Distribution of main ore deposits and strong earthquakes in regard to the lithospheric structure of Central Asia
Khamrabaev, I.; Seiduzova, S.; , Matasova; Yankovskaya, N.
published: Jan 1, 1999
ArtNo. ESP136000701009, Price: 19.00 €
The territory of Central Asia which includes the Hercynian folded structures of the central and western parts of the Tien Shan, the Touran plate, the Pamirs, and the Kopetdagh alpides, contains various ore deposits including giant units. It is also a high seismic region where strong and destructive earthquakes occur rather often. Earthquake foci (hypocenters) in the Tien Shan region mainly appear in the upper crust (up to depths of 25-30 km). In the Pamirs, these events can occur both in the upper crust and in an upper part of the upper mantle (up to depths of 220-240 km). The lower crust in Central Asia (foot depths 30-80 km) appears to be aseismic in almost all areas. The earthquake epicenters trace large sublatitudinal steeply dipping faults that divide tectonic elements and blocks and displace the Moho discontinuity for 5 to 10 km (North Ferghana, South Ferghana, Atbashi-Inylchek, South Tien Shan, North Pamir, and other faults). Large geotectonic units of the Tien Shan and the Pamirs are of well-defined metallogenic specialization: caledonides of the North Tien Shan - ferrous/polymetallic/rare-earths; hercynides of the Middle Tien Shan - copper/ferrous/polymetallic /gold with fluorite and uranium; hercynides of the South Tien Shan - gold/rare metals (W, Mo, Sn, Hg, Sb) etc. The ore deposits are arranged as a belt zonation (the South Tien Shan) or as a node distribution (the Middle Tien Shan). Antagonism between large endogenic ore deposits and epicentral zones of strong earthquakes is being confirmed by evidence from other countries. Within the lithosphere, one can find a certain connection between the distribution of ore deposits and high velocity bodies. The absence of strong crustal earthquake foci in zones of lower seismic velocities, high conductivity, and higher plasticity (Vp/Vs > 1.75) has been established. In the present report, the authors offer an interpretation of the causes of these associations.