Late Eocene microtektites and radiolarian extinctions on Barbados

Abstract

A late Eocene microtektite layer has been found in three exposed sections on Barbados, West Indies. These microtektites and associated tektite fragments are compositionally similar to the North American tektites and thus, like the Caribbean and Gulf of Mexico microtektites, may belong to the strewn field of ‘North American’ microtektites which have been found in deep-sea deposits from the Caribbean Sea, across the Pacific and into the northeastern Indian Ocean^1,2. The ‘North American’ layer has been reported to be approximately synchronous with several radiolarian extinctions^3,4 and with an anomaly in iridium concentrations^5–7, and it has been hypothesized that the microtektites, the extinctions and the iridium anomaly are all related to an asteroid impact. We report here that the radiolarian extinctions predate the microtektite layer and that the highest Ir concentrations apparently coincide with the extinctions. Thus, although the extinctions may be causally related to the Ir anomaly, the microtektites appear not to be.