EGU2020-3184, updated on 12 Jun 2020
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

The State-of-play of geochronology and provenance in the Neoproterozoic Adelaide Rift Complex

Jarred Lloyd1,3, Morgan Blades1, John Counts2, Alan Collins1, Kathryn Amos3, James Hall1, Stephen Hore4, Benjamin Wade5, Ashleigh Job1, Sameh Shahin1, and Matthew Drabsch1
Jarred Lloyd et al.
  • 1The University of Adelaide, Institute of Mineral and Energy Resources, Department of Earth Sciences, Australia (
  • 2Irish Centre for Research in Applied Geosciences (iCRAG), O’Brien Centre for Science, University College Dublin, Belfield, Dublin 4, Ireland
  • 3Australian School of Petroleum and Energy Resources, The University of Adelaide, Adelaide, Australia
  • 4Geological Survey of South Australia, Adelaide, Australia
  • 5Adelaide Microscopy, The University of Adelaide, Adelaide, Australia

The Adelaide Rift Complex is a large sedimentary superbasin in South Australia that formed resultant of Rodinia’s breakup and subsequent evolution of the Australian passive margin of the Pacific basin. It holds a globally significant and exceptionally well-preserved Neoproterozoic–early Cambrian succession. Much work has been done over the last century describing the lithostratigraphy and sedimentology of this vast basin. The rift complex contains evidence for major changes in Earth’s systems, yet, the rocks are poorly dated, and the sediment provenance, and link with tectonic evolution, is remarkably poorly known.

This work provides a centralised database of the currently available, and previously unpublished, detrital zircon geochronology for the Neoproterozoic of the Adelaide Rift Complex, highlighting where the available data is from, and the stratigraphic and spatial gaps in our knowledge. By subjecting the U–Pb detrital zircon data to data analytical techniques, we provide a first look overview of the change in provenance, and subsequently (generalised) palaeo-tectonogeography that this suggests during the Neoproterozoic. These data show a change from dominantly local sources in the middle Tonian, to dominantly far-field sources as the rift-basin develops over time. The Cryogenian icesheets punctuate this with an ephemeral return to more local sources from nearby rift shoulders. This effect is particularly apparent during the Sturtian Glaciation than in the younger Marinoan Glaciation. In the Ediacaran, we see an increasingly stronger influence of younger (<700 Ma) detrital zircons from an enigmatic source that we interpret to be from southern (i.e. Antarctic) sources. We also note that we see a slight shift in the late Mesoproterozoic age peaks, from ca. 1170 Ma to ca. 1090 Ma, with a corresponding decrease in older ca. 1600 Ma detritus.

This work forms the basis of continuing work to improve our understanding of the geochronology, provenance and palaeo-tectonogeography of the Adelaide Rift Complex.

How to cite: Lloyd, J., Blades, M., Counts, J., Collins, A., Amos, K., Hall, J., Hore, S., Wade, B., Job, A., Shahin, S., and Drabsch, M.: The State-of-play of geochronology and provenance in the Neoproterozoic Adelaide Rift Complex, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3184,, 2020