SURFACES OF PLANAFIUN OF THE USSR

Abstract

Extensive data obtained in the process off compiling a summary map of planation surfaces and weathering crusts on the territory of the USSR (on the scale 1 :2.500.000) make it possible to draw some general conclusions. Planation surfaces proved to be widespread both in mountain and plain regions of the USSR. They are the following: 1) ancient Mesozoic and Pre-Mesozoic surfaces of a peneplain and pediplain type; 2) geomorphological levels, often polygenetic, of the Cenozoic age. The stages of formation of planation surfaces in Indo-Atlantic and Pacific regions of the USSR were asyncronous. The formation of Pre-Cenozoic planation surfaces was followed by formation of siallitic and ferralitic weathering crusts; the accumulation of thick crusts coincided with the final stages of relief leveling. The analysis of planation surfaces and weathering crusts helps in prospecting for minerals.