Mid-Pleistocene cosmogenic minimum-age limits for pre-Wisconsinan glacial surfaces in southwestern Minnesota and southern Baffin Island : a multiple nuclide approach

Cosmogenic isotopes in geomorphology

Auteurs :
BIERMAN, P.R.
MARSELLA, K.A.
PATTERSON, C.
THOMPSON DAVIS, P.
CAFFEE, M.
HARBOR, J.

Description :
Paired 10Be and 26Al analyses indicate that pre-Wisconsinan, glaciated bedrock surfaces near the northern (Baffin Island) and southern (Minnesota) paleo-margins of the Laurentide Ice Sheet have long and complex histories of cosmic-ray exposure, including significant periods of partial or complete shielding from cosmic rays. The data demonstrate that exposure ages and erosion rates calculated from single nuclides can underestimate surface stability dramatically because any intermittent burial, and the resultant lowering of nuclide production rates and nuclides abundances, will remain undetected.


Type de document :
Article de monographie

Source :
Geomorphology (Amsterdam), issn : 0169-555X, 1999, vol. 27, n°. 1-2, p. 25-39, Collation : Illustration, Références bibliographiques : 31 ref.

Date :
1999

Editeur :
Pays édition : Pays-Bas, Amsterdam, Elsevier