1. Temperatures recorded by cosmogenic noble gases since the last glacial maximum in the Maritime Alps.
- Author
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Tremblay, Marissa M., Shuster, David L., Spagnolo, Matteo, Renssen, Hans, and Ribolini, Adriano
- Subjects
LAST Glacial Maximum ,NOBLE gases ,BERYLLIUM ,GENERAL circulation model ,QUATERNARY paleoclimatology ,ALPINE regions - Abstract
While proxy records have been used to reconstruct late Quaternary climate parameters throughout the European Alps, our knowledge of deglacial climate conditions in the Maritime Alps is limited. Here, we report temperatures recorded by a new and independent geochemical technique—cosmogenic noble gas paleothermometry—in the Maritime Alps since the last glacial maximum. We measured cosmogenic
3 He in quartz from boulders in nested moraines in the Gesso Valley, Italy. Paired with cosmogenic10 Be measurements and3 He diffusion experiments on quartz from the same boulders, the cosmogenic3 He abundances record the temperatures these boulders experienced during their exposure. We calculate effective diffusion temperatures (EDTs) over the last ∼22 ka ranging from 8°C to 25°C. These EDTs, which are functionally related to, but greater than, mean ambient temperatures, are consistent with temperatures inferred from other proxies in nearby Alpine regions and those predicted by a transient general circulation model. In detail, however, we also find different EDTs for boulders from the same moraines, thus limiting our ability to interpret these temperatures. We explore possible causes for these intra-moraine discrepancies, including variations in radiative heating, our treatment of complex helium diffusion, uncertainties in our grain size analyses, and unaccounted-for erosion or cosmogenic inheritance. [ABSTRACT FROM AUTHOR]- Published
- 2019
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