The Late-Pleistocene glacial traces of the Terminillo Group (Lazio-CentraI Apennine)

Abstract

The Late-Pleistocene Glacial Traces of the Terminillo Group (Lazio-Central Apennine) - The glacial traces present on the Terminillo Massif appear more numerous than what has been indicated by previous Authors. Some useful elements for a chronological framework of the more recent glacial phases present have been underlined and an accumulation of rockglacier has been identified. Besides the moraines of the last glacial maximum, at Terminillo there are moraines deposited during at least eight periods of standstill or re-advance that took place during the glacial retreat, grouped probably in five phases. The glaciers probably reached a length of ca. 5 km in the Meta Valley, a length of 3.5 km in the Organo Valley, facing North, while at the Prato Comune Valley, facing South, they exceeded two kilometers. Other glaciers exceeded 1.5 km in length. On the whole, the Terminillo appears to have been affected by a diffuse presence of quite extensive glacial tongues, some of which were formed by the confluence of glaciers fed by various cirques. On the basis of the presence of a quartz-rich loess and an andosoil it is possible to date the IV phase (and evidently all the preceding phases) to a time older than ca. 13-14,000 years BP, whereas the V phase would be after ca. 13-14,000 and before ca. 12,000 years BP. The moraines of Mt. Terminillo appear therefore older than what was believed before. The presence of a rockglacier in the Organo Valley has also been revealed. The rockglacier permit to calculate that, at the time of his formation, the average annual temperature must have been ca. 6.5-7.5°C below the present one.