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Overview

Location of the Lake Superior portion of the Midcontinent Rift, showing significant orebodies and prospects that are the focus of this study. Image courtesy of Dean Peterson, Duluth Metals.
Location of the Lake Superior portion of the Midcontinent Rift, showing significant orebodies and prospects that are the focus of this study. Image courtesy of Dean Peterson, Duluth Metals.

The North American Midcontinent Rift System is a major metallogenic feature that contains

  1. High-grade nickel-copper-platinum group elements mineralization such as the Eagle mine (Michigan) and the Tamarack prospect (Minnesota)
  2. Lower-grade, large tonnage disseminated nickel-copper-platinum group elements prospects in gabbroic to troctolitic sheet-like intrusions of the Duluth complex
  3. Native copper deposits of the Keweenaw peninsula, which produced 5 Mt Cu between 1845 and 1968, and were the most important source of copper for the United States until metallurgical advances allowed the development of porphyry copper deposits
  4. Sediment-hosted copper mineralization, such as the White Pine and Copperwood deposits, which together contain more than 2.5 Mt copper and more than 1,600 t silver.

Researchers will study the sediment-hosted copper deposits of the Midcontinent Rift, with a focus on:

  • Mineralogy and geochemistry of sediment-hosted copper mineralization
  • Hydrothermal alteration that may provide vectors towards sediment-hosted copper deposits

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Project Activities

Task 1: Ore mineralogy and genesis of sediment-hosted copper deposits

White Pine is the largest sediment-hosted copper deposit in North America, and the nearby Copperwood deposit also contains significant copper resources. Globally, sediment-hosted copper deposits contain significant resources of cobalt and platinum group elements, and White Pine contains significant silver. We will use modern analytical methods to evaluate the chemistry of the ore minerals of these deposits.

Task 2: Alteration accompanying mobilization and transport of metals to sediment-hosted copper deposits

Use whole rock geochemistry and petrography to test for alteration within the aquifer and (or) source rocks, by fluids that mobilized and transported copper to the White Pine and Copperwood deposits.

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