On the fault tectonics of the Baruun Huuray basin by using Remote Sensing images
G. Badarch, D. Dorjnamjaa
Geological Institute of Mongoliah Academy of Sciences
Ulaanbaatar 210351, Mongolia
M. Saandar
Remotes sensing and Geoinformation Center
MGGE, Mongolia
Abstract
This paper discusses the geodynamic environment of formation of the heterogeneous faults within the Baruun Huuray basin. On the remoe sensing images, in the northern side of the basin is established the Bulgan and Mergen thrusts, Turgen and Huvch strike slip faults. Southward of the basin occurred a series of left-lateral strike slip on the northeast trending and a lineer-fold of noth-west trend. The heterogenous faults of the Barun Huuray basin formed during the Late Paleozoic and Cenozoic period.
1. Introduction
The Baruun Huuray basin lies on the western part of the variscides of Southern Mongolia and adjacent to the area of Northwestern China. Previous work in Mongolia ( Tikhonov, 1974; Khilko et al. 1985 ) and China (Wenjun, 1968; Peizhen, 1982; Tapponnier et al. 1979 ) described several strike slip faults and thrusts. However, new data on the fault tectonics of the Baruun Huuray basin by using remote sensing images and as a results of our fieldwork is obtained in the last year.
2. Geology of the Baruun Huuray basin
The study area can be divided into two main tectonic zones such as Northern Baruun Huuray and Southern Baruun Huuray ( Badarch, 1990). Besides, along the Bulgan fault extended narrow tectonic wedge (Bizh), which is characterized by Lower – middle Devonian tholeiitic basaltsm tuffs, cherts, sandstones and siltstones (Fig. 2 ) . This Bizh wedge is analogy to the Ertysh zone of Northern Junggar ( Wenjin, 1968).
The Northern Baruun Huuray zone consists of Devonian and Lower Carbonierous alkaline volcanic rocks, includes trachyandesites,
Quartz lattes, trachydacites, rhyodacites and shoshonites. This volcanic series formed in the continental crust of the active margin.
The Southern Baruun Huuray zone is characterized by Devonian tholeiitic pillow lavas, calc-alkaline basalts, basaltic andesites, dacites, tuffs, siliciliths and volcaniclastic turbidities; the volcanic rocks are covered of Lower Carboniferous flysch like deposites. The west ( in China ) this zone consists of the Armantai ophiolite zone ( Wenjum, 1968 ). In opaleotectonic aspect the Southern Baruun Huuray zone treats of frontal arc, fore-arc and back-are basins.
