The Portage Lake Volcanics (Middle Keweenawan) on Isle Royale, Michigan
Huber NK. 1973. The Portage Lake Volcanics (Middle Keweenawan) on Isle Royale, Michigan. U.S. Geological Survey (USGS) Professional Paper. U.S. Geological Survey. Washington, D.C.
Presents detailed description of the volcanic rock sequence on Isle Royale. On Isle Royale, the Portage Lake Volcanics formations consists of more than 10,000 feet of basaltic and andesitic lava flows with interbedded pyroclastic rocks and fluvially deposited sedimentary rocks. Twelve stratigraphic flow units have been distinguished and named on Isle Roale. Correlation between the Portage Lake Volcanics on Isle Royale and the type area some 50 miles southeast on the Keweenaw Peninsula on the opposite side of the Lake Superior is excellent, and at least one individual lava flow is interpreted as being continuous across the basin.
- Type
- Published Report
- Authors
- Huber, Norman
- Date of Issue
- 1973
- Publisher
- U.S. Geological Survey
- Units
- HIST , ISRO
- Keywords
- ehistory, Geology, Lava Flows, Physical Sciences, Volcanism