ikara — flinders ranges
TRANSCRIPT
Ikara — Flinders Ranges
The Adelaide Rift Complex: a classic record of the Rise of a Habitable Planet
Jim Gehling — Honorary Research Fellow South Australian MuseumIn collaboration with:
Steve Hore, Graeme Worboys, Peter Haslett, Trevor Mount, Nick Langsford, Pierre Kruse, Lidya Tarhan, Liesel Garrett and Mary Droser
Adelaide Rift Complex &FRWH
Sir Douglas Mawson
Serial Sites for Flinders Range World Heritage Nomination —Why?The Adelaide Rift Complex exhibits:1. The Arkaroola “window” to our crystalline basement and mineral
sources.2. The best mapped, least deformed, most accessible Tonian, Cryogenian,
Ediacaran, and early Cambrian stratigraphic successions on Earth.3. The crucial geological record of the rise of a habitable Earth that
documents the evolution of marine animal life.4. A region were, in spite of 130 years of field work, most of its geological
treasures are yet to be discovered and realized.
Arkaroola Wilderness Sanctuary
• A window to the crystalline basement and mechanisms that powered the Adelaide Rift Complex
Cryogenian Ice Ages
• Record of two global ice ages at low palaeolatitudes• Sturt Tillite: from Wirrena & Sturt Gorge to Arkaroola & Bimbowrie• Elatina Ice Age: record of tidal rythmites formed beneath Ice Sheets
Stromatolites and Organic Rich Rocks
Wolfgang Preiss and Malcolm Walter(Martin Glaessner)
Elatina Tidal RhythmitesGeorge Williams and Phil Schmidt: 1. Palaeo-magnetic record of low latitude, seasonal ice2. Record of ~650 Ma old tidal rhythmites
Golden Spike —Ediacaran GSSP
• First for southern hemisphere and for Australia• Base of the Nuccaleena Formation (cap
carbonate)• Age: circa. 635 ma (base Doushantuo Fm. in
South China
South China — Geological Bar-Code
Acraman Ejecta layer – Bunyeroo Fm• Meteor impact crater in the
Gawler Ranges —> Lake Acraman
• Rock fragments blasted 300 km into the Adelaidean Ocean
• A layer of ejected Gawler Ranges rock fragments in Bunyerooshale —> ~ 580 million years
Wonoka Formation
Pichi Richi Pass
Brachina GorgePalaeopascichnus
Brachina Gorge:Ediacara biota
Oldest Ediacara fossils in South Australia are Trace Fossils
Praecambridium— arthropod
Ediacarans that Inherited the Earth
1 cm
Spriggina — arthropod
Marywadea —arthropod Kimberella
— mollusc
Parvancorina — arthropod
Arkarua —echinoderm
‘protochordate’
‘prototrilobite’
Ediacara-Nilpena National Park Excavated samples of Ediacaran seafloor communities
Nilpena Geology
Castle Rock: Parachilnaover
Uratanna Formation
Sabellidites
Ediacaran – Cambrian Transition
Un-interepretedBody Fossils
Archaeocyaths — bioherms — Ajax Plateau
Early Cambrian Small Shelly FossilsMernmerna Formation: Bunkers Range
BrachipodChancellorid Spicular Impressions
Cambrian: Tabulate-grade Corals
Morowie Formation — East end — Chambers Gorge
Mid-Cambrian: ThrombolitesStromatolites grazed and burrowed by small Cambrian animals
Wirrealpa Formation
And so to Phanerozoic Ecosystems
Thank you to the people who made it a career privilege to work on Ediacaran
rocks and fossils in:
• Flinders Ranges, South Australia• Rocky Mountains of Canada• The plateaus of central & southern Namibia• The Avalon terrain of Leicester and Sth. Wales• The Avalon Peninsula of Newfoundland
My Career Associates & Mentors in Geoscience
Peter Haslett, Barry Fehlberg, Trevor Ireland, Maud McBriar, Martin Glaessner, Inara Gehling, Mary Wade, Brian Daily, Wolfgang Preiss, Malcolm Walter, Robin Oliver, Jim Jago, Soren Jensen, Rod Wells, Bren Thompson, Brian Forbes, Hans Mincham, Reg Sprigg, Ron Coats, Victor Gostin, Charles Gabielle, Frank Gaunt, Neville Pledge, John Cann, Haggis Shackleton, Ian Dyson, Chris von der Borch, Ian Dyson, Bruce Runnegar, Adolf Seilacher, Guy Narbonne, Bill Schopf, Charles Marshal, Soren Jensen, Bob Dalrymple, Simon Conway-Morris, Bob Dalgarno, Marg Fuller, Mary-Anne-Binnie, Mary Droser, Pat Vickers-Rich, WenlongZhang, Shuhai Xiao, Maoyan Zhu, Eric Sperling, John Paterson, Glenn Brock, John Paterson, Diego Garcia Bellido, Nick Langsford, Steve Hore, Lidya Tarhan, Felicity Coutts.