鄂尔多斯盆地徐庄组碳酸盐岩风暴沉积发育特征及其地质意义

发布时间：2018-08-06 20:55

【摘要】：鄂尔多斯盆地寒武系徐庄组发育碳酸盐岩风暴沉积现象。风暴沉积主要包括侵蚀底面、风暴砾屑层、丘状和洼状层理等沉积构造。沉积构造在不同的条件下会形成不同的沉积序列,理想的沉积序列包括5个沉积单元,从下到上依次为:A侵蚀底面及砾屑段,代表风暴高峰期和衰减期的沉积作用,底面有突变的底界及特殊的沉积构造;B粒序段,为风暴减弱时沉积物从下向上变细的层段;C平行纹层段;D丘状纹层段,为风暴衰减期流体性质逐渐由密度流变为牵引流时形成的产物;E水平层理泥岩和泥晶灰岩段,为风暴停息期晴天条件下的产物。经野外考察发现研究区共可识别出5种不同类型的沉积序列组合,每种序列组合有不同的沉积特点,代表的沉积环境也不同。研究区寒武系徐庄组碳酸盐岩风暴沉积的发现和研究,对于古板块演化与古纬度恢复、鄂尔多斯盆地古地理研究具有重要的意义。
[Abstract]:The carbonate storm deposits are developed in the Cambrian Xu Zhuang formation in the Ordos Basin. The storm deposits mainly include sedimentary structures, such as erosion bottom, storm gravel layer, hilly and low-lying stratification. The sedimentary structure will form different sedimentary sequences under different conditions. The ideal sedimentary sequence includes 5 sedimentary units, from lower to upper to A invasion. The bottom surface and the gravel segment represent the sedimentation of the storm peak and attenuation period, with the bottom boundary and the special sedimentary structure on the bottom, and the B grain sequence section is the layer of the sediment from lower upward when the storm is weakened; the C parallel layer section and the D colliculate layer are the production of the flow character gradually formed by the density rheology as the traction flow in the storm attenuation period. The E horizontal bedding mudstone and the argillaceous limestone section are the product of the sunny weather conditions in the storm period. It is found that 5 different types of depositional sequences can be identified in the study area. Each sequence has different sedimentary characteristics and the sedimentary environment is different. The present study is of great significance for paleo plate evolution and paleo latitude restoration, and palaeogeography of Ordos Basin.
【作者单位】：中国地质大学(北京)能源学院;中国地质大学(北京)科学研究院;
【基金】：国家自然科学基金项目(41572092) 页岩气资源评价与战略选区国土资源部重点实验室资助
【分类号】：P512.21

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