Holocene glaciation in the mountains of Bulgaria

Abstract

This study presents a review on Holocene glacial traces in Bulgaria. Pleistocene glaciation in this territory was spread over a number of mountains above 2000 m a. s. l., while in the later time, it was restricted only to the highest areas of the two highest mountains, Pirin and Rila. Two major phases can be distinguished on the basis of field evidence-a Little Ice Age (LIA) phase, and a present-day phase. Features of present-day glaciation are only found in the Pirin Mountains, in the highest parts of Northern Pirin which are built of carbonate rocks (marble). The two glacierets in these mountains, which are now the southernmost glacial masses in Europe, occupy only c. 1.5 ha. Several permanent snow patches are also found to fill the bottoms of high altitude karst dolines in the same area, contributing to a total of 3.5 ha of firn and ice, which have not completely melted for several centuries. The post-LIA climatic warming, which has progressed with an increased pace for the last 3 decades, reduced the glaciated area in the highest mountains of Bulgaria by 58%. However, glacierets and snow patches in Bulgaria have appeared to be more stable when compared to most other locations with similar topographic setting in Southeastern Europe.

Response of Very Small Glaciers to Climate Variations and Change: Examples from the Pirin Mountains, Bulgaria

“…This enhanced stability of the glacierets in Pirin is also illustrated by their relatively small post-Little Ice Age shrinkage compared to a number of small glaciers in the Mediterranean region in the Dinaric Mountains, the Apennines, the southeastern Alps, and elsewhere [41][42][43][44][45][46][47][48][49][50][51][52][53], which have reduced their areas from several times to several tens of times, and their volumes often hundreds of times.…”

“…According to the recent studies, the average area of Snezhnika glacieret for the last 25 years has been about 55% of its maximum extent during the Little Ice Age (LIA) and the average area of Banski suhodol glacieret has been about 60% (data from [28,52]). Such a retreat appears quite moderate when compared to the recession of a large number of glaciers and very small glaciers in the other mountains of the Mediterranean which have similar altitude to the Pirin Mountains.…”

Geophysical measurements of the southernmost microglacier in Europe suggest permafrost occurrence in the Pirin Mountains (Bulgaria)

“…There have been no large glaciers on the territory of Bulgaria since the end of the Pleistocene (Gachev, 2020), but small patches of snow and firn have been observed in the high parts of the Rila and Pirin Mountains at the end of the summer. Two microglaciers are also located in the Pirin Mountains.…”

Characteristics of July 2019 Cherna Mesta River flash flood

“…This river is formed by the confluence of the Cherna (Black) and Byala (White) Mesta Rivers. These rivers have their origins in the highest parts of Rila Mountain, a highland affected strongly by Pleistocene glaciations (Kuhlemann et al, 2013;Gachev, 2020). Both rivers have similar in size catchments and the main river channels are predominantly oriented in the N-S direction.…”