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Quantitative seismic geomorphology of a submarine channel system in SE Brazil (Espírito Santo Basin): scale comparison with other submarine channel systems

Qin, Yongpeng; Alves, Tiago M.; Constantine, José; Gamboa, Davide. 2016 Quantitative seismic geomorphology of a submarine channel system in SE Brazil (Espírito Santo Basin): scale comparison with other submarine channel systems. Marine and Petroleum Geology, 78. 455-473. https://doi.org/10.1016/j.marpetgeo.2016.09.024

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Abstract/Summary

Detailed morphological analyses of a Pleistocene-Holocene submarine channel system in terms of its hierarchical framework, were carried out using a 3D seismic volume from offshore Espírito Santo, SE Brazil. The channel morphology shows marked variations, with five segments (Segments a to e) being identified along its full length. For example, the cross-sectional area of the channel decreases by a factor of 70 from Segment a to Segment c, and is then followed by a nearly four-fold increase from Segment c to Segment d. The significant changes in channel morphology relate to temporal and spatial variations in flow volume within the channel. In the same channel system, the valley reveals three distinct segments (Segments A to C), with similar aspect ratios but marked variations in morphology along the valley distance. Valley morphological changes are chiefly affected by erosional processes. Segment B is characterised by the largest valley-base width, valley width, and cross-sectional area compared to the other two segments. Valley enlargement in Segment B results from relatively high degrees of lateral channel migration and associated cut bank erosion, leading to the widening of the valley, especially the valley base. In Segment C, the valley is characterised by inner bank erosion in the form of shallow-seated mass failures, which only enlarged the upper part of the valley wall. The spatial variations in both channel and valley morphology documented here suggest an important role of local factors (e.g. salt diapirs, tributaries, overbank collapse) in the development of channel systems. Hence, the morphological analyses developed in this work provide an effective tool for studying channels and valleys on continental slopes around the world.

Item Type: Publication - Article
Digital Object Identifier (DOI): https://doi.org/10.1016/j.marpetgeo.2016.09.024
ISSN: 02648172
Date made live: 07 Feb 2017 13:57 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/516136

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