Unit symbol: | Ksy |
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Age range | Cretaceous, Coniacian to Albian (113 to 86.3 Ma) |
Lithology: | Igneous - Plutonic |
Group name: | Granitic rocks of central and southeast Alaska |
Source map | Patton, W.W., Jr., Wilson, F.H., Labay, K.A., and Shew, Nora, 2009, Geologic map of the Yukon-Koyukuk basin, Alaska: U.S. Geological Survey Scientific Investigations Map SIM-2909, 26 p., 2 sheets, scale 1:500,000. |
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Symbol | Ksy |
Unit name | Syenite, monzonite, and nepheline syenite |
Description | Composed of syenite, monzonite, and subordinate quartz monzonite, monzodiorite, quartz syenite, and nepheline syenite and related mafic alkaline rocks including malignite, ijolite, shonkinite, and pyroxenite. Unit occurs in two separate Early Cretaceous plutonic belts (fig. 3, sheet 2): a western belt that can be traced from Shungnak quadrangle westward through Selawik quadrangle and southward into the Candle quadrangle and an eastern belt that extends from the northeastern part of Bettles quadrangle to southwestern part of the Nulato quadrangle. Unit is widespread in the western belt, but is confined to a single composite pluton at the northeastern end of the eastern belt |
Lithology | Igneous |
Label | Ksy |
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Description | Syenite |
Geologic age | Albian to Santonian |
Geologic setting | Intrusive |
Lithology | Form | Importance |
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Monzonite < Syenitic < Plutonic < Igneous | Pluton | Major |
Syenite < Syenitic < Plutonic < Igneous | Pluton | Major |