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Sediment storage and reworking on the shelf and in the Canyon of the Indus River-Fan System since the last glacial maximum

Sediment storage and reworking on the shelf and in the Canyon of the Indus River-Fan System since the last glacial maximum
Sediment storage and reworking on the shelf and in the Canyon of the Indus River-Fan System since the last glacial maximum
The transport of sediment from the mouth of the Indus River on to the deep-water submarine fan is complicated by temporary storage within large clinoforms on the shelf on either side of the submarine canyon, where most of the sedimentation since the start of the Holocene has occurred. In contrast, shelf edge clinoform deltas represent the products of forced regression and not the progradation of highstand clinoforms as far as the shelf edge. Clinoform sediments have a mixed provenance that involves significant reworking of older sediment deposited during or before the last glacial maximum. Recent sedimentation in the canyon head has been very rapid in the last few centuries (ca. 10 cm yearÀ1), but has been starved of sand probably because of 20th century damming. Sandy layers appear to represent annual monsoonal floods with a particularly large flood every 50–70 years. This canyon head sediment is also reworked by currents flowing along the canyon axis before being deposited deeper into the canyon. The last sandy sediment to reach the mid-canyon (ca. 1300 m depth) was transported around 7000 year BP at a time of rising sea-levels, and might reflect reworking by the transgression, or local slumping from the walls of the canyon. Dating of the uppermost in a series of terraces in the mid-canyon area suggests that the canyon may have been partly filled and emptied of sediment at least three times since ca. 50 ka. We conclude from the Holocene record that sediment flux to the deep-water fan experiences major buffering, reworking and recycling both on the shelf and within the submarine canyon prior to its deposition, so that turbidite sands in the deep Arabian Sea cannot be used to correlate with climatic or tectonic events onshore over timescales of 103–105 years.
0950-091X
183-202
Clift, Peter D.
24c0646e-f897-45ad-bd50-817eb88fea41
Giosan, Liviu
46802e93-8a58-4660-b2d3-fdd5dfe100b8
Henstock, Timothy J.
27c450a4-3e6b-41f8-97f9-4e0e181400bb
Tabrez, Ali R.
88fb298e-5cca-4d51-a040-692af62cbe49
Clift, Peter D.
24c0646e-f897-45ad-bd50-817eb88fea41
Giosan, Liviu
46802e93-8a58-4660-b2d3-fdd5dfe100b8
Henstock, Timothy J.
27c450a4-3e6b-41f8-97f9-4e0e181400bb
Tabrez, Ali R.
88fb298e-5cca-4d51-a040-692af62cbe49

Clift, Peter D., Giosan, Liviu, Henstock, Timothy J. and Tabrez, Ali R. (2014) Sediment storage and reworking on the shelf and in the Canyon of the Indus River-Fan System since the last glacial maximum. Basin Research, 26 (1), 183-202. (doi:10.1111/bre.12041).

Record type: Article

Abstract

The transport of sediment from the mouth of the Indus River on to the deep-water submarine fan is complicated by temporary storage within large clinoforms on the shelf on either side of the submarine canyon, where most of the sedimentation since the start of the Holocene has occurred. In contrast, shelf edge clinoform deltas represent the products of forced regression and not the progradation of highstand clinoforms as far as the shelf edge. Clinoform sediments have a mixed provenance that involves significant reworking of older sediment deposited during or before the last glacial maximum. Recent sedimentation in the canyon head has been very rapid in the last few centuries (ca. 10 cm yearÀ1), but has been starved of sand probably because of 20th century damming. Sandy layers appear to represent annual monsoonal floods with a particularly large flood every 50–70 years. This canyon head sediment is also reworked by currents flowing along the canyon axis before being deposited deeper into the canyon. The last sandy sediment to reach the mid-canyon (ca. 1300 m depth) was transported around 7000 year BP at a time of rising sea-levels, and might reflect reworking by the transgression, or local slumping from the walls of the canyon. Dating of the uppermost in a series of terraces in the mid-canyon area suggests that the canyon may have been partly filled and emptied of sediment at least three times since ca. 50 ka. We conclude from the Holocene record that sediment flux to the deep-water fan experiences major buffering, reworking and recycling both on the shelf and within the submarine canyon prior to its deposition, so that turbidite sands in the deep Arabian Sea cannot be used to correlate with climatic or tectonic events onshore over timescales of 103–105 years.

Full text not available from this repository.

More information

Submitted date: 15 January 2013
Accepted/In Press date: 5 August 2013
e-pub ahead of print date: 17 January 2014
Published date: 17 February 2014
Organisations: Geology & Geophysics, Ocean and Earth Science

Identifiers

Local EPrints ID: 361416
URI: http://eprints.soton.ac.uk/id/eprint/361416
ISSN: 0950-091X
PURE UUID: 9da86c85-f23f-4469-8960-91d97be1cf43
ORCID for Timothy J. Henstock: ORCID iD orcid.org/0000-0002-2132-2514

Catalogue record

Date deposited: 20 Jan 2014 14:00
Last modified: 12 Nov 2019 01:53

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