Iridium abundance patterns across bio-event horizons in the fossil record
Published:January 01, 1990
C. J. Orth, M. Attrep, Jr., L. R. Quintana, 1990. "Iridium abundance patterns across bio-event horizons in the fossil record", Global Catastrophes in Earth History; An Interdisciplinary Conference on Impacts, Volcanism, and Mass Mortality, Virgil L. Sharpton, Peter D. Ward
Download citation file:
Geochemical measurements have been performed on about 8,000 rock samples collected across bio-event horizons using instrumental neutron activation analysis (INAA) for about 40 major, minor, and trace elements and radiochemical isolation procedures for Ir. On selected samples, Os, Pt, and Au were also radiochemically determined. These studies, some previously reported, have encompassed the time interval from the Precambrian-Cambrian transition to the late Eocene impact (microspherule) horizons. Our early work strengthened the Alvarez impact hypothesis by finding the Ir (platinum group element [PGE]) anomaly at the K/T boundary in continental sedimentary sequences. In collaborations with paleontologists we discovered weak to moderately...