Mountain erosion over 10 yr, 10 k.y., and 10 m.y. time scales

Citation
Jw. Kirchner et al., Mountain erosion over 10 yr, 10 k.y., and 10 m.y. time scales, GEOLOGY, 29(7), 2001, pp. 591-594
Citations number
36
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
GEOLOGY
ISSN journal
0091-7613 → ACNP
Volume
29
Issue
7
Year of publication
2001
Pages
591 - 594
Database
ISI
SICI code
0091-7613(200107)29:7<591:MEO1Y1>2.0.ZU;2-X
Abstract
We used cosmogenic Be-10 to measure erosion rates over 10 k.y. time scales at 32 Idaho mountain catchments, ranging from small experimental watersheds (0.2 km(2)) to large river basins (35 000 km(2)), These long-term sediment yields are, on average, 17 times higher than stream sediment fluxes measur ed over 10-84 yr, but are consistent with 10 m.y. erosion rates measured by apatite fission tracks. Our results imply that conventional sediment-yield measurements - even those made over decades - can greatly underestimate lo ng-term average rates of sediment delivery and thus overestimate the life s pans of engineered reservoirs. Our observations also suggest that sediment delivery from mountainous terrain is extremely episodic, sporadically subje cting mountain stream ecosystems to extensive disturbance.