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FRAGILE EARTH: Geological Processes from Global to Local Scales and Associated Hazards (4-7 September 2011)

Paper No. 10
Presentation Time: 08:30-18:00

THE PALEOTENSION FIELDS RESEARCH OF FORE-MARMAROSH NAPPES (UKRAINIAN CARPATHIANS)


GAYDUK, Taras, Dept. of Problems of the Carpathians Geology, The Institute of Geology and Geochemistry of Combustible Minerals of NAS of Ukraine, 3a, Naukova Str, Lviv, 79060, Ukraine, BONDAR, Roman, Dept. of Deep-Seated Fluids Geochemistry, The Institute of Geology and Geochemistry of Combustible Minerals of NAS of Ukraine, 3a, Naukova Str, Lviv, 79060, Ukraine and YAREMOVYCH, Mykhaylo, Dept. of Problems of the Carpathians Geology, The Institute of Geology and Geochemistry of Combustible Minerals of NAS of Ukraine, 3a, Naukova Str, 3a, Naukova Str, Lviv, 79060, Ukraine, romanbondar@mail.ua

In this paper presented some aspects of flysch and volcanic rocks jointing researches within the south-eastern part of Ukrainian Carpathians – Rakhiv, Burkut and Chorna Gora nappes (Ceahlau and Audia nappes in Romanian Carpathians). This nappes is a result of Fore-Marmarosh accretionary wedge forming during subduction in Early Cretaceous. Within black flysch of Burkut nappe observed here fragments of oceanic crust – the so called Trostyanets volcanogenic complex.

Field observations was analysed by the program FaultKinWin (Kornel University, USA). The field types of the paleotension were determined by a table (Sherman, 1989) in which is regulated interdependence between directions of main tensions axes and morphologic-genetic types of faults in the earth crust is set.

There are the cleavage fissures directed from northwest to southeast and from north to south prevailed within the limits of this region, what coincides with reaching of main discontinuous thrusts in region. In most cases fissures are characterized by a sub vertical batice. It should be noted that the degree of development of fissures is rather uneven, of which the little microfissures as well the large (from first centimeters to first ten meters) were morphologically observed.

Flysch formations of Burkut nappe characterized by northern direction of the pressure axis with shifting and sliding type of the tension field determined. The frontal part of Burkut nappe characterised by movable and upthrust type with a clearly defined sliding component. Volcanic rocks of Trostyanets complex characterised by shifting and sliding tension type. The axis of pressure is directed to the northeast.

Analysis of the paleotension fields separately for sedimentary (flysch) and volcanogic formations of region we come to the conclusion, that lithological composition of the rocks does not have a clear influence on the direction of main axes of tension. Considerably more influence on the local fields of tensions has the distance to the front of thrust and availability of transversal faults of different order. The considerable diversion of main axes directions of the local fields tension is explained as the uneven distributing of paleotension during the overtrusting.

The tectonophysical researches of Fore-Marmarosh nappes can largely shed light on the geodynamic evolution of the Eastern Carpathians as a whole.

Session No. 27--Booth# 13

T2A. Subduction and Collision Processes Through Time in the Mediterranean Area — From the Deep Mantle to the Surface (Posters)
Tuesday, 6 September 2011: 08:30-18:00
Poster Hall P2 (E106, Senatsraum, 1st floor) (Ludwig-Maximilians-Universität München)
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