PROCEEDINGS OF THE 7TH INTERNATIONAL SYMPOSIUM ONWATER-ROCK

INTERACTION - WRI-7 / PARK CITY /UTAH / USA /13-18 JULY 1992

Water-Rock

InteractionEdited by

YOUSIF K.KHARAKA &ANN S.MAEST

U.S. Geological Survey, Menlo Park, California, USA

VOLUME 1

LOWTEMPERATURE ENVIRONMENTS

I IIHSVL I iTihEK

A.A. BALKEMA / ROTTERDAM / BROOKFIELD /1992

Water-Rock Interaction, Kharaka & Maes/(eds)@ 1992 Balkema, Rotterdam. ISBN 905410 0753

Table of contents

Keynote lectures

Kinetics of dissolution and precipitation: Experimental and field results 3S.L.Brantley

The changing face of mineral-fluid interface chemistry 7Michael F.Hochella, Jr

The hydrolysis of aluminum: Conflicting models and the interpretation of aluminum 13

geochemistryHowardMay

Geochemical modeling of water-rock interaction: Past, present, future 23

L.Niel Plummer

Atmospheric C02 over Phanerozoic time 35

RobertA.Berner

Mineral-fluid interface geochemistry

Adsorption and cation exchange

The search for a geochemical indicator of lead and zinc sorption in a sand and gravel aquifer, 41

Falmouth, Massachusetts, USAJACoston, C.C.Fuller & J.A.Davis

Buffering ofpH-changes by an aquifer sediment during miscible displacement of 45

Na-Ca-Mg-Cl-C02 solutions

Jasper Griffioen

Metal-ligand-surface interactions during sorption of uranyl and neptunyl on oxides and 51

silicates

M.Kohler, E.Wieland &J.0. Leckie

Competitive adsorption: The effect of carbonate alkalinity on the adsorption of lead, thorium 55

and plutonium by goethite (aFeOOH)James W.Murray & BarbaraR.Coughlin

XI

Use of batch equilibration data in the retardation equation 59

Hannah F.Pavlik, FredG.Baker & Donald D.Runnells

Development and validation ofa multi-site model for adsorption ofmetals by mixtures of 63

minerals: 1 Overview and preliminary results

M.D.Siegel, V.S.Tripathi,M.G.Rao & D.RWard

Multisite proton adsorption at the feldspar-water interface 69

L.L.Sfillings, S.L.Brantley & M.LMachesky

Modeling ion exchange in clinoptilolite using the EQ3 /6 geochemical modeling code 73

B.E.Viani& CJ.Bruton

Kinetics ofgeochemical reactions

Solution compositional effects on the dissolution kinetics of borosilicate glass 81

W.LBourcier, H.C.Weed, S.N.Nguyen, J.K.Nielsen, L.Morgan, LNewton & K.G.Knauss

Surface complexation and mineral growth: Sepiolite 85

P.V.Brady

Mechanisms controlling NdOHC03-CaC03 solid solution formation 89

SusanACarroll

Dissolution and precipitation kinetics ofkaolinite as a function of chemical affinity 93

(T=150°C,pH = 2and7.8)

J.L.Devidal, J.L.Dandurand & J.Schott

Dissolution of nepheline in an open system 97

D.Klammer

Theoretical approach and modelling of the dissolution and precipitation of minerals under 101

kinetic control

B.Made&B. Fritz

Dissolution rate and solubility of analcime at 25°C 107

WilliamM. Murphy, Roberto T.Pabalan, James D. Prikryl & Christopher J.Goulet

Precipitation kinetics ofcalcite at elevated temperatures 111

Ryoji Shiraki & Susan L.Brantley

Mineral dissolution rates: A comparison of laboratory and field studies 115

N.G.Swoboda-Colberg & J.l.Drever

Rates ofdolomite dissolution in C02 and HC1 bearing solutions from 100-200°C 119

SJ.Talman & W.D.Gunter

The dissolution kinetics of biotite in dilute HN03 at 24°C 123

LTrotignon & M.-P.Turpault

Dissolution of feldspars in oxalic acid solutions 127

Susan AWelch & William J.JJllman

XII

Recent advances in techniques andmethodologyDetermination of clay particle thicknesses and morphology using Scanning Force 133

MicroscopyAlex E.Blum & DennisD.Eberl

Speciation of uranium(VI) sorption complexes on montmorillonite 137

C.J.Chisholm-Brause.D.E.Morris& R.E.Richard

In situ investigation of near-equilibrium calcite precipitation by atomic force microscopy 141

Patricia M.Dove, MichaelF.Hochella, Jr & RichardJ.Reeder

Characterization of olivine-water interface using 'H(I5N, ay) 12C resonant nuclear reaction 145

K.Fujimoto, K.Fukutani, M.Tsunoda, H.Yamashita & K.Kobayashi

Using atomic force microscopy to study the structure, topography and dissolution of albite 149

surfaces

R.Hellmann, B.Drake & KKjoller

Local environment of aluminium in amorphous alumino-silicates by using XANES and MAS 153

NMR

P.Ildefonse, G. Calas, R. J. Kirkpatrick, B. Montez, A. M. Flank & P. Lagarde

Direct observation ofmuscovite basal-plane dissolution and secondary phase formation: 159

An XPS, LEED, and SFM studyPatricia AJohnsson, AlexE.Blum, Michael F.Hochella, Jr, George A.Parks

& Garrison Sposito

Manganese oxidation at mineral-water interfaces, a spectroscopic approach 163

Jodi L.Junta, MichaelF.Hochella, Jr, David W.Harris & Michael Edgell

A quantitative Rietveld and Mossbauer analysis of aluminium deposits: Example from 167

Guinea

G.Morin, P.Ildefonse, D.Bonnin & G.Bouzat

Geochemical modeling

Solution chemistry and thermodynamics

Modeling non-ideal solid-solution aqueous-solution reactions in mass-transfer computer 175

codes

Pierre D.Glynn & DavidLParkhurst

Solubility of siderite (FeC03) in concentrated NaCl and Na2S04 solutions at 25°C 181

C.J.Ptacek & EJ.Reardon

Experimental studies of aluminum solubility and speciation in brines 185

D.J.Wesolowski & D.A.Palmer

The importance of hard core repulsion in models ofactivity coefficients in aqueous 189

electrolyte solutions: Illustration in the case ofhydration theory

T.J.Wolery & K.J.Jackson

XIII

Solubility ofcalcite in mixed aqueous solutions ofNaCl and KC1 at 25°C and C02 partial 195

pressures of about 1 kPa

Manfred Wolf& Harold Rohde

Solute transport

PHREEQM: PHREEQE in a mixing cell flowtube 201

CAJ.Appelo, P.R.Nienhuis & A.Willemsen

Hydrochemical modeling of a seawater diffusion profile, Lake Yssel, The Netherlands 205

CAJ.Appelo & H.E.Beekman

37C1-35C1 transport modeling in accumulating sediments of a former brackish lagoonal 209

environment

H.E.Beekman,H.G.M.Eggenkamp, CAJ.Appelo & R.Kreulen

A new approach to geochemical model! ing with an integrated simulatorgeneration system 213

R.Fabriol & I.Czernichowski-Lauriol

Coupling the spatial distribution of solute concentration and stable isotope enrichments to 217

hydrologic processes in hypersaline paleochannel aquifersJ.VTurner, LR.Townley, M.R.Rosen & M.K.Sklash

Effect of hysteresis and mobile-immobile water on solute transport in heterogeneous porous 223

media

H.Vereecken, G. Lindenmayr & J.Diels

General applications

Interpretation of water-rock interactions in cases of mixing and undersaturation 233

E.Mazor

Speciate; A spreadsheet-based speciation program for aqueous radionuclides 237

H.Wayne Nesbitt, D.Kettlewell & JJ.Cramer

NETPATH: An interactive code for interpreting NET geochemical reactions from chemical 239

and isotopic data along a flow PATH

L.NielPlummer, Eric C.Prestemon & DavidLParkhurst

Geochemical modeling of granitic ground waters at the Stripa site (Sweden) using a mass 243

balance approachN.Waber & D.KNordstrom

Geochemical evolution of groundwater in a limestone aquifer 247

CarolM.Wicks& JanetS.Herman

XIV

Organic geochemistry

Processes involving organics and microbes

Mineral transformations during bacterial leaching ofa complex sulfide ore 253

basse Ahonen & OlliH.Tuovinen

Authigenic mineral formation in aquifers rich in organic material 257

Mary Jo Baedecker, Isabelle M.Cozzarelli, John R.Evans & Paul P.Hearn

Particles in Yellowstone fluid inclusions resemble bacteria 263

K.E.Bargar

Microbial mediation of silicate diagenesis in organic-rich natural waters 267P.C.Bennett & FK.Hiebert

Hydrocarbon geochemistry in coral reefpore waters, French Polynesia 271loanna Bouloubassi, Alain Saliot, Francis Rougerie & Jean Trichet

Oxidation ofhydrocarbons coupled to reduction of inorganic species in groundwater 275

Isabelle M.Cozzarelli & Mary Jo Baedecker

Manner ofaccumulation oflead by the green alga Chlorella vulgaris 279

ZGolab,R.W.Smith & ZJang

Diffusion controlled desorption oforganic contaminants in various soils and rocks 283

Peter Grathwohl

Microbial production ofcarbon dioxide in the unsaturated zone ofa meso scale model 287

MJ.Hendry, J.R.Lawrence, R.Kirkland & B.N.Zanyk

Modeling rates ofmineral dissolution influenced by biodegradation 291

Walton R.Kelly & Janet S.Herman

Evidence for denitrification at a uranium-mill tailings site, Maybell, Colorado, USA 295

P.Longmire & B.M.Thomson

The pyritisation of soft-bodied fossils 301

R.Raiswell

Organic-inorganic interactions

Acetate in hydrothermal solutions: Decomposition kinetics and metal complexation 307

J.LS.Bell, DAPalmer & H.LBarnes

Evidence for oil-derived organic acids in reservoirs 311

James R.Boies

An experimental study of the dissolution of albite in the presence of organic acids 315

Kristin Gestsdottir & David A.C.Manning

Experimental methods used to study metal-organic complexes 319

Thomas H.Giordano

xv

Experimental feldspar dissolution in acetic and oxalic acids at 100°C, 345 bars 325

AHajash, S.P.Franklin & C.LReed

Petroleum as a potential diagenetic agent: Experimental evidence 329

P.D.Lundegard, Y.KKharaka & RJ.Rosenbauer

The reaction between amorphous silica and calcium carbonate at temperatures from 300 337

to700°C

William M.Sackett & KitackLee

Clay precipitation from oxalate-bearing solutions 345

J. S. Small

Oxalate complexation with aluminum(III) and iron(III) at moderately elevated temperatures 349

C.Drew Tait, DavidRJanecky, DavidL.Clark & Philip C.Bennett

Experimental study of the stability of the Al-oxalate complexation at 100°C and calculations 353

ofthe effects ofcomplexation on clastic diagenesisGeoffrey D.Thyne, Wendy J.Harrison & M.Danelle Alloway

Natural hazards and environmental contamination

Integrating seismic, resistivity, and ground penetrating radar data to delineate the water table 361

and groundwater contamination

AlvinK.Benson

Metal contamination ofstream waters from former mining activity 367

R.Caboi, R.Cidu,A.Cristini, L.Fanfani, R. Massoli Novelli & P.Zuddas

Selecting proper sites for the automatic monitoring of geochemical premonitory events 371

of earthquakes: Case histories from ItalyMario Dall'Aglio, Fedora Quattrocchi, Alberto Bencini, Vittorio Duchi & Mauro Brondi

Propagation ofhyperalkaline cement pore waters into the geologic barrier surrounding 377

a radioactive waste repositoryJ.Eikenberg & P.CLichtner

Geochemical classification of mine drainages and natural drainages in mineralized areas 381

W.H.Ficklin, G.S.Plumlee, KS.Smith & JB.McHugh

Geochemical modeling of the deep injection well disposal of acid wastes into a Permian 385

aquifer/aquitard system in Texas, USA

M.A.Gardiner & J.Myers

Groundwater acidification in the unsaturated zone of a sand deposit: Processes and modeling 389

BentKjcerHansen & Dieke Postma

Effect ofinstream pH modification on aluminum 393

BriantA.Kimball, Robert E.Broshears, Diane M.McKnight & Kenneth E.Bencala

Trace metal scavenging by precipitating Mn and Fe oxides 397

Carol J.Lind & Linda D.Anderson

XVI

Helium soil gas surveys related to volcanic hazard: Vulcano Island, North Sicily, Italy 403S.Lombardi

Application of a realistic geological database to safety assessment calculations: An exercise in 407

interdisciplinary communicationMartin Mazurek, PaulASmith & Andreas Gautschi

Acidification: Biogeochemical signature ofeconomic and political systems 413

Tomas Paces

Geological and geochemical controls on the composition ofmine drainages and natural 419

drainages in mineralized areas

Geoffrey S.Plumlee, Kathleen S.Smith, WalterH.Ficklin & Paul HBriggs

Reactions ofcement pore fluids with rock: Implications for the migration ofradionuclides 423

CARochelle, KBateman, AE.Milodowski, D.J.Noy, J. Pearce, D.Savage & C.R. Hughes

Research on pore solution chemistry and environmental significance 427

Zhaoli Shen & Minggao Tang

Impact ofthe 1988 forest fires on the chemistry of non-thermal ground water in Yellowstone 433

National Park, USA

MASiders, D.D.Runnells & D.R.Norton

Hydrothermal precursors to large Californiaearthquakes 437

PaulG.Silver & NathalieJ. Valette-Silver

Metal and arsenic partitioning between water and suspended sediment atmine-drainage sites 443

in diverse geologic settingsKathleen S.Smith, WalterH.Ficklin, Geoffrey S.Plumlee & AllenL.Meier

Influence of mafic minerals on water chemistry and water-column stability ofLake Nyos, 449

Cameroon

MicheleLTuttle, PaulHBriggs, William C.Evans, George W.Kling & John P.Lockwood

Retention processes of cadmium and zinc relevant in acid sandy soils affected bydiffuse 453

pollutionBJ.Wilkens&J.P.G.Loch

Preliminary assessment of clinoptilolite K/Ar results from Yucca Mountain, Nevada USA: 457

A potential high-level radioactive waste repository site

Giday WoldeGabriel, DavidE.Broxton, DavidL.Bish & Steve J.Chipera

Global processes

Volatile release rates from the Grimsvotn volcano, Iceland 465

AMAgustsddttir, S.LBrantley, M.T.Gudmundsson & H.Bjornsson

Influence of Saharian dust and marine spray on the chemical composition of rain in Sardinia, 469

ItalyR.Caboi, R.Cidu, ACristini, LFanfani & P.Zuddas

XVII

The quantitative role of plants in weathering 473

M.F.Cochran &RABerner

Local effects of volcanoes on the hydrosphere: Example from Hekla, southern Iceland 477

S.R.Gislason, AAndresddttir, A.E.Sveinbjdrnsdottir, N.Oskarsson, Th.Thordarson,

P.Torssander, M.Novdk & K.Zdk

Global continental erosion and fluctuations of atmospheric C02 consumed during the last 483

100 years

J.L.Probst, PhAmiotte-Suchet & Y.Tardy

Isotope and trace element record of relative sea level in Albian carbonates from the Congo 487

Atlantic margin

F.Walgenwitz,ALeDluz & H.Eichenseer

Oxidation-reduction reactions in surface and ground waters

Reduction of Cr(VI) under mildly reducing conditions in a sand and gravel aquifer 495

LCD.Anderson, DAKent & JADavis

Chromium redistribution within continental red beds: A function of pore-water chemistry 499

G.N.Breit, M.ECast & M.R.Stanton

Isolated reduction phenomena in red beds: A result ofporewater radiolysis? 503

BAHofinann

Redox geochemistry of arsenic and iron in Mono Lake, California, USA 507

AnnS.Maest, SofieP.Pasilis, Laurence G.Miller & D.KirkNordstrom

The hydrochemistry of arsenic in reservoir sediments, Milltown, Montana, USA 513

George Moncure, James I.Drever & Paul AJankowski

Dissolved gases in ground water as indicators of redox conditions 517

C.G.Patterson& D.D.Runnells

Review ofneutralizing reduction mineralization ofuranium 521

Shi Weijun, Zhou Wenbin & YuanXiaoqin

Trace metals at the oxic/anoxic-H2S boundary in Lake Vanda, Antarctica 527

J.G.Webster

Weathering processes and surface water environments

The 'simplest' watershed: An in-situ study of bedrock-atmospheric deposition reactions 533

James G.Acker & Owen P.Bricker

Ilmenites and ilmenites: A varietal study from the southwest coast ofIndia 537

D.S.Suresh Babu, P.N.Mohan Das & AD.Damodaran

Applications of cosmogenic nuclear methods for studying soil erosion and fonnation rates 541

EBarg, D.Lai, J.Southon, M.W.Caffee, R.C.Finkel, AJ.TJull & M.Pavich

xvm

Geochemistry ofwater and chemical weathering rates under a humid tropical climate 545

M.Benedetti, O.Menard & Y.Noack

Suspended and dissolved river inputs to the NW Pacific 549

VAChudaeva & O.V.Chudaev

Chemical hydrograph separation using field and experimental data with implications for 553

solute cycling in an alpine catchment

/.B. Finley & J. I. Drever

Complex Fe-Mn oxide coatings on boulders in a tropical river 557

AGann & C.LopezE.

Recharge and weathering processes in fractured rock aquifers in Northern Australia 561

Andrew LHerczeg & Timothy E. Payne

Flocculation of Cu, Zn, Ni and Fe during the mixing of Mulki River water and Arabian Sea 565

water, west coast ofIndia

R.Shankar & AR.Karbassi

Tracing watershed weathering reactions with 813C 569

Carol Kendall, MAlisa Mast &. Karen CRice

Effects of water-rock interaction on the porosity and composition ofrock studied by 573

impregnation with carbon-14-polymethylmethacrylateALindberg, K-H.Hellmuth, M.Siitari-Kauppi & J.Suksi

Sulfur isotope ratios in aroof-covered forested catchment, western Sweden 577

Carl-Magnus Morth & PeterTorssander

Consequence ofacid deposition on natural weathering processes: Field studies and modelling 581

AProbst, B.Fritz & P.Stille

PROFILE: A mechanistic geochemical model for calculation of field weathering rates 585

HSverdrup & P.Warfvinge

Controls on the distribution of stable isotopes of meteoric water and snow in the greater 591

Yellowstone National Park region, USA

James J.Thordsen, YousifKKharaka, RobertH.Mariner & LloydD.White

Mobility of trace elements during weathering of some Portuguese granitoids 597

Renata D.van der Weijden & Cornells H.van der Weijden

Weathering of PikesPeak Granite: Field, experimental, and modelling observations 599

RichardB.Wanty, Peter F.Folger, DavidFrishman, PaulHBriggs, Warren C.Day & Eileen

Poeter

Modeling regional soil mineralogy and weathering rates 603

P.Waifvinge & HSverdrup

A three million year weathering record for a soil chronosequence developed in granitic 607

alluvium, Merced, California, USA

Art F.White, Alex E.Blum, Thomas D.Bullen, Maria L. Peterson, Marjorie S. Schitlz & JenniferWHarden

XIX

Strontium isotopes in weathering budgetingT.Wickman & GJacks

611

Saline lakes and evaporite deposits

Magnesium sulfate brine lakes that precipitate dolomite: Evidence that Mg2+-dehydration is 617

more important than removal of S04 2~ inhibition in dolomite formation

EABurton, HG.Machel & T.Hahn

Transition metal geochemistry of sedimentary pore fluids associated with hydrothermal 621

activity in Lake Baikal, Russia

Edward Callender & Liba Granina

Diagenetic stevensite after dolomite in lacustrine deposit of Jbel Rhassoul, Morocco 627AChahi, MAis, P.Duringer & F.Risacher

A hint of recharge at Franklin Lake playa, Inyo County, California, USA 631John B.Czarnecki, DanielRonen, MordeckaiMagaritz & Levy Kroitoru

Controls on trace metal geochemistiy at Walker, Mono, and Great Salt Lakes 635J.L. Domagalski &.H.P. Eugster

The chemicaljump: Hydrologic control ofbrine reaction path within calcareous glacial 639aquifers and alkaline lakes, semi-arid northern Great Plains, USA

JosephJ.Donovan & Arthur W.Rose

Advection and diffusion ofgroundwater brines in modern and ancient salt lakes, Nulla 643groundwater discharge complex, Murray Basin, southeast AustraliaJames Ferguson, GerryJacobson, W.Ray Evans, Ian White, Robin A. Wooding, ChristopherJ.Barnes & Scott Tyler

Fluid inclusion analysis and evaporite modeling 649J.Garcia-Veigas, CAyora & JJ.Pueyo

Geochemical evolution and changes of 313C ofXC02 during sea water evaporation in solar 655pondsC.Pierre & B.Fritz

The origin of brines in Qaidam Basin, China 659Qu Yihua & Cai Keqin

Water-rock interaction in the formation of diagenetic dolomite in a non-marine, coastal 663evaporitic basin, Lake Hayward, Western Australia

M.R.Rosen, LCoshell & J.VTurner

Calcium chloride-dominated brines: An ion-exchange model 669WardESanford, Warren W.Wood& Terry B.Councell

Experimental study ofsaltrock-water interactions 673Vladimir G.Silberschmidt&Vadim V.Silberschmidt

A lake' s solute history from ostracodes: Comparison ofmethods 677Alison J.Smith, LDenis Delorme & RichardM.Forester

xx

Deep-water evaporite deposition in the Kareem Formation, Gemsa Basin, Egypt 681

SAStonecipherJAMayJ.C.Steinmetz & J.N.Dyess

Precipitation of calcite, dolomite, sepiolite and silica from evaporated carbonate and 687

tuffaceous waters of southern Nevada, USADavid T.Vaniman, MichaelHEbinger, DavidL.Bish & Steve J.Chipera

Boron isotope variations during brine evolution and water-rock interactions 693

Avner Vengosh

Unsaturated zone environments

Chemical changes associated with zeolitization of the tuffaceous beds ofCalico Hills, Yucca 699

Mountain, Nevada

David EBroxton

Geochemical modeling of water-rock interactions in the unsaturated zone 705

CJ.Bruton&B.E.Viani

Water infiltration rates in the unsaturated zone at the IdahoNational Engineering Laboratory 709

estimated from chlorine-36 and tritium profiles, and neutron loggingLDeWayne Cecil, Thomas M.Beasley, John R.Pittman, Robert L Michel, Peter W.Kubik,

Pankaj Sharma, UdoFehn & Harry EGove

Geochemistry and isotopes of secondary calcites precipitated by freezing 715

LDever, C.Marlin, MA.Courty & P.Vachier

Solute profiles in unsaturated Quaternary sands from Senegal: Environmental information 719

and water-rock interaction

W.Michael Edmunds, Serigne Faye & Cheikh B.Gaye

Interactions between heavy metals and silty loam soil in flow-through experiments 723

Changmi Gong & RonaJ.Donahoe

Water movementin the unsaturated zone based on a deuterium tracer experiment 727

Li Guiru, B.Mayer & M.Fischer

Chemistry and isotopes ofsoil water during freezing 731

C.Marlin, LDever, MACourty& P.Vachier

Isotopic studies of fracture coatings at Yucca Mountain, Nevada, USA 737

B.D.Marshall, J.FWhelan, ZEPeterman, K.Futa, SAMalvm & J.S.Stuckless

A preliminary study of the chemistry ofpore water extracted from tuffby one-dimensional 741

compressionC.A.Peters, J. D. Higgins, PA.Burger & I.C Yang

Water-permafrost interactions in karst areas 747

E.V.Pinneker

Major and trace element concentrations in waters centrifuged from unsaturated soils 751

HPuchelt&B.Bergfeldt

xxi

Mineralogy and ion exchange property of selected Indian soils 753

B.CRaymahashayAT.W.Kirkos, S.KBisoi & B.K.Panigrahy

Preliminary methodology for the study of heavy metal mobility in the unsaturated zone 757

in tropical climate

M.Szikszay, GAL.Alexandre, R.Hypolito, S.H.Ogihara, M.C.Toledo-Groke,

ED.N.Fernandes & R.C.Orlando

Groundwater environments

Geochemical processes controlling the groundwater composition at Palmottu study site, 763

SW-Finland

LAhonen, R.Blomqvist, T.Ruskeeniemi, M.Vesterinen & P.Pitkanen

Ingesting the consequences of water-rock interaction: Historical notes on bottled water 767

and spas

William Back & EdwardR.Landa

Effects of base exchange softening on fluoride uptake in groundwaters of the Moncton 771

Sub-Basin, New Brunswick, Canada

D.R.Boyle

Saline formation waters in Pliocene clays of the Po Valley, Italy: Tectonic significance 775

M.Chiarle, T.Nanni.E.Sacchi & G.M.Zuppi

The chemical influence ofclay minerals on groundwater composition in a lithologically 779

heterogeneous carbonate aquiferAlison E.Clark, Janet S. Herman & Blair F.Jones

Water-rock interactions and the pH stability of groundwaters from Yucca Mountain, Nevada, 783

USA

MichaelH.Ebinger

A comparison ofcalcite fracture mineralogy and geochemistry for the Canadian 787

and Fennoscandian Shields

S.K.Frape, AR.Blyth.M.GJones, R.Blomqvist, E-L.Tullborg,R.H.McNutt,F.McDermott&M.Ivanovich

Deuterium and' 3C evidence for low temperature production of hydrogen and methane 793

in a highly alkaline groundwater environment in Oman

PeterFritz, Ian D.Clark, Jean-Charles Fontes, Michael J.Whlticar & Eckhard Faber

Characterization ofnatural colloids in groundwaters ofEl Berrocal, Spain 797

P.Gomez, MJ.Turrero, V.Moulin & M.C.Magonthier

CI and Br in mafic and ultramafic rocks: Significance for the origin of salinity in groundwater 801

D.C.Kamineni, M.Gascoyne, TW.Melnyk, S.K.Frape & R.Blomqvist

Ligand-enhanced transport of strongly adsorbing metal ions in the ground-water environment 805

D.B.Kent, JADavis, LDAnderson & BARea

XXII

Ground-water chemistry undertallgrass prairie, central Kansas, USA 809

G.LMacpherson

Sulphur isotope ratios as tracers of natural and anthropogenic sulphur in the Lincolnshire 813

Limestone aquifer, eastern EnglandSJ.Moncaster, S.H.Bottrell, J.HTellam & J.W.Lloyd

Mechanisms of sulphide oxidation in a sandy aquifer 817

A.Parker, J.E.Rae, S.Bierens de Haan & R.T.Kimblin

Hydrogeochemistry of fluorine in shallow aqueous systems of the Golctik area, SW Turkey 821

APekdeger, N.Ozgur & H.-J.Schneider

Strontium isotope characterization of the Ash Meadows ground-water system, southern 825

Nevada, USA

ZE.Peterman, J.S.Stuckless, SAMahan, B.D.Marshall, E.D.Gutentag & J.S.Downey

Hydrogeochemical interpretation of the groundwater at Olkiluoto, Finland 831

P.Pitkdnen, M.Snellman & HLeino-Forsman

Mobilization of As and U in the Central Oklahoma aquifer, USA 835

JLSchlottmann & G.N.Breit

REE distributions in shallow groundwater from two hard-rock aquifers in the British Isles: 839

Carnmenellis (Cornwall) and Jersey

P.LSmedley

Integrated natural and injected multicomponent tracer experiments: Mammoth Hot Springs, 843

Yellowstone National Park, USA

W.D.Spall, D.RJanecky, P.R.Dixon & G.KBayhurst

Experimental interaction between a granite wall and flowing aerated water 847

M.-P.Turpault & LTrotignon

Postglacial land uplift and concentration profiles of anions in granite bedrock 851

M.Valkiainen, M.Olin & KUusheimo

Halogen geochemistry of Cretaceous sandstone aquifers in North America 855

D.O.Whittemore & J.Fabiyka-Martin

Author index

XXIII