四川盆地奥陶系十字铺组与宝塔组接触关系新认识  

New Understanding of the Contact Relationship between Shihtzupu Formation and Pagoda Formation in Sichuan Basin

作　　者：樊茹[1,2,3] 卢远征[1,2,3] 张学磊[1] 张师本[1,2,3] 段文哲[4] 李鑫[1,2,3] 邓胜徽[1,2,3] 

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]提高采收率国家重点实验室,北京100083 [3]中国石油天然气集团公司油气储层重点实验室,北京100083 [4]中化石油勘探开发有限公司,北京100031

出　　处：《地质学报》2013年第3期321-329,共9页Acta Geologica Sinica

基　　金：国家重大科技专项"大型油气田及煤层气开发"(编号2008ZX05004-001);中国石油天然气股份有限公司"十一五"重大科技专项"海相碳酸盐岩大油气田勘探开发关键技术"资助的成果

摘　　要：四川盆地奥陶系十字铺组和宝塔组自上世纪20年代命名以来,在地层学界一直被认为是连续沉积,整合接触。四川盆地东—南缘中—上奥陶统习水良村和武隆黄草两条剖面的牙形石生物地层与碳同位素地层学研究指示,十字铺组与宝塔组之间存在沉积间断,即二者并非整合接触关系。该不整合可与北美地区的M4/M5不整合面对比,二者可能是由桑比期早、晚期的海平面下降引发。与此时代相近的不整合在新疆巴楚地区、塔里木盆地亦有发现。由于十字铺组在四川盆地广泛分布于覆盖区,且岩性多以碳酸盐岩为主,因此不整合的发现将促使我们重新认识并评估该组的油气勘探潜力。Since nomenclature in the 1920s, Shihtzupu and Pagoda Formations of the Ordovician System in Siehuan Basin have long been considered to be conformable contact in the stratigraphic circle. This study analyzed the conodont biostratigraphy and carbon isotopic stratigraphy in the Liangcun and Huangcao sections of the middle-upper Ordovician around the Sichuan Basin. The biostratigraphie and chemostratigraphic results indicate a sedimentary gap between the Shihtzupu and Pagoda formations, suggesting an unconformity contact between two formations. The discontinuity can be contrasted with the M4/M5 sequence boundary which is prominent unconformity in North America. Both of them probably resulted from the regression of sea level in early and late Sandbian. The unconformity occurring at this time can also be found in the Bachu area and Tarim Basin. Due to the fact that the Shizhpu Formation is widely distributed in Sichuan basin and dominated by carbonatic rock, discovery of disconformity between the Sbihtzupu Formation and Pagoda Formation has great significance for us to acquire new understanding of exploration potential for oil and gas in the Sichuan Basin.

关 键 词：四川盆地 奥陶系 十字铺组 宝塔组 接触关系 

分 类 号：P534.42[天文地球—古生物学与地层学]