CRUSTAL CONDUCTOR ASSOCIATED WITH THE TALAS-FERGANA FAULT AND DEEP STRUCTURE OF THE SOUTHWESTERN TIEN SHAN: GEODYNAMIC IMPLICATIONS
E.A. Bataleva, M.M. Buslov*, A.K. Rybin, V.Yu. Batalev, and I.V. Safronov
Science Station of the RAS, Bishkek, 720049, Kyrghizstan
* Institute of Geology and Mineralogy, Siberian Branch of the RAS,
3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
Keywords: MTS, conductivity anomaly, crustal conductor, present stress field, Talas-Fergana Fault, Fergana block, Tien Shan, Pamirs
Pages: 1023-1029
Abstract
MTS data from five profiles across the zone of the Talas-Fergana Fault (TFF), interpreted in geoelectrical models, reveal a 10-15 km thick crustal conductor (consisting of several conductors) traceable to a depth of 45 km. The conductor rises to the upper crust along TFF and flattens out towards the Southwestern and Northeastern Tien Shan. The anomaly attributed to the TFF zone is divided into the Talas, Central, and Southern segments in the map view. TFF, interpreted as a high-angle strike-slip fault from geological data, is recorded in the electromagnetic field as a nearly vertical conductor only in its Central segment and shows a listric geometry in the Talas segment.
Interpretation of the MTS results correlated to geological data suggests that the modern geodynamic framework of the southwestern Tien Shan includes a structure of an arcuate plan view and a listric geometry which deepens to 40-45 km toward the center of the Fergana block. This pattern of the active zone agrees well with structural, paleomagnetic, and GPS data on the rotation of the Fergana block under the effect of pressure from the Pamirs.
|
