Distribution and origin of magnetite spherules in air, waters, and sediments of the greater New York City area and the North Atlantic Ocean.

Perfectly spherical sand to clay size particles composed of magnetite occur in a wide variety of environments, with the abundance decreasing away from industrial centers. The abundance of magnetite spherules in core samples of lake and marsh sediment decreases sharply near the palynologically determined stratigraphic boundary separating sediments deposited before the area was settled and industrialized from sediments deposited afterward. Their abundance in samples of deep ocean-floor sediment also drops off sharply within the upper 10cm of core. We conclude that the great majority of magnetic spherules presently accumulating in sediments are of industrial origin, while we recognize the existence of spherules of probable extraterrestrial origin in ancient sediments. -from Authors