Russian Journal of Earth Sciences
Vol. 6, No. 1, February 2004
Morphology and origin of folding in the South Tien Shan
E. A. Rogozhin
Abstract
The qualitative and quantitative analysis of the
holomorphic folding morphology in the central segment of the
South Tien Shan revealed its heterogeneity in the Paleozoic
rock sequences. Against the background of the gradual folding
simplification from the axial parts of the mountain system to its
periphery, the relatively intense dislocations alternate with less
tense structural fields. The former are restricted to the
anticlinoria and large anticlines, the latter, to the synclinoria
and large synclines. The study of the fold formation history
proved the fact that the recent orogenic structures had been
inherited from the anticlinoria and synclinoria of Hercynian time.
The disharmonic and highly variable folding of the South Tien Shan
seems to have originated as a result of the combined effects of
three factors: (1) the deformation of the allochthone rocks during
the gravitational movement of the tectonic nappes; (2) the
external subhorizontal reduction of the crystalline basement and
the overlying volcanic and sedimentary rock sequences, and
(3) advective movements in the rocks of the sedimentary cover.