High Noble Metal Concentrations in a Late Pliocene Sediment,
CALIFORNIA UNIV LOS ANGELES
Pagination or Media Count:
A 2.3-Myr-old layer in a sediment from the Antarctic Ocean contains Ir and Au at levels comparable with those at the Cretaceous-Tertiary boundary. A sizable fraction of the noble metals is contained in vesicular, millimetre-sized polymineralic grains that closely resemble ablation debris from chondritic meteorites, and there is little doubt that the noble metals resulted from the accretion of a large extraterrestrial object. No massive extinctions or other evidence of environmental stress seem to be associated with this accretionary event.
- Physical and Dynamic Oceanography
- Geology, Geochemistry and Mineralogy