Document Type

Article

Publication Date

9-2019

Department

Earth Sciences

Language

English

Publication Title

Science Advances

Abstract

Weathering in the critical zone causes volumetric strain and mass loss, thereby creating subsurface porosity that is vital to overlying ecosystems. We used geochemical and geophysical measurements to quantify the relative importance of volumetric strain and mass loss---the physical and chemical components of porosity---in weathering of granitic saprolite of the southern Sierra Nevada, California, USA. Porosity and strain decrease with depth and imply that saprolite more than doubles in volume during exhumation to the surface by erosion. Chemical depletion is relatively uniform, indicating that changes in porosity are dominated by processes that cause strain with little mass loss. Strain-induced porosity production at our site may arise from root wedging, biotite weathering, frost cracking, and the opening of fractures under ambient topographic stresses. Our analysis challenges the conventional view that volumetric strain can be assumed to be negligible as a porosity-producing mechanism in saprolite.

Comments

This published version is made available on Dickinson Scholar with the permission of the publisher. For more information on the published version, visit American Association for the Advancement of Science's Website.

© 2019 American Association for the Advancement of Science. All rights reserved.

This publication is made available under the CC-BY-NC 4.0 license: https://creativecommons.org/licenses/by-nc/4.0/

Open access publication of this article was made possible with grant support from Waidner-Spahr Library distributed through the Dickinson College Research & Development Committee.

DOI

10.1126/sciadv.aao0834

COinS