A >200 ka U-Th Based Chronology From Lacustrine Evaporites, Searles Lake, CA
Name
Geochem Geophys Geosyst - 2023 - Stroup - A 200 ka U‐Th Based Chronology From Lacustrine Evaporites Searles Lake CA.pdf
Description
Published version
Size
2.34 MB
Format
Adobe PDF
Checksum (MD5)
db9cbd8a1a1c2755cad931284cd1eefa
Author(s)
Stroup, Justin S
Olson, Kristian J
Lowenstein, Tim K
Jost, Adam B
Mosher, Hayley M
Peaple, Mark D
Feakins, Sarah J
Chen, Christine Y
Lund, Steven P
McGee, David
Date Issued
March 2023
Journal
Geochemistry, Geophysics, Geosystems
Publisher
American Geophysical Union
Citation
Stroup, J. S., Olson, K. J., Lowenstein, T. K., Jost, A. B., Mosher, H. M., Peaple, M. D., et al. (2023). A >200 ka U-Th based chronology from lacustrine evaporites, Searles Lake, CA. Geochemistry, Geophysics, Geosystems, 24, e2022GC010685.
Version
Final published version
Abstract
Well‐dated lacustrine records are essential to establish the timing and drivers of regional hydroclimate change. Searles Basin, California, records the depositional history of a fluctuating saline‐alkaline lake in the terminal basin of the Owens River system draining the eastern Sierra Nevada. Here, we establish a U‐Th chronology for the ∼76‐m‐long SLAPP‐SLRS17 core collected in 2017 based on dating of evaporite minerals. Ninety‐eight dated samples comprising nine different minerals were evaluated based on stratigraphic, mineralogic, textural, chemical, and reproducibility criteria. After the application of these criteria, a total of 37 dated samples remained as constraints for the age model. A lack of dateable minerals between 145 and 110 ka left the age model unconstrained over the penultimate glacial termination (Termination II). We thus established a tie point between plant wax δD values in the core and a nearby speleothem δ18O record at the beginning of the Last Interglacial. We construct a Bayesian age model allowing stratigraphy to inform sedimentation rate inflections. We find that the >210 ka SLAPP‐SRLS17 record contains five major units that correspond with prior work. The new dating is broadly consistent with previous efforts but provides more precise age estimates and enables a detailed evaluation of evaporite depositional history. We also offer a substantial revision of the age of the Bottom Mud‐Mixed Layer contact, shifting it from ∼130 ka to 178 ± 3 ka. The new U‐Th chronology documents the timing of mud and salt layers and lays the foundation for climate reconstructions.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivatives
Persistent DSpace Link
DOI of Published Version
10.1029/2022gc010685
