We have now obtained the first U/Th results which show us the time period when the stalagmites were growing and their maximum and minimum ages. We can now orient to specific sections of the stalagmites to target 8.2 and 4.2 ky events and perform dating with higher resolution.
Novel proxies of the Holocene climate variability in stalagmites in Slovenia, 1.9.2020 – 31.1.2021, Sonja Lojen
In light of current global warming, when the climate seems to be close to the tipping point, the interdisciplinary analysis of its environmental implications is as pertinent as ever. Learning from the past in absence of instrumental or historic written records requires natural multi-proxy archives to reconstruct the response of living environments to climate perturbations. Given the abundance of karst in Slovenia, the choice of stalagmites for reconstruction of past environmental conditions seems to be obvious: because of virtually stable temperature and atmospheric conditions in caves, stalagmites are expected to provide an undisturbed and interconnected timeline of past environmental change. Records of contained climate proxies (δ18O, δ13C, mineral and elemental composition etc.) allow to estimate how the climate, landscape and ecosystems changed with time.
The aim of the project is to elucidate the climate and environmental conditions in Slovenian territory during Holocene, focusing on the 8.2, 4.2 and 2.8 ky events, which are poorly or not at all documented in this region. Isotopic and geochemical records in a stalagmite from the newly discovered cave Jama v Dovčku in SE Slovenia will be analysed. Advanced methods based on laser ablation coupled to the multicollector ICP-mass spectrometry or SIMS will be used for U/Th dating and Sr isotope analysis, while elemental profiling will be performed using LA-ICP-MS and microPIXE methods. Stable isotopes of C and O will be analysed using micromilling and isotope ratio mass spectrometry.
Complementary to the Mg/Ca and Sr/Ca ratios, the δ88Sr will be used as a novel proxy for the prior calcite precipitation in the aquifer, which will be the main analytical challenge of the project and will have strong implications for the credibility of the interpretation of traditional (C, O) isotope and elemental records.
Analyses will be performed in collaboration with partner research institutions from Australia, Germany and France. The obtained records will be compared to existing paleoclimate profiles derived from stalagmites and other archives and proxies (aquatic sediments, peat) in the region and will provide information on how the environment in southern part of Slovenia reacted to climate change in periods of cyclic and rapid temperature fluctuations in Holocene (e.g. 8.2 ky event), events around the beginning of Meghalayan age (around 4.2 ky ago) and later until the beginning of the Common Era.
Find researchers and info on the project in the SICRIS database.
“Jožef Stefan” Institute
Sonja Lojen (project coordinator), Tjaša Kanduč, Katarina Marković, Leja Rovan,
Janez Ščančar, Marko Štrok, Polona Vreča, Tea Zuliani
Matej Lipar (scientific coordinator), Mateja Ferk, Blaž Komac, Jure Tičar, Matija Zorn
After receiving the permit from Slovenian Environment Agency, we have now carefully harvested two stalagmites from the cave. Before any precise analysis can be done, the stalagmites first needed to be sawed on half longitudinally, finely polished and protected with resin.
We have begun to collect dripping water on 15 locations throughout the cave, and measure the humidity and temperature on hourly basis on 5 locations.