Jim Gehling 'Palaeoecology and Environments of the Ediacara Biota Record in the Flinders Ranges'

Jim Gehling presents 'Palaeoecology and Environments of the Ediacara Biota Record in the Flinders Ranges' at the 2023 Adelaide Superbasin Mini-symposium

Abstract:
1. History and Discovery of the Ediacara Biota in the Flinders Ranges: Fossils of the Ediacara biota were first discovered by the late Dr Reginald Sprigg in circa 1946, within the shallow dipping Precambrian sandstones, below the copper-lead bearing basal Cambrian carbonates at north and south Ediacara hills, some 35 km west of the old township of Beltana. It took until 1957 before the late Prof. Martin Glaessner was convinced that these weird impressions in rippled sandstone were true fossils that were clearly older than strata bearing burrows and overlain by limestoes bearing “sponge-like” archaeocyath fossils, that had previously been considered, worldwide, to be the oldest known body fossils. By the 1970s, fossils of the “Ediacara fauna” had been discovered in England, Russia, Canada and China. Before and even after Ediacara was declared a “fossil reserve” fossils from the Ediacara hills were collected by museums and geology departments, world-wide.

2. Ediacara fossil distribution: It was not until 1968, that Ediacaran fossils were discovered elsewhere, firstly at Brachina Gorge, and then traced from Devil’s Peak in the south, along the Heysen and Elder Ranges as far north as Leigh Creek, east of Blinman to Mulga View, and in the Amadeus Basin of the Northern Territory. Such fossil sites are generally protected by the difficult relief of the Rawnsley Quartzite as the virtual backbone formation of the Flinders Ranges.

3. Nilpena: Ediacaran fossils were discovered by pastoralist, Ross Fargher, in the Mt Michael region, south of the Ediacara Hills. These fossils were identified by Pam Hazenhor and Richard Jenkins. The Farghers realized the value of keeping the fossil beds intact, on site, for both scientific and tourism purposes. I approached Ross Fargher in 2000 with the proposition that we study the Ediacara biota and avoid displacing any specimens in order to begin to understand the stratigraphic succession on site. Those fossil taxa, new to science, required as Museum “types” or name holders, are (necessarily) lodged in the SA Museum for global biostratigraphic purposes. This condition has been maintained by a ban on collection, other than for having type specimens in the SA Museum. The use of SA Museum collections, resin casts, photography and digital scanning, enables researchers to do comparative morphology and education.

4. Distribution of Ediacara Biota in the Flinders Ranges: Two assemblages of Ediacara fossils have been discovered, Flinders Ranges wide, within the Rawnsley Quartzite, from the southern tip of Devil’s Peak east of Port Augusta, north to Leigh Creek and Copley, east to Balcanoona, and southeast to Reaphook Hill.

5. Current Research: Based on a recent ARC grant, led by Prof. Diego Garcia Bellido (SA Museum and University of Adelaide), with Prof. Mary Droser (Riverside University, California), and I, managed by Trevor Ireland, two drill holes at Nilpena have produced the first complete core samples, through the Nilpena and Ediacara Sandstone Members of the Rawnsley Quartzite, north of the Nilpena Interpretation Centre. Description and analysis of these cores is a project for a new postdoctoral fellowship.

Biography:
• AO, BSc Hons & MSc (Adelaide), PhD (UCLA), DSc (Adelaide).
• BSc Hons: University of Adelaide (1972).
• Lecturer: University of South Australia and previous CAE’s (1973-1996).
• MSc: Uni. Adel. 1982: “Sedimentology and stratigraphy of the Rawnsley Quartzite, Flinders Ranges”.
• PhD: UCLA, California. 1992: Taphonomy of the Terminal Proterozoic Ediacara Biota, Sth. Aust.
• Post Doc: Queens University, Ontario., on the stratigraphy and palaeobiology of the Ediacaran, Mistaken Point Formation in Newfoundland and Namibia. 1996-1998.
• Senior Research Scientist, Palaeontology: South Australian Museum and Uni. Adelaide, Ediacaran and Cambrian palaeobiology and stratigraphy. (2003-2018).
• Honorary Research Scientist: SA Museum. (2019 —).