Thursday 19th November 2020 - Zoom / lunchtime meeting 12.20pm ACDT
Dr Rachelle Kernan, Honorary Research Fellow & Co-Chair of AAPG Women’s Network & Salt Basins TIG
Lithostratigraphy and chemostratigraphy of salt diapir sedimentary inclusions: unravelling Ediacaran salt tectonics in the Flinders Ranges, Australia
[Rachelle Kernan]
A link to a registration page will be sent to members prior to the event. Once registered you will be sent a link to attend the meeting in Zoom.
Register herehttps://gsa.us1.list-manage.com/track/click?u=3addbef173e1590b09478aef3&id=0e36f28ed0&e=1f26d61f52 - everyone is welcome to join.
Abstract: Patawarta Diapir, approximately 2-6km2 located in the Central Flinders Ranges, South Australia, has been interpreted as a single allochthonous salt sheet containing Tonian-aged igneous and layered evaporite sedimentary intrasalt inclusions derived from the Callanna Group. Using detailed field mapping, petrographic analysis, and lithostratigraphic correlation within Patawarta Diapir, five primarily silty limestone inclusions (0.5-2km2) are re-interpreted as Ediacaran-aged Wonoka Formation and Patsy Hill member of the Bonney Sandstone (Wilpena Group). The Ediacaran-aged inclusions are concentrated on the diapir’s south side where they are juxtaposed against a 1-2 km2, approximately 300-million-year older Tonian-aged Curdimurka Subgroup (Callanna Group) inclusion. The Ediacaran-aged silty carbonate inclusions in the Patawarta Diapir are interpreted to represent a suprasalt condensed section forming a carapace composed of Wonoka Formation and lower beds of the Patsy Hill member (Bonney Sandstone). Based on this geometric configuration, the Patawarta Diapir is composed of two separate evaporite bodies that encase the suprasalt carapace at an allosuture zone. The encasement process was likely driven by a combination of factors including regional shortening during the Delamerian Orogeny, high sedimentation rates forming local depocenters, and down-dip gravity sliding on the low-angle regional shelf. By using modern concepts in salt tectonics, this study represents the first documented example of a diagenetically altered Ediacaran Shuram Excursion due to stratigraphy being encased in a diapir in the Flinders Ranges, South Australia.
Bio: Rachelle did her PhD, at the University of Texas at El Paso, where her focus was to integrate salt tectonic fieldwork, seismic data, physical modelling, and geochemistry to answer complex energy-related questions about geological processes within salt diapirs and along the salt-sediment interface. She has extensive salt tectonic seismic interpretation experience in the oil industry working for Royal Dutch Shell & BP Americas.
Rachelle is passionate about the Energy Transition and DEI where she is actively changing and re-shaping organizations (volunteering for non-profits at the moment). Currently, she is Co-chair of AAPG’s Women’s Network, Co-Founder of AAPG’s Salt Basins Technical Interest Group, & an Honorary Visiting Research Fellow at Australia’s School of Petroleum & Energy Resources at the University of Adelaide.
Prof Louis Moresi
RSES Seminar committee
(Penny King, Brad Opdyke, Voon Hui Lai, Louis Moresi)
Email: seminar.convenor.rses@anu.edu.auhttps://mailto:seminar.convenor.rses@anu.edu.au
Zoom: https://anu.zoom.us/my/rses.seminar.room password jaeger
Web: researchseminars.org - View series
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