Proxy evidence for easterly winds in glacial Lake Algonquin, from the Black River Delta in Northern Lower Michigan

Auteur(s) et Affiliation(s)



Description :
The AA. examined a large, Late Pleistocene delta in northern Lower Michigan, formed by the Black River in Glacial Lake Algonquin. Their subsurface data, taken at 153 sites across the delta, show trends in sediment texture across the delta surface. Gravel and very coarse sands are concentrated near the shoreline, presumably eroded by waves from the till and bedrock that crop out there. Sediments of very fine sand size exist in higher concentrations near the eastern shore, sourced from eroded tills and also carried there on longshore currents. A clear sediment plume of medium and finer sands also traverses the delta SE to NW, which is interpreted as evidence of sand transport by longshore currents flowing east to west, driven by easterly winds. High, perched spits on the head of the delta also suggest westerly longshore drift. These paleoclimate proxy data support previous interpretations of strong easterly winds here during the Late Pleistocene, probably in association with a glacial anticyclone.


Type de document :
Article de périodique

Source :
Physical geography, issn : 0272-3646, 2012, vol. 33, n°. 3, p. 252-268, nombre de pages : 17, Références bibliographiques : 2 p.

Date :
2012

Editeur :
Pays édition : Royaume-Uni, Abingdon, Taylor and Francis