Alaska Range-Talkeetna Mountains volcanic-plutonic belt 

(Late Cretaceous and early Tertiary) 

(Southern Alaska, units TKvi, TKpi, TKps)

Occurs in an elongate, northwest-trending arc for several hundred kilometers, mainly south of Denali fault. 
Consists chiefly large and small volcanic fields composed of rhyolite, dacite, and andesite flows, 
pyroclastic rocks, and interlayered basalt and andesite flows. Volcanic rocks yield 50 to 75 Ma ages and 
calc-alkalic compositional trends (Moll-Stalcup, 1990, 1994). Belt also contains numerous related diorite, 
quartz diorite, granodiorite, and granite and locally monzonite and syenite plutons. Belt is partly coeval 
with Kuskokwim Mountains sedimentary, volcanic, and plutonic belt (unit km) to north in interior Alaska. 
Alaska Range-Talkeetna Mountains volcanic-plutonic belt forms part of Kluane arc of Plafker and others 
(1989b), and is correlated with Coast-North Cascade plutonic belt (unit cn) in east-central Alaska and the 
Canadian Cordillera. The Alaska Range-Talkeetna Mountains belt overlies the Dillinger, Peninsular, and 
adjacent terranes, and the Kahiltna assemblage. For paleomagnetic determinations, three different 
sequences of extrusive volcanic rocks yield grade A results, and one yields grade C results. The ages of 
sampled units range from Paleocene to Eocene. The grade C results and one grade A result indicate no 
displacement for 42 and 60 Ma rocks, respectively. The other two localities, also 40 and 60 Ma, yield small 
northward displacements with respect to North America. REFERENCES: Hillhouse and Gromme, 1982; 
Hudson, 1983; Hillhouse and others, 1985; Panuska and Macicak, 1986; Stamatakos and others, 1988; 
Panuska and others, 1990; Moll-Stalcup, 1994; Moll-Stalcup and others, 1990, 1994; Plafker and others, 
1989b