| Title | Geologic Background of the Hangay Geothermal System, West-Central Mongolia |
|---|---|
| Authors | Erdenesaikhan Ganbat and Orolmaa Demberel |
| Year | 2010 |
| Conference | World Geothermal Congress |
| Keywords | Mongolia, Hangay dome, mantle plume, geotectonic, geothermal gradient, heat flow |
| Abstract | Tectonically the territory of Mongolia occupies key position in the Central Asian Orogenic Supercollage or Altaids, located between the Siberian craton on the north and Katasia (Tarim and sino-Koreon cratons) on the south. The Hangay dome in west-central Mongolia is the western end of Hangay Daurian terrane of the Mongol-Okhotsk orogenic belt. The Hangay region consists of intensely deformed Devonian-Carboniferous and not wide distributed Permian-Triassic sedimentary rocks intruded by late Paleozoic and early Mesozoic granites and granodiorites huge bodies. Late Cenozoic numerous high potassium alkaline basaltic provinces are distributed throughout the Hangay area. According to existing data, mantle plume beneath the region resulted in developing of 4-5 stages of magmatic processes from late Paleozoic to Late Cenozoic (Holocene epoch) in this region. It shows still active long-living mantle plume manipulating geothermal gradient in the crust. Therefore, India-Asian collision stress from the southwest (Algay transpressional belt) and Baikal extensional structures from the north are playing an important role for neotectonic faulting and perhaps Tertiary magmatic activation in the Hangay dome. There are number of NE and NW-trending normal faults within the Hangay mount region. Most of hot springs controlled by intersections of such kind of fractures, faults and contact brecciated zones between Permian, Carboniferous and Devonian sedimentary rocks and Permian-Triassic granitic rocks. The regional heat flow in the Hangay dome reaches 60-70 mW/m2 (Khutorskoi and Yarmoluk, 1989; Dorofeeva, 1992; 2003). The high heat flow of the Hangay dome is reflected in localization of over 30 hot and warm springs from 43 known in whole Mongolian territory with temperatures of 25-92°C. Uplift, alkaline magmatism, high heat flow, asthenosphere upwelling and neotectonic faulting are showing that characteristic signatures of geothermal ability in Hangay region. |