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101.
We report the occurrence of micrometer-sized silver particles in the red (“impact” or “ejecta”) layer of the Fish Clay. These appear to be embedded into the biogenic/abiogenic calcite matrix. Energy dispersive X-ray analysis indicates that these microparticles are composed of pure silver (>99% of the total weight). Scanning electron microscopy images reveal irregular and predominantly rounded shapes with rugged surfaces. Numerous silver microparticles are spherical, and some exhibit dendritic textures. These microparticles were probably originated during the Chicxulub asteroid impact event, or immediately afterwards, and dispersed globally. 相似文献
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104.
Lj. Barić 《Mineralogy and Petrology》1969,13(3-4):233-249
Zusammenfassung In der Umgebung der Stadt Prilep in Mazedonien kommen an mehreren Stellen in einer hochmetamorphen, aus Glimmerschiefern und Amphiboliten bestehenden Zone Calcit- und Dolomitmarmore vor. In den letzterwähnten wurden bisher Dolomit, Calcit, Korund, Diaspor, -Zoisit, Rutil, Fluorit, Achroit, Pyrit, Muskovit, Illit, Margarit und Chlorit (vonErdmannnsdörfer auch Kossmatit) festgestellt. Diese Paragenese ist regionalmetamorph entstanden.
Mit 1 Abbildung 相似文献
Dolomite-marble in the surroundings of the town prilep, macedonia, and its minerals
Summary Calcite- and dolomite-marbles occur in a highly metamorphic series together with micaschists and amphibolites at several localities in the surroundings of Prilep, Macedonia. In the dolomite-marbles, dolomite, calcite, corundum, diaspore, -zoisite, rutile, fluorite, achroite pyrite, muscovite, illite, margarite, chlorite, and kossmatite (the last only byErdmannsdörffer) have been found. The paragenesis is of regional metamorphic origin.
Mit 1 Abbildung 相似文献
105.
Lead-arsenic soil geochemical study as an exploration guide over the Killik volcanogenic massive sulfide deposit, Northeastern Turkey 总被引:3,自引:0,他引:3
A mountainous terrain, the eastern Pontide tectonic belt, located in northeastern Turkey, contains more than 60 known volcanogenic massive sulfide (VMS) deposits that differ in reserves (0.1–30 million tonnes) and grades. Soil geochemistry is conventionally used in exploration programs to discover concealed VMS deposits in the region. In the present study, Pb and As element pair were used as pathfinder elements to investigate the relationship of their anomalies to a completely delineated ore deposit (Killik VMS deposit) in an orientation survey that served as a natural physical model. Two hundred forty soil samples were analyzed in the present study. The two elements, which represent the opposite ends of the mobility range, revealed high contrast and overlapped each other at the location of the ore deposit due to enhancement of the anomalies by hydromorphic dispersion, which is an indication that soil samples would produce reliable results. The successful delineation of the deposit is remarkable considering the rough topography and the climatic limitations. Previously the extremely moist and temperate climate was thought to cause excessive leaching of the trace element pathfinders from the ore deposits to produce extensive anomalies usually extending away from the mineralization thus, leading to erroneous results and/or extensive anomalous areas. But the present research has shown that the method can be used effectively if the sampling and data evaluation is carefully conducted. 相似文献
106.
This work tested the preferential use of fine (<63 μm) or bulk sediment (<2 mm) in environmental research of marine sediments in the Eastern Adriatic. Fine fraction sediment containing silt and clay (<63 μm), predominating in the studied area, was examined to evaluate past and present anthropogenic inputs and to test our hypothesis that investigation of bulk sediment should be preferred. Following aqua regia digestion, chemical analyses of 58 elements were performed by ICP/OES, ICP-MS and cold vapor AAS, and statistical analysis was performed. The concentrations of the majority of the analyzed elements increased with age of the sediment, except for Ag and Sn, which had higher concentrations in recent sediments. The previous main sources of metal contamination in Rijeka harbor were now abandoned municipal-sewage outflow and oil refinery, and continuing harbor activities and antifouling paint use. All activities except of antifouling paint use have been decreasing significantly. Anomalies of selected elements were determined by the box-plot method. More anomalies were found in the bulk sediment than in the fine fraction. Results of Q-modality clustering and factor analysis in the fine fraction almost correlate with that applied on bulk sediments. Thus, it can be said that the differences between the element distribution in the bulk and fine fraction are not statistically significant. Our conclusion is that analysis of bulk marine sediment gives a better insight into the state of pollution and supports previous recommendations to use bulk sediment as a chosen media for environmental studies. 相似文献
107.
Saša Milanović Zoran Stevanović Ljiljana Vasić Vesna Ristić-Vakanjac 《Environmental Earth Sciences》2014,71(2):525-532
Beljanica Mountain in eastern Serbia is a part of the Carpathian Balkan arch (northern Alpine branch). It covers an area of about 300 km2 and consists mostly of Jurassic and Cretaceous limestones. Numerous surface karst features, long caves and several large karstic springs located in Beljanica’s piedmont along the contact of karstic and non-karstic rocks are all indicators of an intense karstification. Currently, the large karstic water reserves of Beljanica Mountain are not properly utilized because of their distance from main consumers, the objection by national water managers that the springs lack a stable and sufficient discharge particularly during recession periods. Due to its unpolluted and high quality water, the area is a great prospect for future water supply, and provides an opportunity for artificial regulation and for the design and implementation of specific tapping structures. This paper includes an analysis of the created 3D ArcGIS model of karst interior and its correlation with historical and newly collected data of spring discharges and groundwater physico-chemical characteristics. The results of karst aquifer monitoring (both quantitative and qualitative) are linked with the results of extensive field geological and speleological survey of the upper non-saturated part of the karst (such as sinkholes, pits and caves) and with the investigation of the permanently saturated deeper part of the aquifer (including the diving methods). The model of karst interior is based on the data from the 69 caves, 15 sinks and 1,682 dolines (sinkholes) surveyed. The total length of the karst channels network, calculated using the GIS model and presented in a 3D environment, is 647 km. The catchment areas of five major springs that drain the areas are estimated to range from only 7 km2 (Malo Vrelo Spring) to 124 km2 (Vrelo Mlave Spring). The groundwater exploitable reserves of Beljanica karst aquifer are estimated to be over 4 m3/s. The waters are low mineralized, unpolluted and have a great potential for water supply. 相似文献
108.
Kopa?ki Rit Nature Park is part of the Danube River natural floodplain and one of the last oases of wild life in the Danube River Basin. Due to its extraordinary value, it was inscribed on the list of Wetlands of International Importance in 1993. More than 2,000 species have been registered in this area, which consists of lakes, canals, grassland, marshland and forests. Even the number of investigations which have been performed on its biological and ecological features, hydrological and water resources characteristics, as a prerequisite for ecohydrological analyses, are still rather unknown in the scientific community. Mainly the Danube River and partly the River Drava cause flooding of Kopa?ki Rit and inundations enter the area from both the northern and southern parts. Results of hydrological and meteorological analysis show a decreasing trend of both mean and minimum, annual water levels in the Rivers Drava and Danube (respectively 1.8 and 1.38 cm/year). These reductions in water level can reduce the replenishment periods of Kopa?ki Rit Nature Park. In addition, a significant rise of mean annual air temperature and consequently water temperature (data 1988–2011) may be causing increasing evapotranspiration and loss of water within Kopa?ki Rit. But an encouraging counteracting finding is that, the results of frequency analysis show, even a discharge of 5-years’ return period on the River Danube inundates 70 % of the Danube floodplain and Kopa?ki Rit Nature Park. 相似文献
109.
Nenad Marić Sanja Mrazovac Kurilić Ivan Matić Stanko Sorajić Jelena Zarić 《Environmental Earth Sciences》2014,72(2):525-534
This paper provides insight into the quality of groundwater used for public water supply on the territory of Kikinda municipality (Vojvodina, Serbia) and main processes which control it. The following parameters were measured: color, turbidity, pH, KMnO4 consumption, TDS, EC, NH4 +, Cl?, NO2 ?, NO3 ?, Fe, Mn, total hardness, Ca2+, Mg2+, SO4 2+, HCO3 ?, K+, Na+, As. The correlations and ratios among parameters that define the chemical composition were determined aiming to identify main processes that control the formation of the chemical composition of the analyzed waters. Groundwater from 11 analyzed sources is Na–HCO3 type. Intense color and elevated organic matter content of these waters originate from humic substances. The importance of organic matter decay is assumed by positive correlation between organic matter content and TDS, HCO3 content. There is no evidence that groundwater chemistry is determined by the depth of captured aquifer interval. The main processes that control the chemistry of all analyzed water are cation exchange and feldspar weathering. 相似文献
110.
介绍散射伽玛能谱测井仪的组成工作原理、探测系统、探测技术、数据采集、处理及传输技术,能谱探测电路、数据采集电路及编制实时数据采集程序。并针对散射伽玛能谱测井在解决复杂岩性地层地质问题,确定空隙度、解释煤层气、裂隙带等方面的独具特点以及在煤田地质勘探中开展散射伽能谱测井的必要性进行了讨论。 相似文献