spurr reported activity

Event Name : Spurr 5200 yBP

Start: 5200

Years BP Tephrochronology

Tephrafall:

Eruption Type:	Explosive
Eruption Product:	basaltic andesite
Chem	Yes
Other	mafic

Description: From Riehle (1985): "Spurr tephra deposits are mainly dark scoriae of basaltic andesite composition which are predominant only within 100 km of the cone and which are assigned to the Crater Peak vent...One group consists of 3, provisionally correlated samples which define a marker horizon about 5200 yr old in the region northeast of Spurr. The 3 samples have nearly equal proportions of clinopyroxene, orthopyrocene, and amphibole and have trace amounts of biotite."