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Terrestrial source to deep-sea sink sediment budgets at high and low sea levels; insights from tectonically active Southern California

Jacob A. Covault, Brian W. Romans, Stephan A. Graham, Andrea Fildani and George E. Hilley
Terrestrial source to deep-sea sink sediment budgets at high and low sea levels; insights from tectonically active Southern California
Geology (Boulder) (July 2011) 39 (7): 619-622

Abstract

Sediment routing from terrestrial source areas to the deep sea influences landscapes and seascapes and supply and filling of sedimentary basins. However, a comprehensive assessment of land-to-deep-sea sediment budgets over millennia with significant climate change is lacking. We provide source to sink sediment budgets using cosmogenic radionuclide-derived terrestrial denudation rates and submarine-fan deposition rates through sea-level fluctuations since oxygen isotope stage 3 (younger than 40 ka) in tectonically active, spatially restricted sediment-routing systems of Southern California. We show that source-area denudation and deep-sea deposition are balanced during a period of generally falling and low sea level (40-13 ka), but that deep-sea deposition exceeds terrestrial denudation during the subsequent period of rising and high sea level (younger than 13 ka). This additional supply of sediment is likely owed to enhanced dispersal of sediment across the shelf caused by seacliff erosion during postglacial shoreline transgression and initiation of submarine mass wasting. During periods of both low and high sea level, land and deep-sea sediment fluxes do not show orders of magnitude imbalances that might be expected in the wake of major sea-level changes. Thus, sediment-routing processes in a globally significant class of small, tectonically active systems might be fundamentally different from those of larger systems that drain entire orogens, in which sediment storage in coastal plains and wide continental shelves can exceed millions of years. Furthermore, in such small systems, depositional changes offshore can reflect onshore changes when viewed over time scales of several thousand years to more than 10 k.y.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 39
Serial Issue: 7
Title: Terrestrial source to deep-sea sink sediment budgets at high and low sea levels; insights from tectonically active Southern California
Affiliation: U. S. Geological Survey, Reston, VA, United States
Pages: 619-622
Published: 201107
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 20
Accession Number: 2011-064692
Categories: Sedimentary petrologyStructural geology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2011199
Illustration Description: illus. incl. sketch map
N32°00'00" - N34°00'00", W117°45'00" - W116°40'00"
Secondary Affiliation: Chevron Energy Technology Company, USA, United StatesStanford University, USA, United States
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 the Geological Society of America, Boulder, CO, United States
Update Code: 201136
Program Name: USGSOPNon-USGS publications with USGS authors
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