Temperatures recorded by cosmogenic noble gases since the last glacial maximum in the Maritime Alps

Tremblay, M. M. , Shuster, D. L., Spagnolo, M., Renssen, H. and Ribolini, A. (2019) Temperatures recorded by cosmogenic noble gases since the last glacial maximum in the Maritime Alps. Quaternary Research, 91(2), pp. 829-847. (doi: 10.1017/qua.2018.109)

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 3He in quartz from boulders in nested moraines in the Gesso Valley, Italy. Paired with cosmogenic 10Be measurements and 3He diffusion experiments on quartz from the same boulders, the cosmogenic 3He 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.

• Item Type: Articles
• Additional Information: MMT and DLS acknowledge support from the National Science Foundation (NSF) Petrology and Geochemistry Program (EAR- -1322086 to DLS), the UC Berkeley Larsen Grant, and the Ann and Gordon Getty Foundation. MMT was supported by an NSF Graduate Research Fellowship. MS acknowledges support from the Royal Society (IE150603), the Leverhulme Trust (IAF-2016-001), and NERC (CIAF 9092.1010). AR acknowledges support from the University of Pisa fund PRA (2017).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Tremblay, Dr Marissa
• Authors: Tremblay, M. M., Shuster, D. L., Spagnolo, M., Renssen, H., and Ribolini, A.
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences; College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Quaternary Research
• Publisher: Cambridge University Press
• ISSN: 0033-5894
• ISSN (Online): 1096-0287
• Published Online: 11 December 2018
• Copyright Holders: Copyright © 2018 University of Washington
• First Published: First published in Quaternary Research 91(2):829-847
• Publisher Policy: Reproduced in accordance with the publisher copyright policy