The age of Glacier Peak tephra in west-central Montana

Auteurs :
MEHRINGER, P. J. Jr.
SHEPPARD, J. C.
FOIT, F. F. Jr.

Description :
At Sheep Mountain Bog, near Missoula, Montana a late-glacial tephra, that probably fell in late summer, is preserved in lake deposits. Sediment surrunding the ash was 14C dated to about 11,200 yr B.P. Electron-microprobe analyses of the volcanic glass and horublende phenocrysts from this ash layer indicate that they are similar in major-element chemistry to those of Glacier Peak layer G previously considered to be about 12,000 yr old or older.


Type de document :
Article de périodique

Source :
Quaternary research New York, 1984, vol. 21, n°. 1, p. 36-41, Références bibliographiques : 15 réf.

Date :
1984