Geology of Unga Island and the northwestern part of Popof Island: Chapter 2 in A geological and geophysical study of the gold-silver vein system of Unga Island, Southwestern Alaska
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- Document: Report
- Larger Work: This publication is Chapter 2 of Geological and geophysical setting of the gold-silver vein systems of Unga Island, southwestern Alaska
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Abstract
The first geologic map of Unga Island was published by Atwood (1911; scale 1:250,000), who correctly inferred the middle Tertiary age of the volcanic rocks and made the important distinction between the lava flows and the intrusive domes. Although Burk's (1964) reconnaissance map of the Alaska Peninsula (scale 1:250,000) has been modified in some respects, it does correct Atwood's map by replacing the Kenai Formation on northwestern Unga Island with the Unga Conglomerate and by recognizing the older Stepovak Formation elsewhere on Unga and Popof Islands.
U.S. Geological Survey (USGS) field studies that were focused on the mineral-resource potential of the Alaska Peninsula began in the late 1970's. These studies led to a geologic map of the Port Moller quadrangle--including Unga Island--at 1:250,000 scale (Wilson and others, 1995), as well as summaries of mineral occurrences and geochronological studies (Wilson and others, 1988, 1994) and a formal revision of the stratigraphic units of the Alaska Peninsula (Detterman and others, 1996). As follow-up to the regional studies, a detailed study of the vein systems on Unga Island was undertaken as a collaborative effort between USGS and private industry (White and Queen, 1989). The fieldwork leading to the present report and geologic map was started in 1978 (Riehle and others, 1982) and was completed as part of the vein study. The objective was a better understanding of the geologic setting of the vein systems: the geologic history of the host rocks, the structural controls on the veins, and the types of processes that likely caused the mineralization.
Study Area
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Geology of Unga Island and the northwestern part of Popof Island: Chapter 2 in A geological and geophysical study of the gold-silver vein system of Unga Island, Southwestern Alaska |
| Series title | Open-File Report |
| Series number | 99-136 |
| Chapter | 2 |
| DOI | 10.3133/70180394 |
| Edition | Version 1.3 |
| Year Published | 1999 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Publisher location | Anchorage, AK |
| Contributing office(s) | Alaska Science Center |
| Description | 19 p. |
| Larger Work Type | Report |
| Larger Work Subtype | USGS Numbered Series |
| Larger Work Title | A geological and geophysical study of the gold-silver vein system of Unga Island, Southwestern Alaska (Open-File Report 99-136) |
| Public Comments | Originally published in a CD-ROM; the file is now available online. |
| Country | United States |
| State | Alaska |
| Other Geospatial | Alaska Peninsula, Popof Island, Unga Island |
| Google Analytic Metrics | Metrics page |