Abstract:
The geochemical features of the strata from the Upper Eocene to Lower Oligocene in the central eastern Pacific are studied by analysing the samples from the Site 573 provided by the ODP and other information in this area. The boundary layer between the Eocene and Oligocene is a layer of metalliferous claystone which is about 3.4 m thick. The metalliferous claystone is of special geological and geochemical characteristics and contains abundant Fe and Fe-group elements such as Ni, Co and Ir, which may imply that this layer was formed by an extraterrestrial impact. Microspherules (microtektites or microkrystites) are also found in the layer, especially at the bottom of the layer. These characteristics indicate that the formation of the metalliferous claystone may have some relationship with meteorite impact. According to the characteristics and composition of the strata between the Late Eocene and the Early Oligocene, the extinction of many organisms, and the distribution of microspherules, we suggest that a catastrophic event might have occurred at the end of the Eocene in the central Eastern Pacific. The catastrophic event may have been caused by a meteorite that impacted the Pacific Plate.