川西石棉地区田湾与扁路岗岩体的锆石U-Pb定年

对扬子板块西缘石棉地区田湾闪长岩体与扁路岗花岗岩体开展了精细的单颗粒锆石Ｕ－Ｐｂ年代学研究。测试结果表明,田湾岩体中锆石的结晶年龄为８２３Ｍａ±１２Ｍａ,扁路岗岩体中锆石的结晶年龄为８７６Ｍａ±４０Ｍａ,表明石棉地区与扬子板块西缘其他地区一样,晋宁期岩浆活动也是相当强烈的。     

龙湾套铜矿岩石学特征及矿床成因

泗水县龙湾套地区发育大面积新太古代角闪辉长岩,为在该区寻找赋存在角闪辉长岩中的岩浆熔离型铜矿床,曾开展过普查工作,最终发现了一小型铜矿床。探讨该区角闪辉长岩岩石学特征,对在该区进一步寻找同类型铜矿床有重要意义。     

鲁西新泰孟家屯2.7Ga变质沉积岩与黑云斜长片麻岩锆石Hf同位素特征

对出露于山东新泰孟家屯2.7Ga的孟家屯岩组中石榴石石英岩(M08)、含十字石石榴石黑云母石英片岩(D242-Y2)和黑云斜长片麻岩(M03)(TTG质片麻岩)进行锆石Lu-Hf同位素分析。石榴石石英岩锆石核部176Lu/177Hf、176Hf/177Hf变化范围为0.001730～0.002546、0.281249～0.281360,锆石变质边部176Lu/177Hf、176Hf/177Hf变化范围为0.000123～0.002070、0.281241～0.281318;含十字石石榴石黑云母石英片岩锆石核部176Lu/177Hf、176Hf/177Hf变化范围为0.001334～0.002169、0.281226～0.281324,锆石变质边部176Lu/177Hf、176Hf/177Hf变化范围为0.000445～0.001375、0.281227～0.281309;黑云斜长片麻岩锆石176Lu/177Hf、176Hf/177Hf变化范围为0.000315～0.000847、0.281186～0.281265。孟家屯岩组石榴石英岩、含十字石石榴石黑去母石英片岩中碎屑(岩浆)锆石和黑云斜长片麻岩中岩浆锆石的εHf(t)分别为3.75～7.26、2.31～7.26和3.21～6.27,同时TDM1与其U-Pb年龄非常接近,表明它们起源于新生地壳的部分熔融。结合区域研究资料认为,2.7Ga是鲁西重要的一期构造岩浆热事件,也可能是华北克拉通重要的构造岩浆活动时期。变质沉积岩中许多变质增生锆石相对于核部岩浆锆石低176Lu/177Hf、高176Hf/177Hf,显示变质作用过程中石榴石的存在对锆石的Lu-Hf同位素体系有很大影响。     

大南盘江地区构造对油气藏破坏作用研究

大南盘江地区发育多套成熟烃源岩,具有良好的油气成藏条件。但由于烃源岩埋藏深、成熟早,成藏之后经历多期强烈的后期构造运动改造,先前形成的油气藏大都被破坏,导致目前地表出露多处古油藏和油气苗。多年的油气勘探证实,后期的构造运动对油气藏的破坏作用是制约该区油气勘探的关键问题。研究表明,大南盘江地区不同构造单元,油气藏的破坏因素不同。南盘江坳陷古油藏沿深大断裂分布,其破坏的主控因素是断裂活动;桂中坳陷古油藏和油气显示出露区缺失区域盖层,其破坏的主控因素是构造抬升剥蚀;十万大山盆地古油藏目前残留的烃类主要是固体沥青,镜质体反射率(Rb)大都落在2.0以上,推算经历的最高热解温度均大于200℃,而且古油藏的分布区也是印支期岩浆岩集中分布区,因此推断该区油气藏破坏的主控因素是岩浆活动。     

吉林省集安沿江一带多金属成矿地质背景及找矿方向

集安沿江构造.岩浆岩带沿鸭绿江断裂带展布,主体由鸭绿江深断裂和与之平行的一系列次一级的北东向断裂构造构成,在带内还发育有北西向、近南北向断裂,目前带内已发现金、铅锌矿床(点)及多金属矿床(点)多处,展示出良好的找矿前景。     

利用地震偏移剖面解释岩浆岩的方法分析

在吉林敦化黑石煤炭资源赋存区,岩浆岩发育,煤层较大范围内受到岩浆岩侵蚀,岩浆岩侵蚀部位在地震剖面上差异十分明显,利用二维地震方法,对水平和偏移时间剖面特征进行分析和解释,就可确定其分布范围及位置。     

淮南煤田朱集井田岩浆侵入特征研究

在对淮南煤田朱集井田钻孔资料分析的基础上,结合侵入岩化学成分测试、X-射线衍射分析以及薄片显微镜下鉴定等结果,得出研究区侵入岩主要以岩床的形式侵入煤系地层,岩性以闪长岩、花岗岩为主,岩床层数多为单层;受NWW—NW向断裂构造带控制,侵入岩体的分布范围呈现从西向东逐渐扩大,在垂向上,从上部煤层到下部煤层,受岩浆影响的程度有明显加大的态势。由于岩浆侵入煤层,严重破坏了煤层的结构和稳定性,同时,降低了煤的工业利用价值,加大了开采难度。     

甘肃侵入岩及岩石构造组合特征

本文简要叙述了甘肃侵入岩的时空分布、构造岩浆旋回和构造岩浆岩带划分,将甘肃侵入岩划分为4个构造岩浆旋回、5个构造岩浆岩省、10个构造岩浆岩带,简述了各构造岩浆岩省侵入岩基本特征和岩石构造组合特征,探讨了其形成的大地构造环境,利用现有资料初步建立了甘肃侵入岩年代格架。     

淮南煤田潘三煤矿4-2煤中矿物对岩浆侵入的响应

以淮南煤田潘三煤矿4-2煤层中的岩浆岩、天然焦和煤样品为研究对象,利用X射线衍射仪和X射线荧光光谱仪测试其矿物组成和主量元素含量,研究地下岩浆侵入对煤中矿物成分的影响。结果表明:煤变质成天然焦后,其总的矿物含量增多,并伴随着后生矿物如微斜长石和镁绿泥石的出现。天然焦中后生矿物的组成元素可能来源于岩浆或热液中的主量元素如Si、Al、Na、K、Fe和Mg。     

Magmatic activity and its geological significance in Early Jurassic in Mangui area of Inner Mongolia

By investigating the U-Pb zircon isotope geochronology and petrogochemistry of the major magmatic rocks in Mangui area, the authors in this paper discussed the forming era, tectonic background and geological significance. A large amount of intrusive rocks and a small amount of medium-acid volcanic rocks in Early Jurassic were found in this area. U-Pb dating by LA-ICP-MS method shows that the ages are from (199±1)Ma to (184±1)Ma and the rock types can be divided into fine-medium-grained quartz diorite, medium-grained granodiorite, fine-medium-grained monzogranite, medium-fine-grained macrophenocryst monzogranite, rhyolite, dacite and andesite, which didn’t ouur in Neoprotezoic-Paleozoic period as previous researchers thought, revealing the tectonic and magmatic activities during the Early Mesozoic period. The geochemical results show that the rocks are Ⅰ-type magmatic rocks of subluminous-peraluminous high-K calc-alkaline series. The fractionation between light and heavy rare-erath elements((La/Yb)_N= 3.42~32.96) and the Eu depletion degree is not complied with the evaluation from basic to acidic. The large ion lithophile element Ba is relatively rich and Rb, Sr are relatively delicient. The high field strength elements Th and U are relatively rich and Nb, Ti, Y are relatively deficient. The magma origin and tectonic setting show that quartz diorite and medium-fine-grained macrophenocryst monzogranite come from crust-mantle mixed magma, while the medium-acid volcanic rocks, granodiorite and fine-medium-grained monzogranite are from the partial melting of crustal materials, whose formation is connected with the evolution of Mongol-Okhotsk Suture Zone. The geology and geochemistry of the Early Mesozoic magmatic rocks indicate that the middle part of Mongol-Okhotsk Ocean might begin subduction at the end of the middle Triassic and close the Early Jurassic. The peak collision might take place at the Early Jurassic, not in the Late Triassic as previous thought. The Mohe over-thrust nappe system might form in the remote effect of southward extrusion during the closing process of the eastem part of Mongol-Okhotsk Ocean. The middle and eastern Mongol-Okhotsk Ocean closing age is of great importance to reveal the basin-range tectonic formation during the Middle Jurassic to the Late Cretaceous in Northeast China.