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Published June 1996 | public
Journal Article

A ~ 24000 year period climate signal in 1.7-2.0 million year old Death Valley strata

Abstract

Continental records of Plio-Pleistocene climatic fluctuations are often confined to fragmentary, localized basins, and not easily dated. One exception is the Confidence Hills of Southern Death Valley. In this study, we present a detailed description of a Plio-Pleistocene section of interfingering alluvial fan and saltpan sediments from the Confidence Hills, southern Death Valley. This well exposed section accumulated with an average deposition rate of ∼ 25 cm/1000 yr with no bioturbation, permitting more precise paleomagnetic dating than in oceanic records [1]. We interpret the sequence of facies changes in the Olduvai Normal Polarity Zone of the Confidence Hills to represent alternations between wetter and drier regional climatic regimes. The frequency of this variation (∼ 24 000 yr) appears to correspond to the Milankovitch precessional cycle (23 000 yr). We believe this section records a Milankovitch-driven climatic variation in the Death Valley basin annual precipitation about 1.7–2.0 Ma. This is the first report of the precessional cycle in continental sediments of this age in the United States.

Additional Information

© 1996 Elsevier Science B.V. The authors would first like to thank John Holt and Joe Kirschvink for assistance in the field and Brian Stewart for the Sr isotope analyses of the anhydrite from Confidence Hills. We would also like to thank David Evans and Nathan Niemi for helpful suggestions regarding tectonic forcings. We thank John Holt, Brian Stewart, Elizabeth Nagy, and Oliver Chadwick for reviews on early version of the manuscript. We also thank G.I. Smith, S. Clemens, and an anonymous reviewer for critical review of the manuscript. This work was partially supported by NSF Grant EAR-9019289 to Joe Kirschvink and internal funding from the Division of Geological and Planetary Sciences at Caltech. Jean Hsieh was in part supported by a Natural Sciences and Engineering Research Council of Canada graduate student scholarship. This is contribution 5676 of the Division of Geological and Planetary Sciences, California Institute of Technology. [MK]

Additional details

Created:
August 22, 2023
Modified:
October 26, 2023