Metallogeny of the Northeastern Pacific Rim: An Example of the Distribution of Ore Deposits Along a Growing Continental Margin

摘要

The distribution of mineral deposits within northwestern North America (Alaska, Yukon, and northern British Columbia) allows for an in-depth examinationof the metallogenic patterns of a growing continental margin. A more complete understanding of the tectonic evolution of this part of the Pacific Rim. achieved over the last 15 to 20 years, now allows for the placement of ore systems into a well-defined plate tectonic framework Ore deposits older than about 185 Ma represetn hydrothermal systems that were active in the platform/shelf environment of ancestral North America's miogeocline or hydrothermal systems developed in oceanic arcs and continental fragments fragments more distal to the craton. These include important SEDEX, VMS, and pre-accretionary porphyry deposits. In contrast, most mineral deposits younger than about 185 Ma were fomed within the growing Cordilleran orogen, as terranes were accreted to the continental margin during interactions between the North America and Pacific/Farallon/Kula plates. Such syn-to post-accretionary mineralised sytems include many large load gold and porphyry/skarn systems.