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前言北山位于甘肃西北部、内蒙西部,向西一部分延入新疆境内,属天山山脉的东延部分(图1)。该区古冰川问题,早在1960年赵祥生在该区工作时,已提到:“在下寒武统下部的一套砾岩局部有冰碛特点,含有巨大之冰川漂砾”,当时未能引起重视。1979年赵祥生等在研究西北地区震旦纪冰碛层的基础上,根据以往资料分析,认为这套冰川沉积应为震旦系,并单独分出,命名为北山组。但缺乏建组剖面,对上下界线也不够明确。作者通过近两年的工作,取得了大量冰川证据,对该区震旦系及冰川沉积进一步加以肯定,并建立了震旦系完整的剖面。
Preface Beishan is located in the northwestern part of Gansu, western Inner Mongolia and part of the westward part of Xinjiang, belonging to the eastern extension of the Tianshan Mountains (Figure 1). As early as 1960 when Zhao Xiangsheng was working in the area, the ancient glacier problem in this area has been mentioned: “A group of conglomerates in the lower part of the Lower Cambrian have features of moraine locally and contain huge glacial boulders” Caused attention. On the basis of studying the Sinian moraine layer in Northwest China in 1979, Zhao Xiangsheng et al. Analyzed the past data and concluded that the glacial sediments should be of Sinian origin and separated separately and named Beishan Formation. However, the lack of group profile, the upper and lower boundaries are not clear enough. Through the work of the past two years, the author has obtained a large amount of glacier evidence and further affirmed the Sinian and glacial deposits in the area and established a complete profile of the Sinian.