ikara — flinders ranges

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.