岩浆矿床 地质英语论文.doc

中国地质大学长城学院地质英语论文 系别 地球科学与资源系 专业 资源勘查工程 学生姓名 学 号 指导教师 2012年12月16日title:orthomagmatic ore depositsone.orthomagmatic ore depositsthe magma contains a certain number of metal and volatile components of the silicate melt. all kinds of magma after crystallization and differentiation, make the forming materials dispersed in the magma gathered and formed deposits.and this deposits is called magmatic deposits.magmatic deposits formed in the magmatic stage, the source of the material of the deposit is the main ore-bearing magma.magmatic deposits is the product of the magma by crystallization and differentiation, and generally have the following properties:1、 deposits have the mainly relationship with the mafic and ultramafic rocks.and a small number of magmatic deposits with alkaline rocks or magmatic carbonatite-related. mineralization and diagenesis often begin at the same time.and this is typical of syngenetic ore deposits. few mineralization of the magmatic deposits may be continued to a later time, but generally does not exceed a total period of magmatic activity.2、 the magmatic deposits ore body majority present stratiform,stratiform, lenticular and podiform and so on.and they produced in the magma body,and the wall rock of containing ore is the mother rock.few cases,orebody presenting vein and stockwork enter the wall rock which outside of the mother rock.between the ore body and the wall rock generally is gradual change or rapid gradual change relationship,.only penetration magmatic deposits have the clear boundaries with the wall rock.3、 except the rare and rare earth elements deposits of the magmatic carbonatite due to special causes have some alteration about the wall rock,the vast majority of magmatic deposits surrounding rock does not have a significant alteration phenomenon.4、 the ore and the wall rock basically have the same mineral composition, when the useful minerals of the rock body aggregate and reach a certain size,they become the orebody.5、 the ore of magmatic deposits often have,disseminated,the banded,eye porphyritic,dense massive,brecciated and so on,ore structure.the ores structure can be broadly divided into the following categories: i.structure sub-the different magmatic condensate crystalline or stacking interactions; ii.reflect the structure of the immiscible fluid crystallization process iii.reflect the changes in the structure of the physical and chemical conditions.iv.epigenetic structure.6、 the magmatic deposits forming temperature is high, generally between 1200 to 700 c. the mineralization depth changes,generally formed in the ground a few kilometers to tens of kilometers.tow.the formation conditions of magmatic depositsmagma deposits are mainly derived from the magma, it is the combined effects of the product by a variety of geological factors, which playing a leading role is the geochemistry of ore-forming elements traits, the magmatic rock conditions, tectonic conditions and physical and chemical conditions and so on.1、 control the conditions of magmatic rocks formed by magmatic depositsmagma is the main provider of the metallogenic material of the magmatic deposits and the medium of containing mineral medium.therefore,how much of the content of useful components of magma is the possibility of the formation of magmatic deposits.i.magmatic rocks metallogenic specializationmetallogenic specialization of magmatic rocks in the genesis of magmatic rocks with endogenous deposits showed regular contact, and specific types of magmatic rocks are often produced specific types of deposits.a) with mafic and ultramafic intrusive rocks related depositsmafic and ultramafic rock is the complex igneous complex formed by the combination of a variety of rock types, rock types from a single rock composed of rock mass is relatively rare.the size of the rock mass ranging mostly small,and rock strains, rock cover, rock, bedrock is the most common form of the rock mass. with facies and the different combinations,the mafic and ultramafic rocks can be divided into three types.b)mineral deposits associated with syenite, nepheline syenite and carbonate igneous complexrelating to magmatic deposits of these rocks are mostly produced with the form of rock strain,the different components of rock mass facies zone often has ring distribution.ii.the role of the volatile components in the magmathe magma volatile components have the low melting point,highly volatile and they can delay the condensation rate of the magma, make the magma have more fully differentiation.iii.magmatic assimilation have an influence on the mineralization of the magma depositsiv.beyond one period of magma intrusion on control of the mineralization2、 tectonic conditions that control the formation of magmatic depositstectonics have a major impact on the type of magmatic deposits, distribution, the most magmatic deposits associated with mafic and ultramafic igneous rocks on the causes and space. mafic and ultramafic magma formed by partial melting of mantle material,so the deep fault cuts through the crust to reach the upper mantle have a strict control effect on the mafic, ultramafic rocks and magmatic deposits which have some relationship with them.three.magmatic deposits formation and its characteristics1、 the process of the magmas useful components analysis, aggregation and positioning is called magmatic mineralization. because the magmatic deposits mafic - ultramafic petrogenesis process is very complex, the mineralization also is varied.according to the way and feature of the mineralization,magmatic mineralization can be divided into four categories,the crystallization differentiation mineralization, melting away from the mineralization the magma eruption mineralization and magma eruption mineralization.when magma is condensed, with the temperature gradually decreased, the various mineral sequentially from which crystallized out, result in magma changing,and the magma changes in the composition promote the crystallization of certain components, liking magma composition changed with the crystallization process is called crystallization differentiation.2、 magmatic liquation mineralization and liquation depositmagmatic liquation, also known as liquid separation action or immiscibility, refers to the the uniform composition magma melt with decreasing temperature and pressure separated into two components of different melt role.3、 magmatic eruptions and effusive the mineralization its depositmagma outbreak mineralization kimberlite magma, together with early crystallized olivine, pyrope, diamond crystals and xenoliths along deep faults,and rise rapidly emplaced at the surface produce 2 to 3 kilometers outbreak and the role of the deposit is formed.the magmatic eruption mineralization is the ore-bearing lava spray overflow to the surface or penetration into the crater near volcanic series along certain channels, the the condensate accumulation of deposit formation. formed deposits called magma eruption deposits.four.implications for researchmagmatic deposits having very important industrial significance, most of chromium, nickel, platinum group elements as well as a substantial portion of iron, copper, titanium, cobalt, phosphorus, niobium, tantalum and rare earth elements and other deposits are all from magmatic deposits in the world. mineralization conditions, the genesis of magmatic deposits and distribution law is of great significance.题目：岩浆矿床一、岩浆矿床岩浆是含有一定数量金属及挥发性组分的硅酸盐熔融体。各类岩浆通过结晶作用与分异作用，使分散在其中的成矿物质得以聚集而形成的矿床称为岩浆矿床。岩浆矿床主要形成于岩浆阶段，矿床的物质来源主要是含矿岩浆。岩浆矿床是岩浆结晶、分异作用的产物，普遍具有下列性质：1、 矿床主要与镁铁质、超铁镁质岩石有成因关系，少数岩浆矿床与碱性岩或岩浆碳酸岩有关。成矿作用和成岩作用往往是同时进行，属于典型的同生矿床。少数岩浆矿床的成矿作用虽可延续到较晚的时间，但大体上不超过总的岩浆活动时期。2、 岩浆矿床中的矿体多数呈层状、似层状、透镜状、豆荚状等产于岩浆岩体内，含矿围岩即为母岩；少数情况下矿体呈脉状、网脉状进入母岩之外的围岩中。矿体和围岩之间一般为渐变或迅速渐变关系，只有贯入式岩浆矿床和围岩界线清楚。3、 除岩浆碳酸岩中的稀有、稀土元素矿床由于成因特殊而有一定的围岩蚀变外，绝大多数岩浆矿床的围岩不具有明显的蚀变现象。4、 矿石的矿物成分和围岩基本相同，当岩体内的有用矿物富集达到一定规模时就成为矿体。5、 岩浆矿床的矿石常具浸染状、条带状、眼斑状、致密块状以及角砾状等矿石构造；矿石结构可大致分为以下几类：i分异岩浆冷凝结晶或堆积作用的结构；ii反映不混溶流体结晶过程的结构iii反映物理化学条件变化的结构iv后生结构。6、 岩浆矿床的形成温度较高，一般在1200700之间。成矿深度变化也较大，一般都形成于地下几公里至几十公里。2、 岩浆矿床的形成条件岩浆矿床主要源于岩浆，是多种地质因素综合作用的产物，其中起主导作用的是成矿元素的地球化学性状、岩浆岩条件、大地构造条件和物理化学条件等。1、 控制岩浆矿床形成的岩浆岩条件岩浆是岩浆矿床成矿物质的主要提供者和携带成矿物质的介质，因此岩浆中有用组分含量的多少对能否形成岩浆矿床有重要影响。i岩浆岩成矿专属性岩浆岩成矿专属性是指岩浆岩与内生矿床间在成因上表现出有规律的联系，一定类型的岩浆岩经常产有一定类型的矿床。a、 与镁铁质、超镁铁质侵入岩有关的矿床镁铁质、超镁铁质岩经常是由多种岩石类型组合而成的复杂的岩浆杂岩体，由单一岩石岩石类型构成的岩体较为少见。岩体的规模大小不等，以小型居多，形态以岩株、岩盖、岩盘、岩床最常见。根据岩相和组合不同，镁铁质、超镁铁质岩可分为3个类型。b、与正长岩、霞石正长岩和碳酸杂岩体有关的矿床与岩浆矿床有关的这类岩石大多呈岩株状产出，岩体内不同成分的岩相带常呈环状分布。ii岩浆中挥发性组分的作用岩浆中挥发性组分的熔点低、挥发性强，能延缓岩浆的冷凝速度，使岩浆得到更充分的分异。iii岩浆同化混染作用对岩浆矿床成矿的影响岩浆在其形成和向上运移的过程中，往往会熔化或溶解一些