The driving force behind Quaternary glacial-interglacial cycles and much associated climate change is widely considered to be orbital forcing. However, previous versions of the iconic Devils Hole (Nevada) subaqueous calcite record exhibit shifts to interglacial values ∼10,000 years before orbitally forced ice age terminations, and interglacial durations ∼10,000 years longer than other estimates. Our measurements from Devils Hole 2 replicate virtually all aspects of the past 204,000 years of earlier records, except for the timing during terminations, and they lower the age of the record near Termination II by ∼8000 years, removing both ∼10,000-year anomalies. The shift to interglacial values now broadly coincides with the rise in boreal summer insolation, the marine termination, and the rise in atmospheric CO2, which is consistent with mechanisms ultimately tied to orbital forcing.
Bibliographical noteFunding Information:
This work was supported by the Austrian Science Fund (FWF) project no. FP263050 to C.S. and in part by NSF grants 1103403 to R.L.E. and H.C., 1103320 to R.L.E., and NSFC grant 41230524 to H.C. This research was conducted under research permit numbers DEVA-2010-SCI-0004 and DEVA-2015-SCI-0006 issued by Death Valley National Park. We thank I. J. Winograd for providing the study with sample DH-2, M. Wimmer for preparation and measurement of the stable isotopes, K. Wilson and R. Freeze for assistance in the field, and M. Cross for discussion of Great Basin paleoclimate. Data can be downloaded from the National Oceanic and Atmospheric Administration''s National Centers for Environmental Information (www.ncdc.noaa.gov/paleo/paleo.html).