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拉脊山位于青海省东部农业区,为黄河和湟水的分水岭。一般海拔在三千米以上,山势陡峻;特别在东段,因深流切割,多跌水悬崖;中段相对平缓。本区在地质构造位置上,属古南山构造体系的一部分,并受古化隆旋卷构造的控制。中新生代以来,为祁吕贺兰山字型构造前弧西翼的南侧,并有河西系和化隆旋卷构造复合和交接。从古地理环境来看,本区在寒武纪和奥陶纪时,为一狭窄细长、快速沉降的深断陷海槽。从地槽说观点来看,则属南祁连地槽褶皱带的东延部分(图1)。
Lajishan is located in the eastern agricultural area of Qinghai Province, a watershed between the Yellow River and the Lushui. The general elevation of more than three kilometers, the steep mountains; especially in the eastern section, due to deep cutting, falling more cliffs; middle relatively flat. The area is located in the geological structure, is part of the ancient Nanshan tectonic system and is controlled by the tectonic cloning. Since the Mesozoic and Cenozoic, the southern part of the western front of the arc has been constructed for Qilu Helan Mountain glyph, and the Hexi Formation and the Hualong spiral volcano have been constructed and transferred. From the perspective of paleogeographic environment, this area was a deep, fault-sag trough narrow and slender and rapidly subsided during the Cambrian and Ordovician periods. From the perspective of geosyncline, it belongs to the eastern extension of the South Qilian Trough fold belt (Figure 1).