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Marbles from the Pohorje area in Slovenia are investigated by mineralogical-petrographical analyses of thin sections as well as by cathodoluminescence in order to detect their local variability in texture and mineral assemblages. The CL colours observed in a cold cathode device are related to the manganese contents. An attempt is made to relate the textures seen under CL to mineral reactions during the process of metamorphism. The predominantly calcite marbles from Pohorje exhibit orange luminescence with some dolomite lenses with red luminescence. The typical mineral assemblages are calcite+tremolite+phlogopite or calcite+dolomite+tremolite+phlogopite. Therefore, the estimated temperature from the stability of mineral assemblage is assumed at approximately 500 °C. 相似文献
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Gregor Muri Branko Čermelj Radojko Jaćimović Tina Ravnikar Andrej Šmuc Janja Turšič Polona Vreča 《Journal of Paleolimnology》2018,59(4):411-426
Increased eutrophication was recently observed in the 5th (5J) and 6th (6J) Triglav Lakes, two remote Slovenian mountain lakes. Sediment phosphorus (P) pools were analysed and potential external P sources affecting the lakes (atmospheric deposition, terrestrial export and nearby hut) evaluated, to assess the effects of internal and external changes on the lakes. A sequential extraction procedure was used to quantify five P fractions from the sediments: adsorbed (NH4Cl–P), redox-sensitive (BD–P), aluminium- (NaOH–P) and calcium- (HCl–P) bound, and refractory organic (Res–P) P. Total phosphorus (TP) contents in surface sediment of 5J and 6J were 1430 and 641 µg P g?1 dry weight sediment (dw), respectively. TP varied with depth in 5J sediments, but displayed no discernible pattern, whereas it decreased steadily downcore in 6J. Contents of all P forms were distinctly higher in 5J than 6J, but their rank order and relative abundances were similar in the two lakes. Res–P was the most abundant P fraction, followed by HCl–P. Together, the two P forms accounted for nearly 80 and 90% of TP in 5J and 6J sediments, respectively. BD–P and NaOH–P were less abundant, with each fraction accounting for 3 to 9% of TP, whereas NH4Cl–P was least abundant. Atmospheric deposition and terrestrial export were substantial sources of P for the lakes. Delivery of the former was estimated to be at least 7.5 mg P m?2 yr?1 and the latter around 20 mg P m?2 yr?1. We concluded that P was not retained in the catchment effectively, likely because of only slightly acidic soil pH (5.9), relatively low aluminium content and high organic matter content (53%) in soils, resulting in higher vulnerability of the studied lakes to eutrophication. The mountain hut could also be a significant source of P for the lakes. Each year, it could potentially contribute ~12 kg of soluble P to the environment, but the true impact of the hut on lake trophic status remains unclear. 相似文献
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Isotopic characteristics of precipitation in Slovenia and Croatia: Comparison of continental and maritime stations 总被引：4，自引：0，他引：4
Polona Vre
a Ines Krajcar Broni&#x; Nada Horvatin
i&#x; Jadranka Bare&#x;i&#x; 《Journal of Hydrology》2006,330(3-4):457-469
The stable isotopic composition of hydrogen and oxygen (δ2H and δ18O) and tritium activity (3H) were monitored in monthly precipitation at two continental stations (Ljubljana, Zagreb) and six stations along the eastern Adriatic coasts of Slovenia and Croatia in the period 2001–2003. Mean air temperatures and amount of precipitation were also recorded.
Distinct differences in both meteorological and isotopic data between the continental and maritime stations were observed. Seasonal variations in δ18O are smaller at the maritime stations than at the continental ones due to smaller seasonal temperature variations. A good correlation between δ18O and δ2H was obtained for each station, and the local meteoric water lines are close to the Global Meteoric Water Line, with a decreasing trend of slope for the south-Adriatic stations. Good correlations between δ18O in monthly precipitation and mean monthly air temperature were observed at all stations. The slope of δ18O vs. T varied between 0.37‰ °C−1 and 0.15‰ °C−1. Mean 3H activity and seasonal variation of 3H activity are smaller at maritime stations than at continental ones. Additionally, 3H activity decreases in the NW–SE direction of the Adriatic coast.
The study of spatial variations over this relatively small area rich in geographical and climatic diversities showed the complexity of the isotopic composition of precipitation and the isotopic data obtained for eight stations, most of them in the karstic area along the Adriatic coast, and gave valuable information for regional hydrological investigations and modelling of isotope variability over the Mediterranean basin. 相似文献
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Production from geothermal reservoirs in volcanic-igneous hydrothermal systems may be disturbed owing to the formation of
authigenic minerals that reduce primary porosity and infill fissure systems. Crystallization may be induced by natural processes
or human activity related to the reservoir exploitation. In volcanic and volcaniclastic rocks, zeolites and related authigenic
silicate minerals commonly develop. Two selected study sites—Pauzhetka geothermal field in Russia and Smrekovec volcanic complex
in Slovenia are characterized by extensive development of progressive stage medium- and low-temperature propylitization and
zeolitization with similar mineral assemblages that reduced original reservoir rock porosity and permeability. Retrograde
and overprinting reactions of argillitization commonly enhance porosity and permeability of rocks, but some other reactions,
like from prehnite to laumontite, from laumontite to heulandite, and from laumontite to analcime, encountered in the Smrekovec
volcanic complex reduced it appreciably. Retrograde reactions recognized in the study sites were not induced by the temperature
drop only, but were accompanied by the change in chemical composition of reacting fluids. Chemical composition of interstitial
waters produced from exploitation wells in the Pauzhetka geothermal field indicate that propylitic and zeolite facies alteration
is related to Na–Cl, slightly alkaline waters, while argillitization involved acidic thermal waters with more complex ion
composition. 相似文献
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Gregor Muri Branko Čermelj Radojko Jaćimović Dragomir Skaberne Andrej Šmuc Martina Burnik Šturm Janja Turšič Polona Vreča 《Journal of Paleolimnology》2013,50(4):457-470
Several geological and geochemical parameters were determined in the sediments of the 5th (5 J) and 6th (6 J) Triglav Lakes, Julian Alps (NW Slovenia), in order to study the impact of natural catchment characteristics and anthropogenic activity. Fish were introduced into both lakes in 1991 and a mountain hut lies on the shore of 5 J. Sedimentary grain size (GS) was distinctly coarser in 5 J than 6 J, with arithmetic means ranging between 46 and 60 and 23–36 μm, respectively. In contrast, the mineralogical composition of the two sediments was similar. Calcite predominated strongly, comprising more than 77 % of total minerals, while dolomite and quartz were rare. Organic carbon (OC) and total nitrogen (TN) concentrations were highest in surficial sediments, with levels of 14.4 and 1.8 %, and 19.3 and 2.4 % observed in 5 J and 6 J, respectively. C/N ratios (atomic) were lowest in the same surface sediments, with the two lakes characterized by similar values (9.6 vs. 9.4, respectively), suggesting a predominance of autochthonous organic matter (OM) in both lakes. Contemporary δ13C values were lower in 5 J (?21.0 ‰) than 6 J (?18.5 ‰) sediments. Considerable changes in these four parameters were observed in recently deposited material, reflecting a shift in the trophic status of both lakes that was likely induced by the introduction of fish. In addition, the smaller and shallower 6 J seemed to respond to changes faster than the larger and deeper 5 J, indicating the higher sensitivity of the former. δ15N values in surface sediments of 5 J and 6 J were ?2.9 and ?4.4 ‰, respectively, with levels increasing gradually with depth to approximately +1.0 ‰ in deeper sediments. The observed changes could most likely be attributed to the atmospheric deposition of reactive nitrogen. The mountain hut has seemingly not had a significant enough impact on the lakes to be recorded in their sediments. 相似文献
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Low-temperature thermal waters (<20–40 °C) from Mesozoic carbonate formations of Outer and Inner Dinarides which outcrop along the margins of small Tertiary basins, are characterised by low content (commonly <500 mg/l) of total dissolved solids and the dominance of calcium-(magnesium) bicarbonate hydrogeochemical facies. Trace elements occur in the ppb to ppt range, and can be substantially enriched in carbon dioxide-rich thermomineral waters. Contacts of thermal waters with clastic sediments affect the abundance of many trace elements, like B, Ni, Mn, Fe, Se, Sr, Ba, REE and Th. The U/Th ratios are commonly very high for the waters from carbonate aquifers, although the U abundance is in the range of some ppb. The influence of clastic sediments is reflected in an increased abundance of Th, and therefore much lower U/Th ratio. Some waters are rich in strontium (over 1 ppm), which probably originates from aragonite in Cretaceous carbonate rocks. 相似文献
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