ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    贺兰山中段寒武系阿不切亥组风暴岩的发现与地质意义

    Geological Characteristics of Tempestite from Cambrian Abuqiehai Formation in Middle Helan Mountain and Its Geological Significance

    • 摘要: 首次报道了宁夏贺兰山地区上寒武统阿不切亥组发育的一套典型灰质风暴岩。在该风暴沉积中发现底面侵蚀构造、砾屑叠瓦状构造、放射状组构、生物扰动构造等,为典型的浅水风暴岩。该组下段发育鲕粒灰岩、砾屑灰岩以及泥质条带灰岩等;中段鲕粒明显减少,变为含砾屑、藻屑灰岩,泥质条带灰岩;上段出现白云质灰岩,表明为潮下浅滩沉积环境。该风暴岩的发现对重建宁夏贺兰山地区中晚寒武世岩相古地理及等时区域地层对比具有重要意义。

       

      Abstract: A suite of typical storm deposition has been discovered for the first time in Helanshan area of Ningxia, which was developed in the middle and lower parts of upper Cambrian. Bottom-erosion texture, bio-disturbed texture, imbricate-boulder texture and radial fabric can be found in these storm sediments, indicating a typical shallow-water storm deposition. The lower part of this formation consists of oolitic limestone, bamboo-like limestone and argillaceous banded limestone. The oolite shows an evident decline in the middle part, which mainly consists of calcirudite, algal limestone and argillaceous banded limestone. Dolomite lime appears in the top part of this formation, indicating a shallow subtidal sedimentary environment. The discovery of storm rock has a great significance for the reconstruction of middle and late Cambrian paleogeography and the comparison of regional strata in Helanshan area of Ningxia.

       

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