Geophysical imaging reveals topographic stress control of bedrock weathering.

Published

Journal Article

Bedrock fracture systems facilitate weathering, allowing fresh mineral surfaces to interact with corrosive waters and biota from Earth's surface, while simultaneously promoting drainage of chemically equilibrated fluids. We show that topographic perturbations to regional stress fields explain bedrock fracture distributions, as revealed by seismic velocity and electrical resistivity surveys from three landscapes. The base of the fracture-rich zone mirrors surface topography where the ratio of horizontal compressive tectonic stresses to near-surface gravitational stresses is relatively large, and it parallels the surface topography where the ratio is relatively small. Three-dimensional stress calculations predict these results, suggesting that tectonic stresses interact with topography to influence bedrock disaggregation, groundwater flow, chemical weathering, and the depth of the "critical zone" in which many biogeochemical processes occur.

Full Text

Duke Authors

Cited Authors

  • St Clair, J; Moon, S; Holbrook, WS; Perron, JT; Riebe, CS; Martel, SJ; Carr, B; Harman, C; Singha, K; Richter, DD

Published Date

  • October 2015

Published In

Volume / Issue

  • 350 / 6260

Start / End Page

  • 534 - 538

PubMed ID

  • 26516279

Pubmed Central ID

  • 26516279

Electronic International Standard Serial Number (EISSN)

  • 1095-9203

International Standard Serial Number (ISSN)

  • 0036-8075

Digital Object Identifier (DOI)

  • 10.1126/science.aab2210

Language

  • eng