Wrangell volcanic field 

(middle Tertiary to Holocene) 

(Eastern-southern Alaska, unit QTvi)

Consists chiefly of andesite and lesser basaltic 
andesite shield volcanoes, satellitic cones, and 
andesite and lesser dacite flows, tuff, breccia, 
volcanic-avalanche deposits, mudflows, and 
domes of 0 to 20 Ma age. Volcanic field includes 
major shield volcanoes at Mount Wrangell, 
Capital Mountain, Mount Sanford, and Tanada 
Peak, and a composite stratocone at Mount 
Drum. Volcanic field also includes lesser 
rhyolite and rhyodacite flows and domes, and 
basalt and basaltic andesite cinder cones, and 
associated flows and dikes. Pyroclastic rocks are 
mainly lithic and crystal tuff with lesser 
agglomerate and ash. Field displays 
predominantly calc-alkalic compositional trend. 
Local associated shallow andesite plutons, dikes, 
dike swarms, and plugs. Coeval with volcanic 
part of Aleutian arc to west. Field overlies 
mainly the Wrangellia superterrane in eastern-
southern Alaska. Locally extensively 
interlayered with Quaternary and Holocene 
glacial deposits. REFERENCES: Richter, 1976; 
MacKevett, 1978; Richter and others, 1989; 
Miller and Richter, 1994.