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2010 |
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An massif, or syndeformation porphyroblastasy zone? Osۥmachko L. National Academy of Sciences of Ukraine. M. P. Semenenko Institute of Geochemistry, Mineralogy and Ore Formation. 34; Kiev, Ukraine The work was carried out in the eastern part of Peri-Azovian megablock Ukrainian Shield (UŜ). Directly within Southwestern contact Kal′miussky array granosienits, sienits, etc. rocks with his source formations metamorphosed entities. The last refers [1] to the Priazovsky charnockite-granulite structural-formational complex (SFC), the rock of massif - is the Vostočnopriazovsky plutonic SFC. According to the hronostratigrafic schema [2] rock of Kal′miussky array are intrusive-igneous and belong to the Hlebodarovsky complex with age 2029 + 29 Ga. We have also found that analyzed station complex alternative and mixedorientation dislocation structures, conctruction and relationships which are entities formed in sheared plastic [3-8] geological environment. All four generating such structures that differ in spatial orientation, real content and degree of secondary transformation of substrate. The structure of the first generation at the meso-level represented banding North-East stretches and subvertical downs. Banding was conditional on the existence of lens-string, which corresponds to the biotite gneisses and granodiorites. The power of such entities vary between 5-50 cm, i.e. this uneven strained lateral stripes and lens-strip above marked compound. The border between dissimilar in composition lens -bands quite gradual. The ratio of long axis in short (а:с) the lenticular entity varies within 3-10. Inside their organization represented by the presence and alternating thin – first mm capacity lens- string with (а:с) 3-10. Due to enrichment/impoverishment dark-coloured minerals microsection as gneisses so granodiorites formulations rocks. Thus formed microlens, and also minerals like within and beyond oriented single-system with the bodies of the meso-level and form schistosity, thin-streak texture of rocks-bodies. Structure of the second generation at the meso-level, represented by Echelon threads fragmented area granitoid composition of lenticular bodies. Granitoides medium to coarse-grained, dominate pinkish-white, rarely white and grey-white. Lens placed subvertical, long their axis oriented Northwest. The dimensions of lenticular bodies phone long axis (a) in 1.5-10 m, correlation а:с – 5-6; distance between individual bodies exceeds their sizes on the short axis (c). Such a lenticular bodies cut first generation banding educated in varying as expressed by bendes its because the last involved differently-intensity schistosity in the north-western direction. Also inside the lenticular bodies this generation are heavily modified, granitization and schistosity relics of the structures of the first generation. Their sizes vary within 1.5-20 cm long axis. The internal organization of the studied lens is also a lenticular (texture), due to enrichment/impoverishment that or others supreme minerals individual lenticular micro-plots of meso-lens; also different dimension of mineral grains such micro-plots. Thus formed microlens have sizes up to 7 cm on а, а:с – 5-6, are they oriented and distributed on area of geological bodies as meso-level lens on the plots. Similarly, within the meso-lens posted and relic education. I.e. education- bodies of this generation at all levels of the Organization are structures shearing-lenticularity and secondary bundle [3-5 etc.]. Third generation have build similar entities of second generation. They differ submeridional the strike, composition of the relevant feldspar quartzite – aplite-granites, and ratio а:с the diversity-level bodies within 4-10 and more intensive schistosity. Dislocation structures fourth generation are actually education Kal′miussky array and at the meso level represented shearing-lenticularity structures. This system lenticularity bodies composition mainly granosienites, sienites (as biotie, amphibolic and piroxenic) and the composition of the relevant entities of the previous phases. Lenticularity of meso-level of the really granosienites expounded irregular at area and at rate shearing. Hence, there are lots of rocks from coarsegrained, trachytoid structures to finegrained, gneissic with all possible between them. The dimensions of lenticular bodies granosienites composition on axis a vary quite widely, from 2 to 15 m, with a ratio а:с reaches 5. The internal organization of such bodies is also a lenticular-banding due to ovate-elongated form grains of feldspar (most often this microcline, microcline-perthite, rarely albite), wrapping them fine-grained mineral mass in the form of a thin (in mm) lenticular-banding, reality small lens-relics, uneven distribution area of meso-lens all components of such lenticular, also the harmonized oriented North-East of their. а:с with all designated micro- mesolens vary from 5 to 7. Lens-shaped granosienits composition mesobodies form almost unified field in which up to 10 % (sometimes more) took lenses composition of granodiorites, gneisses – granodiorites, granitoids, quartzites, etc. rocks. Some patterns in placing lenses a composition of a whole area (from the center to the periphery of the array, etc.) is not committed. Lens-inclusion size on the lot lowers lenses-owners; internal their structure are anisotropic – is also due to the uneven schistosity, lenticularity and some differentiation of substance. All lens-bodies corresponding Kal′miussky array deployed subvertical, long their axis oriented North-North-East. The shear displacement involved all rocks variety geological bodies in volume environment responds to the array. Contacts last with his source quite sharp, in the horizontal plane also have lenticular-harrow form. The evidence of intrusion rocks array is missing. At the level of slide in all selected entities are manifested microstructure that repeat in miniature build of entities in outcrop. But building not only expressed in morphology and placing secondary microbodies, and a material. Namely: mineral paragenesisis each subsequent generation to varying extent substitute minerals each of the previous generation. For example, the formations of fourth generation, secondary their genesis at the micro-level expressed: uneven distribution area of the plates of the mikrocline – microcline-perthite; its zonal structure that in slides expressed as zones of mineral asynchronous extinction, zones with different orientation and morphology of twins lattices, zones with varying degrees of perfection, various thickness (dimensions), form, features of the distribution by area of grain sibling individuals, perthitic intergrowths, also relict minerals and their units. Often twins individuals hanging (nipped to the periphery grains). Boundaries thus separate zones of mikrocline – microcline-perthite underlined accumulated within the relic minerals and their units, and ore. The composition and size of the grains of such accumulations identical are matrix feldšpar. Melanocratic minerals matrix and their units are monoclinal orientation and are parallel to the prolongation of the feldšpar. Such structure at the microlevel plates feldšpar and matrix indicates their formation through substance more ancient mineral paragenesis for the mechanism of collective recrystallization.
Thus, all generations of
structures have congruent motives and single lenticularity-linear
style construction at all levels of their organization. The
lenticular-structure of each successive phase mask and evolve on
like each of the previous phase. Lenticularity does not allow same
within entities one phase petrography-structural/
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