济阳坳陷沾化凹陷沙二段湖相混积岩沉积特征及成因分析——以罗家—邵家地区为例  

Sedimentary Characteristics and Origin of Lacustrine Mixed Rocks of the Second Member of the Eogene Shahejie Formation in Zhanhua Sag,Jiyang Depression: taking Luojia—Shaojia Area for an Example

作　　者：王金友[1,2] 张立强 张世奇 林会喜[3] 

机构地区：[1]中国地质大学,北京100083 [2]中国石油大学地球科学与技术学院,山东青岛266555 [3]胜利油田地质科学研究院,山东东营257015

出　　处：《地质论评》2013年第6期1085-1096,共12页Geological Review

基　　金：国家重大油气专项"渤海湾盆地精细勘探关键技术"(编号2008ZX05006);中央高校基本科研业务费专项(编号10CX04009A)的成果

摘　　要：混积岩是混合沉积的典型产物,研究程度较低。罗家—邵家地区处于济阳坳陷沾化凹陷的南斜坡,古近系沙河街组二段发育了比较广泛的湖相混积岩沉积。本文综合区域地质资料、测井资料、岩芯描述及样品分析等,对其混积岩的沉积特征、成因类型、沉积环境等方面进行了研究。结果表明:本区混积岩类型分为两大类4小类,自下而上混积岩含量增多,展布范围逐渐扩大。混积岩成因以渐变式混合和突变式混合为主,局部存在原地混合沉积,各种类型的混合沉积常相互叠加,频繁交替。本区混积岩形成于两大物源注入背景下的湖泊滨岸沉积环境,可进一步分为泥坪混合沉积微相、生物浅滩混合沉积微相、颗粒滩坝混合沉积微相及砂坝混合沉积微相等类型。不同环境下的混积岩组构、混合沉积类型及垂向沉积序列有较大的差异。混积岩的发育主要受控于物源的供给及复杂的水动力条件,其次为构造背景与湖平面升降等因素。Mixed rock is a typical product of mixing deposits, but the research of mixed rock are in low degree. Located in the southern slope of Zhanhua Sag, Jiyang Depression, western Luojia--Shaojia area widely developed lacustrine mixed rocks throughout the Second Member of Shahejie Formation （Es2 ）. This paper studied the mixed sedimentation in this area based on regional geological data, well logging data, observation of wells cores, indoor sample analysis. The results show that there are various types of mixed rocks in this area, which can be classified into two categories and four kinds. From bottom to top, the amount of mixed rocks increased gradually, and its range also expanded gradually. Mixing deposits with gradual changed facies edge and mixing deposits caused by mutated events are the major genesis of the formation of mixed rocks, while some other genetic types also exist, such as autochthonous mixing deposits. Different types of mixing deposits usually overlap each other, and interlace frequently. In the study area, mixed rocks developed in lacstrine shoreland with input from two large provenances, and can be further classified into the following kinds： mud flat microfacies of mixing deposits, organic bank microfacies of mixing deposits, granular bank microfacies of mixing deposits, sandstone bar microfacies of mixing deposits, and so on. There are marked differences between mixed rocks formed in different environments in terms of their fabrics, types and vertical sequences. The development of the mixed rocks is mainly controlled by supplies from provenance and complicated hydrodynamic conditions, and secondly controlled by factors like structural settings and lake level changes, etc.

关 键 词：混积岩 沉积特征 古近系沙河街组二段 山东济阳坳陷沾化凹陷 

分 类 号：P512.2[天文地球—地质学]