Rates of erosion over time provide a valuable tool for gauging tectonic and climatic drivers of landscape evolution. Here we measure 10Be archived in quartz sediment from the Fish Creek-Vallecito basin to resolve a time series of catchment-averaged erosion rates and to test the hypothesis that aridity and increased climate variation after approximately 3 Ma led to an increase in erosion rates in this semiarid, ice-free setting. The Fish Creek-Vallecito basin, located east of the Peninsular Ranges in Southern California, is an ideal setting to derive a Plio-Pleistocene paleoerosion rate record. The basin has a rapid sediment accumulation rate, a detailed magnetostratigraphic age record, and its stratigraphy has been exposed through recent, rapid uplift and erosion. A well-deﬁned source region of uniform lithology and low erosion rate provides a high, reproducible 10Be signal. We ﬁnd that paleoerosion rates were remarkably consistent between 1 and 4 Ma, averaging 38 ± 24 m/Myr (2σ). Modern catchment-averaged erosion rates are similar to the paleoerosion rates. The uniformity of erosion over the past 4 Myr indicates that the landscape was not signiﬁcantly aﬀected by late Pliocene global climate change, nor was it aﬀected by a local long-term increase in aridity.
Journal of Geophysical Research: Earth Surface
Required Publisher's Statement
©2017. American Geophysical Union.
AGU allows authors to deposit their journal articles if the version is the final published citable version of record, the AGU copyright statement is clearly visible on the posting, and the posting is made 6 months after official publication by the AGU.
Oskin,M.E.,N.E.Longinotti,T. C. Peryam, R. J. Dorsey, C. J. DeBoer,B. A. Housen, and K. D. Blisniuk (2017),Steady10Be-derived paleoerosionrates across the Plio-Pleistoceneclimate transition, Fish Creek-Vallecitobasin, California, J. Geophys.Res. Earth Surf., 122, 1653–1677,doi:10.1002/2016JF004113.
Subjects - Topical (LCSH)
Sedimentation and deposition--California--Salton Trough--Measurement; Pliocene-Pleistocene boundary
Salton Trough (Calif.)
Supporting Information S1
jgrf20742-sup-0002-supplementary.txt (6 kB)
jgrf20742-sup-0003-supplementary.xlsx (21 kB)
jgrf20742-sup-0004-supplementary.txt (1 kB)
Data Set S1
jgrf20742-sup-0005-supplementary.txt (2 kB)
Data Set S2