Sheared Margins of Western AustraliaCompleted

Investment:

$69k (USD) per Sponsor

Status:

Completed

Principal Investigator(s):

Michal Nemčok
421-2-546 30 337 (Slovakia)
mnemcok@egi.utah.edu

John Conolly
61-4862-3311 (Australia)
john.conolly@bigpond.com

Value to Sponsors

  • A refined timing of break-up for large margin segments with detailed break- up propagation timing, associated distinct vertical movement histories of different margin segments, and a better understanding of the associated depositional histories of individual margin segments.
  • Identify exact locations of extensional and sheared margin segments along the Western Australian margins and determine their exact break- up propagation with time, associated uplift histories, magmatism and depositional histories;
  • Ascertain their role in the petroleum system to facilitate development of hydrocarbon exploration models.
  1. Crustal boundary map with main faults and hydrocarbon occurrences.
  2. Color-coded break-up map identifying isostatic-rebound driven exhumation; sedimentary response to erosion in exhumed areas; stratigraphic gaps associated with break-up unconformity, and magnetic stripe anomaly-based ages of oldest oceanic crust. Additionally, continental margin segments, color-coded index of break-up timing, distribution of magma-poor versus magma-rich margin segments, and distribution of magmatic products and their relationship to margin types will be mapped individually.
  3. Map of thinned zones in the continental crust
  4. Map of spreading center locations through time
  5. Multiple gravity maps (different types)
  6. Sediment entry points
  7. 1D expulsion timing modeling approach focused on six different margin segments, each of them covered with five pseudo-wells. Priority will be given to sheared margins.

Each chapter of the report will include a brief text. The main focus of interpretation is a comparison of various phenomena at sheared versus extensional margin segments. Sample descriptions will be included in the report Appendix.

Oil discoveries such as the Jubilee Field located in the Equatorial Atlantic have encouraged exploration in sheared margins worldwide. Sheared margins have a thermal history, which is different from that of extensional margins. Recent studies by EGI in the Equatorial Atlantic and Indian sheared margins have indicated that a successful exploration program in this setting requires a detailed understanding of the thermal and structural history of continental break-up.

Objectives of this project are to refine the existing general timing of break-up for large margin segments with detailed break-up propagation timing, associated distinct vertical movement histories of different margin segments, and attempt to address associated depositional histories of individual margin segments.

EGI will undertake a robust analytical research program with both well samples and dredge samples and interpretation of existing data, focused on:

  1. Low-temperature thermochronology (constraining the exhumation histories of sedimentary provenances geared towards the first 10–40 Ma after break-up);
  2. Seismic interpretation aiming at sedimentary response to erosion in those exhumed areas;
  3. Well and seismic interpretation aiming at stratigraphic gaps associated with break-up unconformity;
  4. Magnetic and gravity anomaly interpretation aiming at ages of oldest oceanic crust; and
  5. Fluid inclusions (constraining migration timing and migration horizons).

This effort will be undertaken in context with a re-interpretation of existing open-file geological and geophysical data.

Results

Project sponsors and participants will be updated regularly regarding analyses and interpretations. Three project meetings will be held to assess progress and provide guidance (project kick-off, mid-term and final meetings). The project kick-off meeting took place February 10–11, 2014 in Perth, Australia.

A written Final Project Report will be delivered to Sponsors at the completion of the Project.