Geophysical Journal | 2007 volume 29 3

The rocks of granulitic complex: elastic parameters and the forecast of their distribution in the earth's crust of the Ukrainian shield

© Korchin V.A., Burtnyi P.A., Karnaukhova E.E.

Four petrophysical groups of rocks have been subdivided among the rocks of granulites complex of the Dniester-Bug area of the USh: charnockites, plagiocharnockites, enderbites, "basic granulites". Differentiation of rocks in accordance with their mineralogical and petrophysical features remains under PT conditions, which imitate different depths of the region. As a result of petrophysical thermodynamic modeling seismic heterogeneity of the crust has been revealed in its upper part up to the depths of 20-25 km, which is identified as a result of wide-spread occurrence here of charnockites, plagiocharnockites, chudnovo-berdichev granites. In the lower horizons stabile mineral composition of rocks is noted, which are represented by enderbites and "basic granulites". The last ones are exposed on the surface of the basement as separate dome structures. In the ancient structure of the Podolian block the rocks of basic-ultrabasic composition of the type of gabbro-norites, pyroxenites,bipyroxene gneisses are absent, which can sometimes occur as thin lenses and interbeds. The given materially-structural features of the models can be used as one of the criteria for revealing the most ancient blocks (relisc) of the Earth's crust according to geophysical data.

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