|
Aleksander Smirnov, Sientific Institute of Natural Resources YUGGEO (Kazakhstan)
Oleg Fedorenko , Sientific Institute of Natural Resources YUGGEO (Kazakhstan)
Victor Krasnoborodkin, Sientific Institute of Natural Resources YUGGEO (Kazakhstan)
Mihail Rafailovich, Sientific Institute of Natural Resources YUGGEO (Kazakhstan)
|
|
Kazakhstan Paleocontinent was formed at the Late Ordovician as the collision result of many microcontinents and island arches. MSZ intersect it from NW to SE, having Z-shape. We researched SE part of MSZ. MSZ consists here of three branches: Sarytuma, Zhalair-Naiman and Kordai-Moinkum. Many small terrains are included in MSZ, which divided by narrow shear-zones composed of dynamic schists. There are many ophiolite and other nappes inside and offside of MSZ. They have an olistostrome trains. As a whole, it is the accretionary complex. According to seismic reflection data MSZ dips to the SW direction beneath Stepniak-Betpakdala island arch terrain at the lower crust, but overthrusted upon it at the upper crust. MSZ is impressed very well on satellite images by dark color. Positive anomalies and high gradient elongated zones fix it at the gravity field. Contrast linear anomalies are connected with it at the magnetic field.
We have restored paleogeographic MSZ history from Riphean to Famenian. There was oceanic basin between Atasu-Jungar and Shu-Kendyktas microcontinents at the Late Riphean-Cambrian. Zheltau microcontinent was located in it. Oceanic crust subduction beneath Shu-Kendyktas microcontinent began at the Late Cambrian, ensimatic island arch and back arch basin had appeared. The volcanic arch, Zheltau and Shu-Kendyktas microcontinents had collided at the Early Ordovician. Zhalair-Naiman suture, Shatyrcol and others ophiolite nappes, Kordai-Moinkum shear zone was formed as a result. Oceanic crust subduction beneath Zheltau terrain began at the end of Early Ordovician, ensialic volcanic arch had appeared. Atasu-Jungar microcontinent had collided with Zheltau terrain at the Late Ordovician. Sarytuma suture with connected nappes was formed. So Main Suture Zone was constructed. Andean type volcanic belt had covered it at the Early-Middle Devonian. Zhailma and others intracontinental rifts were formed at the Famenian. Large NW strike-slip had appeared at the Late Paleozoic.
Following ore deposits disposed in sutures and shear zones or at its hanging walls: Au- Akbakai, Chokpar Severny, Karaguz, Ushalyk, Kepken; Au-Pb-Zn - Burultas; Au-Rare metal - Taskuduk, Sarybulak; Au-Cu - Shatyrkol; Au-Cu-Fe - Hantauskoe. Geodynamic environment and age of ore deposits are established. Pb-Zn sedimentary ore of the Burultas field was deposited at the Vendian-Cambrian passive margin. Chiganak Barite ore had appeared in the same environment at the Early-Middle Ordovician. Au - Kogadyr, Cu-Mo - Shatyrcol, Fe-Cu - Hantauskoe deposits had formed at the Late Ordovician collisional condition. Au - Akbakai and Ashiktas, U - Zhideli fields had formed at the Early-Middle Devonian volcanic belt environment. Fe-Mn field Akshagat had deposited at the Famennian rift stage. Established relationships were used for ore field forecast.
|
