesused in the figures were calculated using the value1931011 yr1 proposed by Blichert-Toft et al(1997) values for Hf and model ages calculated usingthis value lie between other proposed values of thedecay constant (18651011 yr1 Scherer et al 200119831011 yr1 Bizzarro et al 2003)

TDM model ages which are calculated using themeasured 176Lu 177Hf of the zircon give a minimumage for the source material of the magma from which thezircon crystallised These model ages are comparable toNdSm model ages We have calculated also a ldquocrustalrdquomodel age (TDM

C ) which assumes that its parental magmawas produced from an average continental crust (176Lu177Hf=0015) that originally was derived from thedepleted mantle TDM

C gives optimum agesThe analytical data for our samples are given in the

Background Online Dataset

3 Eastern Australian Triassic sandstone andNeogene beach sands

31 Ages

Common peaks (Fig 2) fall within the regional ageclusters defined in Veevers (2000a p 110) and refinedin Veevers et al (2005) (Table 1) As interpreted bySircombe (1999) the near-congruence of the dominant

d+ (07ndash05 Ga) peak suggests that the sands atHummock Hill Island Coffs Harbour StocktonBeach and Robinvale were derived from the Hawkes-bury Sandstone or other eastern Australian body of rockwith the same ages (d+) of zircons Minor peaks (e mdashLachlan Fold Belt f mdash New England Fold BeltVeevers 2000a p 112 ddd c aa aaa) confirm thecongruence

The Triassic Hawkesbury Sandstone and the Ordovi-cian turbidites are first-cycle deposits from the prove-nance Sircombe (1999) suggested and we confirm thatthe beach sands are derived from the HawkesburySandstone The turbidite zircons have spectra similar tothose of the Hawkesbury but with peaks at 520 Ma and538 Ma some 60 million years (my) younger than theHawkesbury peaks at 571 and 600 Ma The peaks at 860(ddd) and 1060 Ma (c) correspond with those in theturbidites Likewise the peak of 550 Ma in theMathinna and Stony Head zircons corresponds to thosein the Ordovician and Triassic rocks and zircons in therange 1300ndash1000 Ma correspond to c It seems that thesame provenance yielded sedimentwith the same spectralpeaks d+ and c during the Late Ordovician and SilurianndashDevonian and 200million years later during theMiddleTriassic The RossndashDelamerian orogen was beingunroofed in the Ordovician and would have provided aflood of 550ndash500 Ma zircons to the depocentres whichcorrespond to the 520 and 538 Ma peaks the situation inthe Permian and Triassic had changed such that peak wasshifted 60 my older to reflect a greater contribution fromslightly older terrane consistent with the idea that part atleast of the Ross orogen was covered by PermondashTriassicsediment In turn this suggests a super-terrane in adjacentAntarctica with d+ and c and capable of supplying sandto the Ordovician and SilurianndashDevonian fans andTriassic rivers

Other examples of d+ in southeastern Australia theTransantarctic Mountains and the Neptune Range areshown in Fig 3 The median age lies about 600 Ma sothat the bulk of the zircons must have been derived fromoutside the Ross orogen which is no older than 550 MaAs we shall see later and according to Goodge et al(2004) sediments in the Transantarctic Mountains werederived from within and west of the Ross orogen itfollows that the preponderance of ages between 700 and550 Ma signifies a provenance that extends in space tothe west and in time to 700 Ma

32 Rock types and model ages (TDM)

An extensive study of the trace-element patterns ofzircons (Belousova 2000) has shown correlations


Fig 2 Probability distribution diagram (Ludwig 2001) of UndashPb SHRIMP zircon ages of eastern Australian samples in order of increasing latitudeover the range 0ndash35 Ga from the dataset in Sircombe (1999) Correlation of peaks by grey lines identified by regional age clusters (Table 1 Veeverset al 2005) with d+ expanded to cover the main cluster (ldquoSouthwest PacificndashGondwana igneous componentrdquo) between 07 and 05 Ga Clusters f(03ndash02 Ga) and e (045ndash035 Ga) in eastern Australia are from Veevers (2000a p 114) The plot of the first-cycle K2258 Hawkesbury Sandstone isaugmented by plots (in fine lines) of two samples of Ordovician turbidite 514U1 mdash the 459 Ma (Gisbornian) Bumballa Formation from theShoalhaven River and CF256mdash the 459 Ma (Gisbornian) Sunlight Creek Formation from the Genoa River (Fergusson and Fanning 2002) The plotof K2250 Stockton Beach (fine line) is augmented by the plot of the OrdovicianndashDevonian Upper Mathinna Supergroup (thick line) and that ofK2411 Robinvale (fine line) by that of the OrdovicianndashDevonian Stony Head Sandstone (thick line) both from Black et al (2004) The lowermostplot shows the Eneabba sand (fine line) (from the dataset in Sircombe and Freeman 1999) and the Leeuwin Complex (Collins 2003) fromsouthwestern Australia


between these patterns and the chemical compositionof the magmatic host rocks The fields for differentrock types tend to overlap in two-dimensional spaceso that CART (Classification And Regression Trees)analysis was applied to classify each individual zircongrain in terms of its rock type (Belousova et al 2002Figs 7 and 8) CART is a diagnostic statisticalprogram that was developed for classifying a set ofobjects (chemical analyses) based on multivariate

measurements of characteristics of each of the objects(zircon grains)

Zircons from some rock types can be discriminatedwith a reasonable degree of probability Zircons fromalkaline rocks (syenites larvikites nepheline syenitescarbonatites) and mafic rocks (diabases basalts) arerecognised with a probability exceeding 80 (Belou-sova 2000) The frequency of finding detrital zirconsfrom the uncommon alkaline rocks (carbonatite syenite)is low For example in analyses of more than 3000detrital zircons Griffin et al (2004) found 6 classifiedas carbonatitic and less than 1 as of syenitic origin

Table 1Clusters of zircon ages of bedrock in southwestern Australia and EastAntarctica (Veevers et al 2005) See also Fig 36

Code Ga

d 06ndash05d+ 070ndash050dd 0725ndash065ddd 100ndash080c 130ndash100 [900 ANT]bb 140ndash130b 150ndash130a 180ndash150aa 210ndash190aa 260ndash250aaa 280ndash260aaaa 305ndash290

Fig 3 Nested age profiles of the d+ (700ndash500 Ma) cluster in samplesAndashH from southeastern Australia (from Fig 2) IndashK from theTransantarctic Mountains L and M from the Neptune RangeAntarctica and a histogram of ages from the Mozambique Belt d+comprises the 550ndash500 Ma range of the Ross orogeny (light grey) andthe 700ndash550 Ma range (clear) of the rest of East Gondwanaland inparticular the Mozambique Belt Three samples peak within the Rossrange two peak at 550 Ma and the eight remaining peak within the700ndash550 Ma range (A) K2607 Hummock Island Hill modern sand(B) K2315 Coffs Harbour modern sand (C) K2250 Stockton Beachmodern sand (D) K2258 Triassic Hawkesbury Sandstone (E) K2411Pliocene Robinvale sand (F) 514U1 mdash the 459 Ma (Gisbornian)Bumballa Formation from the Shoalhaven River (G) CF256 mdash the459 Ma (Gisbornian) Sunlight Creek Formation from the Genoa Riverboth from Fergusson and Fanning (2002) (H) OrdovicianndashDevonianUpper Mathinna Supergroup Tasmania (Black et al 2004) (I)98268G Cambrian Goldie Formation Dolphin Spur central Transan-tarctic Mountains longitude 172degE (Goodge et al 2002) (J) 98206ACambrian Goldie Formation Softbed Ridges central TransantarcticMountains longitude 164degE (Goodge et al 2002) (K) HRS MiddleCambrian to Early Ordovician StarshotDouglas Formation centralTransantarctic Mountains latitude 820degS longitude 1605degE (Goodgeet al 2004) (L) NPAMiddle Cambrian (515Ma) Patuxent FormationNeptune Range latitude 837degS longitude 592degW (Goodge et al2004) (M) NHR Early Cambrian (556ndash510 Ma) Hannah RidgeFormation Neptune Range latitude 838degS longitude 573degE (Goodgeet al 2004) The histogram of ages from the Mozambique Belt(Kroumlner and Stern 2005 after Meert 2003) is enclosed within Lexcept for extremes b500 and N700 Ma


About 70 were classified as granitoids and about 20as mafic rocks

A few grains were classified initially as kimberlitesolely on the basis of Lu These grains contain UN69 ppm YN194 ppm and YbN36 ppm According toBelousova et al (2002) the U content of kimberlite liesbetween 3 and 69 ppm Y between 4 and 194 ppm andYb between 016 and 36 ppm Zircons with contentsgreater than these values lie outside the kimberlite fieldand remain unclassified In the supplementary datasetthey are designated ldquounclassified ex-kimberliterdquo

Some analyses fall outside the fields suggesting thatthe original database was not fully representative In theoriginal database for example zircons from carbonatiteswere represented by samples from only two carbona-tites the 732 Ma Mud Tank carbonatite from centralAustralia and the 380 Ma Kovdor carbonatite from theKola Peninsula Russia Also important to note is thatthe classification is based on zircons from igneous rocksonly

321 Hummock Island sandIn the range of interest (700ndash500 Ma) peaks at 542

and 586 Ma are mirrored by peak ages of alkalinezircons at 540 and 586 Ma (Fig 4) Five zircons areclassified as alkaline (carbonatite) 2 as unclassified 4as mafic rocks 11 as granitoids with b65 SiO2 and 1as granitoids with 70ndash75 SiO2 (Table 2)

Hf ranges from 8 to 13 parts104 176Hf 177Hffrom 02821 to 02826 with outliers at 02816 and02813 Hf model ages (Table 4 Fig 15a) of all but afew grains are concentrated between 10 and 20 Ga

322 Coffs Harbour sandZircons in the Coffs Harbour sand (Fig 5) and the

Hawkesbury Sandstone have common peaks andtroughs within the age clusters (Table 3)

The peak age of all zircons (571 Ma) is slightlyyounger than that of the alkaline zircons (586 Ma) (Fig5) Eleven zircons are classified as alkaline (7 ascarbonatite and 4 as syenite) 1 as unclassified 8 asmafic rocks 24 as granitoids b65 and 20 asgranitoids 70ndash75 (Table 2) Hf ranges from 8 to13 parts 104 176Hf 177Hf from 02821 to 02826with outliers at 02816 and 02813

As in the Hummock zircons Hf model ages (Table 2Fig 15b) of all but a few grains are concentratedbetween 10 and 20 Ga

323 Stockton Beach sandThe peak age of all zircons (592 Ma) is the same as

that of the alkaline zircons (593 Ma) (Fig 6)

Twenty-one zircons are classified as alkaline (carbo-natite) 3 as unclassified 4 as mafic rock 18 as granitoidb65 and 2 as granitoid 70ndash75 (Table 2) Hf rangesfrom 8 to 31 parts 104 176Hf 177Hf from 02821 to02815 with an outlier at 02811

Most Hf model ages (Table 4 Fig 15c) areconcentrated between 10 and 20 Ga with a secondgroup between 20 and 30 Ga

Fig 4 Zircons (sample K2607) from Hummock Hill Island Queens-land (15147degE 2402degS) Above probability distribution diagram(Ludwig 2001) of SHRIMP zircon ages 1000ndash0 Ma (Sircombe1999) out of a total sample of 71 grains with peaks at 542 586 and648 Ma 700ndash500 Ma range is delimited by grey bands and the ages(fine line) of zircons from alkaline rocks (carbonatite) peak at 540 MaMiddle Hf (difference between the sample and a chondritic reservoirin parts 104) vs ages of zircons with trace-element classification ofsource igneous rock (Belousova et al 2002) Below 176Hf177Hf ofzircons with discriminant lines marked CHUR (chondritic unfractio-nated reservoir) and DM (depleted mantle) vs age of zircons withtrace-element classification ALK = alkaline Carb = carbonatite


324 Hawkesbury SandstoneThe peak ages of all zircons (571 600 Ma) overlap


Nine zircons are classified as carbonatite and 2 assyenite 9 as mafic rock 13 as granitoid b65 and 21as granitoid 70ndash75 (Table 2) Hf ranges from 8 to 38parts 104 with an outlier at 535 176Hf 177Hf rangesfrom 02826 to 02813 with an outlier at 028075 Thesevalues correspond to a TDM of 32 Ga suggesting anorigin in a protolith of old recycled crust Outliers inother samples have Hf between 27 and 49 and andTDM between 22 and 29 Ga

As in the Stockton Beach sand most Hf model ages(Table 4 Fig 15d) are concentrated between 10 and20 Ga with a second group between 20 and 30 Ga

325 Robinvale sandThe peak age of all zircons (577 Ma) is slightly

younger than that of the alkaline zircons (585 Ma) (Fig8) Twenty-four zircons are classified as carbonatite 3as unclassified 3 as mafic rock 16 as granitoid b65and 3 as granitoid 70ndash75 (Table 2) Hf ranges from8 to 30 parts 104 176Hf 177Hf ranges from 02826 to02815As in the Stockton Beach sand most Hf modelages (Table 4 Fig 15e) are concentrated between 10

Table 2Rock types of the 238 grains (62 of all 381 grains) aged 700ndash475 Ma plotted in Fig 9

Rock type K2607 Hummock K2315 CH K2258 HS K2250 Stockton K2411 Robinvale Total

Carbonatite 5 7 9 21 24 66 28Alkaline 11 11 (21)

Syenite 4 2 6 2Unclassified 2 1 3 3 9 4Mafic rock 4 8 9 (17) 4 3 28 12Granitoid 70ndash75 1 20 21 (38) 2 3 47 20Granitoidb65 11 24 13 (24) 18 16 82 34Total 23 64 54 48 49 238 100

Fig 5 Zircons (sample K2315) from beach sand at Coffs HarbourNSW (15314deg 3029degS) with the same plots as Fig 4 ALK =alkaline Carb = carbonatite Syen = syenite

Table 3Hawkesbury Sandstone (K2258) and Coffs Harbour sand (K2315)with common peaks and troughs within age clusters

K2258 K2315 Cluster Potential provenance

250 263 f 300ndash200 New England Fold Belt420 361 e 450ndash350 Lachlan Fold Belt571 600 592 d+ 700ndash500 (Part only) BeardmorendashRoss

Mirny860 914 ddd 1000ndash800 Rayner province of East

Antarctica1060 1096 c 1300ndash1000 Adelie Land Musgrave

AlbanyndashFraser1900 1950 aa 2100ndash1900 Capricorn Orogen

TDM of parts of2080 2034 Transantarctic Mountains2740 2720 aaa 2800ndash2600 Yilgarn Craton

Capricorn Orogen

All values in Ma


and 20 Ga with a second group between 20 and30 Ga

33 Differentiation of the second-cycle sands from thefirst-cycle sandstone

Differentiation from the Hawkesbury Sandstone(filled symbols in Fig 9 bold in Fig 10 and below)entails these changes

Unclassified from 0 to 15ndash9 in all other samplesSyenite from 4 to 6 in K2315 0 in the othersEnriched carbonatite from 17 to similar(11 K2315 22 K2607) or greater (44 K2250 49 K2411)and mafic granitoid from 24 to greater (33ndash48)

Impoverished dolerite basalt mafic rock from 17 to the same inone sand and less in the other three and felsic granitoid from39 to less (31 in K2315) to much less(4 to 6 in the others)

According to Sircombe and Stern (2002) ldquoGrainsurvivability has been correlated in some cases with Ucontent (Heaman and Parrish 1991) but survivabilitydepends on metamictization [radiation damage] whichin turn depends on uranium content and possibly mostimportantly age A high U grain will survive transpor-tation through to deposition and subsequent analysis iftransportation occurs before -decay damage becomestoo great The combination of high-energy environ-ments and relatively recent dominant sources (typically650ndash150 Ma) can be seen in data from zircon in modernbeach sand in eastern Australiahellip(Sircombe 1999)rdquo thesubject of our present study Sircombe and Stern (2002)concluded that compared with 3000 Ma zircons theldquorelatively recentrdquo zircons in the eastern Australianbeach sands even those with high U content (median209 ppm 95 percentile 629 ppm) were little damaged

We test this notion from our analyses (Fig 9) InK2258 the zircons classified as felsic granitoids have amean U content of 231 ppm and a median of 153 ppm(range 24ndash849 ppm) which compares with the slightlygreater values in K2315 347 ppm and 297 ppm (109ndash850 ppm) (values from Sircombe (1999)) In the alkalinezircons K2258 has a mean of 210 and a median of212 ppm and a range of 65ndash300 ppm K2315 has amean of 258 ppm a median of 178 ppm and a rangeof 65ndash600 ppm (Fig 9) The mean is slightly higherthan that in K2258 but with the b100 ppm valuesexcluded the K2258 mean would be 326 ppm and therange 101ndash849 ppm which match those of K2315 Asnoted above zircons of felsicndashgranitoid affinity (withlow U) have been preferentially eliminated from thesand (Fig 10) counter to the idea that high U signifies

weak grains The grains with alkaline affinity have asimilar U content in both sandstone and sand and in turnare similar in U content to that of the felsic granitoidzircons Nevertheless the sands have been enriched inalkaline grains during transport In these samples the Ucontent appears to have little or no bearing on thesurvivability of the zircons during transport

34 Summary and discussion

The near-congruence of Hf and176Hf 177Hf of the

700ndash500 Ma zircons is striking (Fig 11) The dominantrock type (Table 2) is alkaline in K2250 and K2411mafic granitoid in K2607 and K2315 and felsic

Fig 6 Zircons (sample K2250) from Stockton Beach NSW(15189degE 3283degS) Ages from alkalines shown by fine line ALK =alkaline Carb = carbonatite


granitoid in K2258 Overall the most common rocktype is mafic granitoid (34) followed closely bycarbonatite and syenite (30) then felsic granitoid(20) mafic rock (12) and unclassified (4)

With abundant 700ndash500Ma zircons (Veevers 2000ap 112 Fergusson and Fanning 2002) Ordovicianturbiditic sandstones of the Lachlan Fold Belt ofsoutheastern Australia are a potential source of theTriassic Hawkesbury Sandstone but the dearth of 450ndash320 Ma zircons from the voluminous zircon-bearinggranites of the Lachlan Fold Belt (BC Chappell perscomm 2004) in the Hawkesbury Sandstone rules outthe Lachlan Fold Belt as a provenance The HawkesburySandstone is the provenance of most of the 700ndash500 Mazircons in the second-cycle beach sands in the north(Sircombe 1999) and probably the zircons in theRobinvale sand of the Murray Basin (Veevers 2000ap 119) which could have come also from recycledOrdovician turbidite of the Lachlan Fold Belt

In seeking the primary provenance we depend on thefirst-cycle zircons in the Triassic Hawkesbury Sandstoneaugmented by the second-cycle zircons from the northernsands such as those from Coffs Harbour whose ages(Table 3) and properties (Fig 11) overlap those of theHawkesbury Parts of the Panthalassan margin includingthose in Antarctica (Ross High Veevers 2000a p 303)and southeastern Australia (265ndash230 Ma Kohn et al2002) were uplifted in the Early Triassic (250ndash242 Ma)

The Ross provenance could have supplied 550ndash490 Mazircons but not the 700ndash550 Ma fraction

Zircons from the Coffs Harbour sand (open symbolsin Figs 12ndash14) plot in the same place as those from theHawkesbury Sandstone (solid symbols) In Fig 12 Yvs NbTa the Hawkesbury carbonatites are overlappedby the Coffs Harbour ones and the Hawkesburysyenites lie in the middle of the Coffs Harbour onesAll except one of the grains (a granitoid) lie within orbetween the carbonatite and syenite fields The sameoverlapping relation applies in Fig 13 yttrium vsuranium Seven fall within the carbonatite and syenitefields 4 fall in the field of mafic rocks 3 in granitoidsand 6 outside In Fig 14 Y vs YbSm the overlappingrelation applies but 9 fall in the carbonatite field 3 ingranitoids 2 in mafic rock and 6 outside

The rock types of the Triassic Hawkesbury Sand-stone zircons (K2258) (Table 2 bold) (Fig 10) reflectthe primary provenance in decreasing order of abun-dance of felsic granitoids mafic granitoids alkalinerocks and mafic rocks The spectrum of rock types andthe range of Hf and 176Hf 177Hf in K2250 Stockton(Fig 6) indubitably from K2258 match those of K2411Robinvale in the Murray Basin (Fig 8) suggesting acommon provenance in the Hawkesbury Sandstone or acommon set of recycled zircons in the HawkesburySandstone and the Ordovician turbidite of the LachlanFold Belt

Table 4TDM (plain) and TDM

C (italics) according to rock type (Figs 15ndash18)

Type Unclassified Carbonatite Syenite Mafic Granitoid

b65 SiO2 70ndash75 SiO2

SampleK2607 132ndash158 097ndash137 101ndash117 097ndash143 147

182ndash226 124ndash188 217 262121ndash151 116ndash198 204315 391

K2315 211 088ndash141 129ndash136 086ndash132 086ndash156 094ndash128310 183 185 184 248

104ndash197 174ndash183 103ndash172 112ndash218 119ndash173265 263 263 364

K2250 125ndash151 093ndash123 093ndash120 102ndash123 104ndash117123ndash202 138ndash230

170ndash207 115ndash164 111ndash161 124ndash167 128ndash152164ndash295 189ndash338

K2258 094ndash131 088ndash105 099ndash135 092ndash156161ndash256 177 188 182ndash250115ndash175 105ndash139 125ndash184 115ndash214225ndash383 247 270 256ndash371

K2411 108ndash133 090ndash228 098 140 193 097ndash129 113ndash193142ndash181 111ndash336 127 191 279 159 220 146ndash264

140ndash173224 317


35 Summary alkaline zircons

All but two of the alkaline zircons are confined to the700ndash500 Ma interval and their properties overlapexcept the lower values of Hf and

176Hf 177Hf of asingle grain in K2258 (Fig 11) which reflect oldrecycled crust

Excluding Hummock Island which has the majorpeak 215 Ma and minor peaks at 542 586 and648 Ma the alkaline zircons have peaks between 572and 593 Ma mean 584 Ma (Fig 11 above)effectively the same as all zircons (571 and 592 Mamean 580 Ma)

Values of Hf range from 8 to 38 parts 104 and of176Hf 177Hf from 02826 to 02810 with all but 10 of

them below the Chondritic Unfractionated Reservoir(CHUR) reference line indicating that their hostmagmas were derived in part from older crustal material

36 Hf model ages

To calculate model ages (TDM) based on a depleted-mantle source we have adopted a model with (176Hf 177Hf)i=0279718 and

176Lu 177Hf=00384 to producea value of 176Hf 177Hf (028325) similar to that ofaverage MORB over 456 Ga Hf values and modelages used in the figures were calculated using the value1931011 yr1 proposed by Blichert-Toft et al (1997)(Figs 15ndash18 Table 4)

Fig 7 Zircons (sample K2258) from the Hawkesbury Sandstone atCalga NSW (15122degE 3343degS) The 700ndash500 Ma concentration ofcarbonatite zircons is delimited by grey bands ALK = alkaline Carb =carbonatite Syen = syenite

Fig 8 Zircons (sample K2411) from Pliocene sand (LoxtonndashParillaSand Murray Basin) at Robinvale NSW (14265degE 3479degS) Ages ofthe alkalines shown by fine line ALK = alkaline Carb = carbonatite


The first observation is that the model ages of mostgrains lie between 200 and 100 Ga (Figs 15 and 16)The few older model ages extend to 391 Ga Groupedby rock type (Figs 17 and 18) the model ages followthe same distribution with these differences

Mafic rock model ages are almost wholly confinedbetween 100 and 200 Ga most lie between 100 and150 Ga Syenite all 4 from K2315 are concentrated inTDMC about 180 Ga with a single value of 263 Ga

Carbonatite model ages from every sample (total of 66)are almost wholly confined between 100 and 200 Gawith a trail extending between 200 and 383 GaSimilarites in the range of ages within clusters are

Carbonatite Mafic rockCoffs Harbour K2315 088ndash197 Ga 086ndash172Hawkesbury Sandstone K2258 094ndash175 Ga 088ndash139

4 Koettlitz Glacier Alkaline Province as a potentialprovenance of 550ndash500 Ma zircons

The nearest known region of alkaline composition isthe Koettlitz Glacier Alkaline Province (KGAP) (Coo-per et al 1997 Read et al 2002) at 16300deg 7825degSin southern Victoria Land within the TransantarcticMountains 100 km southwest of McMurdo Station andsome 2000 km distant in the Triassic from the Hawkes-bury Sandstone (Fig 1) The next nearest 12000 kmdistant are 530ndash490 Ma A2-type granitoids and 512 Masyenites of Dronning Maud Land (Jacobs and Thomas2004) and farther still the 520ndash500 Ma alkali feldspargranite quartz syenite and syenite of the Cape GraniteSuite of South Africa (Da Silva et al 2000)

As summarized by Read et al (2002) the KoettlitzGlacier Alkaline Province encompasses the area ofsouthern Victoria Land that is dominated by alkalinerather than calcndashalkaline igneous rocks which crop out150 km to the south and 60 km to the north The mainrock types are A2-type granite (Eby 1992) alkalinediorite nepheline syenite and carbonatite The carbo-natite contains zircon and the magmas were derivedfrom the mantle and not from carbonate metasedimentin the country rock Ages are by TIMS 238U 206Pb onzircon and titanite a single SHRIMP on zircon and ourLAMndashICPMS ages (Figs 19 and 20) all errors 2 Inorder of increasing age the ages are

507plusmn12 Ma OU63304 nepheline syenite LAMndashICPMS 238U206Pb on 1 piece of zircon (Fig 20)

517plusmn4 Ma mdash OU70692 Penny Hill Granite (A2-type) conventional 238U206Pb on 75 titanites(Read et al 2002 p149 Fig 7)

530plusmn3 Ma mdash OU63300 carbonatite conventional238U206Pb on 6 concordant pieces of a singlezircon (Hall et al 1995)

531plusmn24 Ma mdash OU63304 Radian Ridge (nepheline)Syenite SHRIMP on zircons (n=11) (Cooper etal 1997)

533plusmn13 Ma OU63300 carbonatite LAMndashICPMS238U206Pb on 4 pieces of zircon (Fig 19)

534plusmn3 Ma mdash OU70587 Glee Intrusives (quartzmonzonite) conventional 238U206Pb on N100titanites (Read et al 2002 p149 fig 7)

535plusmn9 Ma mdash OU70393 Panorama Pluton (monzo-nite) conventional 238U 206Pb on N100 titanites(Mellish et al 2002 p 139 fig 7)

Fig 9 Percentage of zircons by rock type from eastern Australia (Table 2) and Eneabba Western Australia The (variable) percentage scale is shownon the left-hand column The values of the Hawkesbury Sandstone zircons are carried through by the dotted line The content of U (ppm) in zirconsfrom the Hawkesbury Sandstone and the derived Coffs Harbour sand is given for the alkaline and felsic granitoid fields in terms of the range ofvalues with the mean (bold) and median (italics)


536plusmn10 Ma mdash OU70455 Dromedary Mafic Com-plex (diorite) conventional 238U206Pb titanite andzircon (Mellish et al 2002 p139 fig 7)

539plusmn4 Ma mdash OU70572 Glee Intrusives (monzo-gabbro) conventional 238U 206Pb on 50 titanites

OU70573 monzonite 60 titanites (Read et al2002 p149 fig 7)

545plusmn12 Ma OU63304 nepheline syenite LAMndashICPMS 238U206Pb on 4 pieces of zircon (Fig 20)

551plusmn4 Ma mdash quartz syenite granite SkeltonGlacier (Rowell et al 1993)

567plusmn12 Ma OU63300 carbonatite LAMndashICPMS238U206Pb on one piece of a large crystal (L-02)

The conventional and LAMndashICPMS 238U206Pbages of OU63300 ndash 530plusmn3 and 533plusmn13 Ma ndash and ofOU63304 ndash 531plusmn24 and 545plusmn12 Ma ndash overlap eachother in the range of 531 to 551 Ma with outliers byLAMndashICPMS analysis of single grains at 567plusmn12 and507plusmn12 Ma

The Koettlitz Glacier Alkaline Province is interpretedas having formed 551ndash530 Ma in a transtensional shearthat pre-dated the 520 Ma onset of Ross Orogenysubduction in this area

Mellish et al (2002) determined the NdndashSm TDM ofa gabbro at 125 Ga and of a monzonite at 142 Ga and

Fig 10 Types of host rock () (Belousova et al 2002) inferred fromdetrital zircons with ages 700ndash470 Ma from eastern Australia (K2258Hawkesbury Sandstone in bold) in order of increasing southernlatitude (from the top) and from Western Australia (at the bottom) Inbetween are 550ndash500 Ma zircons from the bedrock of the KoettlitzGlacier Alkaline Province and the Oates Coast of Antarctica

Fig 11 Summary properties of alkaline zircons from the HawkesburySandstone (K2258) and derived sands mdash Coffs Harbour (K2315)Stockton Beach (K2250) and Robinvale (K2411) The age distributionis above the Hf in the middle and 176Hf177Hf below ALK =alkaline Carb = carbonatite CHUR = chondritic unfractionatedreservoir DM = depleted mantle Syen = syenite


Cooper et al (1997) found 132 Ga for the DismalSyenite

From samples OU63300 OU63304 OU70572OU70573 OU70587 and OU70692 we analysedzircons for trace elements andHf-isotopes (Figs 19ndash24)

41 Trace-element and Hf-isotope analysis

411 OU63300 carbonatite dykeA carbonatite dyke (Fig 19) at Radian Ridge was

dated by conventional UndashPb methods as 530plusmn3 Ma(2) (Hall et al 1995) here using 206Pb 238U toconform with our ages (n=6 U 100ndash600 ppm othergrains up to 2636 ppm) Other zircons from the dyke aredated by LAMndashICPMS as 533plusmn13 Ma (2) (n=4) withconcordance pieces with high U ndash up to 8000 ppm ndash arediscordant A piece of a large (5 mm) zircon (piece noL-02) is dated (concordantly) as 567plusmn12 Ma The 5pieces are classified as derived from mafic rock(Belousova et al 2002)

Of the 3 concordant pieces further analysed for traceelements by LAMndashICPMS and classified for rock type(Figs 25ndash27) 2 are mafic rock and one granitoid with70ndash75 SiO2 Two explanations for the misclassifica-tion are possible (1) the original database is not fullyrepresentative and does not cover the full range of zirconcomposition from carbonatites or (2) the zircons in thecarbonatite dyke are xenocrysts

The lsquomisclassificationrsquo of the 530 Ma zircons usingtrace element signatures is unlikely to be due to axenocrystic origin since the crystals are euhedral (noresorption) and the carbonatites at Radian Ridge occur

Fig 12 Zircons 700ndash500 Ma classified as carbonatite in the ldquoshortrdquoCART tree (Belousova 2000 Belousova et al 2002) mdash6 from theHawkesbury Sandstone (filled symbols) 14 from Coffs Harbour sand(open symbols) After further trace-element analysis the zircons wereclassified in the ldquofullrdquo CART tree mdash Hawkesbury as 4 carbonatite 2syenite Coffs Harbour 7 carbonatite 4 syenite 2 mafic rock 1 granite65ndash70 and plotted on the fields of zircon compositions used asdiscriminants for various rock types This figure shows yttrium vsniobiumtantalum

Fig 13 As in Fig 12 yttrium vs uranium

Fig 14 As in Fig 12 yttrium vs ytterbiumsamarium


Fig 15 Model ages of zircons from eastern Australia TDM (minimum) and TDMC (optimum) are given for each grain as described in Section 2

Zircons with UndashPb age between 734 and 440 Ma (Southwest PacificndashGondwana group) are in black and are discussed here zircons with age outsidethis range are in grey


within nepheline syenite rather than gabbro Nothing inthe exposed Ross orogen bedrock in that part of theTransantarctic Mountains is old enough to haveprovided the 567 Ma crystal Also it is unlikely thatcarbonatitic activity lasted for 30 my (567ndash530 Ma)However by rejecting a xenocrystic origin for all butone of the grains we are simply shifting rather thansolving the conundrum These are unusual carbonatitesfenitization ndash alkali metasomatism ndash is either absent oris dissimilar to the normal highly alkaline type and theSr isotope ratio is elevated above what one wouldexpect of a mantle-derived magma The 567 Mamegaphenocryst (especially with the agreement at

530ndash533 Ma of all the other concordant pieces)would seem to be xenocrystic but from an unknownsource

Calcite from the dyke has a Nd-isotope TDM modelage (X in Fig 28b) of 15 Ga (Hall et al 1995)

412 OU63304 nepheline syeniteZircons from sample OU63304 of a nepheline

syenite at Radian Ridge (Fig 20) are dated by 206Pb238U SHRIMP as 531plusmn24 Ma (Cooper et al 1997)(n=11 U 107ndash1162 ppm a discordant grain has 2079ppm) (Fig 20) Four zircons from the syenite are datedby LAMndashICPMS as 545plusmn12 Ma and one as 507plusmn12


Zircons with UndashPb age between 734 and 440Ma (Southwest PacificndashGondwana group) are in black and are discussed here zircons with age outsidethis range are in grey


The classification is 3 carbonatite and 2 mafic rock Ofthe 5 zircons further analysed for rock type one iscarbonatite 2 syenite and one each of mafic rock andgranitoid with 65ndash70 SiO2 (Figs 25ndash27) Theclassification of 3 zircons as alkalines agrees with thatof the host rock

A whole-rock sample has a Nd-isotope TDM modelage ( Fig 28c) of 14 Ga (Hall et al 1995)

413 OU70572 Glee Intrusives monzogabbroSamples OU70572 and OU70573 of the Glee

Intrusives (Fig 21) at the Royal Society Range are

dated by conventional UndashPb on titanite (n=50) as539plusmn4 (Read et al 2002) Seven zircons areclassified by trace-element content as 4 felsicgranitoid 2 mafic granitoid and 1 mafic rock

414 OU70573 Glee Intrusives monzoniteZircons of the Glee monzonite comprise 3 felsic

granitoid 4 mafic granitoid and 4 mafic rock (Fig 22)

415 OU70587 Glee Intrusives quartz monzoniteTitanite (nN100) is dated by conventional UndashPb as

534plusmn3 Ma (Read et al 2002) 3 zircons are felsic

Fig 17 Model ages of zircons from eastern Australia grouped by rock type


granitoid 1 is mafic granitoid and 2 are mafic rock(Fig 23)

416 OU70692 Penny Hill graniteTitanite is dated by conventional UndashPb as 517plusmn4 Ma

(Read et al 2002) Zircons are 11 felsic granitoid 5mafic granitoid and 7 mafic rock (Fig 24)

417 Trace-element analysis of OU63300 and 63304(Figs 25ndash27)

Three zircons from the OU63300 carbonatite and 5from the OU63304 nepheline syenite were classified byCART on plots (Belousova 2000) of yttrium vsuranium (Fig 25) yttrium vs ytterbiumsamarium(Fig 26) and hafnium vs yttrium (Fig 27) All thezircons have Hf contents less than 11 wt (Fig 27)characteristic of zircons from alkaline rock types

(Belousova et al 2002) The only grain classified asfrom carbonatite falls within the carbonatite field onFigs 26 and 27 The 2 syenites lie near the syenitefield but have Yb100 ppm (Fig 25) which ischaracteristic of zircons that crystallize from maficunfractionated rock Of the 3 grains classified as frommafic rocks 2 plot inside or near the mafic (basic) fieldon Fig 26 The 2 zircons classified as from granitoidsshow high U (N300 ppm) and Y (N1000 ppm)contents typical of zircons in high-Si granitoids

418 Summary of rock typesZircons from the carbonatite and nepheline syenite

have Hf contents less than 11 wt characteristic ofzircons from alkaline rock types Of the 8 analysedzircons of the nepheline syenite 5 are carbonatite andthe others mafic rock Of the 13 analysed zircons of the



carbonatite only 1 is carbonatite and the rest are maficrock Zircons in the remaining samples are mainlygranitoid 70ndash75 SiO2 with minor amounts ofgranitoid b65 SiO2 and mafic rock

42 Model ages (Fig 28)

The model ages of the Koettlitz Glacier AlkalineProvince samples are plotted on Fig 28 between thoseof the Oates Coast granitoids (above) and those of otherTransantarctic Mountains rocks and the detrital zirconsof eastern Australia (below) The Penny Hill Graniteranges from 17 to 10 Ga and the others have anarrower range of 15ndash09 Ga including the 15ndash12 Garange in the Dismal Syenite Panorama monzonite andgabbro (Fig 28a)

From the distribution of SmndashNd model ages (TDM)Borg et al (1990) and Borg and DePaulo (19911994)

distinguished four provinces in the TransantarcticMountains (Figs 1 and 28h)

(a) 19ndash16 Ga in the Transantarctic Mountainsbetween northern Victoria Land and 100 kmsouth of the Beardmore Glacier

(b) 15ndash11 Ga south of the Beardmore Glacierextending to the Horlick Mountains

(c) 20ndash17 Ga in the Bowers and Robertson Bayterranes of northern Victoria Land

(d) In the Miller Range TDM from 510 Ma granites is20 Ga and TDM from metamorphic rocks is272 283 310 and 348 Ga The Archean TDM

are consistent with the 30 Ga primary magmasdated by Goodge and Fanning (1999) The TDM of20 Ga (Borg et al 1990) is interpreted asindicating Proterozoic crust beneath the over-thrusted Nimrod Group In Terre Adeacutelie and King

Fig 19 Zircons from sample OU63300 from a carbonatite dyke atRadian Ridge (Hall et al 1995) Above probability distributiondiagram (Ludwig 2001) of UndashPb LAMndashICPMS zircon ages withpeaks at 533 and 567 Ma 700ndash500 Ma range is delimited by greybands Middle Hf (difference between the sample and a chondriticreservoir in parts 104) vs ages of zircons with trace-elementclassification of source igneous rock (Belousova et al 2002)Below 176Hf 177Hf of zircons with discriminant lines markedCHUR (chondritic unfractionated reservoir) and DM (depleted mantle)vs age of zircons with trace-element classification

Fig 20 Zircons (sample OU63304) from a nepheline syenite at RadianRidge (Hall et al 1995 Cooper et al 1997) Above probabilitydistribution diagram (Ludwig 2001) of UndashPb LAMndashICPMS zirconages with peaks at 507 and 545 Ma 700ndash500 Ma range is delimitedby grey bands Middle Hf (difference between the sample and achondritic reservoir in parts104) vs ages of zircons with trace-element classification of source igneous rock (Belousova et al 2002)Below 176Hf177Hf of zircons with discriminant lines marked CHUR(chondritic unfractionated reservoir) and DM (depleted mantle) vs ageof zircons with trace-element classification


George V Land (TA-KGVL of Fig 1) the TDM of32ndash28 Ga from 2700ndash2400 Ma rocks and TDM

of 22ndash19 Ga from 1700 Ma rocks match those inthe conjugate Australia (Fitzsimons 2003)

A range of 19ndash12 Ga is found in the Oates Coastgranitoids (Fig 28a)

In the Whitmore Mountains 175 Ma granite has TDM

of 17 to 13 Ga (Storey et al 1988) and in the HaagNunataks gneiss has TDM of 13 to 11 Ga (Fig 28h)

TDM of 20ndash10 Ga in the derived eastern Australiansandstone (Fig 28h) embraces the range of model ages

Fig 22 Titanite from sample OU70573 of the Glee intrusives at theRoyal Society Range are dated by conventional UndashPb as 539plusmn4 (Readet al 2002) Eleven zircons were analysed for Hf (middle) and 176Hf177Hf (below) Discriminant lines are CHUR (chondritic unfractio-nated reservoir) and DM (depleted mantle)

Fig 23 Titanite from sample OU70587 of the Glee quartz monzoniteat the Royal Society Range are dated by conventional UndashPb as 534plusmn3(Read et al 2002) Six zircons were analysed for Hf (middle) and176Hf 177Hf (below) Discriminant lines are CHUR (chondriticunfractionated reservoir) and DM (depleted mantle)

Fig 24 Titanite from sample OU70692 of the Penny Hill granite at theRoyal Society Range are dated by conventional UndashPb as 517plusmn4 (Readet al 2002) Twenty-three zircons were analysed for Hf (middle) and176Hf 177Hf (below) Discriminant lines are CHUR (chondriticunfractionated reservoir) and DM (depleted mantle)

Fig 21 Titanite from sample OU70572 of the Glee intrusives at theRoyal Society Range are dated by conventional UndashPb as 539plusmn4 (Readet al 2002) Seven zircons were analysed for Hf (middle) and 176Hf177Hf (below) Discriminant lines are CHUR (chondritic unfractio-nated reservoir) and DM (depleted mantle)


of the Oates Coast and the Transantarctic Mountains(Koettlitz Glacier Alkaline Province Horlick Moun-tains) Whitmore Mountains and Haag Nunataks and isalso represented in the Leeuwin Complex All thissuggests that the potential provenance of primary 700ndash500 Ma age contains model ages 20ndash10 Ga and thatthis terrane may extend to the west of and underlie theRoss orogen

43 Interpretation of Antarctic provenances of EasternAustralian sediment (Fig 29)

The Early Cambrian (525 Ma) turbidites of theKanmantoo Group (Ireland et al 1998 Fig 30f) weredeposited from a northward paleocurrent in a trough thatfrom 520 Ma was transformed into the Delamerianorogen The 700ndash530 Ma predominant age of thedetrital zircons suggests derivation from a provenanceof this age Few zircons have the ages of the exposedrocks in the Terre Adeacutelie and King George V Land ndash2700ndash2400 and 1700 Ma ndash suggesting that this terranewas narrow and did not supply significant amounts ofdetritus to the Kanmantoo Group Accordingly weshow this terrane as marking the southeastern limit ofthe Mawson Continent (Fig 37)

The Ordovician turbidite with predominant 700ndash500 Ma zircons was deposited from axial northerlypaleocurrents and the OrdovicianndashDevonian Mathinna

turbidite with predominant 700ndash400 Ma zircons (Blacket al 2004) was deposited from northeasterly paleo-currents (Veevers 2000a p 209 210 350) that flowedfrom an area of postulated d+ 700ndash500 Ma provenancewhich augments (in 700ndash550 Ma age) the potentialsupply of 550ndash500 Ma zircons from the Ross orogen

The 500ndash400 Ma zircons in the Mathinna turbiditecannot have come from Antarctica because theyoungest rock in this range is 475 Ma (Veevers2000a p 259) The Lachlan Fold Belt of southeasternAustralia has appropriate ages of 480ndash445 Ma in theMolong Volcanic Arc (Veevers 2000a p 162) and450 Ma and younger in granitoids (Veevers 2000ap 175) but is ruled out because of its position downslopefrom Antarctica

The Antarctic provenance (Fig 29) contributes to theHawkesbury Sandstone down the 034deg paleoslopeacross the Lachlan Fold Belt The Lachlan Fold Beltcomprises Ordovician (with 700ndash500 Ma zircons)Silurian and Devonian sediments and volcanics andvoluminous granitoids aged 450 to 320 Ma (also withinherited 700ndash500 Ma zircons Williams 1992 1998Williams and Chappell 1998) On the western edge ofthe Sydney Basin and immediately north of theBumballa Formation the Early Permian TallongConglomerate with zircon age peaks at 420 and330 Ma and few older than 450 Ma reflects theprovenance of Lachlan Fold Belt igneous rocks Thescarcity of zircons of this age (2 out of 75) in theHawkesbury Sandstone effectively rules out the Lachlan

Fig 25 Analysis of 3 zircons from OU63300 carbonatite and 5 fromOU63304 nepheline syenite both from Radian Ridge classified byCART Yttrium vs uranium

Fig 26 Analysis of 3 zircons from OU63300 carbonatite and 5 fromU63304 nepheline syenite both from Radian Ridge classified byCART Yttrium vs ytterbiumsamarium


Fold Belt including the Ordovician turbidite withdetrital zircons of 700ndash500 Ma age as provenance

The mean cross-dip azimuth (034deg) of the fluvialHawkesbury Sandstone indicates the paleoslope and thereciprocal bearing leads to the Ross orogen of theTransantarctic Mountains and in grey with white bandsthe wider area in Wilkes Land south of the Oates Coastmarked with d+

A grey arrow links the Hawkesbury Sandstone andthe beach sands to the north all with distinctive alkaline700ndash500 Ma zircons [[ALK 700ndash500]] Another greyarrow links the Hawkesbury Sandstone with thePliocene Robinvale beach sand with the same alkaline700ndash500Ma zircons arrows of broken lines indicate thepossible provenance of Ordovician turbidite in theLachlan Fold Belt

5 Oates Coast

RbSr ages of the Drake Head granodiorite (649plusmn30 Ma) and the Archangel granite (573plusmn10 Ma) fromthe Oates Coast (Adams 1996 Adams and Roland

2002) suggested Antarctic occurrences of rock in the700ndash550 Ma range The RbSr ages are now supersededby our LAMndashICPMS dating of zircons (from samplessupplied by CJ Adams) in the Drake Head granodioriteas 487plusmn15 Ma (2) (n=8) and in the Archangel graniteas 505plusmn6 Ma (2) (n=8) At the same time weanalysed the zircons for rock type and model ages (Fig28a) The 48 zircons from the Drake Head granodioritecomprise 17 felsic granitoid 28 mafic granitoid 2carbonatite and 1 mafic rock The 10 grains analysedfrom the Archangel granite comprise 8 felsic granitoid1 mafic granitoid and 1 nepheline syenite pegmatite

6 Eneabba beach sand and the Pan-GondwanalandLeeuwin Complex of southwestern Australia

The zircons from the Eneabba mineral sand inWestern Australia come from the same sample as thosewith UndashPb SHRIMP ages between 485 ndash 536 (peak) ndash645 Ma (Figs 2 and 30) (Sircombe and Freeman 1999)Either the zircons are recycled from the underlyingPermian sandstones of the Perth Basin (Cawood and

Fig 27 Analysis of 3 zircons from OU63300 carbonatite and 5 from U63304 nepheline syenite both from Radian Ridge classified by CARTYttrium vs niobiumtantalum


Nemchin 2000) which contain zircons with ages of d(600ndash500 Ma) and dd (725ndash650 Ma) (Veevers et al2005) or they come direct from the underlying Pinjarraorogen in particular from the exposed LeeuwinComplex 450 km to the south with age cluster d(600ndash537ndash500 Ma) and dd (725ndash692ndash650 Ma)(Col-lins 2003 Veevers et al 2005) or from both

The Leeuwin Complex ldquois but a small onshoreoutcrop of an extensive region of Neoproterozoicorogenesis that stretches over 500 km out to seardquo(Collins 2003) ldquoThe 650ndash580 Ma collision of East andWest Gondwanaland by closure of the MozambiqueOcean and continued Pan-African contraction to 500Magenerated the Mozambique Orogenic Belt and anorthogonal belt through Prydz Bay to Cape Leeuwinrdquo(Veevers 2000a p 278) As an offshoot of theMozambique orogenic belt (the East AfricanndashAntarctic

Fig 28 Model ages (Ga) of zircons aged between 470 and 700 Ma (a)to (g) and model ages of whole rocks (a lower part) and (h) Modelages of each zircon are plotted according to their classification in 6groups [symbols in (a) (c) (g)] and from the youngest TDM to theoldest TDM

C TDM is a minimum age for the depleted mantle source ofthe magma from which the zircon crystallised TDM

C is a ldquocrustalrdquomodel age which assumes that its parental magma was produced froman average continental crust (176Lu177Hf=0015) that was derivedoriginally from the depleted mantle (a) (Above) Zircons from sampleGXV44 (IGNS R no 13707) of the Drake Head granodiorite OatesCoast northern Victoria Land (Adams and Roland 2002) dated byLAMndashICPMS as 487plusmn15 Ma (2) (n=8) The 48 grains analysed forrock type comprise 17 felsic granitoids 28 mafic granitoid 2carbonatite and 1 mafic rock (Middle) Zircons from sampleGXV110 (IGNS R no 13779) of the Archangel granite OutriderNunatak northern Victoria Land (Adams 1996) dated by LAMndashICPMS as 505plusmn6Ma (2) (n=8) The 10 grains analysed for rock typecomprise 8 felsic granitoids 1 mafic granitoid and 1 nepheline syenitepegmatite (Below) Samples from the Koettlitz Glacier AlkalineProvince (KGAP) showing the whole-rock Nd-isotope model age ofthe Dismal Syenite (Cooper et al 1997) and the Panorama Monzoniteand Panorama Gabbro (Mellish et al 2002) (bndashg) Samples from theKoettlitz Glacier Alkaline Province (KGAP) southern Victoria Land(b) Zircons from sample OU63300 of a carbonatite dyke at RadianRidge (c) Zircons from sample OU63304 of a nepheline syenite atRadian Ridge are dated by UndashPb SHRIMP (206Pb238U) (n=11 U107ndash1162 ppm a discordant grain has 2079 ppm) as 531plusmn12 Ma(Cooper et al 1997) Four zircons from the syenite are dated byLAMndashICPMS as 545plusmn16 Ma (2) and one as 507plusmn6 (Fig 20) Ofthe 8 zircons analysed for rock type 5 are carbonatite and 3 mafic rockA whole-rock sample has a Nd-isotope TDM model age () of 14 Ga(Hall et al 1995) (d) Titanite from samples OU70572 and OU70573of the Glee monzogabbro at the Royal Society Range are dated byconventional UndashPb as 539plusmn4 (Read et al 2002) 4 zircons are felsicgranitoid 2 mafic granitoid and 1 mafic rock (e) Zircons from sampleOU70573 of the Glee monzonite comprise 3 felsic granitoid 4 maficgranitoid and 4 mafic rock (f) Titanite from sample OU70587 of theGlee quartz monzonite are dated by conventional UndashPb as 534plusmn3(Read et al 2002) In OU70587 3 zircons are felsic granitoid 1 maficgranitoid and 2 mafic rock (g) Titanite from sample OU70692 of thePenny Hill granite are dated by conventional UndashPb as 517plusmn4 (Read etal 2002) Zircons are 12 felsic granitoid 5 mafic granitoid and 7mafic rock (h) Nd TDM model ages in (1) the TransantarcticMountains from Borg and DePaulo (1994) except Miller Rangefrom Fitzsimons (2003) (2) the Whitmore Mountains and HaagNunataks (Storey et al 1988 1994) (3) the Leeuwin Complex(Collins 2003) and (4) Hf TDM model ages of detrital zircons fromeastern Australia (Figs 15ndash18)


orogen of Jacobs and Thomas 2004) the Pinjarraorogen registers typical Pan-Gondwanaland (650ndash500Ma) events (Veevers 2003 2004) including abundantalkaline rocks According to Fitzsimons (2003) ldquoTheLeeuwin Complex is dominated by felsic orthogneissranging from granodiorite to alkali granite hellip 860ndash650and 540ndash520 Ma protoliths are typical A-type graniteshellip Wilde and Murphy (1990) note that the emplacementof relatively alkaline granites hellip was consistent with acontinental rift environment at 550ndash500 Ma hellip Anotherpossibility was suggested by Harris (1994) who notedthat this time period was characterized by sinistraltranscurrent displacement both within the Leeuwin

Complex and Pinjarra Orogen as a whole and arguedthat local extension in the Leeuwin Complex wasgenerated within an extensional jog of the strike-slipsystemrdquo

Veevers et al (2005) found that in 2 of the 3 samplesof Permian sandstone from the Perth Basin analysed forHf and trace elements 6 out of 15 zircons or 40 withinthe range 700ndash500 Ma (minor peak) were alkaline(carbonatite) confirming their provenance in theLeeuwin Complex

Forty-one Eneabba zircons were analysed for traceelements and classified by CART as follows 53alkaline (35 carbonatite 18 syenite) 22

Fig 29 Easternmost Gondwanaland in the Middle Triassic (base from Fig 1) Ages in Ma (eg 520) model ages in Ga (15ndash11) First-cycle 700ndash500 Ma alkaline zircons are denoted by a filled circle and [ALK 700ndash500] and second-cycle ones by an open circle and [[ALK 700ndash500]] DML =Dronning Maud Land B = Bowers terrane RB = Robertson Bay terrane SG = Supergroup TAndashKGVL = Terre AdeacuteliendashKing George V Land


granitoid b65 SiO2 15 unclassified and 5 eachof mafic rock and granitoid 70ndash75 SiO2 (Figs 9and 10) The dominant alkaline group reflects thealkaline provenance in the Leeuwin Complex of thePinjarra orogen With more than half the grainsclassified as alkaline and with a 700ndash500 Ma rangeof age the Eneabba zircons resemble in age and

alkaline rock type the beach sands of eastern Australiaand their immediate provenance of the HawkesburySandstone The Hawkesbury zircons cannot havecome from the Leeuwin Complex or its derivativesbecause the Hawkesbury was in a different drainagesystem in the Triassic that of eastern AustraliandashAntarctica (Fig 31) What the similarity implies is

Fig 30 Probability age distribution of 700ndash500 Ma zircons in Australia and Antarctica all (except those from the Delamerian orogen and NeptuneRange) with a component of alkaline affinity (ALK) Eneabba sand (Sircombe and Freeman 1999) was derived (arrow) from the Leeuwin Complex(Collins 2003) The other distributions are examples of the Southwest PacificndashGondwana igneous component Coffs Harbour and Robinvale sandsfrom Figs 5 and 8 respectively The middle right-hand frame groups b the Hawkesbury Sandstone distribution with c the Ordovician BumballaFormation and d Sunlight Creek Formations (from Fig 2) e an Ordovician turbidite from Mt Kosciusko (Ireland et al 1998) and f the EarlyCambrian Balquhidder Formation of the Kanmantoo Group (Ireland et al 1998) The lower right-hand diagram shows the age range of the 515ndash490Delamerian orogen 550ndash490Ma Ross orogen including the Koettlitz Glacier Alkaline Province 700ndash500 Neptune Range detritus and 800ndash490MaLeeuwin Complex The histogram comprises 695 UndashPb zircon ages of the Mozambique Belt of East Africa and Madagascar from Kroumlner and Stern(2005) updated from Meert (2003)


that both sand and sandstone came from commonprovenances involved in the Pan-Gondwanalandevents (650ndash500 Ma) that accompanied assembly(Veevers 2003)

7 Pan-Gondwanaland (700ndash500 Ma d+) alkalinezircons and rocks

Pan-Gondwanaland (700ndash500 Ma d+) alkalinezircons (Fig 30) are common in Australia within aglobal epoch of carbonatitic magmatism at about600 Ma (Bell 2005) We summarize the derivation ofthe sands and sandstones as follows (1) the Eneabbaalkaline sand was derived (arrow) from the 537 Ma

component of the alkaline Leeuwin Complex (2) TheCoffs Harbour alkaline sand was derived from b theHawkesbury alkaline Sandstone (3) The SouthwestPacificndashGondwana igneous component of b the TriassicHawkesbury alkaline Sandstone c the OrdovicianBumballa Formation and d Sunlight Creek Formations(from Fig 2) e an Ordovician turbidite from MtKosciusko (Ireland et al 1998) and f the EarlyCambrian Balquhidder Formation of the KanmantooGroup (Ireland et al 1998) were derived from thepostulated region with 700ndash500 Ma d+ Pan-Gondwana-land zircons (red lower right-hand diagram) co-extensive with Wilkes Land Antarctica The zircon-producing events d+ as seen in Australian zircons are

Fig 31 Paleogeographic setting of the Hawkesbury Sandstone in the Middle Triassic From Veevers (2000a fig 331 p 303) Arrows indicatepaleoslope including the long arrow for the Hawkesbury Sandstone


weighted towards the younger half with a mode at550 Ma Also shown within this diagram are the 515ndash490 Ma Delamerian orogen 550ndash490 Ma Ross

orogen including the Koettlitz Glacier AlkalineProvince the 800ndash490 Ma Leeuwin Complex andthe Mozambique Belt including Madagascar which


has its mode about 640 Ma found also in the samplefrom the Neptune Range which adjoins the Antarcticextension of the Mozambique Belt in Dronning MaudLand All except the Delamerian orogen and NeptuneRange are known to have a component of alkalineaffinity Near the Neptune Range Dronning MaudLand contains rocks dated 700ndash600 Ma (J Jacobspers comm 2005) so widening the extent of regionsaged 700ndash500 Ma The ages of Australian detritalzircons peak at 550 Ma and those of the MozambiqueBelt peak at 640 Ma The Mozambique peak reflectssyntectonic magmatism during closure of the Mozam-bique Ocean in what Meert (2003) and Kroumlner andStern (2005) call the 660ndash610 Ma East Africanorogeny attributed by Veevers (2003) to obliquesubduction off West Africa between 650 and 570 MaThe younger 570ndash530 Ma Kuunga orogeny reflectspost-tectonic granites and pegmatites (Kroumlner andStern 2005) that are common in much of EastGondwanaland These ages extend to 490 Ma duringoblique subduction along the Pacific margin (Veevers2003)

A-type granites from 550ndash500 Ma left-lateralextension in the Leeuwin Complex and the KoettlitzGlacier Alkaline Province Koettlitz Glacier AlkalineProvince were generated during the operation ofglobal stress 2 which saw the final welding ofGondwanaland (Veevers 2003) At the other end ofGondwanaland ldquoin Morocco hellip the margin became asinistral transform boundary with peak granite intru-sions in extensional jogs at 550ndash540 Mardquo [cf peak537plusmn4 Ma in the Leeuwin Complex (Collins 2003)]Farther afield 550ndash500 Ma alkaline complexes arewidely distributed in Africa and are attributed to the ldquolsquoharpoon effectrsquo hellip when there is reversal in thegeneral sense of movement in a tear fault systemrdquo(Black et al 1985) Other examples are the peripheryof the West African Craton which in PharusianndashAdrardes Iforas contains 580ndash540 Ma alkalicndashperalkalicring-shaped A-type quartz syenites and granites ineastern Nigeria 580 Ma alkalic plutons and in theRokelides belt 533ndash500 Ma syenites and alkalicgranites (Doblas et al 2002) Other examples

elsewhere in Gondwanaland are rift-related peralkalinerhyolites (509 Ma) in Argentina (Rapela et al 2003)650ndash550 Ma peralkaline granites and rhyolites in theArabian Shield (Harris 1985) 590ndash550 Ma alkalinefelsic magmatism in southern India (Miller et al1996) and also in the rest of East Gondwanaland(Rajesh et al 1996) The association of 760ndash550 Maalkali granites and syenites in southern India and SriLanka and elsewhere in East Gondwanaland alongfault lineaments (extensional environments) suggestsldquoa geodynamic signature of East Gondwana during thePan-African periodrdquo (Rajesh et al 1996)

In ldquothe southern [Dronning Maud Land] part of the[East AfricanndashAntarctic] orogen [are] hellip very largevolumes of late-tectonic A2-type granitoids intruded ca530ndash490 Mardquo (Jacobs and Thomas 2004) Thissouthern part of the Mozambique Orogenic Belt inCentral Dronning Maud Land (Jacobs et al 1998Veevers 2000a p 269) contains this assemblage ofzircon-bearing rocks

512 Ma post-tectonic syenite batholiths515 Ma leucogranite dykes530ndash490 Ma A2-type granitoids530ndash515 Ma granulite-facies metamorphics530 Ma granodiorite570ndash550 Ma metamorphic overgrowth of zircon610ndash600 Ma charnockite and anorthosite700ndash600 Ma various events (JJacobs pers comm2005)

In their age weighting towards the 600 Ma end of therange signifying the collision of East and WestGondwanaland (Veevers 2003) and with voluminoussyenite the Dronning Maud Land assemblage reflectsthe compositional range except carbonatite of the 625ndash475 Ma zircons of the Coffs Harbour sand and theHawkesbury Sandstone Its location some 10000 kmfrom the Koettlitz Glacier Alkaline Province and in theTriassic 12000 km from the Hawkesbury Sandstonewould rule it out as a provenance but its voluminoussyenite serves as an example of a more extensivealkaline province

Fig 32 Ordovician paleogeography of East Gondwanaland with detail in black cooling orogens (Ross Delamerian) and Pan-Gondwanaland belts(Mozambique PrydzndashLeeuwin) in grey From Veevers (2000a fig 307) The large arrow at the trench indicates the direction of movement of thepaleo-Pacific plate (Goodge 1997) The paleoslope arrows in southeastern Australia are from Veevers (2000a fig 239) and in New Zealand fromVeevers (2000a fig 307 p 279) in an interpretation that the Western Terrane is rotated to an easterly azimuth The long narrow arrow with tip in NETasmania is the paleoslope indicated by the OrdovicianndashSilurianndashDevonianMathinna Supergroup (Veevers 2000a p 209 210 350) which containsdetrital zircons with ages of 700ndash400 Ma (Black et al 2004) BF = Bumballa Formation HRS = StarshotDouglas Formation from the HolyoakeRange NPA = Pataxent Formation Neptune Range SCF = Sunlight Creek Formation


71 Detrital alkaline zircons in Africa India andAntarctica

In an (as yet) unpublished analysis of detrital zirconsin other parts of Gondwanaland we have found alkaline(carbonatite) zircons within the range 700ndash500 Ma inthese samples

(1) 21 in sample AF5 and and 30 in AF6 of EarlyPermian sandstone from the northeastern KarooBasin South Africa

(2) 13 in the Early Permian sample G7 and 31 inthe Early Triassic G8 of the Godavari (Gondwana)Basin of India

(3) Rare grains in Antarctic samples from theEarly Permian of Dronning Maud Land andfrom the Late Permian of Beaver Lake LambertGraben

The alkaline zircons reflect the 700ndash500 Matranstensional tectonics of Gondwanaland

8 Paleogeography

In tracing the changing paleogeography we stepback through the Phanerozoic into the soft-focussedNeoproterozoic

81 Middle Triassic Hawkesbury Sandstone

The Hawkesbury Sandstone (Fig 31) was depos-ited on the cratonic side of the foreland (Sydney)basin immediately before the 230 Ma terminalGondwanides II uplift of the overthrusting magmaticorogen (horizontal-bar pattern) which shed volcano-lithic sediment cratonwards (Conaghan et al 1982Veevers et al 1994) A foreswell (vertical-line

Fig 33 Late Ordovician eastern Australia showing the longitudinal flow of sediment from Antarctica and the lateral flow from the magmatic arc andthrough the slope canyons The longitudinal currents along the fore-arc basin are inferred from the arrows in Fig 32 From Veevers (2000a fig 240after Powell 1984 fig 192)

Fig 34 550ndash500 Ma end-Neoproterozoic and Cambrian From Veevers (2000a fig 305) The 550ndash500 Ma Ross orogen and Pan-GondwanalandMozambique and PrydzndashLeeuwin Belts were active (black) The 515ndash490Ma Delamerian orogen (shown by the lettering) followed deposition of theKanmantoo Group from northward axial currents and eastward lateral currents The Hannah Ridge Formation in the Neptune Range (NHR) withminimum age of 556plusmn13 Ma (Goodge et al 2004) is a turbiditic sandstone and shale that was intensely deformed before being unconformablyoverlain by the Middle Cambrian (Boomerangian 509 Mamdash Veevers 2000a p 258) Nelson Limestone Sample NHR is a felspathic greywacke ofthe ldquoinboard sandstone unitrdquo (Goodge et al 2004) ldquoAssociated bimodal volcanics formed in an intracontinental rift settingrdquo (Storey et al 1992)during extensional phases generated by oblique subduction (Goodge 1997) Oblique subduction contributed to a second Pan-Gondwanaland stresssystem that operated from 550ndash450Ma (Veevers 2003) Sinistral shears induced local transtension that accommodated the alkaline magmatism of theKoettlitz Glacier Alkaline Province (KGAP) (Read et al 2002) the alkaline protoliths of the Leeuwin Complex (Fitzsimons 2003) and thevoluminous syenite of Dronning Maud Land (DML) (Jacobs et al 1998) Off eastern Australia and Antarctica Chilean-type subduction (Uyeda1981) changed to Mariana-type in southeastern Australia


pattern) in the north shed quartzose sediment into theinterior and in Tasmania into the foreland basin TheHawkesbury Sandstone braided-river system flowed

down a long slope from high ground in Antarcticawhich Sircombe (1999) identified as ldquothe basement ofthe Wilkes Subglacial Basin hellip[an area of] hellip


deformation and magmatism resulting from theNeoproterozoic convergence of the Beardmore Micro-continentrdquo Much later the beach sands were derived

from ldquoan intermediate repository in the SydneyBasinrdquo now some 7000 km from the primaryprovenance


82 Ordovician turbidite

In southeastern Australia Ordovician turbidite (Figs32 and 33) was deposited in fore-arc and abyssal fanslikewise from a northward paleocurrent that flowedparallel to the uplifted RossndashDelamerian orogen InOrdovicianndashSilurianndashDevonian Tasmania turbidite ofthe Mathinna Supergroup was deposited from north-easterly paleocurrents

According to Goodge et al (2004) the PatuxentFormation in the Neptune Range contains detrital zirconsas young as ca 495 Ma indicating latest Cambrian oryounger deposition We regard it as Early Ordovician(490 Ma) Sample NPA of the Patuxent Formation is acoarse feldspathic arenite deposited in the same intra-continental rift setting as the Cambrian Hannah RidgeFormation (NHR in Fig 34) ldquoThe Patuxent containsolder (680ndash580 Ma) grains that may represent eitherearly development of the Ross belt in the PensacolaMountains region or input from early Pan-Africandetritus from the southern part of the East Africanorogenrdquo (our emphasis) (Goodge et al (2004 p 1269)

Sample HRS of the StarshotDouglas Formationcomes from the Holyoake Range near the NimrodGlacier The sandstone and siltstone interfinger withconglomerate which was shed from the 550ndash490 MaRoss orogen Detrital zircons with ages between 700and 550 Ma would seem to indicate that a terrane with700ndash500 Ma zircons extended westward beneath the icein Wilkes Land

83 Cambrian paleogeography

A string of batholiths extends through the Transan-tarctic Mountains (Ross orogen) and Tasmania and inSouth Australia (Delamerian) Left-lateral transtensionin the Koettlitz Glacier Alkaline Province DronningMaud Land and Leeuwin Complex promoted theintrusion of alkaline rocks

The Early Cambrian turbidite of the KanmantooGroup was deposited from an axial northward paleo-current that flowed across adjacent Wilkes LandAntarctica (Jago et al 2003) The Cambrian HannahRidge Formation (NHR) and a volcanicndashmarine sedi-

mentary succession were deposited in the southernTransantarctic Mountains (Fig 34)

84 Late Neoproterozoic 600ndash550 Ma epoch

The closure of the Mozambique Ocean between Westand East Gondwanaland by oblique stresses involvedsinistral shearing in the Mozambique orogenic belt andPinjarra orogen here following earlier dextral strike-slip These motions part of the first Pan-Gondwanalandstress system that operated 650ndash570 Ma (Veevers2003) induced local transtension that accommodatedalkaline magmatism as in the Leeuwin Complex and inthe 551 Ma quartz syenite of the Koettlitz GlacierAlkaline Province (Fig 35) The sedimentary responseto these motions in Antarctica is lacking or has not beenidentified Earlier the Beardmore Group of shallow-water sands was deposited with basalt dated 668 Ma onthe side of a rifted continental margin (Goodge et al2002) Central and northern Australia underwent intensedextral transpression in the Halls Creek Paterson andPetermann areas reflecting oblique subduction alongthe Antarctic margin (Veevers 2003)

9 Timetable of events in Australia and Antarctica

A comprehensive timetable (35 to 05 Ga) ofregional events based on an heroic effort of UndashPbSHRIMP dating (Fitzsimons 2003) allows us to definethe following epochs that preceded the 700ndash500 MaPan-Gondwanaland epoch (Fig 36)

d+ the 700ndash500 Ma Pan-Gondwanaland epochincludes at the end the Ross and Delamerianorogenies

c 1300ndash1000 Ma the ldquoGrenvillerdquo age of authorsa 1800ndash1500 Ma includes the Kimban and

Nimrod orogeniesaa 2600ndash2400 Maaaaa 3000 and back to 3300 Ma

The epochs defined by age clusters of detritalzircons guide the interpretation of provenance Herein the column above Terre Adeacutelie we show our

Fig 35 600ndash550 Ma late Neoproterozoic From Veevers (2000a fig 303) The closure of the Mozambique Ocean between West and EastGondwanaland by oblique stresses involved sinistral shearing (SS in Fig 36) in the Mozambique orogenic belt and Pinjarra orogen (followingearlier dextral strike-slip) These motions part of the first Pan-Gondwanaland stress system that operated 650ndash570 Ma (Veevers 2003) inducedlocal transtension that accommodated alkaline magmatism as in the Leeuwin Complex and in the 551 Ma quartz syenite of the Koettlitz GlacierAlkaline Province Sedimentary evidence from Antarctica is lacking Earlier the Beardmore Group of shallow-water sands was deposited withbasalt dated 668 Ma on the side of a rifted continental margin (Goodge et al 2002) Central and northern Australia underwent intense dextraltranspression in the Halls Creek Paterson and Petermann areas



interpretation of the main ages of the Wilkes Landprovenance beneath ice-covered Antarctica

10 Conclusion Pan-Gondwanaland super-terranebeneath the Antarctic ice (Fig 37)

In the sector near eastern Australia we combine theTerre Adeacutelie (TA) and Gawler blocks (both of age a) in aminimal model of the Mawson Craton in place of themaximal model that stretches a farther 1600 km to theMiller Range The maximal model would providezircons of 17 Ga age with a minor amounts of 24and 30 Ga and would lack the d+ 700ndash500 Ma detritalzircons of eastern Australia We prefer a model of asuper-terrane between the Bunger Hills and theTransantarctic Mountains comprising cratons of age c(1300ndash1000 Ma) embedded in a matrix of Pan-Gondwanaland fold belts of d+ (700ndash500 Ma) ageThis provenance would shed zircons of dominantly d+age with a minor contribution of c age as found ineastern Australia The shape of the hypothetical super-terrane was inspired by the composite cogs of the WestAfrican Congo Amazonia IndiandashEast AntarcticandashWest Australia that are postulated to have rotated withina matrix of Pan-Gondwanaland fold belts (Veevers2003) The size of the individual cratons resembles thatof the Gawler Block and in age that of the nearby 1300ndash1000 Ma Musgrave Block of central Australia

The 550ndash490 Ma subduction-related Ross orogenborders the super-terrane and as suggested by the modelages (Fig 28) that overlap the 1300ndash1000Ma range of cmay well be underlain by the hypothetical super-terrane

The Pinjarra orogen contains d+ ages as well as c(Fig 36) so that the various hypothetical models byFitzsimons (2003) and ourselves would have much ofAntarctica underlain by a super-terrane of cratonsembedded in d+ Pan-Gondwanaland fold belts in theclassic style of Africa

Many Pan-Gondwanaland super-terranes elsewhereare today uplands of isostatically thickened crust (Fig37) Our hypothesis of a proximal Antarctic provenance

in Wilkes Land is supported by the paleogeographicalevidence of uplands sloping northward in at leastCambrian Ordovician Permian and Triassic timesWilkes Land only became a lowland from the 99 Machange in azimuth of the Pacific plate (Veevers 2000b)and the generation of the AustralianndashAntarctic depres-sion (Veevers 1982)

Our view was foreshadowed by Goodge et al (2004p 1277) in their ldquosediment provenance I hellip Precambrianrocks of the East Antarctic Shield and their Grenville-agemobile beltsrdquo Goodge et al (2004) also point toprovenance IV ldquoGrenville and Pan-African sources inQueen [Dronning] Maud Land and the East Africanorogenrdquo with ages in the 700ndash600Ma range newly foundin Dronning Maud Land (J Jacobs pers comm 2005)

ldquoThe Hannah Ridge [NHR] provenance signatureindicated that the sediment was deposited in amarginal basin with a major source of late Neoproter-ozoic detritus Its provenance appears to be chiefly inGrenville-age roots to the Ross and Pan-Africanorogens flanking the Kalahari craton because thedetrital-grain ages are remarkably similar to 1090ndash1030 Ma [Grenville-age] basement in present-daywestern Dronning Maud Land Coats Land and theNamaquandashNatal belt (Fitzsimons 2000) implyingthat the principal source of detritus was an inter-montane or upland region of the East African orogenBecause the Hannah Ridge sample is dominated byGrenville-age and Pan-African-age components andis nearly devoid of any grains older than ca 1200Mathe nearby major shields (Kalahari Indian and EastAntarctic) were likely either covered during EarlyCambrian time or had drainages that flowed awayfrom the present-day Pensacola Mountains Theyounger population (650ndash500 Ma) is also consistentwith an East African orogen provenancerdquo (Goodge etal 2004 p 1268)

We note that older ages back to 1171plusmn25 Ma areknown from Dronning Maud Land (Jacobs et al 2003)The East African orogen was cited by Williams and

Fig 36 Timendashspace diagram for Precambrian terranes on either side of the AntarcticndashAustralian join From Fitzsimons (2003 figs 2 6 9) Ages(Ga) by the UndashPb zircon zircon method The colour bands indicate zircon-producing epochs + = granite wiggly line = deformation A = A-typegranite Alk = alkaline DFZ = Darling Fault Zone E AUS = eastern Australia GDS = Gairdner dyke swarm gr = granulite-facies metamorphismGRV = Gawler Range Volcanics HiM = high-grade metamorphism LC = Leeuwin Complex M = metamorphism MC = Mullingarra ComplexMWDS = Mundine Well dyke swarm N = north NC = Northampton Complex S = south S PCM = southern Prince Charles Mountains SS =sinistral shear SYEN = syenite TDM = model age TAM = Transantarctic Mountains WR = whole-rock Miller Range also from Goodge andFanning (1999) Transantarctic Mountains detrital zircons from Goodge et al (2004 fig 12) Nd model ages from Borg and DePaulo (1994) Hf-isotope model ages of eastern Australian sands and sandstone from this work Yilgarn ages from Cawood and Nemchin (2000) Age clusters (d ndashaaaa) in southwestern Australia and East Antarctica from Veevers et al (2005) d+ is the 700ndash500Ma Pan-Gondwanaland epoch c (1300ndash1000Ma)is the ldquoGrenvillerdquo age of authors (eg Jacobs et al 1998 Goodge et al 2004) The column above Terre Adeacutelie shows our (informed) guess about themain ages of the provenance beneath ice-covered Antarctica


Fig 37 Hypothetical ages and kind of sub-glacial bedrock in Antarctica on a base from Fig 1 which should be seen for abbreviations The greyvertical-line pattern signifies ldquothe three potential pathways for the Pinjarra Orogen [oblique-line pattern] across East Antarcticardquo (Fitzsimons 2003)including that [1] of Boger et al (2001) [2] and [3] split off past the Gamburtsev Sub-glacial Mountains which Veevers (1994) modelled asoriginating by mid-Carboniferous shortening of an intracratonic basin but without generating zircons (cf the Alice Springs orogen of centralAustralia) The 700ndash500 Ma Southwest PacificndashGondwana igneous component has a hypothetical provenance in the stippled areas marked d+ inproximal Wilkes Land Antarctica between the Transantarctic Mountains and the Bunger Hills


Chappell (1998) as a potential source of 650ndash500 Mazircons in Australia but the proximal Wilkes Land is thesimpler choice

Acknowledgements

We thank CJ Adams for providing the samples fromthe Oates Coast CL Fergusson for Excel files of theOrdovician turbidite and L P Black of the Mathinnaturbidite and J Jacobs and JJW Rogers for commentson the manuscript Bill Griffin provided good counselJJVacknowledges the support of an Australian ResearchCouncil grant and a special grant from MacquarieUniversity We thank Norm Pearson Carol Lawson andSuzie Elhlou for analytical assistance This is publica-tion number 417 from the ARC National Key Centre forGeochemical Evolution and Metallogeny of Continents(httpwwwesmqeduauGEMOC)

Appendix A Supplementary data

Supplementary data associated with this article canbe found in the online version at doi101016jearscirev200511001

References

Adams CJ 1996 Geochronological evolution of the eastern marginof Northern Victoria Land RbndashSr and KndashAr dating of the BergGroup and BergArchangel Granites Geologisches Jahrbuch B89179ndash194

Adams CJ Roland NW 2002 Pre- and syn-Ross orogenicgranitoids at Drake Head and Kartografov Island Oates Coastnorthern Victoria Land East Antarctica In Gamble JA SkinnerDNB Henrys S (Eds) Antarctica at the Close of a Millenium8th International Symposium on Antarctic Earth SciencesRoyalSociety of New Zealand Bulletin vol 35 pp 93ndash98

Bell K 2005 Carbonatites Encyclopedia of Geology vol 1Elsevier Oxford pp 217ndash233

Belousova EA 2000 Trace elements in zircon and apatiteApplication to petrogenesis and mineral exploration PhD thesisMacquarie University 310 pages

Belousova EA Griffin WL Shee SR Jackson SE OReilly SY 2001 Two age populations of zircons from the Timber Creekkimberlites Northern Territory Australia as determined by laserablationndashICPMS analysis Australian Journal of Earth Sciences 48757ndash766

Belousova EA Griffin WL OReilly SY Fisher NI 2002Igneous zircon trace element composition as an indicator of sourcerock type Contributions to Mineralogy and Petrology 143602ndash622

Bizzarro M Baker JA Haack H Ulfbeck D Rosing M 2003Early history of Earths crustndashmantle system inferred fromhafnium isotopes in chondrites Nature 421 931ndash933

Black R Lameyre J Bonin B 1985 The structural setting ofalkaline complexes Journal of African Earth Sciences 3 5ndash16

Black LP Calver CR Seymour DB Reed A 2004 SHRIMPUndashPb detrital zircon ages from Proterozoic and Early Palaeozoicsandstones and their bearing on the early geological evolution ofTasmania Australian Journal of Earth Sciences 51 885ndash900

Blichert-Toft J Chauvel C Albarede F 1997 The LundashHfgeochemistry of chondrites and the evolution of the mantlendashcrustsystem Earth and Planetary Science Letters 148 243ndash258Erratum Earth and Planetary Science Letters 154 (1998) 349

Boger SD Wilson CJL Fanning CM 2001 Early Paleozoictectonism within the East Antarctic craton the final suture betweeneast and west Gondwana Geology 29 463ndash466

Borg SG DePaulo DJ 1991 A tectonic model of the AntarcticGondwana margin with implications for southeastern Australiaisotopic and geochemical evidence Tectonophysics 196 339ndash358

Borg SG DePaulo DJ 1994 Laurentia Australia and Antarcticaas a Late Proterozoic supercontinent constraints from isotopicmapping Geology 22 307ndash310

Borg SG DePaulo DJ Smith BM 1990 Isotopic structure andtectonics of the central Transantarctic Mountains Journal ofGeophysical Research 95 6647ndash6669

Cawood PA Nemchin AA 2000 Provenance record of a rift basinUPb ages of detrital zircons from the Perth Basin WesternAustralia Sedimentary Geology 134 209ndash234

Collins AS 2003 Structure and age of the northern LeeuwinComplex Western Australia constraints from field mapping andUndashPb isotopic analysis Australian Journal of Earth Sciences 50585ndash599

Conaghan PJ Jones JG McDonnell KL Royce K 1982 Adynamic fluvial model for the Sydney Basin Journal of theGeological Society of Australia 29 55ndash65

Cooper AF Worley BA Armstrong RA Price RC 1997Synorogenic alkaline and carbonatitic magmatism in the Transan-tarctic Mountains of South Victoria land Antarctica In Ricci CA (Ed) The Antarctic Region Geological Evolution andProcesses 7th International Symposium on Antarctic EarthSciences Terra Antartica Publication Siena pp 245ndash252

Da Silva LC Gresse PG Scheepers R McNaughton NJHartmann LA Fletcher I 2000 UndashPb SHRIMP and SmndashNdage constraints on the timing and sources of the Pan-African CapeGranite Suite South Africa Journal of African Earth Sciences 30795ndash815

Doblas M Loacutepez-Ruiz J Cebriaacute J-M Youbi N Degroote E2002 Mantle insulation beneath theWest African craton during thePrecambrianndashCambrian transition Geology 30 839ndash842

Eby GN 1992 Chemical subdivision of the A-type granitoidspetrogenetic and tectonic implications Geology 20 641ndash644

Fergusson CL Fanning CM 2002 Late Ordovician stratigraphyzircon provenance and tectonics Lachlan Fold Belt southeasternAustralia Australian Journal of Earth Sciences 49 423ndash436

Fitzsimons ICW 2000 A review of tectonic events in the EastAntarctic Shield and their implications for Gondwana and earliersupercontinents Journal of African Earth Sciences 31 3ndash23

Fitzsimons ICW 2003 Proterozoic basement provinces of southernand southwestern Australia and their correlation with AntarcticaIn Yoshida M Windley BF Dasgupta S (Eds) ProterozoicEast Gondwana Supercontinent Assembly and Breakup Geolog-ical Society London Special Publications vol 206 pp 93ndash130

Goodge JW 1997 Latest Neoproterozoic basin inversion of theBeardmore Group central Transantarctic Mountains AntarcticaTectonics 16 682ndash701

Goodge JW Fanning CM 1999 25 by of punctuated Earthhistory as recorded in a single rock Geology 27 1007ndash1010


Goodge JW Myrow P Williams IS Bowring SA 2002 Ageand provenance of the Beardmore Group Antarctica constraintson Rodinia supercontinental breakup Journal of Geology 110393ndash406

Goodge JW Williams IS Myrow P 2004 Provenance ofNeoproterozoic and lower Paleozoic siliciclastic rocks of thecentral Ross orogen Antarctica detrital record of rift- passive-and active-margin sedimentation Geological Society of AmericaBulletin 116 1253ndash1279

Griffin WL Pearson NJ Belousova E Jackson SE vanAchterbergh E OReilly SY Shee SR 2000 The Hf isotopecomposition of cratonic mantle LAMndashMCndashICPMS analysis ofzircon megacrysts in kimberlites Geochimica et CosmochimicaActa 64 133ndash147

Griffin WL Wang X Jackson SE Pearson NJ OReilly SYXu X Zhou X 2002 Zircon chemistry and magma genesis SEChina in-situ analysis of Hf isotopes Pingtan and Tonglu igneouscomplexes Lithos 61 237ndash269

Griffin WL Belousova EA Shee SR Pearson NJ OReilly SY 2004 Archean crustal evolution in the northern Yilgarn CratonUndashPb and Hf-isotope evidence from detrital zircons PrecambrianResearch 131 231ndash282

Groenewald PB Moyes AB Grantham GH Krynauw JR1995 East Antarctic crustal evolution geological constraints andmodelling in western DronningMaud Land Precambrian Research75 231ndash250

Hall CE Cooper AF Parkinson DL 1995 Early Cambriancarbonatite in Antarctica Journal of the Geological Society ofLondon 152 721ndash728

Harris NBW 1985 Alkaline complexes from the Arabian ShieldJournal of African Earth Sciences 3 83ndash88

Harris LB 1994 Neoproterozoic sinistral displacement along theDarling Mobile Belt Western Australia during Gondwanalandassembly Journal of the Geological Society of London 151901ndash904

Heaman L Parrish R 1991 UndashPb geochronology of accessoryminerals In Heaman L Ludden J (Eds) Applications ofRadiogenic Isotope Systems to Problems in Geology vol 19Mineralogical Association of Canada pp 59ndash102

Hoskin PWO Ireland TR 2000 Rare earth element chemistry ofzircon and its use as a provenance indicator Geology 28 627ndash630

Ireland TR Bradshaw JD Muir R Weaver S Adams C 1994Zircon age distributions in granites greywackes and gneisses fromthe southwest PacificndashGondwana region Eighth InternationalConference on Geochronology Cosmochronology and IsotopeGeologyAbstracts US Geological Survey Bulletin vol 1107p 151

Ireland TR Floumlttmann T Fanning CM Gibson GM Preiss WV 1998 Development of the early Paleozoic Pacific margin ofGondwana from detrital-zircon ages across the Delamerian orogenGeology 26 243ndash246

Jacobs J Thomas RJ 2004 Himalayan-type indenter-escapetectonics model for the southern part of the late Neoproterozoicndashearly Paleozoic East AfricanndashAntarctic orogen Geology 32721ndash724

Jacobs J Fanning CM Henjes-Kunst F Olesch M Paech H-J1998 Continuation of the Mozambique Belt into east AntarcticaGrenville-age metamorphism and polyphase Pan-African high-grade events in central Dronning Maud Land Journal of Geology106 385ndash406

Jacobs J Fanning CM Bauer W 2003 Timing of Grenville-agevs Pan-African medium to high grade metamorphism in western

Dronning Maud Land (East Antarctica) and significance forcorrelations in Rodinia and Gondwana Precambrian Research125 1ndash20

Jago JB Gum JC Burtt AC Haines PW 2003 Stratigraphy ofthe Kanmantoo Group a critical element of the Adelaide Fold Beltand the Palaeo-Pacific plate margin Eastern Gondwana Austra-lian Journal of Earth Sciences 50 343ndash363

Knudsen T-L Griffin WL Hartz EH Andresen A Jackson SE 2001 In situ hafnium and lead isotope analyses of detritalzircons from the Devonian sedimentary basin of NE Greenland arecord of repeated crustal reworking Contributions to Mineralogyand Petrology 141 83ndash94

Kohn BP Gleadow AJW Brown RW Gallagher K OSullivanPB Foster DA 2002 Shaping the Australian crust over the last300 million years insights from fission track thermotectonicimaging and denudation studies of key terranes Australian Journalof Earth Sciences 49 696ndash717

Kroumlner A Stern RJ 2005 Africa Pan-African Orogeny Encyclo-pedia of Geology vol 1 Elsevier Oxford pp 1ndash13

Ludwig KR 2001 IsoplotEx rev 249 Berkeley GeochronologyCenter Special Publication vol 4

Meert JG 2003 A synopsis of events related to the assembly ofeastern Gondwana Tectonophysics 362 1ndash40

Mellish SD Cooper AF Walker NW 2002 Panorama Pluton acomposite gabbrondashmonzonite early Ross Orogeny intrusion insouthern Victoria land Antarctica In Gamble JA Skinner DNB Henrys S (Eds) Antarctica at the close of a millenium 8thInternational Symposium on Antarctic Earth Sciences RoyalSociety of New Zealand Bulletin vol 35 pp 129ndash141

Miller JS Santosh M Pressley RA Clements AS Rogers JJW 1996 A Pan-African thermal event in southern India Journalof Southeast Asian Earth Sciences 14 127ndash136

Mojzsis SJ Devaraju TC Newton RC 2003 Ion microprobe UndashPb age determination on zircon from the Late Archean granulitefacies transition zone of southern India Journal of Geology 111407ndash425

Powell CMcA 1984 Uluru regime In Veevers JJ (Ed)Phanerozoic Earth History of Australia Oxford pp 290ndash340

Rajesh HM Santosh M Yoshida M 1996 The felsic magmaticprovince in East Gondwana implications for Pan-African tecton-ics Journal of Southeast Asian Earth Sciences 14 275ndash291

Rapela CW Pankhurst RJ Fanning CM Grecco LE 2003Basement evolution of the Sierra de la Ventana Fold Belt newevidence for Cambrain continental rifting along the southernmargin of Gondwana Journal of the Geological Society of London160 613ndash628

Read SE Cooper AF Walker NW 2002 Geochemistry and UndashPb geochronology of the NeoproterozoicndashCambrian KoettlitzGlacier Alkaline Province Royal Society Range TransantarcticMountains Antarctica In Gamble JA Skinner DNB HenrysS (Eds) Antarctica at the Close of a Millenium 8th InternationalSymposium on Antarctic Earth SciencesRoyal Society of NewZealand Bulletin vol 35 pp 143ndash151

Rowell AJ Rees MN Duebendorfer EM Wallin ET vanSchmusWR Smith EI 1993An activeNeoproterozoicmarginevidence from the Skelton Glacier area Transantarctic MountainsJournal of the Geological Society of London 150 677ndash682

Scherer E Munker C Mezger K 2001 Calibration of thelutetiumndashhafnium clock Science 293 683ndash687

Sircombe KN 1999 Tracing provenance through the isotope ages oflittoral and sedimentary detrital zircon eastern Australia Sedi-mentary Geology 124 47ndash67


Sircombe KN Freeman MJ 1999 Provenance of detrital zircon onthe Western Australian coastlinemdash implications for the geologicalhistory of the Perth Basin and denudation of the Yilgarn cratonGeology 27 879ndash882

Sircombe KN Stern RA 2002 An investigation of artificialbiasing in detrital zircon UndashPb geochronology due to magneticseparation in sample preparation Geochimica et CosmoschimicaActa 66 2379ndash2397

Storey BC Hole MJ Pankhurst RJ Millar IL Vennum W1988 Middle Jurassic within-plate granites in West Antarctica andtheir bearing on the break-up of Gondwanaland Journal of theGeological Society of London 145 999ndash1007

Storey BC Alabaster T Macdonald DIM Millar IL PankhurstRJ Dalziel IWD 1992 Upper Proterozoic rift-related rocks inthe Pensacola Mountains precursors to supercontinent breakupTectonics 11 1392ndash1405

Storey BC Pankhurst RJ Johnson AC 1994 The GrenvilleProvince within Antarctica a test of the SWEAT hypothesisJournal of the Geological Society of London 151 1ndash4

Uyeda S 1981 Subduction zones and back arc basins mdash a reviewGeologisches Rundschau 70 552ndash569

Veevers JJ 1982 AustralianndashAntarctic depression from the oceanridge to the adjacent continents Nature 295 315ndash317

Veevers JJ 1994 Case for the Gamburtsev Subglacial Mountains ofEast Antarctica originating by mid-Carboniferous shortening of anintracratonic basin Geology 22 593ndash596

Veevers JJ (Ed) 2000a Billion-Year Earth History of Australiaand Neighbours in Gondwanaland GEMOC Press Sydney400 pp

Veevers JJ 2000b Change of tectonondashstratigraphic regime in theAustralian plate during the 99 Ma (mid-Cretaceous) and 43 Ma(mid-Eocene) swerves of the Pacific Geology 28 47ndash50

Veevers JJ 2003 Pan-African is Pan-Gondwanaland obliqueconvergence drives rotation during 650ndash500 Ma assemblyGeology 31 501ndash504

Veevers JJ 2004 Gondwanaland from 650ndash500 Ma assemblythrough 320 Ma merger in Pangea to 185ndash100 Ma breakupsupercontinental tectonics via stratigraphy and radiometric datingEarthndashScience Reviews 68 1ndash132

Veevers JJ Conaghan PJ Powell CMcA 1994 EasternAustralia In Veevers JJ Powell CMcA (Eds) PermianndashTriassic Pangean Basins and Foldbelts Along the PanthalassanMargin of Gondwanaland Geological Society of AmericaMemoir vol 184 pp 11ndash171

Veevers JJ Saeed A Belousova EA Griffin WL 2005 UndashPbages and source composition of detrital zircons in Permiansandstone and modern sand from southwestern Australia and areview of the paleogeographical and denudational history of theYilgarn Craton Earth-Science Reviews 68 245ndash279

Wilde SA Murphy DMK 1990 The nature and origin of LateProterozoic high-grade gneisses of the Leeuwin Block WesternAustralia Precambrian Research 47 251ndash270

Williams IS 1992 Some observations on the use of zircon UndashPbgeochronology in the study of granitic rocks Transactions of theRoyal Society of Edinburgh Earth Sciences 83 447ndash458

Williams IS 1998 Inheritance in granites the response of zirconmonazite and their PbndashU isotopic systems to regionalmetamorphism leading to host metasediment partial meltingGeological Society of Australia Abstracts 49 468 (14th AGCTownsville)

Williams IS Chappell BW 1998 Crustal evolution in southeasternAustralia a zircon viewpoint AGSO Record 199833 p 44

JohnVeeversAdjunct Professor in the Depart-ment of Earth and Planetary Sciences atMacquarie University graduated BSc (1951)and MSc (1954) from Sydney University andPhD (1956) from London University Heworked in the Bureau of Mineral Resourceson sedimentary basins of northern Australiabefore moving to Macquarie University in1968 where he worked in Australia and itsGondwanaland neighbours of Antarctica NewZealand India South America and southern

Africa Currently he works in the Australian Centre for Astrobiology(ACA) and the ARC National Key Centre for Geochemical Evolutionand Metallogeny of Continents (GEMOC) He was elected Fellow ofthe Australian Academy of Science in 1995 He published Billion-yearearth history of Australia and neighbours in Gondwanaland in 2000 asupplementary coloured ATLAS in 2001 and Gondwanaland from650ndash500 Ma assembly through 320 Ma merger in Pangea to 185ndash100Ma breakup supercontinental tectonics via stratigraphy and radio-metric dating in 2004

Elena Belousova graduated with BSc(Hons) degree in geology from Kiev StateUniversity Ukraine in 1988 She obtainedher PhD degree from Macquarie UniversitySydney in 2000 studying the trace-elementsignatures of zircon and apatite in a widerange of rock types and mineral deposits Sheis currently an ARC Research Fellow in theARC National Key Centre for GeochemicalEvolution and Metallogeny of Continents(GEMOC) at Macquarie University

Ayesha Saeed did her MSc from Universityof New South Wales in 1993 Her PhD in2001 from Auckland University is on thegeochemistry of North Island rocks NewZealand She joined GEMOC MacquarieUniversity in Oct 2001 as a Geochemist andsince then has worked with the TerraneChrontrade team

Keith Sircombe earned a BSc and MSc inEarth and Computer Sciences at University ofWaikato New Zealand (1990 1993) His PhDin 1998 from the Australian National Uni-versity investigated the provenance of ancientand modern sediments in eastern Australiausing detrital mineral geochronology From1998 to 2000 he held a Visiting Fellowship atthe Geological Survey of Canada aiding thestudy of metasedimentary sequences in theSlave Craton He returned to Australia with

University and Australian Research Council Fellowships at theUniversity of Western Australia from 2001 to investigate the detritalprovenance evolution of the Ashburton Basin between the PilbaraandYilgarn cratons Hemoved to GeoscienceAustralia in 2003 and iscurrently involved in projects dating events in Western Australia andenhancing the application of detrital mineral geochronology


Alan Cooper graduated BSc (1966) from theUniversity of Sheffield and PhD (1970) fromthe University of Otago He has taught at theUniversity of Otago from 1966 to the presentday

Stephen Read graduated from the Universityof Otago with BSc (Hons) in 1994 and DipGrad in 1995 In 1998 and 1999 he went toAntarctica to collect rocks for his PhD on themagmatic and tectonic evolution of part ofsouthern Victoria Land He now works parttime in the Department of Geology Uni-versity of Otago


from high ground in Antarctica The Hawkesbury Sandstone was deposited in a braided-river system on a surface that sloped to thenorth-northeast from high ground in Antarctica Together with the zircon data the paleogeographical evidence in the CambrianOrdovician OrdovicianndashSilurianndashDevonian and Triassic all point to a provenance in Wilkes Land Antarctica of Pan-Gondwanaland (700ndash500 Ma) terranes with alkaline rockscopy 2005 Elsevier BV All rights reserved

Keywords Australia Antarctica detrital zircons 700ndash500 Ma Pan-Gondwanaland Hf-isotopes trace elements TDM paleogeography alkalineprovenance

1 Introduction

As a sequel to Sircombes (1999) UndashPb SHRIMPdating of zircons from eastern Australian sands andsandstone we analyse the same grains by LAMndashICPMSto ascertain the rock type and Hf model age of theigneous host

Detrital or inherited zircons of late NeoproterozoicndashEarly Cambrian (700ndash500 Ma) age ldquothe SouthwestPacificndashGondwana igneous componentrdquo (Ireland et al1994) are the dominant grouping in many Paleozoicgranites greywackes and gneisses of the Delamerianand Lachlan orogens (Ireland et al 1998 Williams1992) and in Triassic sandstone and Neogene littoralsands in eastern Australia (Sircombe 1999) summed upin Veevers (2000a p 110ndash130) chapter calledldquoAntarcticndashBeardmorendashRoss and Mirny provenancessaturate PaleozoicndashMesozoic East Gondwanaland with06ndash05 Ga zirconsrdquo (Fig 1) According to Sircombe(1999) ldquoAlthough the 480ndash520 Ma RossndashDelamerianOrogeny may explain some of the Southwest PacificndashGondwana age grouping the bulk of these provenanceages occur between 550ndash650 Ma and require furtherexplanation hellip Neoproterozoic convergence of theBeardmore Microcontinent in the Central TransantarcticMountains may have been more widespread than iscurrently exposed in Antarctica In particular thebasement of the Wilkes Subglacial Basin is unknownbut lies in a location that palaeodirection studies andtectonic history suggest could have been the source ofthe Lachlan Orogen and the Hawkesbury Sandstone of

the Sydney Basin hellip beaches [on the eastern Australianmargin] are dominated by Neoproterozoic zirconsprobably derived from a source that now lies over7000 km [away] due to a favourable pathway through anintermediate sediment repository in the Sydney Basinrdquo

In Western Australia the Eneabba sand (Sircombeand Freeman 1999) was derived from the Perth Basin orLeeuwin Complex or both and the Perth BasinOrdovician (490ndash450 Ma) and Permian (300ndash250 Ma)sandstones were derived from the Leeuwin Complex(Cawood and Nemchin 2000 Veevers et al 2005)

In the Adelaide region the Early Cambrian Kanman-too turbidite with 700ndash500 Ma zircons (Ireland et al1998) was deposited from paleocurrents that came fromAntarctica (Veevers 2000a p 200 206) before theintrusion of the Delamerian granites The presumedprovenance of the Kanmantoo is an ice-covered part ofEast Antarctica Following Sircombe (1999) Veevers(2000a p 114 121) regarded an unexposed Beard-morendashRoss orogen resulting from the collision of aBeardmore microcontinent with Antarctica (Borg andDePaulo 1991) as a potential source of the 600ndash550 Mazircons in the Kanmantoo and other sediments in easternAustralia Subsequent work in Antarctica (eg Goodgeet al 2002 2004) and our recognition of the older (700ndash600 Ma) part of the Southwest PacificndashGondwanaigneous component (Ireland et al 1994 Sircombe1999) seem to invalidate the concept of the Beardmoreorogen The 650ndash500 Ma interval saw Gondwanalandassembled by oblique convergence that drove internalrotation and counter-rotation of cratons (cogs) embedded

Fig 1 East Gondwanaland (Veevers 2000a fig 127) including the Mozambique Orogenic Belt and the PrydzndashLeeuwin Belt (Veevers 2003)showing bedrock of ages (Ma) and TDM model ages (Ga) represented in detrital zircons Archean of India (34ndash29 25 Ga) fromMojzsis et al (2003)and of Dronning Maud Land (30 Ga Grunehogna province) from Groenewald et al (1995) The beach sands are shown by open circlessedimentary rocks by filled circles East Antarctic data from Fitzsimons (2003) Transantarctic Mountains from Goodge et al (2004) Read et al(2002) TDM (Ga in bold) from Borg et al (1990) Borg and DePaulo (1991 1994) and Storey et al (1988 1994) The 550ndash520Ma Koettlitz GlacierAlkaline Province (KGAP) has a TDM of 142 and 125 Ga (Mellish et al 2002) within the range 17ndash09 Ga as described below marks the 175 Magranite in the Whitmore Mountains (Storey et al 1988) and the 1000 Ma gneiss in the Haag Nunataks (Storey et al 1994) The mildly deformedAdelaide Fold Belt is paralleled by the 520ndash500 Ma Delamerian granites and intensely deformed Kanmantoo Fold Belt (K)(Veevers 2000a)continuous through the 505 and 487 Ma granites (dated below) of the Oates Coast with the Ross orogen Younger fold belts are the 450ndash310 MaLachlan Fold Belt and 300ndash200 Ma New England Fold Belt (NEFB) B = Bowers Terrane HRS = Holyoake Range KGAP = Koettlitz GlacierAlkaline Province NHR = Hannah Ridge Formation NPA = Patuxent Formation Neptune Range RB = Robertson Bay Terrane TAndashKGVL = TerreAdeacuteliendashKing George V Land



























31 Ages














Code Ga






































Capricorn Orogen

All values in Ma

































140ndash173224 317








36 Hf model ages


















































































































5 Oates Coast














































8 Paleogeography















































Acknowledgements




References



















































































































31 Ages














Code Ga






































Capricorn Orogen

All values in Ma

































140ndash173224 317








36 Hf model ages


















































































































5 Oates Coast














































8 Paleogeography















































Acknowledgements




References
































































































Code Ga






































Capricorn Orogen

All values in Ma

































140ndash173224 317








36 Hf model ages


















































































































5 Oates Coast














































8 Paleogeography















































Acknowledgements




References




























































































































Capricorn Orogen

All values in Ma

































140ndash173224 317








36 Hf model ages


















































































































5 Oates Coast














































8 Paleogeography















































Acknowledgements




References

























































































































140ndash173224 317








36 Hf model ages


















































































































5 Oates Coast














































8 Paleogeography















































Acknowledgements




References
































































































36 Hf model ages


















































































































5 Oates Coast














































8 Paleogeography















































Acknowledgements




References






































































































































































































5 Oates Coast














































8 Paleogeography















































Acknowledgements




References

































































































































8 Paleogeography















































Acknowledgements




References


































































































































Acknowledgements




References


























































































pan-gondwanaland detrital zircons from ... - gemoc.mq.edu.augemoc.mq.edu.au/terranechronpds/417...

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