| dc.description.abstract | I present a precisely dated, high-resolution stable isotope (δ13C and δ18O) and trace element (Mg/Ca, Ba/Ca, Sr/Ca, Zn/Ca) record of mid-Holocene hydroclimate variability using a speleothem (WMC5) from White Moon Cave (WMC) in central California. Geochemical analyses of WMC5, which grew from ~8,000–5,900 cal. years BP, reveal a multi-centennial baseline drying trend from ~6400–5,900 cal. years BP. This trend is indicated by more positive δ¹³C and increases in Mg/Ca, Ba/Ca, and Sr/Ca, along with a decrease in Zn/Ca, suggesting the potential regional onset of the mid-Holocene Warm Period (MHWP), a globally expressed yet asynchronous event. Comparison with previously published stable isotope and trace element data from another WMC speleothem (WMC1) demonstrate that WMC5 proxies exhibit a positive offset and higher range of variability. These offsets, alongside weak correlations between WMC5 and WMC1 δ¹³C and δ¹⁸O during coeval growth, suggest complex controls on WMC proxies. Statistical comparison of WMC5 proxy records with coeval paleoclimate records from the western US reveals strong positive and moderate negative correlations with Nevada and Oregon speleothem proxy records, respectively; though, statistical comparison is constrained by the WMC5 record’s comparatively higher temporal resolution. Visual comparison shows that mid-Holocene drying at WMC ~6,400 cal. years BP overlaps warming and drying trends in coeval western US paleoclimate records and wetter conditions in a Pacific Northwest record. Future work extending WMC1 proxy record temporal coverage and resolution will elucidate regional hydroclimate volatility, variable hydroclimate expressions in WMC speleothems, and spatio-temporal dynamics of the MHWP as recorded at WMC. | |
