Quaternary Volcanic Activity And The New Structure, Xilinhot, Inner Mogolia

Xilinhot - Abaga volcanoe group is in the centre of Xilin Gol League Inner Mongolia Autonomous Region, located in the Xilin Gol Plateau ; and the terrain decreases from east to west and from south to north, usually in the 800-1200m above sea level. It belongs to the Tianshan - Mongolian fold system, Late Variscan fold belt Inner Mongolia, and is across the midst of Abaga Banner - Xiwuzhuqin Qi synclinorium. The time of the Cenozoic is Daxinganling - Datong volcanic belt. Volcanic rocks which are most of basalt are mainly distributed in the south Xilinhot and north ABaga. Volcanic rocks, NW, NE trending, about 750km longteh, 50-100km width, are exposed about 9300km 2, and are fourth basalt order in the north Abaga and south Xilinhot.Volcanic activity in this area is multi-stage and multi-cycle. Erupting age from the old to the new world divides into Pliocene, middle Pleistocene, early late Pleistocene, late late Pleistocene and Holocene. Pliocene volcanic activity means the large-scale fissure eruptions, forming fourth terraces; early Late Pleistocene forms large maar-type volcanoes; Late lare Pleistocene is the Stone Boley-type and Hawaii eruption; Holocene is Brod Rini type. Basalt composition transforms from the tholeiitic basalt to the alkai basalt according to the time, and since the late Pleistocene, the performance of each cycle shows the feature that basalt volves from alkaline to sub-alkaline. The formation background of a continental is the rift as a whole.The results show that volcanic activity in this area is closely related with the regional tectonic activity, indicating the regional tectonic uplift and volcanic activity coupled. Each of the volcanic eruptions are accompanied by regional tectonic uplift, and uplift rate are the same with the volcanic intensity. Late Pliocene crustal uplift rate is the most, leading the Great Lakes shrink or split, and at the same time volcanic activity is strongth, emitting large Laban basalt and forming the prototype of the Mongolian Plateau. Once again in the late Pleistocene, uplift forms third terrace. With Late Pleistocene tectonic uplift in general, Northeast and Northwest basement fault activity intensifies, forming a series of shooting steam - erupted magma type Maar volcanos and Hawaiian and Stone Boley volcanos composed by alkaline basalt along the fault. Late Pleistocene, the difference mainly reflects up-down movement, and volcanic activity becomes weak. During Holocene there is only few volcanic activity, mainly Brod Rini eruption. During different periods magnitude of the tectonic uplift and the intensity of volcanic activity is different , so multi-stage tectonic uplifts and volcanic activity shap the platform in this area landscape.