Il Quaternario: quadro cronostratigrafico e oscillazioni climatiche dall’Ultimo Massimo Glaciale (UMG/LGM) al presente

Scapozza, Cristian (2022) Il Quaternario: quadro cronostratigrafico e oscillazioni climatiche dall’Ultimo Massimo Glaciale (UMG/LGM) al presente. Bollettino della Società ticinese di Scienze naturali, 110. pp. 141-146. ISSN 0379-1254

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Abstract

In recent years, several modifications and new ratifications have affected the stratigraphic subdivision of the Quaternary, and new dates concerning the Last Glacial Maximum in the Southern Swiss Alps were published. The current reference framework for the Quaternary System / Period is then presented, in which the main palaeoclimatic events that occurred in the Southern Swiss Alps during Marine Isotope Stages MIS 2 and MIS 1 are contextualized. New cosmogenic nuclides exposure ages of erratic boulders, new radiocarbon dates and the re-calibration of those already published using the new IntCal20 calibration curve, allow to date the paroxysmal phase of the Last Glacial Maximum between 28.90 and 23.06–20.54 ka b2k, i.e. between the GI-4 interstadial and the GS-2.1c stadial of the Greenland event stratigraphy INTIMATE. The end of the Last Glacial Maximum and the beginning of deglaciation occurred between 20.54 and 19.98–19.94 ka b2k, i.e. during the Greenland Stadial GS-2.1b. Deglaciation of the upper valleys, which ended before 14.82 ka b2k, occurred during the Greenland Stadial GS-2.1a. For the Holocene, the chronology of 9 cold and 4 warm climate oscillations defined in the Alpine framework were refined, including the Holocene Thermal Maximum, which can be considered the warmest multi-secular period in the last 109 ka.

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