Stratigraphic variation in petrographic composition of Nanushuk Group sandstones at Slope Mountain, North Slope, Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998
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Abstract
Fluvial, deltaic, and marine sediments of the Nanushuk Group (Albian to Cenomanian), North Slope, Alaska, record Early Cretaceous orogenic events in the Brooks Range to the south. The 1,060-m section at Slope Mountain is part of the Lower Cretaceous Umiat Delta, shed from the Endicott and De Long Mountains subterranes in the central Brooks Range. These sandstones are litharenites dominated by metasedimentary lithic fragments. Subtle and previously unrecognized stratigraphic variations in composition (up-section increases in metasedimentary lithic fragments, volcanic lithic fragments, and quartz interpreted to be of metamorphic origin) reflect a combination of facies migration and changes in provenance associated with unroofing of the ancestral Brooks Range. We recognize stratigraphic variation in sandstone composition at Slope Mountain whereas previous workers have not, probably because of our use of finely subdivided point-counting categories. The source of the volcanic lithic fragments in the Nanushuk Group remains enigmatic; the most likely candidate is a now-eroded volcanic arc, perhaps a volcanic superstructure to granitic rocks of the Ruby terrane to the south.
Study Area
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Stratigraphic variation in petrographic composition of Nanushuk Group sandstones at Slope Mountain, North Slope, Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998 |
| Series title | Professional Paper |
| Series number | 1615 |
| DOI | 10.3133/70180644 |
| Year Published | 2000 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Publisher location | Denver, CO |
| Description | 18 p. |
| Larger Work Type | Report |
| Larger Work Subtype | USGS Numbered Series |
| Larger Work Title | Geologic studies in Alaska by the U.S. Geological Survey, 1998 (Professional Paper 1615) |
| First page | 83 |
| Last page | 100 |
| Country | United States |
| State | Alaska |
| Other Geospatial | North Slope, Slope Mountain |
| Google Analytic Metrics | Metrics page |