Western Alaska Range Metallogeny and Tectonics

Science Center Objects

There are many different types of mineral deposits present in the Western Alaska Range: plutonic gold, porphyry copper-gold (Pebble prospect), epithermal gold, tin-silver skarns, sedimentary barite, mafic hosted nickle-platinum-group elements, uranium-thorium rare earth elements, and even a diamond prospect.

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Scientific Issue and Relevance

There are many different types of mineral deposits present in the Western Alaska Range: plutonic gold, porphyry copper-gold (Pebble prospect), epithermal gold, tin-silver skarns, sedimentary barite, mafic hosted nickle-platinum-group elements, uranium-thorium rare earth elements, and even a diamond prospect. All of these have been the targets of recent exploration efforts, but their relationships to the regional magmatic belts and stratigraphy is not known. Improved understanding of Alaska's geologic framework will help to put these mineral deposits into a regional magmatic and tectonic framework, which is the best predictor of mineral occurrence and contribute to improved assessments of undiscovered resources. The Nation will have more accurate estimates of the national mineral endowment as improvements are made concerning the distribution of these deposits, their age, and genetic processes that define the localization of the mineralizing events.

Research Activities

The project objectives were to produce an improved model of the geologic framework underpinning the Western Alaska Range in south-central Alaska. Numerous ore deposits are present in this region, and most appear to be associated with magmatic events, but the ages and types of mineral deposits in relation to their host rocks needed to be identified. We conducted detailed geologic studies to delineate the magmatic, stratigraphic, and tectonic differences that distinguish this area from adjacent geologic terranes. Field mapping, geochronology, thermochronology, geochemical analyses, and geophysical data contributed to an improved understanding of the relationship between ore deposits and tectonic architecture that is critical to an assessment of the overall mineral potential of the area. Our main tasks are below.

  • Produce a new geologic map of the western Alaska Range.
  • Metallogeny of the western Alaska Range.
  • Petrogenesis of western Alaska Range igneous rocks.
  • Geophysical framework of the western Alaska Range.
  • Exhumation, erosion, and tectonics of the western Alaska Range.
  • Framework geology for mineral assessment.