Uros Herlec
University of Ljubljana, Department of Geology, Faculty Member
Research Interests:
Research Interests:
The Idrija mercury mine is situated 50 km west of Ljubljana, in the region which belongs to the Alpine promontary, transitional zone between Alps, Dinarides and Adriatic microplate. The ore deposit was formed by hydrothermal and... more
The Idrija mercury mine is situated 50 km west of Ljubljana, in the region which belongs to the Alpine promontary, transitional zone between Alps, Dinarides and Adriatic microplate. The ore deposit was formed by hydrothermal and exhalative processes within a Middle Triassic trough, deepened by extensional tectonics during the Tethyan rifting stage. Middle Triassic tectonics gave way to the upwelling hydrothermal solutions, which expelled their load onto the sea bottom through a thick pile of the Upper Paleozoic, Permian, Scythian, and Anisian clastics and carbonates, forming stratiform, synsedimentary mercury, pyrite rich ore in the black Sconca shales (Mlakar & Drovenik, 1971 ; Placer, 1976). On their way to the sea bottom, they mineralized fissures, pores, faults, breccia zones, and metasomatically replaced carbonates, and cement in clastics, assigning to the mineralization a clear epigenetic character. Mineral paragenesis of the deposit is almost monomineralic and consists of cinnabar, metacinnabar, native mercury, sporadic iron sulphides and gangue minerals, calcite and quartz. The objects of FIs study were colourless, transparent single quartz crystals, prepared as 0.2 mm thick wafers, and red, irregular cinnabar grains, prepared as 0.05-0.1 mm thick wafers. The most widespread FIs in Idrija ore deposit are low saline (1, 75-11, 50 wt.% equ. NaCl), L+V, CaCl2- NaCl-H2O with NaCl/CaCl2 ratio between 25 and 40%. Total homogenization into liquid phase was observed in the temperature interval between 175 and 215°C. Homogenization temperature could not be recorded into cinnabar samples due to decrepitation in temperature interval between 120 and 160°C. High saline CaCl2-NaCl-H2O FIs, with presence of isotropic daughter minerals, were observed only within one quartz crystal. NaCl/CaCl2 ratio and homogenization temperature are into the same range as in the low saline FIs. In the same sample the low saline (6, 75-8, 00 wt.% equ. NaCl), L+V, NaCl FIs were observed.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
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Fluid inclusions in cinnabar, quartz and barite from the Grübler orebody of the giant Idrija mercury deposit in the NW Dinarides of Slovenia were studied by microthermometry, laser Raman spectrometry, and bulk crush-leach analysis using... more
Fluid inclusions in cinnabar, quartz and barite from the Grübler orebody of the giant Idrija mercury deposit in the NW Dinarides of Slovenia were studied by microthermometry, laser Raman spectrometry, and bulk crush-leach analysis using ion chromatography and atomic ...
Research Interests: Geology and Geochemistry
Research Interests:
The sulfur isotope composition of sulfide ore minerals of the Drau Range varies considerably, down to centimeter-scale variations, both on a regional and a local scale. Broadly scattering 34 S values, ranging between +2 and 25 per mil... more
The sulfur isotope composition of sulfide ore minerals of the Drau Range varies considerably, down to centimeter-scale variations, both on a regional and a local scale. Broadly scattering 34 S values, ranging between +2 and 25 per mil with a mean around 17 per ...
Research Interests:
In the Southern Alps and the northern Dinarides the main Variscan deformation event occurred during Late Carboniferous (Bashkirian to Moscovian) time. It is represented locally by an angular unconformitiy, the “Variscan discordance”,... more
In the Southern Alps and the northern Dinarides the main Variscan deformation event occurred during Late Carboniferous (Bashkirian to Moscovian) time. It is represented locally by an angular unconformitiy, the “Variscan discordance”, separating the pre-Variscan basement from the post-Variscan (Moscovian to Cenozoic) sedimentary cover. The main aim of the present contribution is to investigate whether a Variscan thermal overprint can be detected and distinguished from an Alpine thermal overprint due to Permo-Mesozoic basin subsidence in the Alpine-Dinaric Transition Zone in Slovenia. Vitrinite reflectance (VR) is used as a temperature sensitive parameter to determine the thermal overprint of pre- and post-Variscan sedimentary successions in the eastern part of the Southern Alps (Carnic Alps, South Karawanken Range, Paški Kozjak, Konjiška Gora) and in the northern Dinarides (Sava Folds, Trnovo Nappe). Neither in the eastern part of the Southern Alps, nor in the northern Dinarides a br...
Research Interests:
In the Southern Alps and the northern Dinarides the main Variscan deformation event occurred during Late Carboniferous (Bashkirian to Moscovian) time. It is represented locally by an angular unconformitiy, the “Variscan discordance”,... more
In the Southern Alps and the northern Dinarides the main Variscan deformation event occurred during Late Carboniferous (Bashkirian to Moscovian) time. It is represented locally by an angular unconformitiy, the “Variscan discordance”, separating the pre-Variscan basement from the post-Variscan (Moscovian to Cenozoic) sedimentary cover. The main aim of the present contribution is to investigate whether a Variscan thermal overprint can be detected and distinguished from an Alpine thermal overprint due to Permo-Mesozoic basin subsidence in the Alpine-Dinaric Transition Zone in Slovenia. Vitrinite reflectance (VR) is used as a temperature sensitive parameter to determine the thermal overprint of pre- and post-Variscan sedimentary successions in the eastern part of the Southern Alps (Carnic Alps, South Karawanken Range, Paški Kozjak, Konjiška Gora) and in the northern Dinarides (Sava Folds, Trnovo Nappe). Neither in the eastern part of the Southern Alps, nor in the northern Dinarides a br...
Research Interests:
Research Interests:
The methods used in geology to determine colour and colour coverage are expensive, time consuming, and/ or subjective. Estimates of colour coverage can only be approximate since they are based on rough comparison- based measuring etalons... more
The methods used in geology to determine colour and colour coverage are expensive, time consuming, and/ or subjective. Estimates of colour coverage can only be approximate since they are based on rough comparison- based measuring etalons and subjective estimation, which is dependent upon the skill and experience of the person performing the estimation. We present a method which accelerates, simpli es, and objecti es these tasks using a computer application. It automatically calibrates the colours of a digital photo, and enables the user to read colour values and coverage, even after returning from eld work. Colour identi cation is based on the Munsell colour system. For the purposes of colour calibration we use the X-Rite ColorChecker Passport colour chart placed onto the photographed scene. Our computer application detects the ColorChecker colour chart, and nds a colour space transformation to calibrate the colour in the photo. The user can then use the application to read colours within selected points or regions of the photo.
The results of the computerised colour calibration were compared to the reference values of the ColorChecker chart. The values slightly deviate from the exact values, but the deviation is around the limit of human capability for visual comparison. We have devised an experiment, which compares the precision of the computerised colour analysis and manual colour analysis performed on a variety of rock samples with the help of geology students using Munsell Rock-color Chart. The analysis showed that the precision of manual comparative identi cation on multi- coloured samples is somewhat problematic, since the choice of representative colours and observation points for a certain part of a sample are subjective. The computer based method has the edge in veri ability and repeatability of the analysis since the application the original photo to be saved with colour calibration, and tagging of colour- analysed points and regions.
The results of the computerised colour calibration were compared to the reference values of the ColorChecker chart. The values slightly deviate from the exact values, but the deviation is around the limit of human capability for visual comparison. We have devised an experiment, which compares the precision of the computerised colour analysis and manual colour analysis performed on a variety of rock samples with the help of geology students using Munsell Rock-color Chart. The analysis showed that the precision of manual comparative identi cation on multi- coloured samples is somewhat problematic, since the choice of representative colours and observation points for a certain part of a sample are subjective. The computer based method has the edge in veri ability and repeatability of the analysis since the application the original photo to be saved with colour calibration, and tagging of colour- analysed points and regions.