IL TARDOGLACIALE NELLE ALPI ITALIANE E IN PIANURA PADANA. EVOLUZIONE STRATIGRAFICA, STORIA DELLA VEGETAZIONE E DEL POPOLAMENTO ANTROPICO

Abstract

C. Ravazzi, M. Peresani, R. Pini, E. Vescovi, The Late Glacial in the Italian Alps and in the Po Plain: stratigraphy, vegetation history and human peopling. (IT ISSN 0394-3356, 2007).
The palaeoenvironmental evolution and its relationship with the human peopling of the southern side of the Alps, their foreland and the Po plain during the Lateglacial, i.e. the interval following the global Last Glacial Maximum between 19 and 11.5 ka cal BP, is reconstructed on the base of high-resolution stratigraphic successions. After the major glaciers retreat from the pedemontane amphitheatres and from the great pre-alpine lakes, a collapse of the dendritic valley glaciers occurred during the first part of the Lateglacial and well before the Bølling –Allerød interstadial. Forest vegetation was limited to the foreland and the external belt of Pre-Alps, and did not enter the inner valleys, still subjected to intense paraglacial evolution. This period records the first human occurrences at the PreAlpine foothills. The onset of the Bølling–Allerød interstadial, dated 14.7 – 14.3 ka cal BP, allowed the treeline to reach 1700-1800 m a.s.l., promoted productivity in the lacustrine and palustrine systems, and peat formation commenced up to an altitude of 1800 m a.s.l.
Together with warming and reforestation, human settlements expanded in the Eastern Alps. As a consequence of the interstadial ecological modifications, the epigravettian colonization of the Pre-Alps and the Dolomites starts. Sites increase in number and differentiate in altitude and function. The second part of this interstadial is marked by the expansion of thermophilous broad-leaved trees, the peak of which coincided with the deposition of the Laacher See Tephra in Lago Piccolo di Avigliana, dated 13 or 12.9 ka cal BP, and anticipated the beginning of the Younger Dryas by about two centuries. The YD onset, therefore, appears to be synchronous in Northern Italy and Central Europe. The YD in the Po Plain was characterized by continental dry climate, close to the semiarid regime, with strong seasonal contrast. During the second half of YD, a renewed glacial activity (Egesen, Kartell, and Kromer stadials) is recorded in the high valleys. This glacial multiphase extends well into the early Holocene. At the present state, the archaeological data are still unsufficient for revealing the possible impact of the YD on the settlement dynamics.