鄂尔多斯古陆南部大陆边缘寒武纪奥拉谷存在的沉积学证据及其油气勘探意义

Sedimentary Characteristics and Hydrocarbon Exploration Implications on the Cambrian Aulacogen of the Southern Ordos Continental Margin,North China

奥拉谷是被动大陆边缘一个重要的构造现象,是勘探家们重点关注的地区之一。以鄂尔多斯陆块南部深部构造为研究重点,以板块构造理论及构造控制沉积思想为指导,通过野外地质剖面及岩心观察,结合地震资料,剖析南缘寒武纪沉积建造特点及所反映的构造方面的信息,确定寒武系沉积地层厚度进而了解盆地南部构造轮廓,确定古陆南缘可能存在奥拉谷,其分布面积约为20 000km2,主要发育时期为寒武纪黔东世都匀期—武陵世台江期,是下一步鄂尔多斯盆地深部油气勘探重要地段去之一。

Aulacogen is an important tectonic phenomenon on a passive continental margin,and is also a concerned area among oil-gas exploration.Taking the deep structure of southern Ordos ancient land as a research object,using plate tectonic theory and the thought of＇tectonic controlling sedimentation′,combined with the investigation of field geological sections and core observation,together with seismic data,the authors analyzed the Cambrian sedimentary formation and facies in the southern Ordos,ascertained the Cambrian sedimentary formation thickness and the structure outline which is an aulacogen with an area of about20000km^2.The main development period is expected to be from Duyun Age of Qiandong Epoch to Taijing age of Wuling Epoch of Cambrian.The areas of the aulacogen should be an important oil-gas exploration field for the next oil/gas exploration in the deep Ordos Basin.