白云岩的残余结构及由此引发的孔隙分类问题  

Relict Textures of Dolomite and the Related Porosity Classification

作　　者：张学丰[1,2] 蔡忠贤[3] 李林[3] 谷晓丹[2] 赵文光[3] 

机构地区：[1]北京大学石油与天然气研究中心,北京100871 [2]中国石油大学油气资源与探测国家重点实验室,北京102249 [3]中国地质大学资源学院,武汉430074

出　　处：《沉积学报》2011年第3期475-485,共11页Acta Sedimentologica Sinica

基　　金：国家重点基础研究发展计划"973"项目(编号:2005CB422105);国家自然科学青年科学基金项目(批准号:41002029);中国博士后科学基金(编号:20100470162)联合资助

摘　　要：对碳酸盐岩的结构分类方法进行了评述,但目前的分类并未对白云岩的残余结构问题进行充分论述。为了能更准确地恢复岩相古地理和进行精细的成岩研究,有必要对残余结构进行细分。白云岩的残余结构是由于原始粒屑结构的灰岩,经白云岩化、重结晶、溶蚀、胶结等成岩作用之后,岩石原始结构遭到不同程度的破坏,但仍残留有部分原始结构信息而形成的。根据颗粒与胶结物的可识别性和颗粒内部结构的保存程度,把残余结构划分为残余粒屑结构、残余粒形结构和残余影像结构,并分别给出相应的判别标准、鉴定特征、描述方法和相关实例。残余结构白云岩的孔隙分类也与原始粒屑结构灰岩有所不同。在Choquette和Pray(1970)孔隙分类方法的基础上,把残余结++构白云岩的孔隙分为组构选择性孔隙、部分组构选择性和非组构选择性孔隙三大类。其中,组构选择性孔隙包括粒内孔(含铸模孔)、粒间孔和晶间孔三大类,其中前两者还包括不同形态的亚类;非组构选择性孔隙主要包括溶蚀扩大孔;非组构选择性孔隙按孔隙形态和大小划分为溶孔、溶沟、溶洞、裂缝和角砾孔隙。The popular theory on texture classification of carbonates has not shed much light on the relict texture of dolomites, which is defined here as the texture remained of original limestone with 〉 10% of grains after complete dolomitization and associated recrystallization, dissolution, fillings, and so on. It is emphasized for its important role in reconstructing the paleo-environment of sedimentation. Based on whether most of the grains can be clearly and quantitatively distinguished with matrix and cements, and tile inner texture of grains is preserved or not under microscope, the relict textures can be classified as the mimetic texture, the nonmimetic texture, and the ghost texture. These textures are described in detail with typical examples. The porosity classification of these relict textures should coincidently he refined after Choquette and Pray （1970）. The pores are firstly classified as selective, partly selective or non-selective. Intragranular, intergranular, and intercry, stal pores are selectively developed within individual grains, between grains, or between individual dolomite crystals, respectively. Furthermore, if the intercrystal pores are selectively developed within individual grains, then they are classified into intragranular and called intragranular-intercrystal pores. Similarly there are intergranular-intercrystal pores. Notably, moldic porosity hereby is also intragranular because they are always within individual grains. Partly selective pores ill this case refer to dissolution enlarged intragranular, intergranular, or intercrystal pores. And the common non-selective pores are vugs, channels, caverns, fractures and breccia pores, as defined by Choquette and Pray （1970）.

关 键 词：白云岩 残余结构 孔隙分类 

分 类 号：P588.245[天文地球—岩石学]