In:
Quaternary Research, Cambridge University Press (CUP), Vol. 91, No. 2 ( 2019-03), p. 829-847
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 cosmogenic 10 Be measurements and 3 He diffusion experiments on quartz from the same boulders, the cosmogenic 3 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.
Type of Medium:
Online Resource
ISSN:
0033-5894
,
1096-0287
DOI:
10.1017/qua.2018.109
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
2019
detail.hit.zdb_id:
1471589-2
detail.hit.zdb_id:
205711-6
SSG:
13
SSG:
14
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