Seismic inversion for acoustic impedance and porosity of Cenozoic cool-water carbonates on the upper continental slope of the Great Australian Bight

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doi: 10.1016/j.margeo.2004.12.005
Author(s): Huuse, M.; Feary, D. A.
Author Affiliation(s): Primary:
Cardiff University, 3D Laboratory, Cardiff, United Kingdom
Other:
Australian Geological Survey Organisation, Australia
Volume Title: Marine Geology
Source: Marine Geology, 215(3-4), p.123-134. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0025-3227 CODEN: MAGEA6
Note: In English. 33 refs.; illus., incl. sketch map
Summary: Seismic inversion is used to estimate detailed seismic and rock properties, such as acoustic impedance and porosity, from seismic data. The method is widely used and proven successful by the petroleum industry, but has hitherto not been widely adopted for academic studies. This paper outlines a workflow and reports the application of model-based seismic inversion to a Cenozoic cool-water carbonate succession on the upper continental slope of the Great Australian Bight that was cored during Ocean Drilling Program Leg 182. Acoustic impedance data and the derived porosity distribution facilitate detailed studies of lithology, compaction and fluid flow in the shallow subsurface (0-500 m). A comparison of reflection and impedance data support the notion that seismic reflection events arise from bed boundaries rather than from lateral changes in impedance, even where these are significant. The uppermost continental slope of SW Australia is swept by a strong (>0.5 m/s) geostrophic current, the Leeuwin Current, and seismic profiles across the upper slope show geometrical similarities with contourite drifts. Cores taken through a conspicuous mounded seismic facies at ODP Site 1131 suggest that bryozoan build-ups nucleated on top of contourite mounds on the uppermost slope. Core recovery at three sites on a transect across the uppermost continental slope systematically decreased with increasing acoustic impedance and depth of the drilled section regardless of age. Because of the enhanced interpretability afforded by acoustic impedance and porosity data, and the possibility of predicting core recovery, the workflow outlined here should be of use in a broad spectrum of continental margin studies. afforded by acoustic impedance and porosity data, and the possibility of predicting core recovery, the workflow outlined here should be of use in a broad spectrum of continental margin studies. Abstract Copyright (2005) Elsevier, B.V.
Year of Publication: 2005
Research Program: ODP Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; 20 Geophysics, Applied; Acoustical methods; Australasia; Australia; Bottom features; Bryozoa; Carbonate sediments; Cenozoic; Continental margin sedimentation; Continental slope; Contourite; Cores; Geophysical methods; Geophysical profiles; Geophysical surveys; Great Australian Bight; Impedance; Indian Ocean; Inner slope; Inverse problem; Invertebrata; Leeuwin Current; Leg 182; Marine environment; Marine sediments; Mounds; ODP Site 1131; Ocean Drilling Program; Ocean floors; Paleo-oceanography; Paleoclimatology; Paleocurrents; Porosity; Reflection methods; Sedimentation; Sediments; Seismic methods; Seismic profiles; Slope environment; Southern Australia; Surveys
Coordinates: S331934 S331934 E1282852 E1282852
Record ID: 2010050387
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands