Quartz cement in sandstones: a review
Quartz cement in sandstones: a review
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DOI：
10.1016/0012-8252(89)90019-6
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发表时间：
1989
影响因子：
12.1
通讯作者：
E. McBride
中科院分区：
文献类型：
--
作者：
E. McBride
作为结构增生的石英胶结物是砂岩中两种最丰富的胶结物之一。控制砂岩中石英胶结物含量的主要因素有：骨架组成；在“二氧化硅流动窗口”中的停留时间；以及流体成分、流量和路径。因此，沉积砂子的沉积盆地类型强烈控制着胶结过程。裂谷盆地（长石岩）和碰撞边缘盆地（岩屑岩）的砂岩通常仅含有百分之几的石英胶结物；克拉通内盆地、前陆盆地和被动边缘盆地的石英岩和其他石英砂岩含有最多的石英胶结物。碎屑石英颗粒上的粘土和其他矿物涂层以及孔隙中碳氢化合物的截留会延迟或阻止石英的胶结，而作为主要流体管道的渗透性极高的砂子往往会封存最大量的石英胶结物。在快速沉降的盆地中，如墨西哥湾沿岸和北海盆地，大多数石英胶结物是通过埋藏时冷却、上升的地层水沉淀出来的。 深度达数公里，温度范围为 60°C 至 100°C。胶结作用持续数百万年，通常在不断变化的流体成分和温度下进行。含有超过 10% 进口石英胶结物的砂岩会带来流体通量和二氧化硅传输的特殊问题。如果二氧化硅完全以 H4SiO4 的形式输送，那么地层水的对流循环似乎对于解释大多数砂岩中存在的水泥体积至关重要。仅当大量二氧化硅以不明复合物形式输送时，单循环向上运移地层水的沉淀足以提供一定量的水泥。模拟表明，尽管缺乏独立的岩石学、同位素或流体包裹体数据，但克拉通内盆地砂岩的石英胶结作用受到平流大气水的影响。用于石英胶结物的二氧化硅来自沉积盆地内的页岩和砂岩层，包括可能深埋的正在经历低级变质作用的岩石，但潜在来源的相对重要性仍然存在争议和可能 不同的阵型有不同的效果。未变质页岩中最可能重要的二氧化硅来源包括粘土转变（主要是蒙脱石的伊利石化）、碎屑颗粒的溶解/压溶以及蛋白石骨架颗粒的溶解；未变质砂岩中最可能重要的二氧化硅来源包括颗粒接触处和缝合线处碎屑石英颗粒的压溶、长石蚀变/溶解，以及硅酸盐矿物和一些石英颗粒边缘的碳酸盐替代。许多砂岩中压力溶液释放的二氧化硅晚于石英胶结作用的发生；因此，这种二氧化硅必须迁移并胶结盆地中较浅的砂岩，或者完全逸出。一些石英胶结砂岩与潜在的硅源层垂直相隔一公里甚至更远，需要长距离的硅迁移。不同成分和年龄的砂岩中成岩序列的相似性显然是沉积盆地埋藏期间沉积物、有机质和孔隙流体在正常温度和时间依赖性成熟的结果。形成过度生长的二氧化硅是由一种或多种成岩过程释放的，这些过程显然是由温度和时间控制的。大多数石英胶结作用发生在砂岩层处于特定沉积盆地的二氧化硅流动窗口中时。重要的二级控制是由...产生的划分域引入的
Quartz cement as syntaxial overgrowths is one of the two most abundant cements in sandstones. The main factors that control the amount of quartz cement in sandstones are: framework composition; residence time in the “silica mobility window”; and fluid composition, flow volume and pathways. Thus, the type of sedimentary basin in which a sand was deposited strongly controls the cementation process. Sandstones of rift basins (arkoses) and collision-margin basins (litharenites) generally have only a few percent quartz cement; quartzarenites and other quartzose sandstones of intracratonic, foreland and passive-margin basins have the most quartz cement. Clay and other mineral coatings on detrital quartz grains and entrapment of hydrocarbons in pores retard or prevent cementation by quartz, whereas extremely permeable sands that serve as major fluid conduits tend to sequester the greatest amounts of quartz cement.In rapidly subsiding basins, like the Gulf Coast and North Sea basins, most quartz cement is precipitated by cooling, ascending formation water at burial depths of several kilometers where temperatures range from 60° to 100° C. Cementation proceeds over millions of years, often under changing fluid compositions and temperatures. Sandstones with more than 10% imported quartz cement pose special problems of fluid flux and silica transport. If silica is transported entirely as H4SiO4, convective recycling of formation water seems to be essential to explain the volume of cement present in most sandstones. Precipitation from single-cycle, upward-migrating formation water is adequate to provide the volume of cement only if significant volumes of silica are transported in unidentified complexes. Modeling suggests that quartz cementation of sandstones in intracratonic basins is effected by advecting meteoric water, although independent petrographic, isotopic or fluid inclusion data are lacking.Silica for quartz cement comes from both shale and sandstone beds within the depositional basin, including possibly deeply buried rocks undergoing low-grade metamorphism, but the relative importance of potential sources remains controversial and likely differs for different formations. The most likely important silica sources within unmetamorphosed shales include clay transformation (chiefly illitization of smectite), dissolution/pressure solution of detrital grains, and dissolution of opal skeletal grains; the most likely important sources of silica within unmetamorphosed sandstones include pressure solution of detrital quartz grains at grain contacts and at stylolites, feldspar alteration/dissolution, and perhaps carbonate replacement of silicate minerals and the margins of some quartz grains. Silica released by pressure solution in many sandstones post-dates the episode of cementation by quartz; thus, this silica must migrate and cement shallower sandstones in the basin or escape altogether. Some quartz-cemented sandstones are separated vertically from potential silica source beds by a kilometer or more, requiring silica transport over long distances.The similarity of diagenetic sequences in sandstones of different composition and ages apparently is the result of the normal temperature and time-dependent maturation of sediments, organic matter and pore fluids during burial in sedimentary basins. Silica that forms overgrowths is released by one or more diagenetic processes that apparently are controlled by temperature and time. Most cementation by quartz takes place when sandstone beds were in the silica mobility window specific to a particular sedimentary basin. Important secondary controls are introduced by compartmentalized domains produced by …