GEOCHEMICAL SIGNATURE OF THE PERMIAN-TRIASSIC TRANSITIONAL ENVIRONMENT, PINE FOREST RANGE, NEVADA

The history of Earth has been shaped by a handful of mass extinction events that have dramatically shifted the course of life on this planet. The most severe of these occurred approximately 250 million years ago at the end of the Paleozoic era. The transition during the Permian-Triassic (P-Tr) interval saw devastation on a global scale that has no equal in all of the Phanerozoic. The causes of the end-Permian extinction event remain elusive and intensely debated due to the rarity of intact and accessible P-Tr boundaries. Proposed catalysts include, but are not limited to sea level fluctuation, large-scale volcanism, and oceanic anoxia.

The accreted terranes of Northwestern Nevada contain a conformable P-Tr boundary section within the Pine Forest Range that is comparable to other localities of the same age range. Results generated by the SAIC Exploranium GR-320 Portable Gamma Ray Spectrometer (Th/U) on previously collected samples from the unnamed formation in the Pine Forest Range support hypotheses regarding the onset of global anoxic conditions during the end of the Permian. In order to explore these consistencies in more detail, the presence of certain rare earth elements (REE) will be analyzed by the use of an Inductively Coupled Plasma (ICP) mass spectrometer. (La/Ce)_N has been shown to indicate similar environmental conditions at the time of deposition and concentrations of other REE such as La, Ce, Nd, Sm, Eu, Gd, Tb, Yb, and Lu, have exhibited characteristic patterns in the rocks found in other P-Tr boundary localities. Preliminary results of this study include REE concentrations in the Pine Forest Range samples that may show similar patterns to those recorded from the same age strata found elsewhere.