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1

Thrust structures in Trangoska syncline, Low Tatras, Slovakia

Sokol E, Melichar R.

Geologia Sudetica

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2014

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Vol. 42

88--88

2

The Clay and Zavist faults - one large strike-slip fault in the east part of Barrandian (Bohemian Massif)

Knizek M, Melichar R.

Geologia Sudetica

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2014

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Vol. 42

36--37

3

Tectonic contact of the Brno Massive and Devonian sediments in the north part of the Moravian Karst

Marhansky T, Melichar R

Geologia Sudetica

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2014

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Vol. 42

55--55

4

Studies of AMS fabrics in Ordovician sedimentary rocks, Barrandian, Czech Republic

Černy J., Melichar R

Geologia Sudetica

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2014

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Vol. 42

7-7

5

Magnetic anisotropy and tectonics of the Upper Proterozoic rocks of Barrandian

Dudinskiy K, Melichar R.

Geologia Sudetica

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2014

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Vol. 42

11--11

6

Insight into the main structural and tectonic elements of the southwestern part of Jordan

Radaideh O, Melichar R.

Geologia Sudetica

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2014

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Vol. 42

76--76

7

Anisotropy of rock ruptures - experimental study

Proisl T, Melichar R.

Geologia Sudetica

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2014

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Vol. 42

75--75

8

AMS of Cambrian volcanic rocks in Barrandian

Kolarova K, Cerny J., Melichar R

Geologia Sudetica

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2014

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Vol. 42

40--40

9

A general comparison between the Paleostress methods

Radaideh O, Melichar R

Geologia Sudetica

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2014

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Vol. 42

77--77

10

Hydrothermal veins linked with the Variscan structure of the Prague Synform (Barrandien, Czech Republic): resolving fluid-wall rock interaction

Halavínová M., Melichar R., Slobodník M.

Geological Quarterly

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2008

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Vol. 52, No 4

309-309

EN

Variscan syntectonic hy dro ther mal veins of the Prague Synform are important traces of small-scale fluid migration in Lower Palaeozoic sedimentary rocks — a process induced by late Variscan tectogenesis. Two main structural types of Variscan syntectonic calcite veins were recognised during fieldwork. Veins of Type I have an irregular or sigmoidal shape and are often arranged in en echelon arrays. A shearing regime during the formation of this type is deduced. Veins of a second structural type (Type II) have a more regular and straight shape relative to those of Type I and in some places form a dense network. The structural position of the Type II veins is related to structural elements of Variscan folds. Veins were formed due to interlayer-slip combined with fold- related fracturing that gave rise to the infilling of dilational structures. A tensional regime also permits growth of the fibrous veins. Two princpal directions were distinguished within the Type II veins. The first one is NNW–SSE and the second one shows a perpendicular ENE–WSW orientation. These directions seem to be parallel and/or perpendicular to the nappearchitec ture of the Prague Synform. Variscan syntectonic veins crystallised in a relatively closed, rock-buf fered system. Extraction of chemical components from surrounding rocks is indicated by a combined microprobe/cathodoluminescent study and by isotope geochemistry. The carbon isotope values of hydrothermal calcites reflect the carbon isotope composition of the host rocks. The delta exp.13C values of vein calcites and their host Silurian rocks are between –0.29 and –1.98‰ PDB. The same relationships were found between the veins and the host Devonian limestones (from 1.72 to 2.52‰ PDB). Samples close to the Silurian/Devonian boundary show transition values between 0.25 and + 1.16‰ PDB. The Sr-isotopic signature supports a genetic link between the calcite veins and the host rocks. The 87Sr/86Sr ra tio in calcites ranges between 0.708619 and 0.708738 and in wall rocks be tween 0.708755 and 0.709355. Aqueous and hydrocarbon-rich fluid systems have been found in fluid inclusions. Liquid hydrocarbons show mostly a light blue fluorescence suggesting the presence of higher hydrocarbons. They are more abundant in dark Silurian rocks, which are rich in organic matter. Lower salinities (0.5–8.9 eq. wt.% NaCl) and homogenization temperatures with a maximum around 140gradeC are typ i cal for the aqueous (H2O–NaCl) system. The oxygen isotopic composition of fluids ranges between –2.80 and +3.33‰ SMOW. This indicates that transformed formation waters in teracted with the host rocks and/or deeply circulating isotopically depleted meteoric waters. Intersections with the isochore specify border trapping temperatures between 127 and 160grade C and pressures from 300 to 1070 bars.

11

Flat-ramp-flat thrust geometry in the Outer Western Carpathians (Palava Hills, Czech Republic)

Poul I., Melichar R.

Volumina Jurassica

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2006

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Vol. 4, no. 1

62-63

EN

The Pavlov Hills are situated in the NW margin of the outer units of the Carpathian Flysch Belt. The structure of the Pavlov Hills (Klippen Belt) is a result of thrusting of the Carpathian accretionary wedge. The hills are formed by Jurassic to Cretaceous preflysch sediments incorporated into nape slices of the Carpathian Flysch Belt. In the Jurassic the preflysch sediments are represented by (Upper Jurassic), dark- grey deep marine claystones (Klentnice Fm.), which are laterally replaced by nodular limestones and light-coloured shallow marine limestones (Ernstbrunn Limestones) in the top of the Jurassic carbonate facies of the Zdánice Unit. The Cretaceous sediments consist of glauconitic sandstones (Klement Fm.) and grey claystones (Palava Fm.). Flysch sediments (Maastrichtian to Eggenburgian) are represented by red claystones, brown and green claystones, menilite layers, and typical flysh sediments (rhythmic layers of sandstones, claystones and calcareous pelitic sediments). The Mesozoic rocks were derived from the platform basement during the younger phase of the Alpine orogenesis. The beds in the area under study are striking mostly in a the NE-SW direction and dip either to the SE or to the NW (Fig. 1). The opposite dip directions were interpreted as a result of large-scale folding. At least two large antiformal structures were recognized, the first one in the eastern part of the town of Mikulov, and the second one in the northern surroundings of Klentnice Village. As the fold axes are plunging to the NE, it was possible to recognize their prolongation in the seismic cross-sections. These anticlines are associated with thrusts documented by stratigraphic inversion, as the Jurassic and Cretaceous rocks overlie Palaeogene sediments. Fault-related anticlines indicate location of ramps on these fault planes and unfolded sediments are typical of flat fault geometry. The main detachment (flat) is situated in the basal part of the Klentnice Fm. and the other flats are in the younger "nodular limestones" and above the uppermost part of the Ernstbrunn Limestones as well (Poul & Melichar 2005). Competent parts of the Ernstbrunn Lm. are cross-cut by the fault plane forming ramps with angle Φ=20°. This model was confirmed by compass data, seismic cross-sections and sequences in boreholes with duplicated thicknesses and tectonic slices. The thrusted Jurassic slices were cut by several, but three main dextral strike-slip faults striking in NW-SE direction. Slipped blocks were rearranged into a N-S trending klippen zone, which is, in fact, a large-scale en echelon structure. Using this model a new geological map was completed with new tectonic features. The flat-ramp-flat geometry model of the thrusts is suitable for the arrangement of the Pavlov Hills as well as for another limestone slices incorporated into the accretionary wedge of the Outer Western Carpathians.