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Earth is (mostly) flat; apportionment of the flux of continental sediment over millennial time scales

Jane K. Willenbring, Alexandru T. Codilean and Brandon McElroy
Earth is (mostly) flat; apportionment of the flux of continental sediment over millennial time scales
Geology (Boulder) (January 2013) 41 (3): 343-346


We use a new compilation of global denudation estimates from cosmogenic nuclides to calculate the apportionment and the sum of all sediment produced on Earth by extrapolation of a statistically significant correlation between denudation rates and basin slopes to watersheds without denudation rate data. This robust relationship can explain approximately half of the variance in denudation from quartz-bearing topography drained by rivers using only mean slopes as the predictive tool and matches a similar fit for large river basins. At slopes >200 m/km, topography controls denudation rates. Controls on denudation in landscapes where average slopes are < approximately 200 m/km are unclear, but sediment production rates in these areas average approximately 45 mm/k.y., 75% of the denudation rates being >10 mm/k.y. We use global topographic data to show that the vast majority of the Earth's surface consists of these gently sloping surfaces with modest, but positive, gross denudation rates, and that these areas contribute the most sediment to the oceans. Because of the links between silicate weathering rates and denudation rates, the predominance of low sloping areas on the Earth's surface compared to areas of steep mountainous topography implies that mountain uplift contributes little to drawdown of CO (sub 2) at cosmogenic nuclide time scales of 10 (super 3) -10 (super 6) yr. The poorly understood environmental controls that set the pace of denudation for the largest portion of Earth's surface hold the key to understanding the feedbacks between erosion and climate.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 41
Serial Issue: 3
Title: Earth is (mostly) flat; apportionment of the flux of continental sediment over millennial time scales
Affiliation: University of Pennsylvania, Department of Earth and Environmental Science, Philadelphia, PA, United States
Pages: 343-346
Published: 20130104
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 22
Accession Number: 2013-014358
Categories: Geomorphology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2013091
Illustration Description: illus.
Secondary Affiliation: Deutsches GeoForschungsZentrum-Potsdam, DEU, GermanyUniversity of Wyoming, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2022, 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: 201310
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