江西武功山早古生代花岗岩的岩石学、锆石U- Pb和Lu—Hf同位素地球化学特征及其地质意义

武功山造山带位于华夏地块与扬子地块碰撞缝合带南侧,记录了新元古代以来的多次构造运动。本文对其中的黑云母二长花岗岩和二云母二长花岗岩进行了全面的矿物学、岩石地球化学、锆石U-Pb同位素年代学及Lu—Hf同位素研究。LA-ICP-MS锆石U-Pb同位素年代学研究指示武功山黑云母二长花岗岩和二云母二长花岗岩结晶于早志留世(441.6～442.2 Ma)。武功山早志留世花岗岩具有富硅(SiO₂含量为67.43%～73.06%)、富碱(Na₂O+K₂O含量为6.47%～8.46%)、贫钙(CaO=0.78%～2.64%)、贫镁(MgO=0.46%～1.61%)等特征,为强过铝质高钾钙碱性花岗岩(A/CNK=1.09～1.35)。同时,岩相学和地球化学指示岩石属于亚碱性系列,分异程度较低,ΣREE较低,轻重稀土分异程度较高,为S型花岗岩且岩浆源区物相为角闪石+斜长石+石榴子石。结合花岗岩锆石f_Lu/Hf值均小于-0.9,ε_Hf(t)均为负值(-6.7到-4.8),指示岩浆来源于古元古代古老...     

Prediction of permafrost distribution on the Qinghai-Tibet Plateau in the next 50 and 100 years

The Qinghai-Tibet Plateau(QTP)has the highestand largest permafrost coverage in the low-middlelatitudes all over the world.With the progress ofChina’s Western Development,human activities areincreasing significantly on the QTP.For instance,theQinghai-Tibet Railway project started in June2001iscurrently under construction,but permafrost problemwill be one of the critical factors for the engineeringconstruction.Frost heave and permafrost settlementmay destroy engineering construction[1,2]…     

地应力影响煤层气勘探开发的研究现状与展望

通过总结评述前人关于地应力影响煤层气勘探开发的相关文献和成果,讨论了地应力与煤层气成藏、地应力与煤储层渗透率、地应力与煤储层压裂改造、地应力与煤层气井位部署的关系,对相关研究工作的未来走势进行了展望。认为：地应力控制着煤层气成藏过程中的各个环节,是影响煤层渗透率中最主要的因素,也是煤层气井压裂设计和井网部署必须考虑的重要参数。地应力研究对煤层气勘探开发意义重大,且亟待加强。     

贵州省煤炭资源优度评价

基于贵州省煤炭资源分布和赋存特点,构建了煤炭资源评价体系。运用灰色聚类分析方法,对贵州省166个勘查区进行分析评价,确定其优劣顺序。结果表明:单元优度值介于44.46~83.13,各单元间差异不大;贵州省具有良好的煤炭资源条件,“优”和“良”级资源占参评总资源量一半以上;煤炭资源在毕节和六盘水分布优势明显,适于优先带动开发。      

内蒙古孟恩陶勒盖银铅锌铟矿床成因研究

文章从地质特征及地球化学特征方面论证了孟恩陶勒盖矿床的成因。地质特征显示该矿床的形成与花岗岩之间不存在成因联系，矿床相对于岩浆岩围岩是后成的，花岗岩及断裂构造只是为矿床提供了储存空间。矿床地球化学特征显示该矿床的成因与可能位于深部的燕山期岩浆活动有关，成矿元素及硫主要来自岩浆，成矿流体以岩浆水为主。因此该矿床属于岩浆热液型多金属矿床。     

粤西金、银矿床成矿规律探讨

粤西是我国华南的主要金、银矿床集中区，区内金矿床与银（金）多金属矿床具有相间排列的分布规律，即从南到北分为以下５个矿带：廉江地区银（金）多金属矿带、高州—信宜金矿带、罗宁—云浮银（金）多金属矿带、德庆—清远金矿带、连山地区银（金）多金属矿带。本文从区域地层、岩浆岩及成矿作用等方面对粤西金、银矿床区域分布规律进行了探讨，认为影响金、银矿床分布的主要因素是不同区域地层、岩浆岩Ａｕ、Ａｇ含量的差异及金矿床与银（金）多金属矿床成矿作用的差异     

Geochemistry of rare earth elements in a marine influenced coal and its organic solvent extracts from the Antaibao mining district, Shanxi, China

Twenty-six samples including roof, bottom and coal plies of a marine influenced coal bed were collected from the Antaibao mining district, Shanxi, China. The rare earth elements (REEs) were determined in solids and organic solvent extracts. The distribution pattern showed three distinct patterns: shale-like, LREE-rich and HREE-rich. This is attributed to the variable microenvironment of peat-forming swamp, the degree of marine influences and different REE sources. REEs in the coal are mainly controlled by detrital minerals but also affected by seawater. The chondrite-normalized REE patterns of the organic solvent extracts are distinctly different from those of corresponding original coal samples, which show a negative Eu anomaly, a depletion of middle REEs and an enrichment of HREEs. The LREEs in coal extracts are likely adsorbed by hydrogen-containing functional groups, and HREEs are likely bonded to carbon atoms.     

Lead Isotopic Composition and Lead Source in the Bainiuchang Ag-polymetallic Deposit, Yunnan Province, China

The Bainiuchang deposit in Yunnan Province, China, is located geographically between the Gejiu ore field and the Dulong ore field. In addition to the 〉7000 t Ag reserves, the deposit also boasts of large-scale Pb, Zn and Sn reserves with a lot of dispersed elements （In, Cd, Ge, Ga, etc.）. We have determined systematically the Pb isotope composition of the deposit. The Pb isotope ratios of the ores that are of sea-floor exhalative sedimentary origin in the northwest of the mining district, are 206pb/204pb = 17.758-18.537, 207pb/204pb = 15.175-15.862 and 206pb/204pb = 37.289-39.424, while those of ores that are of magmatic hydrothermal superimposition origin in the southeast of the mining district, are 206pb/204pb = 17.264-18.359, 207pb/204pb = 14.843-15.683 and 208pb/204pb = 36.481-38.838, respectively. In terms of the Pb isotope composition of feldspar in magmatic rocks or magmatic whole- rock samples from the mining district, we have determined the Pb isotope composition and acquired the Pb isotope ratios as： 206pb/204pb -- 18.224-18.700, 207pb/204pb -- 15.595-15.797 and 208pb/204pb -- 38.193-39.608. Then, in the light of the Pb isotope composition of metamorphic rock samples from the Proterozoic basement exposed in the Dulong ore field, we have determined the Pb isotope composition and obtained the isotope ratios as： 206pb/204pb -- 18.434-19.119, 207pb/204pb -- 15.644-15.693, and 208pb/204pb = 38.514-38.832. And the Pb isotope ratios of Cambrian sedimentary rocks, which are exposed in the Bainiuchang mining district, are 206pb/204pb = 18.307-19.206, 207pb/204pb = 15.622-15.809, and 208pb/204pb = 38.436-39.932. By comparing the two types of ores with respect to their Pb isotope compositions, it is indicated that lead in the Bainiuchang deposit was derived largely from the lower-crust granulite which is earlier than Neoproterozoic in age, but the Yanshanian magmatic hydrothermal fluids probably provided a part of ore-forming elements such as Sn for the ore blocks in the south of the mining district.     

海南岛红树林泥炭有机组成特征及其地质意义

海南岛红树林泥炭形成于热带泥炭聚积区,成炭质料为适盐性的红树林植物群落,堆积环境为泥炭坪,与陆相沼泽泥炭相比,这些特殊性必然反映到泥炭的有机组成上。红树林泥炭有机成份的研究将为合理开发利用海南的泥炭资源提供依据。红树林泥炭有机组成特征及其在泥炭化过程中的变化也必然为探讨泥炭化机理提供大量地质信息。一、海南岛红树林泥炭的一般特征海南岛红树林泥炭以埋藏泥炭为主,主要分布于海南岛东北部沿海地区,以琼山县东寨港和琼海县福田地区发育最好,其成炭环境为泥炭坪。现在正在发育的泥炭坪仅见于文     

深部煤层CO2注入煤岩力学响应特征及机理研究进展

为揭示CO₂注入煤岩力学响应特征及机理,回顾了CO₂注入煤岩力学性质影响因素、CO₂注入对煤岩大分子-孔隙-裂隙结构改造作用和煤岩力学参数的统计模型、理论模型与智能预测模型.结果表明:CO₂注入煤岩力学性质受控于煤阶、CO₂压力、水分、围压和时间等因素,CO₂注入压力的增高、水的加入及时间的延长均会进一步降低煤岩力学性质,而围压对CO₂注入力学性能弱化具有一定改善作用.CO₂水溶液通过溶胀作用、萃取作用和塑化作用促使煤岩大分子结构重组,通过微晶结构改变、化学溶蚀和非均匀变形改造煤岩孔隙结构,通过化学溶蚀、膨胀应力和化学-应力耦合作用诱发煤岩结构损伤,均不同程度引起煤岩力学性能弱化.在CO₂注入煤岩力学参数预测模型中,类Langmuir模型、广延指数模型和修正的粘聚力模型具有明确的物理意义,而智能预测模型具有更高的预测精度,预测准确度可达99%以上.本次研究为科学评价CO₂-ECBM安全性和促进深部煤层CO₂高效注入奠定了理论基础.