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GEOREF RECORD

Outer-bank bars; a new intra-channel architectural element within sinuous submarine slope channels

Takeshi Nakajima, Jeffrey Peakall, William D. McCaffrey, Douglas A. Paton and Philip J. P. Thompson
Outer-bank bars; a new intra-channel architectural element within sinuous submarine slope channels
Journal of Sedimentary Research (December 2009) 79 (12): 872-886

Abstract

This study describes for the first time "outer-bank bars", an intra-channel architectural element that is unique to sinuous submarine channels. The study is based on interpretation of 3D seismic data of sinuous channels in the upper slope of the Amazon Fan, offshore Brazil. Outer-bank bars comprise channel-fill deposits found in tight meander loops at outer corners of bend apices or slightly upstream or downstream of apices. This architectural element can be up to 1.5 km wide and up to 150 m thick with continuous internal reflectors dipping 1-20 degrees towards the inner bend of the meander loop, a direction of dip opposed to that of fluvial point bars or submarine lateral-accretion packages. The angles of outer-bank bar surfaces increased to a maximum at bend apices. Outer-bank bars occur in the final aggradational channel fill in the two separated channel-levee systems in the Amazon data set. They may have been formed as a result of enhanced deposition on the outside of the bend caused by a combination of flow-volume reduction and flow superelevation. Accretion of outer-bank bars may cause the thalweg position to shift towards the inner bends leading to sinuosity reduction. Since this architectural element is likely to be sand prone, its recognition may have significant implications for prediction of hydrocarbon reservoirs.


ISSN: 1527-1404
EISSN: 1938-3681
Serial Title: Journal of Sedimentary Research
Serial Volume: 79
Serial Issue: 12
Title: Outer-bank bars; a new intra-channel architectural element within sinuous submarine slope channels
Affiliation: Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
Pages: 872-886
Published: 200912
Text Language: English
Publisher: Society for Sedimentary Geology, Tulsa, OK, United States
References: 54
Accession Number: 2010-014050
Categories: Economic geology, geology of energy sourcesApplied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., geol. sketch maps
N04°35'44" - N06°57'01", W49°05'28" - W46°37'59"
Secondary Affiliation: University of Leeds, GBR, United KingdomUniversity of Aberdeen, GBR, United Kingdom
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by SEPM (Society for Sedimentary Geology), Tulsa, OK, United States
Update Code: 201009
Program Name: ODPOcean Drilling Program
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