Bowers Ridge volcanic belt 

(early Tertiary?) 

(Bering Sea, unit Czv)

Consists chiefly of intermediate composition volcanic rocks, mainly altered andesite, breccia, 
volcaniclastic sedimentary rocks, and lesser diatomaceous siltstone. Sparse dredge samples and DSDP 
drilling suggest a Miocene age for the volcanic rocks. A trench filled with as much as 12 km of 
sedimentary rocks is located at the base of the northern and eastern slopes of Bowers Ridge suggesting that 
the unit formed in an early Tertiary arc-trench system that faced toward the northeast. REFERENCES: 
Cooper and others, 1992; Scholl and others, 1992