Ninth International Conference on Permafrost ... - IARC Research

Ni n t h In t e r n at i o n a l Co n f e r e n c e o n Pe r m a f r o s tAcknowledgmentsThe authors are grateful to numerous students from WestUniversity of Timişoara for their committed help in carryingand installing the heavy equipment in the field. Financialexpenses was supported by National Council for UniversityResearch (grant CEEX 738/2006).Figure 2. 2-D resistivity longitudinal section at Pietrele rockglaciers.to the special characteristics, in the case of solifluction lobeand fossil patterned ground, the electrodes were arranged ina different configuration, on equal distance of 1 m, whichpermits a differentiation of distinct layers of 40–50 cm. Twodimensionalmodel interpretation was undertaken using thesoftware package RES2DINV (Loke 1999). This softwarepackage produces a two-dimensional subsurface model fromthe apparent resistivity pseudosection.Results and InterpretationApplication of 2-D electrical resistivity tomographybegan with measurements in Făgăraş, Retezat, and ŞureanuMountains on different geomorphic landforms, such as rockglaciers, scree slopes, solifluction lobes, fossil patternedground, and glacial overdeepening depression filled withpostglacial sediments. In all cases the results show varyingresistivity. Starting with this design, we can know and interpretthe structure of different deposits and, importantly, the depthand configuration of the surface contact with bedrock. Inthe case of scree deposits is the evidence of the presenceof quasi-layered structure and some different bodies of rockblocks and/or fines—made by downwash and debris flowprocesses—with contrasting resistivity (more than 10 kΩ/mand, respectively, less than 2 kΩ/m). For fossil-patternedgrounds are revealed undulating layers and elipsoidal bodiesof fines, more humid and with low resistivity (500–800Ω/m). In the case of Ana and Pietrele rock glaciers, electricaltomography reveals typical structures, and, important forpermafrost scientists, the presence of ice-rich bodies in theAna rock glaciers or ice-rich layer on Pietrele rock glaciers,revealed by high resistivities, on the order of more than 900k Ω/m (Fig. 2).We must mention that the presence of permafrost in thereported area was indicated by BTS measurements and bythe low temperatures (