苏北淮阴凹陷上白垩统浦口组盐岩成因探讨  

A Discussion on Characteristics and Genesis of Salt Deposit in Pukou Formation of Late Cretaceous, Huaiyin Depression

作　　者：赵彦彦[1] 林春明[1] 汪亚军[2] 牟荣[2] 张浩东[2] 

机构地区：[1]南京大学地球科学系成矿作用国家重点实验室,江苏南京210093 [2]中石化江苏油田分公司物探技术研究院,江苏南京210046

出　　处：《高校地质学报》2004年第3期468-476,共9页Geological Journal of China Universities

基　　金：国家自然科学基金资助 (4 0 2 72 0 6 3)

摘　　要：淮阴凹陷浦口组的二段和三段为一套厚度达千米的膏盐岩—碎屑岩沉积体系 ,对含盐层系的主要沉积相类型及其特征的分析和研究 ,结合该区构造、钻井、测井、地震、盐岩化学等资料的综合分析 ,初步认为该套厚层盐岩主要与半深湖沉积有关 ,深部古老地层中的盐类物质是盐岩的主要盐源 。The Pukou Formation in Huaiyin depression is composed of cyclothemes of salt rocks, mudstones and shales, which formed saline-lake sedimentary assemblage of more than 1000 m thick. During the aggradation of Pukou formation, the Huaiyin area was a wide lake which consisted of alluvial fans, littoral facies, shallow-lake facies and semi-deep-water facies. The saline sediments were formed in the semi-deep-water saline lake. In this paper, based on the geologic, seismic, geochemical, and palaeobiogical data, the sedimentation environment of Pukou Formation and the genesis of saline sediments are discussed. Nowadays, there are three viewpoints on the formation of saline substances: (1) the saline substances from the marine transgression, in association with arid or semi-arid climate, and precipitated as saline deposits. (2) in the high-mountain-deep-basin environments, the saline substances from the weathering and leaching rocks such as carbonates, gypsolytes or other salinastones. (3) the saline substances derived mainly from the deep sources which were evidently related with faults or volcanism of the tectonic zone. In this paper, the author agrees with the third point. The reasons are as follows: ①the sedimentary characteristics: the saline deposits mainly belong to sodium-sulfate-chloride type. The sediments are cyclothems of saline rocks, mudstones and shales. ②the depositional conditions: many faults developed in Huaiyin depression during the formation of the saline deposits.③the asymmetry of salinity.④the palaeontological characteristics. All above-mentioned proofs show that the salt in deep strata was the major source and the deep fractures were the paths thtough which the salt substances entered into the depression.

关 键 词：淮阴凹陷 浦口组 盐岩 成因 

分 类 号：P534.5[天文地球—古生物学与地层学]