Last Glacial Maximum and early deglaciation in the Stura Valley, southwestern European Alps

Adriano Ribolini* (Corresponding Author), Matteo Spagnolo, Andrew J. Cyr, Paolo Roberto Federici

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

We combined data from geomorphologic surveys, glacial modelling, and 10 12 Be exposure ages of boulders on moraines, to investigate the Last Glacial Maximum (LGM) and the early retreat glacial phases in the Stura Valley of the Maritime Alps. We used the exposure ages to reconstruct the timing of standstills or readvances which interrupted the post-LGM withdrawal, initiated ~24 ka. We mapped and dated the frontal moraines of a first glacial standstill/readvance at a short distance (~17 7 km) from the maximum external limit of the LGM, which occurred at ~22 ka, and a second one at 18 ~19 ka (Bühl stadial). This morpho-chronologic succession is congruent with that obtained in the adjacent Gesso Valley and, combined with the similarity of Equilibrium Line Altitude values, demonstrates a consistent glacial response in the Maritime Alps to climatic forcing. Our data are chronologically consistent with those of the southern flank of the European Alps, stressing not only a general synchroneity of the LGM across the various sectors, but also that of a LGM recessional standstill or readvance at ~22 ka. The short distance between the LGM moraines and the recessionary phase moraines indicates a modest variation in the mass balance of the Maritime Alps glaciers during this time interval. A similar modest variation between LGM and the first recessional phase glacier mass balance is also found throughout the western sector of the Southern Alps but is considerably more pronounced for the glaciers of the central-eastern sectors. This behaviour can be explained by the interplay between the moisture supplied by southern
currents sourced in the Western Mediterranean and that advected by the westerlies sourced in the North Atlantic, which affected the various sectors of the Southern Alps differently
Original languageEnglish
Article number107770
Number of pages17
JournalQuaternary Science Reviews
Volume295
Early online date3 Oct 2022
DOIs
Publication statusPublished - 1 Nov 2022

Bibliographical note

Acknowledgments: The fund “The termination I. The environmental and palaeoclimatic variations occurred during the 25–11 ka period” (leader A. Ribolini) supported this work (Progetti di Ricerca di Ateneo PRA, 2020–21, University of Pisa). Exposure dating was completed with the support of the National Science Foundation, Continental Dynamics Program grant EAR-0208169 (RETREAT) and by
PRIME Lab, Purdue University, West Lafayette, IN, USA. We thank Cal Ruleman and Will Odom for thorough and constructive reviews. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Data Availability Statement

Data will be made available on request.

Keywords

  • Last Glacial Maximum
  • glacial retreat
  • cosmogenic exposure ages
  • Equilibrium Line Altitude
  • Maritime Alps

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