Evidence for offset of Cretaceous plutons by the Tintina fault in eastern Alaska: Implications for regional metallogeny
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Abstract
Cretaceous magmatism in eastern interior Alaska is voluminous, but temporally and spatially diverse – suggestive of varying sources and drivers. More than 150 new U-Pb zircon and more than 500 geochemical analyses of Cretaceous plutonic units allow for the grouping of distinct plutonic suites. Magmatism was continuous from 120-66 Ma but can be grouped into temporally distinct pulses from ca. 115-100 Ma, 100-90 Ma, and 75-66 Ma. Geochemical diversity occurs during each pulse, further distinguishing multiple suites. Diverse metallogenic epochs are strongly correlated to pluton chemistry. Mineralization is largely absent prior to 108 Ma. From 108-100 Ma, plutonism is coeval with sparse, but notable Au-quartz veins with variable Bi, As, W, and Mo. From 100-90 Ma, intrusion-related mineralization zones from Au-Cu(-Bi) and U-Th in the northwest to central Au- Bi-As-Te(-W), and Mo-W to the southeast. Porphyry style Cu-Mo(-Au) occurrences occur with the latest Cretaceous plutons emplaced from 75-66 Ma . Restoration of ~450 km of dextral movement on the Tintina fault and comparison of metallogenic and geochemical characteristics of Alaska plutons suggest 100-90 Ma plutons may be the continuation of the metallogenically significant Tombstone, Mayo, and Tungsten suites from the Yukon.
Suggested Citation
Kreiner, D.C., Todd, E., Jones, J.V., Holm-Denoma, C., Pianowski, L., O’Sullivan, P., 2025, Evidence for offset of Cretaceous plutons by the Tintina fault in eastern Alaska: Implications for regional metallogeny, 18th SGA Biennial Meeting, v. 1, Golden, CO, August 3-7, 2025, p. 29-32.
Study Area
| Publication type | Conference Paper |
|---|---|
| Publication Subtype | Conference Paper |
| Title | Evidence for offset of Cretaceous plutons by the Tintina fault in eastern Alaska: Implications for regional metallogeny |
| Volume | 1 |
| Year Published | 2025 |
| Language | English |
| Publisher | Society of Geology Applied to Mineral Deposits |
| Contributing office(s) | Alaska Science Center Geology Minerals |
| Description | 4 p. |
| First page | 29 |
| Last page | 32 |
| Conference Title | 18th SGA Biennial Meeting |
| Conference Location | Golden, CO |
| Conference Date | August 3-7, 2025 |
| Country | United States |
| State | Alaska |