自19 世纪70 年代板块构造理论引入中国后, 一些学者把拗拉槽(Aulacogen) 一词赋予了鄂尔多斯盆地西缘贺兰山地区, 并认为贺兰山、秦岭、北祁连中新元古代至早中寒武世为裂谷发育阶段, 秦岭、北祁连、贺兰山构成了三叉裂谷系。该论点很快被国内众多学者认同并引用。在一些文献和论著中, 一些学者将拗拉槽的概念进一步引伸、发挥。由此, 引起了笔者的极大关注。通过对国内外大量关于拗拉槽文献资料的查阅和对秦祁贺地区的构造形迹、地层及沉积特征的研究观察, 以及对盆地中几条横穿所谓中、下元古界拗拉槽的地震和重、磁、电剖面的仔细核实, 深感其证据不足, 在沉积、构造上都与国内外定义的拗拉槽存在较大的差别。对此, 就关系到大陆动力学、盆地动力学以及鄂尔多斯盆地发展、演化的这一重大地质问题提出了质疑。

Since the plate tectonic theory was introduced into China in 1970’s, aulacogen has been considered in the area of Helan Mountain in Ordos Basin by some geologists. It is believed that Helan Mountain, Qinling and northern Qilian area were at the stage of rifting development fromMid-Neoproterozoic to Early-Mid Cambrian, and that Qinling, northern Qilian, Helan Mountain formed a trifurcate rift valley system. This viewpoint was quickly accepted and quoted by many geologists in China. The concept of aulacogen was extended and developed by some scholars. This paper raises the queries about the aulacogen in Helan Mountain. Through consulting a large amount of documents and data about aulacogen both at home and abroad, researching the shapes and sedimentary features of Qinling-Qilian- Helan Mountain area, and carefully verifying seismic, gravity, magnetic and electric profiles of the so-called aulacogens that cross the Mid-Lower Proterozoic, the authors think that the evidence of aulacogen in Helan Mountain is insufficient, and it is quite different from the aulacogen defined at home and abroad in the aspects of sedimentation and structure. So it is believed that aulacogen does not exist in Helan Mountain area.