Interior Alaska volcanic belt 

(middle Tertiary) 

(West-Central Alaska and Saint Lawrence Island, Alaska, unit mTvf)

Consists chiefly of rhyolite and dacite tuff, breccia, and flows of 37 to 44 Ma. Predominantly felsic 
composition with minor mildly alkalic basalt and andesite. Local basalt and andesite flows. For 
paleomagnetic determinations, one set of localities in the 53 Ma basalts near Fairbanks yield grade A 
results which indicate zero displacement with respect to North America (-3o+14o). The Interior Alaska 
volcanic belt is either observed or interpreted to overly the Ruby, Angayucham, Koyukuk, and adjacent 
terranes. REFERENCE: Moll Stalcup, 1990, 1994; Roe and Stone, 1993; Moll-Stalcup and others, 1994.