Climate evolution and forcing during the last 40 ka from the oscillations in Apennine glaciers and high mountain lakes, Italy

Abstract

The results of studies carried out on the variations of glaciers and lakes in the higher Apennines during the last 40 ka are considered for correlation with some climate forcing agents, e.g. changes in insolation, variations in origin of the air masses carrying moisture and North Atlantic events, acting both at regional and hemispheric scales. The origin of air masses was assessed using the Apennine equilibrium line altitude pattern, the presence of a quartz‐rich loess in the former glacial environment and the sedimentation rate of Sahara quartz in maar lakes. Temperature and humidity variations have been deduced from glacier expansions and retreats and lake oscillations. The data discussed in the paper show that variations in insolation have driven climatic changes in the Apennines for most of the considered time span, producing gradual changes that took place during periods lasting several thousand years. However, during some periods, insolation seems to have been of minor importance compared to variations in frequency and intensity of southern air currents, and to the influence of North Atlantic events. The data, as a whole, allow us to highlight the climatic evolution of the high Apennine mountains during the last 40k cal a BP.

Historical ecology reveals landscape transformation coincident with cultural development in central Italy since the Roman Period

“…The LALIA is not as strongly expressed in the Northern Iberian temperature signal 30 . The Calderone Glacier 31 , 32 did not advance before 600 CE, suggesting either that central Italy did not experience such cold temperatures, or there was insufficient moisture for glacier growth. There is an inverse relationship between temperature and percent tree pollen, primarily seen during the Medieval period (900–1400 CE) with less tree pollen during warmer periods and more during cold periods, especially at the beginning of the Little Ice Age (LIA).…”

“…All climatic proxy data were multiplied by a factor of 10. Glacial advances are for the Calderone Glacier 31 , 32 . Numbered divisions are the 5 pollen zones described in Fig.…”

“…We also include reconstructed glacial advances of the Calderone Glacier (Fig. 3 ) that has low temporal resolution, but provides a local proxy of cooling temperatures 31 , 32 . Temperature, North Atlantic Oscillation (NAO) indexes, and pollen series were smoothed with a Gaussian filter (weighted moving average using a Gaussian kernel with standard deviation set to 1/5 of the window size 23 .…”

Geomorphology of the Mt. Cusna Ridge (Northern Apennines, Italy): evolution of a Holocene landscape

“…Since deglaciation, slope dynamics were subject to periodical phases of reactivation. At the beginning of the Early Holocene, slope denudation and continuous talus deposition, with phases of landslide detachment, were probably favoured by the end of a cooler phase (c. 13-12,000 years BP: Giraudi, 2017). Glacier retreat also possibly triggered the activation of DGSD detachment.…”

“…In such a dynamic geologic environment, surface processes are continuously working and reshaping the landscape in a variety of forms through time. This is especially true at higher elevations, where the tectonic forces are better expressed and geomorphic evolution has been triggered in time by a wider range of factors, both from geological settings and exogenous surface processes (Carton & Panizza, 1988;Giraudi, 2017). Since the Last Glacial Maximum (LGM), when surface processes were largely inhibited by the presence of glaciers, many areas of the Apennines underwent their full reactivation and have been heavily remodelled.…”