Abstract

Five types of spherule were found in Quaternary sediments from the Canada Abyssal Plain. They include: type A spherules composed of magnetite and hematite surrounding metallic iron cores, exsolution blebs, or veinlets (Ni, Fe, Co); type B, of nearly pure homogeneous magnetite; type C, displaying intergrowths of magnetite and hematite and containing minor Ti (< 1%); type D, composed predominantly of magnetite with significant amounts of Ti (up to 4.8%); and type E, consisting of ilmenite and rutile with Ti, Si, Fe, Mn, Al, K, and Mg as major elements and Cr, Ca, and Na as minor elements. Ni and Co were detected only in a small metallic veinlet (with Fe) surrounded by magnetite containing significant amounts of Ti.Three possible sources are considered: industrial, volcanic, and extraterrestrial. Industrial input is unlikely in view of the great distances to possible sources and the relatively large size of the particles. The high Ti content of most of the spherules suggests a volcanic origin. The five type B spherules are the only possible candidates for a cosmic origin.

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