准噶尔盆地南部四棵树河地区新近系龟壳状结构石膏脉的发现及成因  

Finding and Genesis of Gypsum Veins with Tortoise Shell Structure of Neogene in SiKeshu Area,Southern Junggar Basin

作　　者：赵晓东[1] 杨少春[1] 向奎[2] 刘金华[3] 张世奇[1] 魏晓晴 

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]中国石化胜利油田新疆勘探开发中心,山东东营257017 [3]中国石化江苏油田地质科学研究院,江苏扬州225012

出　　处：《新疆地质》2014年第1期96-101,共6页Xinjiang Geology

基　　金：国家科技重大专项课题(2011ZX05009-003);中央高校基本科研业务费专项资金(13CX06013A)联合资助

摘　　要：原生的石膏脉通常呈层、片状分布,在准噶尔盆地南部四棵树河地区野外地质考察中发现有龟壳状结构的石膏脉晶体。通过对周边地区露头实测、探勘、取样及盆地腹部钻井取心资料分析,结合前人研究成果,对龟壳状结构石膏脉形成的古环境背景、盆内沉积证据、龟裂成因和充填石膏成因进行系统研究。准噶尔盆地在三叠—新近纪为内陆浅水湖盆沉积,南部山前地区新近系沙湾组发育辫状河三角洲相和湖泊相,岩相古地理特征受湖平面升降及构造综合控制。研究区发育大量红层沉积,盆地岩石的"先成岩、后胶结"为龟壳状结构石膏脉形成提供了必要条件。综合认为,龟壳状结构石膏脉的形成可能是经"两期盐湖、四个阶段"的作用而成,主要分为一期盐湖作用的原始状态阶段和龟裂状态阶段、二期盐湖作用的龟裂注溶盐水状态和龟裂充填石膏状态。龟壳状结构石膏脉的发现可推测盆地腹部存在天然储层裂缝改造区,为预测有利区带提供地质依据,并对中国西北地区新近纪干旱沉积环境指示具一定参考意义。The primary gypsum veins are usually distributed in layers,but in a recent field geological investigation in SiKeshu river area, gypsum veins with tortoise shell structure have been founded,which are quite rare.On the basis of Measurement,exploration and sampling of surrounding outcrops as well as a detailed analysis of core information from hinterland of basin,combined with early researches,a study is carried out ,which includes setting of paleoenvironment, evidence of sedimentary basin, causes of cracks and causes of filling gypsums. The study shows that Junggar basin is hot and dry during Triassic and Neogene period, which deposits in inland shallow lacurstrine basins. Shawan formation of the pediment region of southern Junggar basin develops braided river delta facies and lacurstrine facies during Neogene period. The paleogeography feature is controlled by fluctuation of lack level and structure. The studying area develops a lot of red layer sediments, cmentation after diagenesis provides a necessary condition for the formation of gypsum veins with tortoise shell structure. The development of gypsum veins with tortoise shell structure in SiKeshu river during Neo-gene period may undergo two stages of salt lack with four periods, and the first stage of salt lake can divided into origi-nal period and crack period, while the second stage of salt lake can divided into crack injection of saline solution period and crack filling gypsum veins period. The finding of fiber gypsum with tortoise shell structure can predict that the cen-tral part of the northern sedimentary area may exist naturally fracture-affected reservoir, thus providing geological proofs for the prediction of favorable zones, in addition,it is a reference for indicting the arid sedimentary environment of tertia-ry strata in northwestern area.

关 键 词：准噶尔盆地南部 四棵树河地区 新近系 龟壳状结构 龟裂 石膏脉 

分 类 号：P618.13[天文地球—矿床学]