常见胶结物类型
胶结物成分: 常见的胶结物成分有钙质、硅质、铁质、泥质四种。
主要区别如下表
不同成分胶结物的区别
主
要胶结物为硅质(石英、玉髓等)、碳酸盐矿物(方解石、白云石等),其次是铁质(赤铁矿、褐铁矿等),有时可见硫酸盐矿物(石膏、硬石膏等)、沸石类矿物(方沸石、浊沸石等)、粘土矿物(高岭石、水云母、绿泥石等)。
(1)硅质作为胶结物在砂岩里出现。
其出现的形式是多样的。
主要有非晶质的蛋白石、隐晶质的玉髓和结晶质的石英。
多见于石英砂岩、长石质石英砂岩,砾岩(常与铁质混合)中。
(ZP1硅质胶结)
(2)钙质一般出现在碳酸盐岩地区,与硅质特征有些相近,但硬度较低,角砾成分也以碳酸盐为主。
钙质胶结端口较平,有时贝壳状。
胶结物成分 颜色 岩石固结程度 硬度 加稀盐酸 硅质 灰白 致密坚硬 >小刀 无反应 铁质 褐红、褐 致密坚硬 ≈小刀 无反应
钙质 灰白 中等 <小刀 剧烈起泡
泥质 灰-灰黄色
松软 <小刀 无反应
(ZP2钙质胶结,擦痕比较明显、典型。
白色可以刻划,附近常见方解石脉或附近有碳酸盐岩分布)
(3)铁锰质胶结:一般为暗红色,小刀很容易刻动,刻下来的粉末仍为暗红色,加酸不起泡。
铁锰质胶结,断口较粗糙。
(4)泥质胶结:灰-灰黄色,小刀很容易刻动,刻下来的粉末仍为灰色-黄色。
加酸(一般是稀盐酸),不起泡。
泥质胶结断口粗糙。
注:砂岩,胶结物主要为泥质胶结,另有钙质、铁质及硅质胶结
粉砂岩,胶结物以泥质、钙质为主,另有硅质,铁质胶结。
胶结物
1.定义:胶结物是碎屑岩在沉积、成岩阶段,以化学沉淀方式从胶体或真溶液中沉淀出来,充填在碎屑颗粒之间的各种自生矿物。
2.成因:化学沉淀3.常见的胶结物类型(1)硅质胶结物:蛋白石、玉髓、石英(2)碳酸盐胶结物:方解石、白云石、菱铁矿等(3)铁质胶结物:赤铁矿、褐铁矿(4)其它胶结物:粘土矿物、石膏、硬石膏、黄铁矿、磁铁矿、磷酸盐类矿物等泥质一般较软,如果填隙物多的话,可以看到贝壳状断口,比较滑,用手捻不会有沙质感,铁质一般颜色比较深,红褐色,硅质较硬,一般在石英、长石质石英砂岩中,沉积石英岩中,碎屑成份一般含石英较多,色浅(一般浅灰白,有铁染时呈肉红色),石英多时会看到岩石断面上的油脂光泽,钙质一般出现在碳酸盐岩地区,与硅质特征有些相近,但硬度较低,角砾成分也以碳酸盐为主。
泥质、铁质、钙质、硅质胶结物在显微镜下简单的能区别,但是铁质和钙质区分不开。
再说泥质可以有钙质也可以有铁质,楼主的问题也欠妥。
楼主是想区分胶结物形态呢还是想做胶结物的成分,但是我说得这些方法绝对有用,而不像5楼说得一物用处,我觉得你们还没接触这些方法,你可以和你们的导师探讨一下。
假设片中有大量碳酸盐胶结物不能确定类型,x射线显示为白云石,只需要鉴定其铁含量就能确定矿物,当然如果连胶结物都不认识,x射线显示石英,你非把这个做胶结物,那就没办法了。
阴极发光也是同样道理,首先你得知道,哪些是胶结物,哪些不是,在加以判断,在阴极发光下铁含量高的胶结物一般发红色光;镁含量高的胶结物一般发橙色光;菱铁矿发橙红色光;方解石发黄色-橙色光;白云石暗红色光,铁白云石不发光;菱镁矿橙色光。
人工方解石,颜色偏粉一些,这些很多科研和外协项目都是通过这些手段区分胶结物的。
茜素红是典型的也是最简单的区分碳酸盐的方法:胶结物方解石遇S茜素红,变粉红-红,颜色深浅由方解石中铁含量决定;白云石遇S茜素红不变色;铁白云石变蓝色;菱铁矿不变色。
菱铁矿和白云石就得配合阴极发光,菱铁矿和白云石发光不同。
地质学沉积岩部分复习资料
以粉砂、细砂、泥沉积为主。有小型交错层理及水平层理。有冲刷构造,含有一些植物化石碎片。
(三)、河漫亚相
位于天然堤亚相的外侧,在河谷后总地势偏高。主要是粉砂岩和粘土岩。具有波状层理和水平层理。
1、 河漫滩微相
以粉砂岩,泥质粉砂和粘土岩沉积为主。具有层理构造以水平层理为主。粉砂岩和泥质粉砂岩中含有炭屑,有时可见炭质页岩。化石很少,一般见植物碎片。
(一)盆地边缘 (相当于X带)
2、 河漫湖泊微相
沿河漫分布的呈串珠状的小型常年的蓄水洼地。以黏土沉积为主,其次是粉砂。水平层理发育,泥岩红中含有泥裂、干裂等。可出现淡水生物化石,干旱地区课形成盐湖。
3、 河漫沼泽微相
在河漫湖泊后期充填淤塞满பைடு நூலகம்后形成的。
以泥炭沉积为主具有水平层理,炭屑、植物化石丰富。
七、鲍马序列及其沉积特征(由下到上)
A段 (底部递变层段)
是经直接悬浮沉积作用由高密度的浊流堆积成的。下粗上细由砾、砂组成的韵律层。具有递变层理,底部具有冲刷界面。岩层呈块状。
B段 (下平行纹层段)
二、影响沉积机械分异作用的因素
主要因素有颗粒大小、颗粒形状、相对密度、以及搬运介质的性质和速度。(1)沉积物按照颗粒大小和相对密度发生分异,使相对密度大的体积小的物质与相对密度小的体积大的物质堆积在一起。(2)颗粒形状也影响着物质分异,片状矿物医悬浮而搬运得远,等轴粒状搬运至近处;作滚动搬运的颗粒,圆度球度高者易滚动而有利于被搬运。(3)颗粒的相对密度和形状与矿物成分密切相关,大小与矿物物理性质有关,因此机械沉积分异在一定程度上是依矿物的成分分异的。(悬浮状态是片状的物质易沉积,滚动状态粒状物质易沉积)。
9、交错层理形成与(介质运动多变的环境)
《油层物理学》第5节:储层岩石的敏感性研究
油藏物理学——储层岩石的敏感性研究
华北坳陷第三系:
接触胶结中的φ:23~30%,K:(50~1000)×10-3μm2 孔隙胶结中的φ:18~25%,K:(1~150)×10-3μm2 基底胶结中的 φ:8~17%, K < 1×10-3μm2
油藏物理学——储层岩石的敏感性研究
5. 影响粘土膨胀的因素:effect factor on clay swelling 粘土类型 clay type 含量 clay content 分布clay distribution 水的矿化度 water saltiness/salinity 阳离子交换性cation exchange
第五节 储层岩石的敏感性研究
Research on sensitivity of reservoir rock
油藏物理学——储层岩石的敏感性研究
讲课提纲
一. 问题的提出 二. 胶结物与胶结类型 三. 敏感矿物
●水敏性矿物 ●盐敏性矿物 ●酸敏性矿物 ●碱敏性矿物 ●速敏性矿物 ● 盐敏 四. 储层敏感性的评价方法 ●推荐程序 ●试验流程 ●发展趋势
油藏物理学——储层岩石的敏感性研究
(1)粘土遇水膨胀 ― 水敏性矿物
Clay swelling ——water sensitivity mineral 1. 起因:晶层间联系的牢固性 水敏性矿物由于其在晶层间的吸水引起的膨 胀,砂粒上的粘土颗粒的絮解和在粘土片外表形 成的定向水化层。
如:蒙脱石是硅氧四面体结构,晶层间的 距离与所嵌离子的离子半径的差会引起阳离子 的交换,或水分子的进入,因而引起膨胀。
油藏物理学——储层岩石的敏感性研究
胶结物
胶结物胶结物指成岩期在岩石颗粒之间起粘结作用的化学沉淀物引。
主要胶结物为硅质(石英、玉髓等)、碳酸盐矿物(方解石、白云石等),其次是铁质(赤铁矿、褐铁矿等),有时可见硫酸盐矿物(石膏、硬石膏等)、沸石类矿物(方沸石、浊沸石等)、粘土矿物(高岭石、水云母、绿泥石等)。
碎屑颗粒和基质之外的化学沉淀物质。
在碎屑岩中含量一般不超过50%,它对碎屑颗粒起胶结作用,使其变成坚硬的岩石。
粘结岩土颗粒或结构面的物质,有钙质、硅质铁质、泥质及可溶盐等。
分类:基底式胶结、孔隙式胶结、接触式胶结和镶嵌式胶结。
命名:在同一岩石中可出现二种以上的胶结物结构和胶结类型,可用复合命名法,如再生孔隙胶结、连生基底胶结等。
胶结类型指碎屑物与填隙物(包括胶结物及杂基)之间的关系。
胶结类型或叫支撑性质,它首先与碎屑颗粒与杂基的相对数量比例(即基粒比)有关,另一重要因素是颗粒之间的相互关系。
如当水动力强时,和碎屑同时沉积下来的杂基将被冲走,使碎屑颗粒彼此相接触,颗粒之间留有空隙,造成“颗粒支撑”的结构,成岩后形成化学胶结物的碎屑岩;如果水动力弱或介质为密度流时,大小碎屑与泥质一起沉淀,造成“杂基支撑”的结构,碎屑呈“游离状”分布于杂基之中,成岩后形成杂基填充的碎屑岩。
在成岩期的压固作用下,特别是当压溶作用明显时,砂质沉积物中的碎屑颗粒会更紧密地接触。
颗粒之间由点接触发展为线接触、凹凸接触,甚至形成缝合状接触。
这种颗粒直接接触构成的镶嵌式胶结,有时不能将碎屑与其硅质胶结物区分开,看起来像是没有胶结物,因此有人称之为无胶结物式胶结。
A cement is a binder, a substance used in construction that sets and hardens and can bind other materials together. The most important types of cement are used as a component in the production of mortar in masonry, and of concrete- which is a combination of cement and an aggregate to form a strong building material.Cements used in construction can be characterized as being either hydraulic or non-hydraulic, depending upon the ability of the cement to set in the presence of water (see hydraulic and non-hydraulic lime plaster).Non-hydraulic cement will not set in wet conditions or underwater; rather, it sets as it dries and reacts with carbon dioxide in the air. It can be attacked by some aggressive chemicals after setting.Hydraulic cements(e.g., Portland cement) set and become adhesive due to a chemical reaction between the dry ingredients and water. The chemical reaction results in mineral hydrates that are not very water-soluble andso are quite durable in water and safe from chemical attack. This allows setting in wet condition or underwater and further protects the hardened material from chemical attack. The chemical process for hydraulic cement found by ancient Romans used volcanic ash (activated aluminium silicates[citation needed]) with lime (calcium oxide).The word "cement" can be traced back to the Roman term opus caementicium, used to describe masonry resembling modern concrete that was made from crushed rock with burnt lime as binder. The volcanic ash and pulverized brick supplements that were added to the burnt lime, to obtain a hydraulic binder, were later referred to as cementum, cimentum, cäment, and cement.CaCO3→ CaO + CO2The calcium oxide is then spent (slaked) mixing it with water to make slaked lime (calcium hydroxide):CaO + H2O → Ca(OH)2Once the excess water is completely evaporated (this process is technically called setting), the carbonation starts:Ca(OH)2 + CO2→ CaCO3 + H2OThis reaction takes a significant amount of time because the partial pressure of carbon dioxide in the air is low. The carbonation reaction requires the dry cement to be exposed to air, and for this reason the slaked lime is a non-hydraulic cement and cannot be used under water. This whole process is called the lime cycle.Conversely, hydraulic cement hardens by hydration when water is added. Hydraulic cements (such as Portland cement) are made of a mixture of silicates and oxides, the four main components being:Belite (2CaO·SiO2);Alite (3CaO·SiO2);Tricalcium aluminate (3CaO·Al2O3) (historically, and stilloccasionally, called 'celite');Brownmillerite (4CaO·Al2O3·Fe2O3).Cements in the 20th centuryThe National Cement Share Company of Ethiopia's new plant in Dire Dawa.Calcium aluminate cements were patented in 1908 in France by Jules Bied for better resistance to sulfates.In the US, the long curing time of at least a month for Rosendale cement made it unpopular after World War One in the construction of highways and bridges and many states and construction firms turned to the use of Portland cement. Because of the switch to Portland cement, by the end of the 1920s of the 15 Rosendale cement companies, only one had survived. But in the early 1930s it was discovered that, while Portland cement had a faster setting time it was not as durable, especially for highways, to the point that some states stopped building highways and roads with cement. Bertrain H. Wait, an engineer whose company had worked on the construction of the New York City's Catskill Aqueduct, was impressed with the durability of Rosendale cement, and came up with a blend of both Rosendale and synthetic cements which had the good attributes of both: it was highly durable and had a much faster setting time. Mr. Wait convinced the New York Commissioner of Highways to construct an experimental section of highway near New Paltz, New York, using one sack of Rosendale to six sacks of synthetic cement. It was proved a success and for decades the Rosendale-synthetic cement blend became common use in highway and bridge construction.[22]Portland cement[edit]Main article: Portland cementPortland cement is by far the most common type of cement in general use around the world. This cement is made by heating limestone (calcium carbonate) with other materials (such as clay) to 1450 °C in a kiln, in a process known as calcination, whereby a molecule of carbon dioxide is liberated from the calcium carbonate to form calcium oxide, orquicklime, which is then blended with the other materials that have been included in the mix to form calcium silicates and other cementitious compounds. The resulting hard substance, called 'clinker', is then ground with a small amount of gypsum into a powder to make 'Ordinary Portland Cement', the most commonly used type of cement (often referred to as OPC). Portland cement is a basic ingredient of concrete, mortar and mostnon-specialty grout. The most common use for Portland cement is in the production of concrete. Concrete is a composite material consisting of aggregate (gravel and sand), cement, and water. As a construction material, concrete can be cast in almost any shape desired, and once hardened, can become a structural (load bearing) element. Portland cement may be grey or white.Portland cement blends[edit]Portland cement blends are often available as inter-ground mixtures from cement producers, but similar formulations are often also mixed from the ground components at the concrete mixing plant.[26]Portland blast-furnace slag cement, or Blast furnace cement (ASTM C595 and EN 197-1 nomenclature respectively), contains up to 95% ground granulated blast furnace slag, with the rest Portland clinker and a little gypsum. All compositions produce high ultimate strength, but as slag content is increased, early strength is reduced, while sulfate resistance increases and heat evolution diminishes. Used as an economic alternative to Portland sulfate-resisting and low-heat cements.[27]Portland-fly ash cement contains up to 40% fly ash under ASTM standards (ASTM C595), or 35% under EN standards (EN 197-1). The fly ash is pozzolanic, so that ultimate strength is maintained. Because fly ash addition allows a lower concrete water content, early strength can also be maintained. Where good quality cheap fly ash is available, this can be an economic alternative to ordinary Portland cement.[28]Portland pozzolan cement includes fly ash cement, since fly ash is a pozzolan, but also includes cements made from other natural or artificial pozzolans. In countries where volcanic ashes are available (e.g. Italy, Chile, Mexico, the Philippines) these cements are often the most common form in use. The maximum replacement ratios are generally defined as for Portland-fly ash cement.Portland silica fume cement. Addition of silica fume can yield exceptionally high strengths, and cements containing 5–20% silica fume are occasionally produced, with 10% being the maximum allowed additionunder EN 197-1. However, silica fume is more usually added to Portland cement at the concrete mixer.[29]Masonry cements are used for preparing bricklaying mortars and stuccos, and must not be used in concrete. They are usually complex proprietary formulations containing Portland clinker and a number of other ingredients that may include limestone, hydrated lime, air entrainers, retarders, waterproofers and coloring agents. They are formulated to yield workable mortars that allow rapid and consistent masonry work. Subtle variations of Masonry cement in the US are Plastic Cements and Stucco Cements. These are designed to produce controlled bond with masonry blocks.Expansive cements contain, in addition to Portland clinker, expansive clinkers (usually sulfoaluminate clinkers), and are designed to offset the effects of drying shrinkage that is normally encountered with hydraulic cements. This allows large floor slabs (up to 60 m square) to be prepared without contraction joints.White blended cements may be made using white clinker (containing little or no iron) and white supplementary materials such as high-purity metakaolin.Colored cements are used for decorative purposes. In some standards, the addition of pigments to produce "colored Portland cement" is allowed. In other standards (e.g. ASTM), pigments are not allowed constituents of Portland cement, and colored cements are sold as "blended hydraulic cements".Very finely ground cements are made from mixtures of cement with sand or with slag or other pozzolan type minerals that are extremely finely ground together. Such cements can have the same physical characteristics as normal cement but with 50% less cement particularly due to their increased surface area for the chemical reaction. Even with intensive grinding they can use up to 50% less energy to fabricate than ordinary Portland cements.[30]Other cements[edit]Pozzolan-lime cements. Mixtures of ground pozzolan and lime are the cements used by the Romans, and can be found in Roman structures still standing (e.g. the Pantheon in Rome). They develop strength slowly, but their ultimate strength can be very high. The hydration products thatproduce strength are essentially the same as those produced by Portland cement.Slag-lime cements.Ground granulated blast-furnace slag is not hydraulic on its own, but is "activated" by addition of alkalis, most economically using lime. They are similar to pozzolan lime cements in their properties. Only granulated slag (i.e. water-quenched, glassy slag) is effective as a cement component.Supersulfated cements contain about 80% ground granulated blast furnace slag, 15% gypsum or anhydrite and a little Portland clinker or lime as an activator. They produce strength by formation of ettringite, with strength growth similar to a slow Portland cement. They exhibit good resistance to aggressive agents, including sulfate. Calcium aluminate cements are hydraulic cements made primarily from limestone and bauxite. The active ingredients are monocalcium aluminate CaAl2O4(CaO · Al2O3 or CA in Cement chemist notation, CCN) and mayenite Ca12Al14O33(12 CaO · 7 Al2O3, or C12A7 in CCN). Strength forms by hydration to calcium aluminate hydrates. They are well-adapted for use in refractory (high-temperature resistant) concretes, e.g. for furnace linings.Calcium sulfoaluminate cements are made from clinkers that includeye'elimite (Ca4(AlO2)6SO4or C4A3S in Cement chemist's notation) as a primary phase. They are used in expansive cements, in ultra-high early strength cements, and in "low-energy" cements. Hydration produces ettringite, and specialized physical properties (such as expansion or rapid reaction) are obtained by adjustment of the availability of calcium and sulfate ions. Their use as a low-energy alternative to Portland cement has been pioneered in China, where several million tonnes per year are produced.[31][32] Energy requirements are lower because of the lower kiln temperatures required for reaction, and the lower amount of limestone (which must be endothermically decarbonated) in the mix. In addition, the lower limestone content and lower fuel consumption leads to a CO2emission around half that associated with Portland clinker. However, SO2 emissions are usually significantly higher."Natural" cements correspond to certain cements of the pre-Portland era, produced by burning argillaceous limestones at moderate temperatures. The level of clay components in the limestone (around 30–35%) is such that large amounts of belite (the low-early strength, high-late strength mineral in Portland cement) are formed without the formation of excessive amounts of free lime. As with any natural material, such cements have highly variable properties.Geopolymer cements are made from mixtures of water-soluble alkali metal silicates and aluminosilicate mineral powders such as fly ash and metakaolin.Green cementGreen cement is a cementitious material that meets or exceeds the functional performance capabilities of ordinary Portland cement by incorporating and optimizing recycled materials, thereby reducing consumption of natural raw materials, water, and energy, resulting in a more sustainable construction material.New manufacturing processes for producing green cement are being researched with the goal to reduce, or even eliminate, the production and release of damaging pollutants and greenhouse gasses, particularly CO2.[56]Growing environmental concerns and increasing cost of fuels of fossil origin have resulted in many countries in sharp reduction of the resources needed to produce cement and effluents (dust and exhaust gases).[55]Peter Trimble, a design student at the University of Edinburgh has proposed 'DUPE' based on Sporosarcina pasteurii, a bacterium with binding qualities which, when mixed with sand and urine produces a concrete said to be 70% as strong as conventional materials.[57。
《沉积岩石学》第三章 碎屑岩的成分
表3—8 化学成分与粒度的关系(引自裴蒂庄,1975)
组成 SiO2 TiO2
AL2O3 氧化铁 MgO
CaO Na2O K2O
细砂 71.15 0.50 10.16 3.72 1.66 3.65 0.86 2.20
粉砂 61.24 0.85 13.30 3.94 3.31 5.11 1.32 2.33
镇川1井,h8,黑云母受压变形 100倍
3、重矿物
指碎屑岩中比重大于2.86的矿物。
在岩石中含量很少,一般<1%,主要分布在在0.25~ 0.05mm的粒级范围内(细砂—粗粉砂岩) 根据风化稳定性
稳定重矿物
电气石、锆英石、金红石、石榴石、榍石、磁 铁矿 等
不稳定重矿物
重晶石、磷灰石、绿帘石、黄铁矿等
长石砂岩中,砾岩、粉砂岩中含量较少。
(2)来源:主要来自花岗岩、花岗片麻岩 (3)长石大量出现的有利因素:
地壳运动比较剧烈,地形高差大,气候干燥, 物理风化作用为主,搬运距离近,快速堆积。
(4)稳定性:钾长石>钠长石>钙长石;正长石>微 斜长石。
长石
斜长石,白云石胶结,细砂岩,东濮,100(+)
锆石,石榴石,角闪石
各类岩石的轻重矿物组合
母岩 花岗岩 花岗闪长岩 安山岩和玄武
岩 橄榄岩和辉长
岩 变质岩
沉积岩
重矿物 轻矿物 重矿物 轻矿物 重矿物 轻矿物 重矿物 轻矿物
重矿物
轻矿物
矿物组合(包括部分岩屑) 锆石 金红石 榍石 磷灰石 黑云母 石英 正长石 微斜长石 酸性斜长石
辉石 角闪石 安山岩或玄武岩岩屑 中性和基性斜长石
碎屑岩的成分可以用其所含的矿物成分表示,也可用化学成 分表示。
常见沉积岩肉眼鉴定简介
常见沉积岩肉眼鉴定简介鉴定内容和方法:碎屑岩:砾岩、砂岩、粉砂岩粘土岩:页岩、泥岩化学岩及生物化学岩:碳酸盐岩:石灰岩、泥灰岩、白云岩;硅质岩;铁质岩等火山碎屑岩:火山角砾岩、凝灰岩对照教材中所列沉积岩的主要鉴定特征,在肉眼下借助于放大镜、小刀等观察不同岩石类型的主要矿物成分、结构构造特征。
沉积岩是外动力地质作用形成的沉积物经过成岩作用形成的。
沉积岩的特征主要通过其颜色、构造、结构和成分来认识,沉积岩一般呈层状。
按成因及成分可大致分类为:1、碎屑岩类:包括正常的碎屑岩、火山碎屑岩;2、化学岩和生物化学岩。
一)沉积岩的颜色:沉积岩的颜色往往反映了岩石的成分和形成的环境。
白色的沉积岩多为纯净的高岭土、石英、方解石、盐类成分组成。
深灰色-黑色一般说明岩石中含有有机成分或散状的硫化铁等杂质。
是还原环境下形成的岩石;肉红色或深红色可能含有较多的正长石或氧化铁,是在氧化环境下形成的;含二价铁的硅酸盐组成绿色沉积岩,形成于弱还原环境。
沉积岩的系统分类表:二)沉积岩的构造:层理和层面构造是沉积岩特有的构造。
沉积岩因层理构造显示其非均匀性,层理有:水平的、波状起伏的、倾斜的、交错的等,肉眼看不到层理构造的为块状层理。
层面构造是各种地质作用在沉积物表面留下的痕迹。
常见的有波痕、泥裂、雨痕、虫迹等。
三)沉积岩的结构:沉积岩的结构与沉积岩的成因紧密相关可分为:碎屑岩具有碎屑结构、化学岩具有化学结构、生物成因的生物结构。
碎屑结构:按碎屑颗粒的直径大小又可分为:砾状结构:>2mm砂状结构:0.05—2mm之间粉砂状结构:0.O05—0.05mm之问.泥质结构:<0.005mm。
化学结构:矿物是通过胶体溶液或真溶液中以化学方式沉淀而生成的结构,它可以是隐晶的,也可以是显晶的。
生物结构:岩石中几乎全部或大部分由生物遗体(如贝壳等)所组成.四)沉积岩的矿物成分:沉积岩中的常见矿物有二十多种,各类沉积岩中的矿物成分有较大差别。
第四纪地质(细则部分内容)
第四纪地质第四纪地质是1:5万平原深覆盖区区调的组成部分,这些调查既服务于经济建设,又与人类的生产、生活密切相关。
区调工作要在经济和社会生活中发挥更大作用,就要开阔眼界拓展服务领域,重视上述方面的调查。
本《细则》根据《区域地质调查总则(1:50000)》、《工程地质调查规范(1:2.5万-1.5万)》、《城市区域地质调查技术要求(1:50000)》要求进行编制的。
一第四纪野外记录描述内容(一)第四纪岩石命名及岩性描述粘土类描述内容:颜色、岩性名称、成份及含量(包括粒和砾径)、构造(包括层厚等)、结构、粘性、塑性、透水性、胶结性等。
1、粘土灰黄色……粘土,粘粒含量大于30%,块状构造,泥质结构。
干后坚硬,裂隙发育,手压不碎,铁锤打击成粉末。
湿土能搓成1mm左右细条,粘性和塑性大(好),不透水等。
2、亚粘土 (粉砂质粘土)灰黄色……亚粘土,粘粒含量5-30%,块状构造,粉砂泥质结构。
干后较硬,裂隙少,手压不易碎,手搌有少量砂感。
湿土能搓成球体或3mm左右细条,粘性和塑性较大(好),透水性极弱等。
3、亚砂土(含粘土质粉砂、粉土)灰黄色……亚砂土,粘粒含量小于5%,块状(层状等)构造,泥质粉砂结构,土质粗糙、松散、空隙发育。
干后无裂隙、结构松散、手压极易碎,砂感强,土块完整性极差。
不能搓成细条和球体,湿时也无粘聚力,过湿时成流动状态。
无粘性和塑性,透水性能好等。
4、淤泥质土主要有{粉砂质淤泥(淤泥质亚粘土)、淤泥质粉砂(淤泥质亚砂土、工程地质称淤泥质粉土)。
灰黑色……淤泥,块状(层状等)构造,泥质结构,岩性较软(稀)、水份大时不成形,水份含量较高,一般大于50%,水份特高时呈流动状态,具油脂光泽,手搌污手,有异味,粘性和塑性好,透水性弱等。
5、砂类颜色、成份、大小(粒径)、含量(各粒级含量)、构造、结构(砂质结构等),磨园度(滚园状、园状、次园状、次棱角状、棱角状)、分选性(分选性好、分选性中等、分选性差),胶结物成份、含量、胶结性(胶结松散、胶结紧密等)等。
石油大学地质学基础——第四章 沉积岩
常用的碎屑颗粒粒度分级表
2的几何级数制 粒 巨 粗 中 细 粗 中 细 砾 砾 砾 砾 砂 砂 砂 粉砂 细粉砂 砂 级 划 分 巨 中 砾 卵 砾 砾 石 石 颗粒直径(毫米) >256 256~64 64~4 4~ 2
2~1 1~0.5 0.5~0.25 0.25~0.125 0.125~0.0625 0.0625~0.0312 0.0312~0.0156 0.0156~0.0078 0.0078~0.0039
包括发生变质作用以前或因构造运动重新抬升到
地表遭受风化作用以前所发生的一切作用。
成岩作用类型:
压实作用、压溶作用 胶结作用、交代作用
重结晶作用和矿物的多形转变作用
溶解作用
(1)压实作用 沉积物在上覆水层和沉积层的重荷(压力)下, 或在构造形变的作用下,发生水分排出、孔隙度降低、 体积缩小的作用。
粘土的孔隙度80%
20%
(2)压溶作用 随埋藏深度的增加,碎屑颗粒接触点上因压力增大, 发生晶格变形和溶解作用。 压实作用和压溶作用是持续进行的。
(3)胶结作用 从孔隙溶液中沉淀出矿物质(胶结物),将松散 的颗粒固结起来的作用。 是碎屑沉积物的主要成岩方式。
常见的胶结物有:硅质、钙质、铁质、粘土、石膏等。
2. 沉积岩的分类
根据沉积岩原始沉积物质成分的来源 1.母岩风化产物为主的沉积岩 碎屑岩 化学岩
砾岩 砂岩 粉砂岩 粘土岩 碳酸盐岩 硫酸盐岩 卤化物岩 硅岩 其它化学岩
3.生物遗体为主的沉积岩 2.火山碎屑物质为主的沉积岩
可燃有机岩 非可燃有机岩
火山碎屑岩
煤 油页岩
第二节 沉积岩的一般特征
1. 沉积岩的化学成分 与岩浆岩类似,相对富Fe 3+ 、Na2O、H2O、CO2。 2. 沉积岩的矿物成分 岩屑、矿屑、粘土、蒸发矿物、碳酸盐等。暗色矿物很少。 3. 沉积岩的颜色
常见岩石、矿物、胶结物、元素英汉对照
常见岩石、矿物、胶结物、元素:岩石:u Magmatite,Magmatic rock(岩浆岩)/Igneous(火成岩),u Plutonic(深成岩),u Gabbro (辉长岩),u Diabase(辉绿岩),u Diorite (闪长岩),u Basalt (玄武岩) ,u Peridotite(橄榄岩),u Andesite (安山岩),,u Granite(花岗岩),u Gneiss (片麻岩) u Quartzite(石英岩),u Lamprophyre (煌斑岩) ,u Breccia(角砾岩),u Schist(片岩)u Metamorphic (变质岩),u Slate(板岩),u Argillite(泥质板岩、厚层泥岩),u Sedimentary rock (沉积岩),u Conglomerate(砾岩)/Gravel(砾岩、砂砾、碎石),u Clastic(碎屑岩),u Breccia(角砾岩),u Boulder(巨砾),u Cobble(粗砾),u Pebble(中砾),u Granule (细砾),u Very Coarse Sand(砾状砂\含粒状砂),u Coarse Sand (粗砂岩),u Medium Sand(中砂岩),u Fine Sand(细砂岩),u Very Fine Sand(粉细砂)/Sandy Siltstone (粉细砂、砂质粉),u Siltstone(粉砂岩),u Bentonite(膨润土、坂土),u Oil Shale, Pil Shale, Resinoid Shale (油页岩) ,u Clay(粘土),u Shale, Mudstone (泥岩),u Gumbo (Clay)(强粘土),u Limy Sand(石灰质砂岩),u Carbonate(碳酸盐岩),u Marble (大理岩),u Limestone(灰岩),u Sandy Lime(砂质灰岩),u Dolomite(白云岩),u Bio- limestone(生物灰岩) ,u Oolitic Limestone (鲕状灰岩),u Tuff (凝灰岩) ,u Clastic Limestone(碎屑灰岩),u Evaporite(蒸发岩),u Rock Salt(盐岩),u pelitic siltstone 泥质粉砂岩,u argillaceous limestone 泥质灰岩,u calcirudite砾屑灰岩矿物:u Quartz(石英),u Feldspar(长石),u Orthoclase/Syenite(正长石),u Plagioclase Feldspar(斜长石),u Potassium Feldspar(钾长石),u Mica(云母),u Biotite Mica (黑云母),u Dolomite(白云母),u Calcite(方解石),u Olivine(橄榄石),u Amphibole (角闪石),u Pyroxene(辉石),u Pumice(浮石),u Felsite (霏细石),u Fluorite(荧石),u Apatite(磷灰石),u Topaz(黄玉),u Corundum(刚玉),u Opal(蛋白石),u Garnet(锆石),u Garnet(石榴石),u Anhydrite(硬、无水石膏),u Gypsum(石膏),u Kaolinite(高岭石),u Illite(伊利石),u Magnetite/Ferromagnesian Mineral(磁铁矿),u Hematite(赤铁矿),u Pyrite(黄铁矿),u Halite(岩盐),u Chert(燧石、黑硅石)/Flint(燧石),u Glauconite(海绿石),u Barite(重晶石),u Sodium Chloride (NaCl),u Sulphur(硫),u Carbide(电气石,CaC2)胶结物:u Calcium,Limy,Calcareous(灰质),u Dolomite(白云质),u Silicon(硅质),Silica(SiO2),u Gypsum(石膏)/Anhydrite(硬、无水石膏)----(石膏质),u Ferrous(铁质)----Iron,u Quartz Cement(石英胶结物),u Clay Cement(粘土胶结物),u Kaolinite(高岭石)----高岭土质,u Argillaceous(泥质)----Mud,Clay。
岩石学-沉积岩第五章-碎屑岩-1
孔 隙
碎 屑 颗 粒
基 质
胶结物
第二节
1.碎屑本身的结构
(1)粒度
陆源碎屑岩的结构
碎屑颗粒的大小称为粒度。粒度是以颗粒直径来度量的。
粗砾 >64mm 64-4mm 4-2mm 0.5-2mm 0.5-0.25mm 0.25-0.05mm 0.05-0.005mm <0.005mm
砾
中砾 细砾 粗砂
3)常见的砾岩类型
.石英岩砾岩:砾石以石英岩、燧石岩、 脉石英等为主,中-细砾级,分选、磨圆较好, 颗粒支撑。常见胶结物为石英、方解石、赤铁 矿等。
.火山岩砾岩:砾石主要为火山岩或火山 凝灰岩,单成分或复成分,多中砾级,中等分 选磨圆,常含砂基或混基,砂基成分与砾石成 分相近,但有较多石英、长石单晶。胶结物通 常为泥质、钙质或铁质。
嵌在一个光性一致的大晶体内。方解石、石膏、硬
石膏、重晶石、沸石等胶结物易形成这种结构。
1). 胶结类型 碎屑和填隙物之间的关系称胶结类型, 胶结类型划分为以下几种:
基底式胶结 接触式胶结 孔隙式胶结
镶嵌式胶结
基底式胶结(Basal cement-ation)
填隙物含量较多,碎
粒分选、磨圆度好,颗粒支撑;基质极少,胶结物
主要为硅质、海绿石。以孔隙式和镶嵌式胶结类型
为主。硅质胶结物为主时,常形成石英自生加大结
构。
.石英砂岩的古环境意义
纯净的石英砂岩具有高成分成熟度和结
构成熟度,通常代表砂粒经过成河流长时间 搬运之后,又在滨岸浪的作用下,反复冲洗 的结果。石英砂岩多形成于滨—浅海砂质海 岸沉积环境。
A, 微晶结构,
作用阶段。
B, 镶嵌粒状结构, C, 栉壳状结构, D, 加大边结构,
