塔东南寒武系-中下奥陶统碳酸盐岩台缘带的迁移与相对海平面变化的关系

发布时间：2019-04-19 12:30

【摘要】：在岩心、薄片以及测井资料分析的基础上,结合地震相、地震属性以及古地貌来识别台地边缘带,追踪和揭示了塔里木盆地东南部寒武系-中下奥陶统不同期台地边缘相带分布与变迁。台地边缘带发育的岩石类型主要为砂屑灰岩、生屑灰岩、鲕粒灰岩与泥晶灰岩等。台缘滩在地震反射剖面上呈杂乱反射或空白反射特征,礁(丘)滩复合体外部呈丘状外形,内部为显杂乱反射或空白反射。较大的礁(丘)滩复合体快速生长形成地层厚度增大的建隆特征,以及向盆地区沉积厚度急剧减薄形成的陡坡或远端变陡特征是判断台地边缘的证据。应用自然伽马能谱测井资料识别碳酸盐岩岩性和沉积能量的方法,结合有机碳、碳氧同位素等资料,编制塔里木盆地东南部地区的相对海平面变化曲线,探讨海平面变化对不同时期台地边缘相带迁移的控制作用。早寒武世塔东南地区以斜坡-盆地相为主,台缘不发育;中晚寒武世海平面不断下降,台地类型为局限台地,台地边缘相发育且向盆地方向迁移;早奥陶世全球海平面开始上升,蓬莱坝组沉积期台地边缘宽度变窄;鹰山组下段沉积期海平面下降,台地类型变为开阔台地,台地边缘相带变宽;鹰山组上段沉积期经历了快速的水进,海平面又开始下降,台地边缘相带向盆地内侧进一步加宽;一间房组沉积之后随海平面快速上升,台地被淹没。
[Abstract]:Based on the analysis of core, thin slice and logging data, the seismic facies, seismic attributes and paleogeomorphology are used to identify the edge zone of the platform. The distribution and evolution of Cambrian-Middle-Lower Ordovician platform margin facies in southeastern Tarim Basin were traced and revealed. The rock types developed in the platform margin zone are mainly sandstone limestone, bioclastic limestone, oolitic limestone and mudstone, etc. The seismic reflection profile of the platform margin beach is characterized by disordered reflection or blank reflection. The reef (mound) complex is mound-shaped outside and the interior of the reef (mound) complex is characterized by disordered reflection or blank reflection. The rapid growth of the larger reef (hilly) beach complex leads to the increase of the formation thickness, and the steep slope or the steepening of the distal slope formed by the sharp thinning of the sedimentary thickness towards the basin area is the evidence to judge the platform margin. Using natural gamma spectrum logging data to identify lithology and sedimentary energy of carbonate rocks, combined with organic carbon, carbon and oxygen isotopes, the relative sea level change curves in southeastern Tarim Basin are compiled. The control effect of sea level change on the migration of platform marginal facies in different periods is discussed. The southeast area of the early Cambrian tower is dominated by slope-basin facies and the margin of the platform is not developed, the sea level of the middle and late Cambrian is decreasing continuously, the platform type is limited platform, the marginal facies of the platform develops and migrates to the basin direction. The global sea level of the early Ordovician began to rise, and the margin width of the platform became narrower during the sedimentary period of the Penglaiba formation, the sea level of the lower part of the Yingshan formation decreased, the platform type became open platform, and the margin facies belt of the platform became wider. During the upper part of Yingshan formation, the sea level began to decline again, and the margin facies zone of the platform widened further to the inner part of the basin, and after the deposition of one chamber formation, the platform was inundated with the rapid rise of sea level.
【作者单位】：核工业北京地质研究院;中核集团铀资源勘查与评价技术重点实验室;中国地质大学(北京);中国石油大庆油田有限责任公司勘探开发研究院;中国石油勘探开发研究院;
【基金】：国家自然科学基金重点项目(41130422) 国家重点基础研究发展计划(973计划)(2011CB201100-03)
【分类号】：P534.4;P588.245

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