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通过在湘潭县毛塘海泡石黏土矿区留君庵矿段开展矿产勘查工作,基本查明了海泡石黏土矿床的地质特征。矿区海泡石黏土矿赋存于中二叠统小江边组“含泥质段”风化层中,矿体形态平面上呈长条带状,剖面上矿体形态呈透镜体状、似层状,矿床规模为小型。根据X衍射定量测试分析和化学分析,矿石主要矿物成分为海泡石、石英、方解石、滑石和蒙脱石等组成;矿石化学成分总体富硅、镁、低钾、钠。矿石中海泡石含量与MgO、SiO2含量呈正相关关系,与CaO含量总体呈负相关,结合矿石扫描电镜分析结果,区内海泡石形成于沉积过程的新生作用。综合矿区成矿地质特征和矿石物理化学特点,矿区位于古陆边缘局限性的富Mg2+、Si4+及高pH值的浅海环境中,海泡石经原生沉积于钙镁质页岩、泥灰岩,再经长期化学风化改造,在表生条件下不断富集形成海泡石黏土矿床,矿床成因类型为沉积风化残余型。 相似文献
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晶质菱镁矿矿床赋存于海相碳酸盐岩建造,为富镁碳酸盐经后期变质重结晶的产物,属沉积- 变质型矿床。本次研究将中国境内的晶质菱镁矿矿床按变质重结晶程度分为三类 (高、中和低),并进行了地质和地球化学研究,获得如下认识：① 产于古生代海相碳酸盐岩中的菱镁矿矿床经历低程度变质重结晶作用(绿片岩相),矿石结晶度差,品位相对较低(44. 98%~47. 35%),且保留有海相碳酸盐岩建造的碳同位素地球化学特征(δ13CV- PDB：0. 4‰~+0. 3‰);② 大型(>5000万t)优质(MgO>46%)晶质菱镁矿矿床集中分布在华北克拉通东部的古元古代胶- 辽- 吉活动带海相碳酸盐岩中,矿体后期经历中等程度变质重结晶作用(中—低角闪岩相),矿石发生中等程度的重结晶作用,继承了海相碳同位素地球化学特征(δ13CV- PDB1. 9‰~+1. 7‰);③ 经历高角闪岩相(高级)变质作用的菱镁矿矿床矿石结晶程度最优,但强烈的变质作用引发外源含硅热液流体加入而发生蛇纹石化作用,矿石品位低(MgO=44. 42%~45. 55%),具有较高的TFeO、Mn和Ti含量,整体亦显示较低的碳同位素组成(δ13CV- PDB：4. 1‰~3. 5‰)。因此,沉积- 变质型菱镁矿矿体的镁质富集可能发生在海相沉积成岩期,后期变质作用引发富镁碳酸盐矿物重结晶作用,镁质碳酸盐和钙质碳酸盐矿物进一步发生近原地分离重结晶作用,形成晶质菱镁矿矿体和富镁白云石夹石,但过高(高角闪岩相及以上)或过低(绿片岩相)的变质作用可能均不利于形成大型优质晶质菱镁矿矿床。 相似文献
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桂阳县荷叶石墨矿床地质特征 总被引：2，自引：0，他引：2
荷叶石墨矿是由二叠系煤层变质而成的石墨矿床,石墨与煤呈同层异矿关系。按照变质特征,矿区从东到西划分为角岩带、强角岩化带和中弱角岩化带。前两个变质带内的煤全部变质成石墨,中弱角岩化带东部的煤已石墨化,西部的煤全变质为无烟煤。故矿层划分为石墨带和石墨化无烟煤带。 相似文献
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天湖铁矿床是新疆东部已知大型铁矿床之一。矿床以层状、似层状产于晚元古代天湖群(1060Ma)角闪岩相变质火山-沉积岩系内,呈以白云质大理岩为容矿岩的条纹一条带状磁铁矿,属变质含铁碳酸盐建造。本文从成矿地质环境、变质作用、矿石矿物学等几个方面对其地质特征、矿床类型和成因进行了探讨,并与国内同类型矿床进行了比较。 相似文献
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曲阳金红石矿含矿带长约4km，出露宽度约1km，总体呈东西向展布。矿床受层位控制，赋存于下元古界东焦群豆村组二段含金红石赤铁绢云母石英片岩和赤铁白（绢）云母石英片岩中，共圈定矿体8个，矿体长500m-1700m，平均厚度1m-2m，TiO2平均品位1％～4．02％，矿体产状与围岩一致。矿床形成于古元古代山间盆地相沉积一变质建造中，经历了多次变形变质作用，变质程度达低绿片岩相，为沉积变质矿床。矿床特点与内蒙古羊蹄子山钛矿床相似。目前矿床控制规模为中型，有望成为大型。 相似文献
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延边地区官地铁矿床形成时代及其构造意义 总被引：1，自引：1，他引：0
官地铁矿床位于吉林省和龙地区,地处华北克拉通北缘与兴蒙造山带东段接合带附近的和龙地块北部。主矿体呈层状、似层状、透镜状赋存于鞍山群甲山组下段;含矿岩石以磁铁石英岩、长英片麻岩、云母片岩、斜长浅粒岩为主,其变质程度为绿片岩相-角闪岩相的中低级区域变质;主要矿石类型为条带状铁建造。为确定矿床的形成时代,重点对含矿变质岩系中的斜长浅粒岩开展了LA-ICP-MS锆石U-Pb年代学研究。结果表明,官地铁矿床含矿变质岩的原岩(酸性火山岩)形成于(2551±44)Ma,在(2525±48)Ma经历区域变质作用,随后又受古元古代构造热事件的改造。官地铁矿床与华北克拉通内鞍山地区铁矿床具有相似的成矿地质条件、矿床特征和形成时代,同属于鞍山式(阿尔戈马型)沉积变质型铁矿床。根据测年结果,并与邻区的锆石年龄对比分析,认为和龙地块应归属华北克拉通,这为索伦-西拉木伦-长春缝合带的东延问题研究提供了新的证据。 相似文献
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海泡石用途广泛。在我国境内已有 13个省 (区 )发现这一矿产。赣、湘、苏、陕等地海泡石占全国已知海泡石储量的 80 %以上。海泡石矿床多产于地台沉积坳陷带边缘 ,成矿时代主要为二叠纪和第三纪 ,矿床分为沉积型 (陆相沉积、海相沉积、火山沉积 )和热液型两大类 相似文献
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Sepiolite phase-transformation has been successfully imitated in laboratory for many years, but no natural example has been reported yet. In this paper the authors intend to provide a good natural example in southern China, especially in the Pingle depression, where the Permian sepiolite has been generally converted to talc and minor stevensite (magnesium montmorillonite) due to anadiagenesis during post-sedimentation. In our opinion, the degree of transformation can be indicated by the degree of metamorphism of coal (rank of coal). In order to study the relationship between clay transformation and coal rank, the authors have proposed some parameters of coalification correlated with sepiolite conversion. It happens that volatile matter in the Permian coal comprises 30–52% and a vitrinite reflectance of approximately 0.4–0.8% (R°) is reliable to indicate the existence of sepiolite. The consideration that sepiolite phase-transformation has a linear relationship with the rank of coal can be justified on the trend surface analysis diagrams which show that the areas of lower coal rank are obviously consistent with the sepiolite-distributed areas. Therefore, there is such a possibility as to predict new occurrences of sepiolite on the basis of the distribution of the lower coal ranks. 相似文献
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Bat-Orshikh Erdenetsogt Insung Lee Delegiin Bat-Erdene Luvsanchultem Jargal 《International Journal of Coal Geology》2009,80(2):87-104
This paper presents geological settings, stratigraphy, coal quality, petrography, reserves and the tectonic history of the Mongolian coal-bearing basins. This is based on a synthesis of the data from nearly 50 coal deposits. The results of ultimate and proximate analyses, and calorific value, maceral composition and vitrinite reflectance data is given.The coal deposits of Mongolia tend to become younger from west to east and can be subdivided into two provinces, twelve basins, and three areas. Main controlling factor of coal rank is the age of the coal bearing sequences. Western Mongolian coal-bearing province contains mostly high rank bituminous coal in strata from Late Carboniferous. The basins in southern Mongolia and the western part of central Mongolia have low rank bituminous coal in strata from the Permian. The northern and central Mongolian basins contain mainly Jurassic subbituminous coal, whereas the Eastern Mongolian province has Lower Cretaceous lignite. The Carboniferous, Permian and Jurassic coal-bearing sequences were mainly deposited in foreland basins by compressional tectonic event, whereas Cretaceous coal measures were deposited in rift valleys caused by extensional tectonic event. Petrographically, Mongolian coals are classified as humic type. Vitrinite/huminite groups of Carboniferous, Permian, and Cretaceous coal range from 44.9% to 82.9%. Inertinite group varies between 15.0% and 53.3%, but liptinite group does not exceed more than 7%. Jurassic coals are characterized by high percentages of vitrinite (87.3% to 96.6%) and liptinite groups (up to 11.7%). This might be explained by paleoclimatic conditions. Mongolian coal reserves have been estimated to be 10.2 billion tons, of which a predominant portion is lignite in the Eastern Mongolian province and coking coal in the South Gobi basin. 相似文献
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不同变质程度煤的激光拉曼光谱特征 总被引：7，自引：1，他引：7
对不同矿区，不同变质程度煤的9个镜煤样品进行了激光拉曼光谱测定，并对其特征光谱进行了参数化。在1000－2000cm^-1的波数范围内有两个明显的拉曼频率振动峰G峰和D峰。当镜质体反射率R0＜2．28％时，D峰位置随R0的增大向低波数位置偏移。G峰与D峰峰位差和峰高比随R0的增大而增加。当R0约为2．1％时，拉曼光谱特征趋势发生逆转性变化。在2500－3250cm^-1之间有一个明显的拉曼谱带，并随煤变质程度的增加呈现如下规律，其谱带的变化与有机质的成熟度演化具有一珲的同步性，特别是在有机质进入成熟门限后，由于油相和气相成分的大量生成，出现明显的振动峰，而进入无烟煤（R0＞4．4％）后，其振动峰变弱，因此，煤的激光拉曼光谱特征可作为油气盆地判断有机质成熟度的一个指标。 相似文献
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通过１４件高温高压实验样品及其原样的电子顺磁共振研究,论述了温度、压力、应力、应变速率和应变强度等是影响变形煤化学结构演化的重要因素,但在不同的煤级中和不同的实验条件下,各因素所起的作用是不同的。变形煤ＥＰＲ参数的演化与镜质组反射率的变化密切相关,并且具有较好的规律性。说明镜质组反射率是煤化学结构演化的外在反映,是煤田构造研究中极为重要的标志物之一。 相似文献
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中国泥盆纪煤煤岩研究 总被引：4，自引：0，他引：4
中国泥盆纪煤是形成于一定地质历史条件下的特种煤、显微组成以富含角质本为特征，其它壳质组分、镜质组、惰性组含量均低。泥盆纪煤阶的确定可用角质体荧光参数、角质体反射率及富氢镜质组的反射率。 相似文献
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This paper presents an experimental investigation of coal rank and maceral composition influences on the coal mechanical behaviors. The complete stress–strain behavior, uniaxial compressive strength, Young's modulus, and acoustic compressional velocity were measured and correlated to coal ranks and microstructures. The test results show that coal is an elasto-brittle geo-material and its uniaxial compressive strength and Young's modulus increase as coal rank increases. This occurs because as vitrinite reflectance or coal rank increases, coal has less microporous structure and thus higher uniaxial compressive strength. Therefore, using vitrinite reflectance value instead of vitrinite content is advantageous for correlating coal strength. The experimental results also demonstrate that compressive strength and Young's modulus have positive exponential correlation, even for different types of coal. Therefore, the compressive strength of coal is highly related to its Young's modulus. The uniaxial compressive strength and acoustic compressional velocity of coal are also correlated, but a single correlation does not exist for different coal ranks; instead, different relationships occur for different types of coal. 相似文献
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《Organic Geochemistry》1999,30(8):985-1010
The Buller Coalfield (South Island, New Zealand) is an inverted late Paleogene Basin that contains middle Eocene bituminous coals which exhibit considerable variation in both coal rank (across-basin), and coal type (in-seam). Twenty-two fractionated bitumen extracts of Brunner Coal Measures coal samples from 12 drillholes were analyzed by GC and GC–MS to characterize the effect of coal rank and type on conventional hydrocarbon maturity indices at the beginning and end of the oil window (0.56–1.26% Romax).The Carbon Preference Index, pristane/phytane and isoprenoid/n-alkane ratios evolve throughout the high volatile bituminous B rank stage, while other biomarker ratios [18α(H)-22,29,30-trisnorneohopane/17α(H)-22,29,30-trisnorhopane (Ts/Tm), 18α(H),21β(H)-30-norneohopane (C29 Ts)/17α(H),21β(H)-30-norhopane and C30 diahopane/hopane] do not show appreciable change in value until medium volatile bituminous rank. Various aromatic based ratios appear to be more effective in delineating rank throughout the entire oil window; in particular the Methylphenanthrene Index and vitrinite reflectance are positively correlated over the entire bituminous rank range. However, subtle changes in depositional conditions (variable coal type) complicate these rank estimates. Within a given coal seam, variation in CPI, isoprenoid/n-alkane and hopane/sterane ratios appear to be related to the hydrogen content of the coal, while the homohopane index and the oleanane/hopane ratio covary with sulfur content. As with depressed vitrinite reflectance values, MPI is similarly lowered in the perhydrous samples. The mechanisms that control these hydrocarbon parameters during deposition and diagenesis are complex and convoluted, however, changes in bacterial activity and community (with marine incursion) appear to play an important role. Due to these anomalies, none of the hydrocarbon maturity indices calculated can be singularly used to constrain coal rank. 相似文献
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在四川盆地东部古生界地层发现大量天然气资源,鲜有原油发现。重庆天府磨心坡煤矿下二叠统茅口组石灰岩上部地层裂隙发现沿层间裂隙随水渗出的黄绿色液态轻质油苗。研究表明:油苗碳数分布较窄,为C4~C26,具有明显的姥鲛烷优势,Pr/Ph值为1.64,δ13C值为-26.2‰;油苗所反映的成熟度较高,折算Ro约为1.6%,一维盆地模拟验证二叠系的热演化程度可达与之相当的热演化程度。综合研究认为油苗与二叠系煤系地层关系密切。油苗的发现表明,在四川盆地古生界整体高过成熟的大背景下,某些成熟度相对较低,保存条件适宜的区域仍有发现一些中小型油藏的可能,这对四川乃至南方古生界油气勘探具有一定的启示意义。 相似文献
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埋藏史、受热史和有机质成熟史(简称"三史")模拟技术已广泛应用于油气地质研究,但其在煤和煤层气地质领域则应用较少。根据实测煤的镜质组最大反射率、古地温梯度和地层残余厚度等资料,运用Petromod 1D模拟软件对贵州织纳煤田水公河向斜上二叠统8煤层"三史"演化过程进行研究。结果显示,水公河向斜地质演化史可分为3个阶段:第1阶段从晚二叠世至侏罗纪末,煤层埋深增加,最大至5 925~5 959 m,地温梯度为2.91/hm℃,受深成变质作用影响,煤级从褐煤演化至焦煤阶段;第2阶段从侏罗纪末至白垩纪末,受燕山运动影响,煤层埋深降低,地温梯度为3.29~3.46/hm℃,区域岩浆热变质作用使煤级从焦煤演化至无烟煤阶段;第3阶段从白垩纪末至今,地层少量沉积后发生抬升作用,地温梯度为2.78℃/hm,煤化作用基本停止。总之,深成变质作用是向斜煤层气生成的主要影响原因,距今230~170 Ma是煤有机质生烃的关键时期。 相似文献
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成岩-极低级变质作用及油气勘探意义 总被引：12，自引：3，他引：9
采用粘土矿物学、成岩变质矿物组合、镜质体反射率及流体包裹体数据等指标,综合讨论了准噶尔盆地西北缘晚古生代地层成岩极低级变质作用的特征和油气勘探意义。变质指示矿物和古地温梯度研究确认,西北缘玛湖坳陷北段下二叠统火山岩存在极低级变质作用,具水热变质特征,变质相为葡萄石阳起石相,温度为２２０～３２０℃,压力ｐ＜２００ＭＰａ,表明极低级变质事件发生于早二叠世,未对上二叠统地层产生影响;下二叠统风城组和上二叠统地层于侏罗纪（１５０Ｍａ）达到最大古地温,为１３０～１８０℃,压力ｐ为１００～２００ＭＰａ,处于晚成岩Ａ,Ｂ期。与西准噶尔界山上古生界相比,盆地西北缘变质程度较低。因此,盆地深部上古生界仍是寻找油气、尤其是天然气的有利地带 相似文献