Reconnaissance mapping on St. Lawrence Island, Alaska has revealed seven epizonal granitic plutons of mid-Cretaceous age with a combined outcrop area of about 350 square miles. The plutonic rocks are dominantly quartz monzonite, but include minor amounts of granodiorite, monzonite, syenite, syenodiorite, and alaskite. The plutons are structurally and petrologically similar to and about the same age as plutons on the Chukotsky Peninsula, U.S.S.R. and in western Alaska. They suggest tectonic continuity between Siberia and Alaska since at least Cretaceous time. Several mineralized areas containing molybdenum, copper, lead, and zinc sulfides are associated with the plutonic bodies in the western part of the island.

Alaska↗

USGS1970

Analyses of stream-sediment samples from western St. Lawrence Island, Alaska

Analytical data for 207 stream-sediment samples from western St. Lawrence Island are presented in this report, together with a statistical treatment of the data. The samples were collected in 1968 and 1969 as part of the Heavy Metals Program of the U.S. Geological Survey. This report is intended to supplement Geological Survey open-file report entitled "Preliminary geologic investigations of western St. Lawrence Island, Alaska" (Patton and Csejtey, 1970) which describes the general geology of the area and discusses several localities where anomalous amounts of metals were found.

Alaska↗

USGS1970

Preliminary geologic investigations of western St. Lawrence Island, Alaska

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Open-File Report↗