LE OSCILLAZIONI DEL GHIACCIAIO DEL CALDERONE (GRAN SASSO D'ITALIA, ABRUZZO - ITALIA CENTRALE) E LE VARIAZIONI CLIMATICHE DEGLI ULTIMI 3000 ANNI

Abstract

The variations of the Calderone Glacier (Gran Sasso d'Italia, Abruzzo, Central Italy) and the climatic oscillations during the last 3000
years. The age of the debris of glacial origin, lying just downvalley of the threshold of the cirque of the Calderone Glacier, has been
obtained dating interbedded soils by means of radiocarbon analysis. The datings point out four glacial expansions: the first, following
2650±60 years BP, the second bracketed between 1450±40 and 670±40 years BP, the third following 670±40 years BP, the last datable to the XIX century.
The expansions of the Calderone Glacier can be correlated to the advances of the alpine glaciers.
In order to try to date with greater precision the periods favourable to expandig glacier and to reduce the uncertainty of the datings, the
variations of the Fucino and Trasimeno lakes have been considered; these lakes, according to previous works, increased in level during
the glacial advances. The comparison between lake and glacial data indicates that the first glacial advance (stage Calderone 2) occurred during the period between the VII and the II÷III century BC, the second (stage Calderone 3a) between the VII and X century AD, the third (stage Calderone 3b) between the XVI and part of the XIX century AD, the last (stage Calderone 3c) during the XIX century AD.
As a consequence, one can assume that some climatic warmings took place producing glacial retreat between III÷II BC and VII century
AD, X and XIII century AD, and at the end of the XIX century AD.
Based on the differences in the equilibrium line altitude, the mean yearly temperature during the periods of maximum glacial advance
must have been lower than the present one of, at least, 1,1° ÷ 0,8°C.