Two scientific world firsts achieved as part of a project carried out by the Faculty of Geography of the University of Bucharest, the first drilling in permafrost in South-Eastern Europe

Within the postdoctoral project entitled “Low Altitude Permafrost in Temperate Zones: The Response to Climate Variability and Environmental Factors – FrozenCORE” (PN-III-P1-1.1-PD-2019-1275), carried out within the Faculty of Geography of the University of Bucharest by the team comprising assistant prof. Răzvan Popescu, PhD, project director, and prof. Alfred Vespremeanu-Stroe, PhD, mentor, two Romanian and Southeast European geographical scientific firsts have recently taken place, respectively: the first scientific drilling with coring in an unconsolidated shale in Romania and the first thermally monitored drilling in a shale with permafrost from South-Eastern Europe.

The activity took place between June 23-26, 2021, in Detunata Goală, Metaliferi Mountains in Bucium – Alba County, and the collected samples certify the probable existence of low-altitude permafrost in the Carpathian space. In the next period, the drilling will be equipped with thermal sensors that will continuously record the temperature at different depths, data that will be transmitted to the Global Terrestrial Network for Permafrost (GTN-P). The collected samples will be used for sedimentological, petrographic, absolute dating and stable isotope analyzes to determine the evolutionary pattern of the deposit and estimate the age of the ice deposits.

Permafrost and climate change

Permafrost is an “essential climate variable” (ECV – essential climate variable), i.e., an environmental element whose transformations are an indicator of climate change. Thus, globally there is a network of over 9000 boreholes (GTN-P) in permafrost that monitor the thermal regime of the permafrost and the thickness of the active layer that thaws seasonally, these being the most sensitive parameters to climate variability in the case of permafrost.

In this context, the long-term goal of the drilling carried out in the low altitude permafrost site Detunata Goală is to install a system of temperature sensors at different depths to continuously monitor the thermal regime. With their help, it will be possible to determine to what extent the frozen substrate is maintained throughout the year and how the thickness of the active layer varies and how the temperature of the substrate affected by prolonged or permanent frost evolves in relation to climate change. Thus, this location will be integrated into the international drilling network, which will contribute to the understanding of regional differences in climate evolution. A separate objective of the project is the paleoenvironmental reconstruction aimed at establishing the period of formation of the deposit, the ice in the substrate and reconstructing the evolution of the deposit as a relief form.

Drilling and permafrost maintenance conditions at Detunata Golă

Drilling is the only direct method of permafrost investigation, but also the most expensive and difficult (technically) because basalt is one of the hardest rocks and the basalt deposit at Detunata (gravel stones and relict stone glaciers) is unstable. In addition, drilling in permafrost is even more complicated because it involves drilling at low temperature and preferably with air cooling in order not to melt the subsurface ice and to disturb the sample as little as possible. With all these conditions, the drilling carried out with the involvement of the Tehnofor Star company was successfully carried out up to a depth of 20 m and the ice was observed (and harvested) up to a depth of 9.7 m. The identification of a consistent layer of ice thus certifies the efficiency of the circulation system of air inside this gravel deposit, a process described in the team’s previous study: although the altitude in the Detunata Goală site is relatively low (1050 m) and the average annual temperature is well above 0°C (ca. 7.5 °C) the prolonged maintenance during summer of the underground ice is possible as a result of the production of a process known in the specialized literature as the “chimney effect”. It involves the circulation of air almost all year round as a result of the thermal and density contrast of the air in the scree compared to the atmospheric one and the continuous maintenance of a negative thermal anomaly at the bottom of the scree.

Interested persons can access more information on the research contucted by the researchers of the Faculty of Geography of UB here. At the same time, more details on the project’s activities and results can be consulted on the FrozenCORE website or on the project’s Facebook page.