Document Type

Article

Publication Date

2017

Abstract

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.

Publication Title

Journal of Geophysical Research: Earth Surface

Volume

122

First Page

1653

Last Page

1677

Required Publisher's Statement

doi:10.1002/2016JF004113.

©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.

Language

English

Format

application/pdf

Share

COinS