GEOLOGIC NATURE OF INTRACRUSTAL WAVE GUIDES IN SOUTHERN SIBERIA

Abstract

In seismic sections of many regions in the world, there are discrete intracrustal wave-guide or inversion layers with low elastic-wave velocities relative to the host rocks. From our model of the development of intracrustal wave guides, we conclude that they are mostly Precambrian in age, and that their presumed granitic origin explains why these forms are geologically and geophysically diverse in southern Siberia. Thus, theories concerning the granitic origin of intracrustal wave guides in southern Siberia most satisfactorily explain the data on the structure and geophysical properties of the enclosing crustal segments. More accurate determination of the structure of the bodies of granitic origin that form wave guides is important for the seismotectonic zoning of regions. Establishing the paragenetic relationship between intracrustal wave guides and old, rift and lip (labigenic) structures should also enable geophysical and, most of all, seismic exploration data to be used in paleotectonic reconstruction, metallogenic analysis and prediction of potential areas of endogene ore mineralization genetically related to plutonic rocks.