Did the onset of high amplitude glacio-eustatic cycles trigger mass-transport processes on the Northwest Shelf of Australia? Insights from IODP Expedition 356

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Author(s): Gallagher, S. J.; McCaffrey, Jackson; Wallace, M. W.; Keep, M.; Fulthorpe, C.; Bogus, K.; McHugh, C.
Author Affiliation(s): Primary:
University of Melbourne, Parkville, Victoria, Australia
University of Western Australia, Perth, West. Aust., Australia
University of Texas at Austin, Austin, TX, United States
International Ocean Discovery Program, College Station, TX, United States
CUNY Queens College, Flushing, NY, United States
Volume Title: AGU 2017 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2017; American Geophysical Union 2017 fall meeting, New Orleans, LA, Dec. 11-15, 2017. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: Mass-transport processes on continental margins may have catastrophic consequences, causing tsunamis, major rock falls and avalanches and can destroy offshore hydrocarbon installations. Mass-transport deposits (MTD's) with volumes ≈17 to >162 km3 are common along the northwest margin of Australia. One of the largest is the Gorgon slide which is offshore from Barrow Island with a minimum volume of ≈250 km3. Age estimates for slides on the Northwest Shelf are variable and range from Miocene to Recent (Gorgon MTD), late Pliocene to Recent (Thebe/Bonaventure MTD's) and Pleistocene to Recent. This age uncertainty is related to a lack of cored sections through these slides and relies on pre-existing ages and correlations from poorly dated sections (usually industry well sections with minimal samples in the upper 500 m) distal from the MTD's. Therefore, the age, origin and history of these MTD's is not well known. A recent International Ocean Discovery Program Expedition (IODP Expedition 356) to the region obtained a series of continuous cores from the upper 600m to 1.1 km of the Northern Carnarvon and Roebuck Basins. Four sites were cored adjacent to hydrocarbon wells; West Tryal Rocks-2 (Site U1461), Fisher-1 (Site U1462), Picard-1 (Site U1463) and Minilya-1 (Site U1464). Site U1461 yielded 100% core recovery through the Gorgon Slide. Preliminary data from this section suggests that it is relatively young (<1 Ma) with ongoing activity from 0.5 Ma continuing to today. We suggest neotectonism combined with the onset of high amplitude glacio-eustatic cycles may have been triggering factors for this slide.
Year of Publication: 2017
Research Program: IODP2 International Ocean Discovery Program
Key Words: 24 Surficial Geology, Quaternary Geology; Australasia; Australia; Cenozoic; Continental shelf; Eustasy; Expedition 356; Glacial environment; Glacial rebound; Indian Ocean; International Ocean Discovery Program; Isostatic rebound; Paleoclimatology; Paleoenvironment; Quaternary
Coordinates: S284000 S180300 E1183800 E1125500
Record ID: 2018093813
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