GEOLOGY: Tracking Canadian Hotspots

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Science  09 Jun 2000:
Vol. 288, Issue 5472, pp. 1705a-1705
DOI: 10.1126/science.288.5472.1705a

Hotspots are areas of stable active volcanism in the mantle. The movement of tectonic plates across these mantle hotspots leads to the formation of a volcanic chain, most notably seen in the Hawaiian Islands and Emperor Seamounts. Heaman et al. may now have helped delineate a long-lived hotspot track across North America. Recently, a large number of kimberlites—volcanic rocks derived from deep in the mantle and the source of most diamonds—have been discovered or studied in central and eastern Canada. Heamon et al. provide accurate uranium-lead dates on many of these samples and show that the ages of the fields generally increase from southeast to the northwest over about 1000 km. The oldest fields seem to be located in central Canada, on the western shore of Hudson Bay, and date to the Triassic, which is the period when the Atlantic Ocean began to open up. This magmatism and hot spot may help delineate a previously proposed hotspot track, based in part on Atlantic Ocean seamounts, known as the Great Meteor hotspot.—BH

Earth Planet. Sci. Lett. 178, 253 (2000).

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