ABSTRACT This field trip is designed to highlight recent findings in regard to the tectonic history of the southern Death Valley region. During the first day, stops will take place in the Ibex Hills and adjacent Ibex Pass area. These stops were chosen to emphasize recent work that supports multiple phases of extension in the region, and is recorded by the interactions of complexly overprinted normal faults. Mapping of the Ibex Hills revealed an older set of normal faults that have a down-to-the-SW sense of movement and are cross-cut by down-to-the-NW style normal faults. Additionally, the Ibex Pass basin poses a number of questions regarding its stratigraphy and how it relates to the timing and kinematics of the region. Multiple stops within the basin will show the variation of volcanic and sedimentary units across Ibex Pass. The second day of the field trip is focused more so on the more recent transtensional and strike-slip history of southern Death Valley. In particular, recent mapping has correlated features in the Avawatz and Owlshead Mountains that indicate ~40k m of offset along the Southern Death Valley Fault Zone (SDVFZ). Stops will take place along traces of the SDVFZ in the Avawatz Mountains and the Noble Hills. The final stop of the trip is in the Mormon Point turtleback, where the implications of the SDVFZ offset are discussed, alongside the metamorphic rocks at the stop, suggesting the restoration of the Panamint Range partially atop the Black Mountains.

Pleistocene deposits in Panamint Valley, California, document the changes in pluvial lake level, source water, and elevation of the regional groundwater table associated with climate change. The oxygen isotope stage (OIS) 2 and 6 lacustrine record is well preserved in surficial deposits, whereas the OIS 3–5 lacustrine-paludal and lacustrine record is mainly derived from an archived core sample. Amino acid racemization ratios in ostracodes and gastropods suggest that the shoreline and groundwater-discharge features that lie between ∼600 and 550 m elevation formed during one highstand, probably during OIS 6. A fossiliferous part of the ∼100-m-deep core DH-1, which was drilled in the Ballarat Basin during the late 1950s, was resampled in this study. Comparison of DH-1 with core DH-3 from Panamint Valley and core OL-92 from Owens Lake suggests the 34–78-m-depth interval of DH-1 may span all or much of OIS 4. The microfauna from this depth interval indicate a saline marsh or shallow lacustrine environment, but not a large lake. The ostracode assemblage requires low ratios of alkalinity to calcium (alk/Ca) water likely indicative of solutes in deep regional groundwater sources rather than the high alk/Ca solutes common to the Owens River system. OIS 2–aged sediment from surficial deposits, a shallow auger hole, and core DH-1 contain faunas, including the ostracode Limnocythere sappaensis , which require the high alk/Ca evolved solutes common to the Owens River. The elevation of the lacustrine sediments further indicates a moderate-sized saline lake around 180–200 m depth. In the northern Lake Hill basin, a saline lake persisted until at least 16 ka, and it was succeeded by fresh, groundwater-supported wetlands, which were fully developed by ca. 12,575 14 C yr B.P. and which persisted until around 10,500 14 C yr B.P., when the basin became a dry playa.