岩浆矿床地质英语论文.doc

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1、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 mate

2、rials 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 differe

3、ntiation, 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 typic

4、al 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

5、 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 mag

6、matic 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 ph

7、enomenon.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 o

8、n,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 ph

9、ysical 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

10、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.

11、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 m

12、agmatic 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

13、 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, be

14、drock 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

15、 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

16、 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 impac

17、t 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 s

18、trict 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 th

19、e 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

20、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 crystalliz

21、ation 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 co

22、mposition 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 x

23、enoliths 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 ch

24、annels, 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, copp

25、er, 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，

26、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。

27、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。二、 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

28、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待添加的隐藏文字内容2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

29、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外来物质，从而使岩浆成分发生改变的作用，即同化作用。在岩浆侵位的过程中，对围岩的同化作用在一定程度上影响岩浆的成分，也影响着其中的成矿组分的分异和聚集能力。当围岩成分与岩浆成分相差较大时，它既降低了岩浆中成矿物质的浓度，也

30、影响成矿物质分异、聚集的程度。一般认为，在地壳活动强烈地区，岩浆与被同化围岩成分差别越大、侵入体的规模越大、侵位越深、成分越基性、挥发分越多以及围岩破碎程度越高时，同化作用愈强烈而完全。IV岩浆的多期次侵入作用对成矿的控制2、 控制岩浆矿床形成的大地构造条件大地构造对岩浆矿床的类型、分布等有重要影响、大多数岩浆矿床在成因和空间上与镁铁质、超镁铁质岩浆岩有关。由于镁铁质、超镁铁质岩浆系地幔物质部分熔融而成，所以切穿地壳而达上地幔的深大断裂对镁铁质、超镁铁质岩及与之有关的岩浆矿床有严格的控制作用。三、 岩浆矿床的形成作用及其特征岩浆中有用组分分析、聚集和定位的过程称为岩浆成矿作用。与岩浆矿床有关的

31、镁铁-超镁铁质岩体的成岩过程十分复杂，因此成矿作用也是多种多样的。根据成矿作用的方式和特点，岩浆成矿作用主要可分为结晶分异成矿作用、熔离成矿作用、岩浆爆发成矿作用和岩浆喷溢成矿作用四类。1、 结晶分异成矿作用与岩浆分结矿床岩浆冷凝时，随着温度的逐渐下降，各种矿物依次从中晶出，导致岩浆成分不断改变，岩浆成分的改变又促使某些组分的结晶，这种随结晶作用岩浆成分发生改变的过程称之为结晶分异作用。2、 岩浆熔离成矿作用与熔离矿床岩浆熔离作用亦称液态分离作用或不混溶作用，是指成分均匀的岩浆熔融体随着温度和压力的降低，分离成两种成分不同的熔融体的作用。3、 岩浆爆发和喷溢成矿作用及其矿床岩浆爆发成矿作用是指金伯利岩岩浆，连同早期晶出的橄榄石、镁铝榴石、金刚石晶体及捕虏体一起，迅速地沿深断裂上升，侵位于地表23千米处产生爆发并形成矿床的作用。岩浆喷溢成矿作用是指含矿熔浆沿一定通道喷溢至地表或贯入到火山口附近的火山岩系中，冷凝堆积形成矿床的作用。形成的矿床称为岩浆喷溢矿床。四、 研究意义岩浆矿床具有十分重要的工业意义，世界上绝大部分的铬、镍、铂族元素以及相当大部分铁、铜、钛、钴、磷、铌、钽和稀土元素等矿床资源均来自岩浆矿床。因此研究岩浆矿床的成矿条件、矿床成因和分布规律等具有重要意义。