Paper No. 9
Presentation Time: 8:00 AM-5:00 PM
GEOCHEMICAL CORRELATION OF BASALTS IN NORTHERN DEEP SPRINGS VALLEY, CALIFORNIA, BY X-RAY FLUORESCENCE SPECTROSCOPY (XRF)
In northern Deep Springs Valley (DSV), between Owens Valley and Death Valley, California, Miocene-Pliocene-age, olivine basalts lie on the valley floor and atop the adjacent White/Inyo Mountains to the west and the Deep Springs Range to the east. Previous geologic mapping shows the DSV basalt flows and the Last Chance Range (LCR) basalts found to the southeast as the same geologic unit with a source in the White/Inyo Mountains. The basalts in northern DSV are offset ~400 m by the Deep Springs fault and have a K/Ar age of 10.8 Ma. To determine if the olivine basalts found in the region are all from the same source, four samples were collected in a linear pattern from west to east across northern DSV. The samples were powdered and analyzed for major and trace element composition by X-ray Fluorescence spectrometer (XRF). Trace-element plots (e.g., Ba, Nb, Zr) show that the DSV basalts are similar and are likely one flow, however, the DSV basalts are distinct from the LCR basalts. I interpret these data to show that the DSV and LCR basalts have different sources and should not be mapped as the same geologic unit. The likely source of the DVS basalts is in the White/Inyo Range. The geochemical correlation shows that the DSV basalts flowed NW to SE in a paleochannel 10.8 Ma and that DSV did not exist at that time.