海平面周期性升降变化与岩溶洞穴层序次关系探讨  

The Relationship between Sea Level Change and Cave Formation Sequence

作　　者：徐国强[1] 刘树根[1] 武恒志[2] 李智武[1] 孙玮[1] 

机构地区：[1]成都理工大学能源学院 [2]中国石油化工集团公司石油勘探开发研究院西部分院,北京100083

出　　处：《沉积学报》2005年第2期316-322,共7页Acta Sedimentologica Sinica

摘　　要：层序地层学理论为全球或跨地区的等时地层对比提供了理论和技术方法,它对洞穴层的跨地区对比及序次分析同样适用。从洞穴层的发育期总是与水平面稳定期对应关系出发,通过水平面周期性升降变化与岩溶洞穴层序次关系研究,探索层序地层学与岩溶学交叉学科研究领域中的一些基本问题。认为同一个水平面稳定期发育的所有水平洞穴可形成一个跨地区对比的洞穴层,岩溶旋回应包括侵蚀基准面上升和下降两种旋回,在海平面的间歇性上升(或下降)过程中可以发育多个水平洞穴层及下老上新(或上老下新)的洞穴层序列。在总结前人研究成果及美国YATE油田、四川峨眉山剖面、塔河油田实例分析基础上,概括了3种受海平面间歇性上升(或下降)变化控制的洞穴层序次模式,包括层序地层内部同生期岩溶形成的下老上新的洞穴层序次,以及碳酸盐岩陆块近地表风华壳岩溶形成的上老下新和下老上新的洞穴层序列。利用塔河油田早海西期古岩溶地质条件、洞穴充填结构等直接和间接证据,求证该洞穴系统的洞穴层序次,指出该特大洞穴系统为晚泥盆—早石炭世海平面间歇性上升过程中形成的下老上新的洞穴层序列,并由此推测塔里木盆地早海西期大规模岩溶的时代。指出利用水平洞穴层同时期形成的沉积地层等地质体可以确定洞穴层的形成年代,预测洞穴的发育分布。Sequence stratigraphy provided a theory and significant tool for the global or regional stratigraphic isochronous correlation, it was also suitable for karst events analysis and regional correlation of caves related to sea level changes. The main topic for this paper is to discover the fundamentals in the intersecting domain between paleokarst and sequence stratigraphy through the study of the relationship between the sea level change and the cave formation sequence followed by the principle of the water table changed with sea level and the cave formation was only developed in the period of standing sea level. By the study of Yate （in U. S. A. ） and Tahe （in Tarim basin） oil field, outcrop of Emei Mountain, as well as the integrated analysis of previous study, 3 general models about the relationship between the sea level change and the cave formation sequence are provided including that one is for the multiple karst island lenses corresponding to sedimentary cycles within the sequence-stratigraphic framework in which developed a normal succession of cave formation （the upper the younger, the lower the older） ; and the other two are for paleokarst in the continent carbonate blocks, in which it could develop the normal or reversed cave formation sequence followed by sea level intermissive rising or dropping. With the direct or indirect evidences, such as the started outcropping time of carbonate blocks, paleokarst environments and other geological conditions, the characteristics of karst and the deposits in the horizontal caves, indicating that the great cave system in the residue of Ordovician of Tahe oil field were developed in a sea level intermissive rising half cycle of 2-order sequence. The isochronous relationship of depositional sequence and cave can be applied in dating the paleokarst events, predicating the possible depth of caves; it has significant value in minerals exploration and engineering geology.

关 键 词：层序地层学 古岩溶 洞穴层序次 沉积层序 等时对比 

分 类 号：P539.2[天文地球—古生物学与地层学]