Independent evaluation of conflicting microspherule results from different investigations of the Younger Dryas impact hypothesis.

ABSTRACT: Firestone et al. sampled sedimentary sequences at many sites across North America, Europe, and Asia [Firestone RB, et al. (2007) Proc Natl Acad Sci USA 106:16016-16021]. In sediments dated to the Younger Dryas onset or Boundary (YDB) approximately 12,900 calendar years ago, Firestone et al. reported discovery of markers, including nanodiamonds, aciniform soot, high-temperature melt-glass, and magnetic microspherules attributed to cosmic impacts/airbursts. The microspherules were explained as either cosmic material ablation or terrestrial ejecta from a hypothesized North American impact that initiated the abrupt Younger Dryas cooling, contributed to megafaunal extinctions, and triggered human cultural shifts and population declines. A number of independent groups have confirmed the presence

SUBMITTER: LeCompte MA 

PROVIDER: S-EPMC3497834 | biostudies-literature | 2012 Oct

REPOSITORIES: biostudies-literature