Abstract: Tectonics, Middle Paleozoic Volcanism, and Sulfide Mineralization in North-Central Alaska Range

Wyatt G. Gilbert, Thomas K. Bundtzen

The Totatlanika Schist and correlative rocks are a metamorphosed volcanic sequence that once covered at least 5,000 sq km in the north-central Alaska Range. These rocks include metabasalt, metarhyolite, felsic schist, metatuff, and volcaniclastic metasedimentary units, and commonly overlie black phyllite, black quartzite, and stretched conglomerate of the Keevy Peak Formation. The Keevy Peak Formation and Totatlanika Schist probably represent a continental-margin ocean floor and andesitic volcanic arc which were present during Devonian-Mississippian time and which later were strongly affected by Mesozoic and early Tertiary orogenic events.

Studies of 2,000 stream-sediment and bedrock geochemical samples from the north-central Alaska Range indicate several areas of high lead, zinc, and copper concentration. This geochemical signature and the presence of sulfide-bearing units within the Totatlanika Schist and Keevy Peak Formation suggest that these units contain significant sulfide mineral deposits.

AAPG Search and Discovery Article #90966©1977 Alaska Geological Society 1977 Symposium, Anchorage, Alaska