Vol. 38 No. 1 (203) (2004)

Results of the study of the source area of strong earthquakes are brought, which occurred in Central and Southern parts of the Republic of Armenia in prehistoric and historic times, as well as recently. Some time after the publication of the first report in scientific literature, as well as in the results of own researches new data appeared, which demand making corrections in the geological characteristics of the source areas, as well as make amendments in regard to the authenticity of this or that seismic event. A series of regularities of geological structure of source areas of strong earthquakes in Armenia are singled out.

It is stated in the article the petrographic description of contact-metasomatic granitizied and basificated rocks, structural-textural peculiarities of rare and little known types of rocks in the geological literature, form of metasomatic bodies, their internal structure and correlation with enclosing volcanic rocks of basalt-andesite composition. It is proved that the opportunity of formation of ores like granite and gabbro by the volcanic rocks of andesite-basalt composition by the contact-metasomatic granitization is possible. The described geological-petrographic data are the only objective basis for decision of petrogenesis problems of these problematic rocks.

The ruptures within Yeghvard plateau that cut upper pliocen - upper quaternary formations were investigated. The description of these ruptures and the nature of their interaction with surrounding rocks are presented. The position of these ruptures within the general structure of Middle-Araksian trough was observed. The conclusion about their voulcano-tectonic nature and comparison with several similar kinds of ruptures of the surrounding area were made.