Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/119917
Type: Thesis
Title: The nature of the Precambrian-Cambrian transition in the northern Flinders Ranges, South Australia
Author: Nedin, C.
Issue Date: 1990
School/Discipline: School of Physical Sciences
Abstract: Previous investigations into the Ediacara Member of the late Proterozoic Rawnsley Quartzite in the Flinders Ranges have produced differing interpretations of the depositional environment. Studies at Nilpena Hills indicate that deposition was influenced by back barrier lagoonal conditions with the intermittent influx of fluidised sands which mantled lagoonal muds. Re-interpretation of the Ediacara assemblage shows a hitherto unrecognised benthonic bias. This abundance of sessile, benthonic forms supports a sub-tidal depositional environment. However, the increase in the numbers of motile forms compared with sessile forms, preserved towards the top of the member, accords well with one of two inferred shallowing upward cycles within the sequence. A recent re-evaluation of the nature of the Precambrian-Cambrian boundary in the Flinders Ranges suggests a conformable relationship between the Pound Subgroup and the overlying Early Cambrian beds. This is at odds with previous interpretations, which proposed that a regional disconformity occurs at the boundary. Mapping at Mt. Scott Range, Puttapa Syncline and Red Range provided ample evidence that several periods of at least partial lithification occurred within the Pound Subgroup, before the onset of Cambrian deposition. Erosive downcutting marks the contact of the Pound Subgroup-Uratanna Formation at Mt. Scott Range, Red Range and Puttapa Syncline. Erosive downcutting of the Parachilna Formation into the Uratanna Formation was mapped at Mt. Scott Range. The Pound Subgroup-Parachilna Formation contact was mapped as a disconformity which becomes a high angle unconformity near the Beltana Diapir.
Dissertation Note: Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 1990
Where: Adelaide Geosyncline, Flinders Ranges, South Australia
Keywords: Honours; Geology; Adelaide Geosyncline; Flinders Ranges; Precambrian-Cambrian boundary; stratigraphy; depositional environments
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Appears in Collections:School of Physical Sciences

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