Mineralogical and geodynamical conditions of transformation of peridotites from ophiolites in the Marmarosh zone roc
Journal Title: Геодинаміка - Year 2016, Vol 21, Issue 2
Abstract
Purpose. The purpose of our research is to reconstruct geodynamic condition of transformation of Marmaroch zone peridotites. This investigation is based on the study of rock petrography, chemical composition of minerals and recognizing of thermodynamic condition of mineral formation. Methodology. The occurrences of peridotites bodies in the basin of Mala Ugolka and Velyka Ugolka river have been studied. Laboratory study includes petrographic microscopic observations and analysis of mineral composition by using scanning electron microscope equipped with an energy dispersive spectrometer. Results. Ophiolites of the Marmaroch zone rocks are represented by cataclastic varieties of lherzolites and harzburgites. Rocks are characterized by the following minerals: olivine, orthopyroxene, clinopyroxene, amphibole, talc, chlorite, serpentine, magnetite, spinel. Based on microanalitycal data, the new varieties of spinel in peridotites have been recognized for the first time. According to Pavlov’s diagram (Pavlov, 1949), the first group of spinel can be attributed to pycotite, the second one to chrom-pycotite. Two equilibrium mineral association in ophiolite peridotites were originally distinguished: first – olivine+spinel+ orthopyroxene+clinopyroxene, second – spinel +amphibole+talc. In the context of temperature and pressure of mineral transformation, some mineral association have been analysed. For spinel and olivine-spinel geothermometer P-T parameters for first mineral association are estimated in a range – 900–1290 °С, ~ 15 kbar; for second mineral association – 430–450 °С, 4,0–4,5 kbar. Thermodynamic conditions of transformation of peridotites are displayed in the degree of partial melting and spreading velocity. First mineral association shows melting degree not exceed 14 %, that is the characteristic of slow-spreading peridotites; second mineral association shows 25 %, that is the characteristic of high-spreading peridotites. First stage of peridotite formation can be related to the slow-spreading condition in spinel peridotite zone of oceanic crust. On the second stage, peridotites are changed in above-subduction zone under condition of back-arc spreading. Scientific novelty. Application of scanning electron microscope equipped with an energy dispersive spectrometer enabled to specify the mineral content and petrotypes of peridotites, to distinguish two equilibrium mineral association, to determine thermodynamic conditions of formation and transformation of peridotites from Marmaroch rocks zone. Original model of multistage formation of peridotites in the Ukrainian Carpathians is proposed. Practical meaning. The study of substantial and geodynamic features of peridotite evolution is topical from point of view of problems, that concern Earth crust formation and formation of folded region lithosphere (based on the example of the Ukrainian Carpathians). The obtained results can be bused to forecast estimation of ore potential, related to the studied peridotite complexes
Authors and Affiliations
N. Bilyk, l. Generalova, I. Yatsenko, V. Stepanov
Keywords
Related Articles
- EP ID EP195298
- DOI -
- Views 89
- Downloads 0
"Young platform"- traditional intelligence and reality (geodynamic aspect)
Purpose. Transition of theoretical tectonics to the mobilistic position has changed a notion of the nature of geological processes, and hence approaches to re-comprehesion on the new high-quality level of views of the te...
Pokuttia deep fault and its influence on tectonics and the oil- and gas-bearing of the south-eastern segment of the Carpathians
Objective. The objective of this study is to analyze the influence of the Pokuttia deep fault on tectonics and the oil- and gas-bearing structures in the south-eastern part of the Ukrainian Carpathians. Methodology. It...
Using data of infrasound measurements in Ukraine for explosions and earthquakes identification
Purpose. The purpose of research is to determine the possibility of using of infrasound measurements that carried out in Ukraine for verification of registered seismic events and using of infrasound method as one of the...
Geological and paleooceanographic models of the Carpathian-Black Sea continental margin of the Tethys
Purpose. To clear up geological-paleooceanographic conditions of sediment-lithogenesis of the Mesozoic-Cenozoic deposits of the Carpathian-Black Sea continental margin of the Tethys. Methodology. Multi-aspect complex app...
The association of physical properties of deep reservoirs with the geomagnetic field and fault-block tectonics in the Hlynsko-Solokhivskyi oil-and-gas region
Purpose of the study. To study physical properties of the reservoir rocks of Semyrenkivske field in the Hlynsko-Solokhivskyi oil and gas region (OGR) of the Dnipro-Donets Aulacogene with the aim of evaluating their filtr...