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Abstract

The Kiskunhalas-NE (KIHA-NE) fractured hydrocarbon reservoir is part of the structurally rather complex crystalline basement of the Great Hungarian Plain. In the course of petrologic and thermometric examinations various rock types of the investigated area have been classified and characterized. There are four basic lithological units in the area. In the lowest structural position orthogneiss is common, which according to its petrographic features is assumed to be identical to the orthogneiss body of the adjacent Jánoshalma (JH) basement high (metamorphic peak temperature T < 580 °C according to Zachar and M. Tóth 2004). The next rock unit upward is the highly mylonitized variety of the orthogneiss with textural features suggesting deformation in an extensional stress regime. In the higher section of the mylonite zone graphitic gneiss mylonite is characteristic, with a peak metamorphic T of 410±45 °C. The lithology in the shallowest position of the area is a graphitic carbonate phyllite, with a T of 375 ± 15 °C. Estimation of the deformation temperature for both mylonitic rocks results in approximately Tdef ∼ 455 °C. All data together suggest that between the top (graphitic carbonate phyllite) and the bottom (orthogneiss) of the ideal rock column there is about 200 °C peak metamorphic temperature deviation. The two extreme metamorphic blocks probably became juxtaposed along an extensional fault zone in the basement at approximately 15 km depth.

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Central European Geology
Authors: János Haas, Tamás Budai, István Dunkl, Éva Farics, Sándor Józsa, Szilvia Kövér, Annette E. Götz, Olga Piros and Péter Szeitz

chert. In some places (Kálvária Hill and Kő Hill), a large amount of andesite clasts occurs in the basal beds ( Hofmann 1871 ; Horváth and Tari 1987 ). Recent investigations pointed out that the petrographic features of these clasts are similar to those

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Central European Geology
Authors: Zsófia Pálos, István János Kovács, Dávid Karátson, Tamás Biró, Judit Sándorné Kovács, Éva Bertalan, Anikó Besnyi, György Falus, Tamás Fancsik, Martina Tribus, László Előd Aradi, Csaba Szabó and Viktor Wesztergom

Si orthoclase, for Al corundum, for Cr chromite, for Ti rutile, and for Fe almandine. Results Petrographic description Instead of geochronologic order, we describe petrographic features according

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 al. ( 2004 ). Based on these works, some typical paleocave formations are recognizable not only by well-log analysis but also in cores or thin sections. Our goals are to observe, document, and interpret the petrographic features of the Triassic

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Central European Geology
Authors: Attila Demény, Alexandra Németh, Zoltán Kern, György Czuppon, Mihály Molnár, Szabolcs Leél-Őssy, Mihály Óvári and József Stieber

substratum. While the lowermost part (under 54 mm from the top of the sample) is also calcite, it has strikingly different petrographical features. The macroscopically clear calcite here is made of two different types of crystals. The first type is a

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