Radiocarbon dating of fossil bats from Dobšina Ice Cave (Slovakia) and potential palaeoclimatic implications

Abstract

Although Dobšina Ice Cave (DIC, Carpathians, Slovakia) is located outside the high-mountain area, it hosts one of the most extensive blocks of perennial subterranean ice, the volume of which is estimated at more than 110,000 m 3 . Frozen bat remains were found in the lowermost part of the perennial ice block. They belong to Myotis blythii (Tomes) and the M. mystacinus morpho-group. The radiocarbon dating of bat soft tissues yielded ages of 1266-1074 cal. yr BP and 1173-969 cal. yr BP. The undetermined bat, found in the same part of the ice section in 2002, was previously dated at 1178-988 cal. yr BP (Clausen et al., 2007). The dates testify that the ice crystallized at the turn of the Dark Ages Cold Period and the Medieval Warm Period. The calculated accumulation rate of cave ice varies between 0.7 cm/year and 1.4 cm/year at that time, and is similar to the present ice accumulation rate in DIC. Constant crystallization of ice during the Medieval Warm Period is hypothesized to reflect dry summer seasons since the supply of relatively warm water in the summer is one of the key factors causing the erosion of cave ice. The uppermost sample was covered with 20.6 m of ice. Between ca 1065 cal. yr BP and the present day, the ice grew faster than between ca 1210 yr BP and ca 1065 yr BP by a factor of 1.3-1.8.

Record summer rains in 2019 led to massive loss of surface and cave ice in SE Europe

“…Snezhnika glacieret (41 • 46 9 N, 23 • 24 12 E) is located on an eastward-facing slope and lies at 2440-2490 m a.s.l., whereas Banski Suhodol (41 • 46 9 N, 23 • 23 40 E) faces north and lies at 2620-2700 m a.s.l. Both glacierets are a legacy of the Little Ice Age (Hughes, 2009) and occupy less than 1 ha (Grunewald and Scheithauer, 2010), with recent geophysical investigations revealing maximum ice thicknesses of 14 and 17 m for Snezhnika and Banski Suhodol, respectively (Onaca et al, 2019).…”

“…Between 1959 and 2008 Snezhnika glacieret lost almost half of its surface (from 13 000 to 7000 m 2 ; Grunewald and Scheithauer, 2010), and between 2008 and 2018 lost another 1300 m 2 , while during 2019, it lost 1100 m 2 . The average annual loss of Snezhnika glacieret between 1959 and 2018 was rather constant between 122 and 130 m 2 yr −1 but dramatically increased by 1 order of magnitude (1100 m 2 yr −1 ) in 2018/19.…”

Radiocarbon-Dated Vegetal Remains from the Cave Ice Deposits of Velebit Mountain, Croatia

“…Isolated individual objects found in otherwise organic-free ice layers might indicate rapid embedding in firn and ice representing positive cave ice balance (e.g. Spötl et al, 2014, Hercman et al 2010, Gradziński et al 2016. Organic inclusions concentrated along discrete layers are frequently observed in cave ice deposits.…”

“…Vegetal macroremains have been analyzed frequently (e.g. Fórizs et al 2004; Sancho et al 2012; Spötl et al 2014; Perşoiu et al 2017; Munroe et al 2018), and occasionally animal remains (Yonge and MacDonald 1999; Citterio et al 2005; Hercman et al 2010; Gradziński et al 2016) have also been dated with the aim of placing constraints on the age of cave ice deposits.…”

Age Estimates on the Deposition of the Cave Ice Block in the Saarhalle Dachstein-Mammoth Cave (Mammuthöhle, Austria) based on 3H and 14C

“…There might be plenty of options for dating near-surface cave ice deposits (Luetscher et al 2007; Kern 2018). Radiocarbon ( 14 C) analysis has became the most frequently used option, allowing the direct dating of cave ice sequences, at least when sufficient organic remnants are to be found (e.g., Hercmann et al 2010; Perşoiu and Pazdur 2011; Sancho et al 2012, 2018; Spötl et al 2014; Gradziński et al 2016; Munroe et al 2018; Perşoiu et al 2017). However, the dating of cave ice bodies settled deep in the high mountain karstic environment is often a great challenge due to the relative scarcity of embedded organic materials (e.g.…”