SUMMARYTotal number of nineteen mafic extrusive rock samples is subjected to the detailed optical examination. Based on definition of mineral composition, structure, texture, type and intensity of alteration processes, and taking into consideration the recent classification schemes, different lithotypes are defined. The most frequent are spilites distinguished by classical "spilite" mineralogy (albite), and very often with "quench" texture and amygdaloidal structure. Diabases consist of primary plagioclase and clinopyroxene which are often decomposed and disintegrated. Diabase rocks are mostly characterised with ophitic texture and massive structure. Coarse grained varieties are characterized as dolerites, the rocks in which intensity of alteration process is significantly lower than in previous lithotypes. Varieties with frequent occurrences of amphibole got adjective amphibolic. The most common and the most intense alteration processes are albitization and chloritization. Alteration processes of lower intensity are actinolitization, pumpellytization, zeolitization, carbonation-calcitization, limonitization, kaolinitization and silicification. Depending on alteration degree a certain lithotypes are named with prefix meta (metadiabases and metadolerites).
In Bosnia and Herzegovina, Tertiary volcanic rocks occur within two geotectonically different areas: (1) in northeastern Bosnia, the wider area of Srebrenica and, (2) to a lesser extent in central Bosnia, the wider areas of Maglaj, Teslić and Nemila (Kolići). The major and trace element variations in the rocks surrounding Maglaj indicate their high-K calc-alkaline character, and are consistent with fractionation of the observed phenocryst assemblages (plagioclase, sanidine, biotite and hornblende). The scatter in some graphs cannot be explained by simple crystal fractionation from a common parent magma. More likely, such variations are affected by variable contribution and assimilation of continental crust within the magmas generated in the mantle. The presence of reverse zoned plagioclase phenocrysts, as well as a resorbed rim enclosing the coexisting quartz phenocrysts, can be interpreted by mixing of magmas with different temperatures and compositions.All analyzed rocks show enrichment of the LILEs over the HFSEs and have significant negative Ta-Nb, P and Ti anomalies, and positive U and Pb anomalies, which are characteristic of subduction-related volcanic rocks generated in (post) collisional zones. Chondrite-normalized REE patterns exibit enrichment on the LREEs over the HREEs with (La/Yb) cn ranging from 21.4 to 21.9. All analyzed rocks have small negative Eu anomalies (Eu/Eu * =0.86-0.89) which suggests that plagioclase fractionation played a minor role in the genesis of the dacites. Ratios of some diagnostic elements versus SiO 2 diagrams are best explained as a result of assimilation of varying degree in the continental crust during magma ascent and continuing fractional crystallization. High values of LILE/HFSE ratios in K/Ti (6.6 to 11.9), K/Zr (124-169), K/Nb (1598-2692) and Ba/Nb (44-65) and negative anomalies of Ti and Nb in the volcanic rocks surrounding Maglaj can be explained as the result of complex processes in the magmatic system originally derived from a mantle wedge.
SUMMARYThe railway Samac -Sarajevo was built in the fifties of the twentieth century, as a significant part of the railway that connects the central part of the former Yugoslavia with the Sava River. Later, in the seventies another track of Doboj and Zenica was built what was the most important by that time. In general the railway is situated on the corridor V, which links the Adriatic Sea via Sarajevo and Buda pest. Over time, the tracks are worn, damaged and speed has been reduced to about 40 km/hour.As part of the revitalization of the railway network in the former Yugoslavia, the reconstruction of the Samac -Adriatic Sea began, which is divided by sections. One of these sectionsis the section km 103 + 500 -Maglaj, a more demanding one compared to previous section from Samac to the now named section. The point is that the terrain along the route of the railway needs to be viewed from the aspect of geologi cal features, then the characteristics of the embankment so the geotechnical conditions for the revitalization of the railway line for speeds of 120 km/hour can be provided.Conducted field investigations along the route of the railway, as well as laboratory tests on samples provided enough data in the corridor route, while the wider area could not be perceived because of the mine field. However, the previous studies for the purposes of the General Geological Map, scale 1: 100 000, and field observations along the route line gave a satisfactory level of data for assessment of geological and engineering geological characteristics of the terrain.
SUMMARYQualitative characteristics of bauxite deposit "Oštrelj" are defined through extensive laboratory testing of chemical and mineralogical-petrographic composition, and geomechanical characteristics. Chemical composition has shown that it is a relative poor bauxite with low Al/Si module (2,28). Low values of Al/Si module are result of lower Al 2 O 3 concentration (48 %), and higher SiO 2 concentration (21 %), what these bauxites define as high silicic or »acidic«. Identified are increased concentrations of larger number of analyzed trace elements (B, Co, Cr, Li, Mn, Ni, Sn, V, Zn) comparing to the medium content in the Earth's crust. Mineralogical composition, structure and texture are uniform.Holders of Al mineralization are bemite and diaspor (to a lesser extent) as crypto-crystalline phases of rock matrix. Lower Cretaceous age (K 1 ) of roof layers over bauxite deposit is paleontologicaly documented, while in the bauxite any fossils are not registrated. Values of geomechanical paramers of layers under and over bauxite is uniform. In bauxite value of compressive strength is increased, which is equivalent to chemical and mineralogical composition, and structural and textural characteristics of tested bauxite samples.
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