丽江—攀枝花—者海地带二维地壳结构及其构造意义

本文利用攀西地区通过攀枝花的东西向剖面爆炸地震资料,进行了震相的重新识别和二维射线追踪与理论图计算.结果表明,沿剖面地表附近有4个低速区和若干高速带,它们与地质和构造有很好的对应关系.渡口附近的高速岩体一直延伸到了上地壳的底部,形成一个统一的地垒状构造,该高速体与攀枝花成矿岩体相关,并推断华坪及其以西地带也是找矿的有利地区.中地壳下部有一厚度约9km的低速层,它可能是壳内的韧性剪切带.低速层顶部深度为27.0—29.5km,与研究地区的居里面深度及天然地震震源深度的分布基本符合.剖面东段中地壳顶部还有一层很薄的低速层,反映了构造带两侧运动的不对称性.地壳厚度为53—56km,构造带中部的Moho界面没有明显的上隆.     

晶须在复合材料中的应用及其作用机理

阐述了晶须增强复合材料的主要机理,介绍了晶须对复合材料尤其是对聚合物基的复合材料性能的影响,并展望今后的研究方向。     

华北板块南缘中段中上三叠统软沉积变形构造的发现及其地质意义

豫西地区中上三叠统主要出露在济源、义马、伊川和南召一带。印支期秦岭造山运动控制和影响着邻区中上三叠统盆地属性和沉积地层展布。通过观察研究区野外露头剖面,发现中上三叠统发育一系列典型的软沉积变形构造,包括液化底辟、枕状构造、液化柱、液化卷曲变形、负载、球-枕、火焰状构造、液化角砾岩。这些软沉积变形在垂向上表现出明显的复现性,在侧向上表现为沿地层连续展布,表明该时期研究区内地层受到频繁强烈的地震影响。通过对这些软沉积现象的识别和形成机制解释,判定其触发因素为秦岭造山过程中伴生的地震。区内地层中震积岩的存在即是对秦岭造山过程中构造活动的响应。     

柴达木盆地北缘滩间山金矿区斜长花岗斑岩锆石LA-MC-ICPMS测年及其岩石地球化学特征

滩间山金矿区斜长花岗斑岩出露于柴达木盆地北缘构造带,是区内出露较大的斑岩体。利用LA-MC-ICPMS锆石定年方法,测得斜长花岗斑岩锆石的年龄为2 416～336Ma,可分为3组:2 416～2 365,1 797～1 602,358～336Ma。对锆石矿物成因研究表明,第一组和第二组年龄为继承性锆石的年龄,反映其源岩有前寒武纪变质岩或同期岩浆岩的物质;第三组为斜长花岗斑岩的结晶年龄,表明岩体形成于早石炭世,为华力西中期斜长花岗斑岩。岩石地球化学特征表明,岩石属钙碱性系列偏铝质岩石,为I型花岗岩,形成于后碰撞环境。结合锆石的年龄测定数据,认为斜长花岗斑岩物质具有多来源的特点,华力西中期是本区金矿形成的一个重要成矿期。     

Water diffusion in dacitic melt

H₂O diffusion in dacitic melt was investigated at 0.48-0.95 GPa and 786-893 K in a piston-cylinder apparatus. The diffusion couple design was used, in which a nominally dry dacitic glass makes one half and is juxtaposed with a hydrous dacitic glass containing up to ∼8 wt.% total water (H₂O_t). H₂O concentration profiles were measured on quenched glasses with infrared microspectroscopy. The H₂O diffusivity in dacite increases rapidly with water content under experimental conditions, similar to previous measurements at the same temperature but at pressure <0.15 GPa. However, compared with the low-pressure data, H₂O diffusion at high pressure is systematically slower. H₂O diffusion profiles in dacite can be modeled by assuming molecular H₂O (H₂O_m) is the diffusing species. Total H₂O diffusivity D_H2Ot within 786-1798 K, 0-1 GPa, and 0-8 wt.% H₂O_t can be expressed as: where D_H2Ot is in m²/s, T is temperature in K, P is pressure in GPa, K = exp(1.49 − 2634/T) is the equilibrium constant of speciation reaction (H₂O_m+O?2OH) in the melt, X = C/18.015/[C/18.015 + (100 − C)/33.82], C is wt.% of H₂O_t, and 18.015 and 33.82 g/mol correspond to the molar masses of H₂O and anhydrous dacite on a single oxygen basis. Compared to H₂O diffusion in rhyolite, diffusivity in dacite is lower at intermediate temperatures but higher at superliquidus temperatures. This general H₂O diffusivity expression can be applied to a broad range of geological conditions, including both magma chamber processes and volcanic eruption dynamics from conduit to the surface.     

塔里木陆块西北缘萨热克砂岩型铜矿床构造-流体演化对成矿的制约

塔里木陆块西北缘萨热克砂岩型铜矿床构造演化、流体演化与成矿之间具有密切关系,处于一个统一系统中。矿床成岩期方解石中包裹体水的δD值为-65.3‰~-99.2‰,改造成矿期石英包裹体水的δD值为-77.7‰~-96.3‰,成岩成矿期成矿流体δ~(18)OH_2O变化范围为-3.22‰~1.84‰,改造成矿期成矿流体δ~(18)OH_2O变化范围为-4.26‰~5.14‰,指示萨热克铜矿成岩期、改造期成矿流体主要为中生代大气降水及其经水岩作用而成的盆地卤水。矿石中辉铜矿δ~(34)S值为-24.7‰~-15.4‰,指示硫主要源自硫酸盐细菌与有机质还原,部分源于有机硫。构造与成矿流体演化对砂岩铜矿成矿起关键制约作用。盆地发展早期强烈的抬升运动使盆地周缘基底与古生界剥蚀,为富铜矿源层的形成提供了丰富物源,至晚侏罗世盆地发展晚期,长期演化积聚的巨量含矿流体在库孜贡苏组砾岩胶结物及裂隙中富集,在萨热克巴依盆地内形成具有经济意义的砂岩型铜矿床。     

内蒙古兴和县曹四夭超大型斑岩钼铅锌金成矿系统年代学及其地质意义

曹四夭斑岩钼矿床位于内蒙古兴和县,是华北克拉通北缘最大的钼矿床。该矿床中部发育斑岩型钼矿体,外围和上部产出热液脉型铅锌金矿体。文章选取1件与斑岩钼矿化共生的绢云母样品进行了40Ar-39Ar定年,获得40Ar-39Ar坪年龄为(144.4±1.2)Ma,相应的39Ar/36Ar-40Ar/39Ar等时线年龄为(146.4±2.2)Ma(MSWD=0.31),将等时线年龄认作绢云母的Ar封闭年龄,表明曹四夭斑岩钼矿化发生在约146 Ma前。选取14件脉型铅锌矿石中的闪锌矿、黄铁矿和磁黄铁矿样品开展了Rb-Sr定年,获得4件闪锌矿的Rb-Sr等时线年龄为(145.1±3.0)Ma(MSWD=0.63);5件黄铁矿的Rb-Sr等时线年龄为(145.2±1.3)Ma(MSWD=0.53);4件闪锌矿、5件黄铁矿和1件磁黄铁矿的Rb-Sr等时线年龄为(145.3±1.0)Ma(MSWD=0.43)。硫化物Rb-Sr定年结果表明曹四夭矿床脉型铅锌矿化形成于约145 Ma前。本次绢云母40Ar-39Ar和硫化物Rb-Sr定年结果表明,曹四夭矿床斑岩型钼矿化和脉型铅锌金矿化为同期产物,两者均形成于晚侏罗世末期,属于同一个斑岩成矿系统。曹四夭矿床硫化物的w(Rb)和w(Sr)分别为0.1867×10~(-6)~1.305×10~(-6)和0.3175×10~(-6)~6.935×10~(-6),Sr同位素初始比值(87Sr/86Sr)i介于0.709 919~0.711 951之间,平均值0.710 952,结合前人获得的辉钼矿Re含量,认为曹四夭矿床的成矿物质主要来源于地壳。     

The Metamorphic Evolution and Tectonic Significance of the Eclogite in the Sumdo Complex,Tibet, China

As the main tectonic component of the Himalayan–Tibetan orogen, the Lhasa terrane has received much attention as it records the entire history of the orogeny. The occurrence of high pressure eclogite in the Sumdo complex in central Lhasa terrane has a significant bearing on the understanding of the Paleo‐Tethys subduction and plate itineration processes in this area. The petrological, geochemical and geochronological data from eclogite and associated blueschist and garnet‐bearing mica schist from Sumdo, Jilang and Bailang area have been briefly review to explore the origin and metamorphic evolution of this suture. Eclogites from the Sumdo complex have experienced low temperature, high pressure to ultrahigh pressure metamorphism, revealing a fast subduction and exhumation process in a typical oceanic subduction zone. The large P‐T span between different eclogites in the literature may be affected by the big error of unappropriated using geothermobarometry and may also because of slices of subducted blocks derived from different depths juxtapose together during exhumation. By summarizing the U‐Pb, Lu‐Hf and Sm‐Nd ages of eclogites, the eclogite facies metamorphism is likely to occur in early Triassic during 245‐225 Ma, but not the previously accepted late Permian at ca. 260 Ma by the reinterpretation of the former geochronological data from literature. The opening of Paleo‐Tethys Ocean between the Lhasa terrane initiate prior to ca. 280 Ma and ultimate closure to integrate the Lhasa terrane was no earlier than 225 Ma and may triggered by the initial subduction of Bangong‐Nujiang Tethys Ocean in the north.     

试论煤层气藏概念与成藏要素

通过对前人煤层气藏概念的调研和对煤层气性质及成藏要素的研究, 认为: 煤层气藏是在压力封闭作用下, 吸附煤层气达到相当数量的煤岩体或煤层, 是煤层气聚集和煤层气勘探开发的基本地质单元。煤层气藏的成藏要素主要包括煤层条件、压力封闭和保存条件。煤层条件是煤层气藏形成的物质基础, 压力封闭是煤层气藏的必要条件, 保存条件是煤层气藏从形成到现今能够存在的前提。     

辽宁红透山铜锌矿床地质特征及成因浅析

红透山铜锌矿床赋存于辽北太古宙绿岩红透山岩组,为极具工业意义的大型矿床.通过对矿石H、O、S、Pb同位素特征的分析,结合矿床矿体形态、矿石结构、构造及围岩蚀变等宏观特征,认为红透山铜锌矿床成矿物质来源于太古宙晚期火山-沉积岩系,成矿流体来源于变质水和大气降水,成矿热力来源于变质作用,从而认为红透山铜锌矿床属“火山-沉积变质热液叠加”型层控矿床.