Contents lists available at ScienceDirect Quaternary International journal homepage: www.elsevier.com/locate/quaint Small glaciers in Pirin (Bulgaria) and Durmitor (Montenegro) as glacio- karstic features. Similarities and differences in their recent behaviour Emil Gachev ∗ , Ilia Mitkov South-west University "Neofit Rilski", Ul. Ivan Mihailov 66, 2700, Blagoevgrad, Bulgaria ARTICLE INFO Keywords: Pirin Durmitor Small glaciers Climate Inter-annual variations ABSTRACT Small glaciers on the Balkan Peninsula are tiny masses of firn and ice (areas from 0.5 to 5 ha) which have been proved permanent at least since the coldest phases of the Little Ice Age, and are slowly moving under their own gravity. These are considered glacial, but also karstic features at the same time, because the topography that provides for their existence in the marginal conditions of the Mediterranean climate is result of the occurrence of Pleistocene glaciation together with the carbonate rocks and the karst processes related to them. Small glaciers on the Balkan Peninsula are among the most southerly situated in Europe. They are very sensitive to short-term variations of climate, and serve as natural indicators for climate change. The present study is dedicated to small glaciers in Pirin (Bulgaria) and Durmitor (Montenegro) as representative high mountain glacio-karstic features from the western and the eastern part of the Balkan Peninsula respectively. The similarities and differences in their inter-annual behaviour (changes of size) reflect the general and peculiar characteristics of high mountain climate, and the specific influence of topography. In the conditions of climatic warming a downward trend is registered in their development for the period on the focus of this study: 2005–2017. In the last several years this trend has a stronger expression in the western Balkans. 1. Introduction Scattered across the mountains of 2000–3000 m altitude that en- compass the Mediterranean from the north, small glaciers (tiny pieces of centennial firn and ice) exist down to 800 m below the altitude of the present climatic equilibrium line altitude. These glaciers, with areas rarely larger than several hectares, have managed to persist constantly at least for several centuries. Their latest history is marked by con- siderable fluctuations in size from year to year, reflecting short-term variations in climate conditions. Thus these small glaciers have been widely used as tools to analyze and reveal the local and regional pe- culiarities of high mountain climate. The latter is insufficiently covered by instrumental measurements, although it is expected to be among the climates most strongly affected by global change. Researches in recent decades revealed that at least 16 small glaciers can still be found in the mountains of the Balkan Peninsula: Prokletije in Albania, Durmitor in Montenegro and Pirin in Bulgaria (Gachev et al., 2016). At present the Pirin Mountains are home to the southernmost glacial masses in Europe, the only ones situated south of the parallel 42° N(Grunewald and Scheitchauer, 2010). Several teams of scientists have studied the perennial snow features in those mountains, especially in the last two decades. Four features have been proved to have the character of small glaciers, and for 12 more a glacier nature is proposed based on the morphology of firn/ice bodies and surrounding landforms (Milivojević et al., 2008; Grunewald and Scheitchauer, 2008, 2011; Grunewald et al., 2008; Hughes, 2007, 2008, 2009; Gachev et al., 2009, 2016; Gachev and Stoyanov, 2012, 2013a,b). Some sustainable snow patches exist also in other mountains in the region (such as Olympus), but none of them has been proved permanent in a longer term (Grunewald and Scheitchauer, 2010; Gachev, 2017a). Situated well below the climatic equilibrium line altitude (ELA), these features are products of topography as well as climate. More in particular, their existence is due to the favourable conditions provided by glacio-karstic topography, and on this base they can be considered as elements specific to the high mountain glaciokarstic environment of the region. The combined action of glacial erosion and karstification during the cold phases of the Pleistocene produced a highly dissected topography in high mountain karstic areas (following the definition of high mountain karst (Gachev, 2017b)). Throughout the Balkan Peninsula this is probably best demonstrated in Prokletije mountain range. With a relict glacial relief of smoother gradients and shallow cirques with grassy floors, its eastern flanks, built up of various silicate rocks (granite, schist, gabbro, serpentinite) sharply differ from the much https://doi.org/10.1016/j.quaint.2018.03.032 Received 31 May 2017; Received in revised form 11 January 2018; Accepted 22 March 2018 ∗ Corresponding author. E-mail addresses: emil.gachev@swu.bg (E. Gachev), iliamitkov@gmail.com (I. Mitkov). Quaternary International xxx (xxxx) xxx–xxx 1040-6182/ © 2018 Published by Elsevier Ltd. Please cite this article as: Gachev, E., Quaternary International (2018), https://doi.org/10.1016/j.quaint.2018.03.032