Porosity-depth trends of carbonate deposits along the northwest shelf of Australia (IODP Expedition 356)

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http://meetingorganizer.copernicus.org/EGU2017/EGU2017-3023.pdf
Author(s): Lee, Eun Young; Kominz, Michelle; Reuning, Lars; Takayanagi, Hideko; Knierzinger, Wolfgang; Wagreich, Michael
International Ocean Discovery Program, Expedition 356 Shipboard Scientists, College Station, TX
Author Affiliation(s): Primary:
University of Vienna, Department of Geodynamics and Sedimentology, Vienna, Austria
Other:
Western Michigan University, United States
Rheinisch-Westfälische Technische Hochschule Aachen University, Germany
Tohoku University, Japan
Volume Title: European Geosciences Union general assembly 2017
Source: Geophysical Research Abstracts, Vol.19; European Geosciences Union general assembly 2017, Vienna, Austria, April 23-28, 2017. Publisher: Copernicus GmbH on behalf of the European Geosciences Union (EGU), Katlenburg-Lindau, Germany. ISSN: 1029-7006
Note: In English
Summary: The northwest shelf (NWS) of Australia extends from northern tropical to southern temperate latitudes situated offshore from the low-moderate-relief and semi-arid Australian continent. The shelf environment is dominated throughout by carbonate sedimentation with warm-water and tropical carbonate deposits, connected to the long-term northward drift of Australia bringing the NWS into tropical latitudes. IODP expedition 356 cored seven sites (U1458-U1464) covering a latitudinal range of 29 S-18 S off the NWS. This study focuses on porosity-depth trends of the Miocene - Pleistocene carbonate sediment on the NWS. The NWS is an ideal area to study regional (and furthermore general) carbonate porosity-depth relationships, because it contains a nearly continuous sequence of carbonate sediment ranging in depth from the surface to about 1,100m and in age from Pleistocene to Miocene. Porosity-depth trends of sedimentary rocks are generally controlled by a variety of factors which govern the rates of porosity loss due to mechanical compaction and of porosity loss (or gain) due to chemical processes during diagenesis. This study derives porosity data from Moisture and Density (MAD) technique conducted during IODP Expedition 356. MAD samples were collected from packstone (44%), wackestone (27%), mudstone (15%) and grainstone (7%), with the rest from floatstone, rudstone, dolostone, sandstone and other subordinate lithologies. To understand porosity-depth trends, the porosity data are arranged both exponentially and linearly, and correlated with age models and lithologic descriptions provided by IODP shipboard scientists. Porosity(%)-depth(m) trends of all the porosity data are Porosity=52e-0.0008/Depth (exponential) and Porosity=-0.03Depth+52 (linear). Porosities near surface and in the deepest parts of each well are least well represented by these trend lines. Porosity values of Pleistocene sediment are generally higher than those of Miocene - Pliocene sediment. The initial porosity in porosity-depth trends increases from 52% to 57% with increasing mud content from grainstone to packstone, wackestone, and mudstone. Carbonate sediment that includes non-skeletal grains usually has lower porosity values than the trend lines. *This research was a part of the project titled 'International Ocean Discovery Program', funded by the Ministry of Oceans and Fisheries, Korea. [Copyright Author(s) 2017. CC Attribution 3.0 License: https://creativecommons.org/licenses/by/3.0/legalcode]
Year of Publication: 2017
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Australasia; Australia; Cenozoic; Continental shelf; Expedition 356; IODP Site U1458; IODP Site U1459; IODP Site U1460; IODP Site U1461; IODP Site U1462; IODP Site U1463; IODP Site U1464; Indian Ocean; International Ocean Discovery Program; Neogene; Pliocene; Quaternary; Tertiary; Western Australia
Record ID: 2018016368
Copyright Information: GeoRef, Copyright 2018 American Geosciences Institute. Reference includes data from European Geosciences Union, Munich, Germany

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