In 2013 only two groups were engaged in periglacial geomorphology and permafrost researches, the University of Timisoara and Bucharest. The group of periglacial researchers from West University of Timişoara (P. Urdea, A. Onaca, F. Ardelean, A. Ardelean, R. Şerban, R. Puţan, F. Sîrbu) continued to study permafrost distribution and other significant periglacial landforms (solifluxions, block streams, talus slope deposits) in Southern Carpathians. The main goal of the approach was to capture the current amplitude of periglacial processes from Southern Carpathians, taking into account the complex relationship between the detailed morphology of analyzed landforms, their internal structure and their thermal regime and actual movement. To achieve this goal, several test sites were chosen for detailed analysis of selected periglacial phenomena and structures.
In case of permafrost distribution, several rock glaciers from Retezat (Fig. 1) and Parâng Mountains have been investigated through different techniques and methods (ERT, GPR, GST, BTS, GIS modelling), following few main objectives: identification of permafrost occurence; investigating the internal structure of rock glaciers and determining permafrost characteristics by means of geophysical investigations; establishing an effective methodology for permafrost mapping in the Southern Carpathians; long term monitoring of permafrost occupied areas for future evaluation of permafrost degradation induced by global warming; evaluating the influence of local conditions for permafrost preservation and generating a permafrost distribution model. All these results confirm the hypothesis that isolated patches of permafrost could exist in the Southern Carpathians at sites particularly favorable to permafrost conservation. The preservation of permafrost in these rock glaciers it is possible because of the openwork structure (Fig. 2) of the active layers, allowing a significant cooling beneath the bouldery mantle and the storage of cold air in winter below thick snow cover. In addition, an inventory of the rock glaciers and protalus ramparts from Southern Carpathians was realized by the team coordinated by P. Urdea.
Figure 1. GPR investigations in Pietrele rock glaciers, Retezat Mountains (Photo B. Magori).
Some of the results formed the basis for two papers, important for Romanian geomorphological community, by the novelty of the approach (Onaca, A., Urdea, P., Ardelean, A., 2013, Internal Structure and Permafrost Characteristics of the Rock Glaciers of Southern Carpathians (Romania) Assessed by Geoelectrical Soundings and Thermal Monitoring, Geografiska Annaler, Series A: Physical Geography, 95 (3), 249-266, doi:10.1111-geoa.12014; Onaca, A., Urdea, P., Ardelean, A., Şerban, R., 2013, Assessement of internal structure of periglacial landforms from Southern Carpathians (Romania) using DC resistivity tomography, Carpathian Journal of Earth and Environmental Sciences, 8 (2), 113-122).
Figure 2. Openwork structure in Judele rock glaciers, Retezat Mountains (Photo F. Ardelean).
In case of the measurements performed on the talus slope deposits from Făgăraş Mountains the preliminary findings reveals evidence for a complex architecture with several clear strata. More homogeneous layers composed by fine grained deposits intercalated between coarse-grained layers were identified along the GPR profiles. Buried features like the bedrock, morainic materials, different geological structures, drainage systems in the bedrock, rockfall deposits and debris-flows materials could be recognized. The GPR data allowed us to formulate an evolution scenario of the investigated talus slopes from Făgăraş Mountains for the Holocene.
With excellent qualificative, under the coordination of the undersigned, in September was sustained two PhD thesis by A. Onaca, ,,Periglacial processes and landforms from Southern Carpathians. Geomorphological and geophysical approach’’ (237 p.) and F. Ardelean, ,,Semi-automated classification of some landforms for geomorphological mapping. Case study: Ţarcu Mountains’’ (172 p.).
Also, P. Urdea made field investigations on the periglacial forms in some middle mountain area of the Roamanian Carpathians, like Găina Mountain (Apuseni Mountains) (Fig. 4), and Ciucaş (Fig. 4), Suhard and Giumalău Mountains (Eastern Carpathians) (Fig. 5).
The permafrost research team from Bucharest (Răzvan Popescu, Mirela Vasile, Alfred Vespremeanu-Stroe, Nicolae Cruceru and Loredana Bîzgan) continued the main investigations on alpine and low altitude permafrost from Romania by combining traditional methods and new approaches. Seasonal BTS measurements were performed and the functionality of the established GST investigation points was assured. Also, topographical survey for rock glacier dynamics assessment was repeated and dendrogeomorphological investigations were initiated on Retezat Mountains. DC resistivity soundings were also initiated by our team. Besides, extensive measurements on rock deposit porosity variations were performed across different massifs of Southern Carpathians in the attempt to explain the lower permafrost altitudes in the granitic mountains (Retezat and Parâng) in comparison with the crystalline ones (Făgăraş). Several tens of vertical photographs were taken from a 3 meters height using a tripod and additional in situ measurements of clast volume were performed. Monica Voinea processed the images in GIS to obtain the characteristic mean clast volume for each site. The debris porosity was estimated by considering a direct relationship between clast volume and porosity.
Figure 3. ,,Goliath’’ a conglomeratic tor in Ciucaş Mountains (Photo P. Urdea).
Fig. 4. Frost sorting and relict altiplanation terrace in Găina Mountain, Apuseni Mountains (Photo P. Urdea).
Fig. 5. Pleistocene slope failures in Fărăoane area (Suhard Mts.) and in Giumalău Mountains (Photo P. Urdea).
Using temperature and snow depth meteorological data from alpine stations, multiple indices were computed in order to reconstruct the climate favorability for permafrost in Southern Carpathians for the last 70 years.
The researches on seasonal frost and freeze-thaw processes in the alpine environment in the Southern Carpathians also continued this year. The thermal monitoring of rockwalls has been still running, at about 20 locations, with intensive measurements in Bucegi, Făgăraş and Retezat Mountains. We concentrated more on in-depth measurement (50 cm) and on the role of the exposition and slope of the rock faces, following these parameters in more sites.
With the wide purpose of determining the temporal and spatial patterns of frost-induced phenomena such as rockfalls in the specific climate, topographic and geo-tectonic conditions of the Southern Carpathians, we have initiated in several test areas observations and measurements on the joints and cracks density and patterns on the steep rockwalls. This initiative is complementary to the temperature and crack dynamics continuous monitoring in the same rockwalls. By the GIS analysis of images and high resolution photographs taken on the field we are now trying to identify specific characteristics (explicitly the dimensions of the rocks to be detached) of these potential areas for rockfalls, mainly function of exposure and lithology. In the same time, the thickness of the fissures at the surface of the wall was measured, highlighting different joints typologies with specific role in frost propagation and rockfall generation. We are thus trying to correlate these elements (joints characteristics, frost-depth and propagation) in order to get a clear view in respect to seasonal frost as a preparing and triggering factor of such phenomena.
Members of the two universities teams participated with papers in special sessions held at the 8th IAG/AIG International Conference on Geomorphology (Paris, August 27-31) and at the Carpatho-Balkan-Dinaric Conference on Geomorphology (Stara Lesna, Slovakia, June 24-28).
In January 2013 was approved the status and structure of the National Committee for Antarctic Research (CNCA) of the Romanian Academy, in the Geonomic Section Prof. P. Urdea being appointed deputy scientific coordinator.
Report prepared by Petru Urdea (email@example.com).