Description
Giraudi (2009) examined long-term relations among glacial activity, periglacial activity, and soil development in northwestern Italy's alpine River Orco headwaters (~45.5°N, 7.3°E), based on "studies carried out by means of geological and geomorphologic surveys on the glacial and periglacial features," including a sampling of soils involved in periglacial processes, which together with a stratigraphic sequence derived from a peat bog "provided a basis for development of a chronological framework of late Holocene environmental change." This work revealed that between about 200 BC and AD 100 -- i.e., during the Roman Warm Period -- "soils developed in areas at present devoid of vegetation and with permafrost," indicative of the likelihood that temperatures at that time "probably reached higher values than those of the present [our italics]." He also concluded that "analogous conditions likely occurred during the period of [the] 11th-12th centuries AD, when a soil developed on a slope presently characterized by periglacial debris," while noting that "in the 11th-12th centuries AD, frost weathering processes were not active and, due to the higher temperatures than at present [our italics] or the longer duration of a period with high temperatures [our italics], vegetation succeeded in colonizing the slope."