Full Title: Petrology of the Duke Island Ultramafic Complex, Southeastern Alaska
Author: T.N. Irvine
Buy the e-book (not available in print)
Duke Island, with an area of about 60 sq. mi., is situated on the North American Pacific Coast at latitude 55 ° N. The ultramafic complex exposed on the island is the southernmost of some thirty distinctive ultramafic bodies of Early Cretaceous age distributed along the 350-mi. length of southeastern Alaska. A similar belt of corresponding bodies occurs in the Ural Mountain; there are at least two complexes of the same type in British Columbia, a possible occurrence in California, and two in Venezuela. The oldest rocks on Duke Island are clastic sedimentary and volcanic rocks of probable Late Triassic or Jurassic age. These are metamorphosed to greenschist- and amphibolite-facies grades and intruded by gabbroic and granitic rocks. The ultramafic rocks underlie two main areas totaling 9 sq. mi., and about a dozen minor areas. They are emplaced in gabbro that is intensely amphibolitized1 around their edges and permeated by highly aluminous hornblende-anorthite pegmatite derived from the ultramafic complex…
Published: 11/01/1974
ISBN Number: 0-8137-1138-X
Pages: 240
Product Category: Memoirs