陆相火山岩铜矿床成矿条件研究   总被引：1，自引：1，他引：1  

胡正纲 《四川地质学报》1996,(1)

研究陆相火山岩铜矿床的成矿条件，对于多发现新的铜矿资源有着重要的意义。本文就陆相火山岩型铜矿床的实际存在，大陆玄武岩型铜矿的成矿系列，大陆裂谷的成矿环境和热液成矿作用等方面进行讨论。  相似文献   

秦岭造山带新生代构造隆升与区域环境效应研究   总被引：16，自引：0，他引：16  

滕志宏  王晓红 《陕西地质》1996,(2)

据沉积，构造、地貌并结合地球物理资料综合研究认为，秦岭造山带新生代构造隆升是在中生代白垩纪晚期构造隆升基础上，于晚第三纪中新世迅速隆升，而早更新世早期则是新构造活动最强烈时期。秦岭造山带的新生代构造隆升的方式主要有地垒式、掀斜式、振荡式和翘板式4种。诱发这一地区新构造抬升的主要原因和动力学机制是华北地块自北而南，扬子地块自南而北相向向秦岭造山带之下陆内俯冲和秦岭地块深部软流圈抬升共同作用所致。  相似文献   

碱性玄武岩中的某些巨晶单斜辉石──Ⅱ:穆斯堡尔谱──兼论单斜辉石的异常穆斯堡尔谱和铁结构态的测定     

章礼明  傅平秋  张恩林 《矿物学报》1996,(1)

本文对辽宁宽甸碱性玄武岩中巨晶单斜辉石进行穆斯堡尔谱研究。应用晶体结构研究结果较合理地解释了单斜辉石的异常穆斯堡尔谱。结合XRD讨论了单斜辉石中Fe结构态的测定以及穆斯堡尔谱的可应用性。巨晶应结晶于相当氧化的环境。  相似文献   

玄武岩深源岩石包体及金伯利岩中的尖晶石     

董振信 《岩石矿物学杂志》1996,15(3):241-249

我国东部新生代玄武岩中深源岩石包体内的尖晶石类矿物属铬尖晶石和铁尖晶石，金伯利岩及其地幔岩包体和金刚石中的尖晶石类矿物主要为铝铬铁矿。玄武岩中橄榄岩类包体内的尖晶石比其辉石岩类包体中的尖晶石含Ｃｒ高，含Ａｌ低，这与Ｃｒ为相容元素、Ａｌ为不相容元素、玄武岩中橄榄岩类包体是上地幔部分熔融出玄武岩浆后的残留物及其上地幔岩石的捕虏体、而辉石岩类是玄武岩浆结晶的产物有关。玄武岩中深源岩石包体中的尖晶石明显地比金伯利岩中的粗晶、地幔岩石包体及金刚石中的尖晶石含Ｃｒ低，含Ａｌ高，其主要原因是前者比后者形成的压力低  相似文献   

湘南中新生代玄武岩成因研究及构造环境分析   总被引：2，自引：0，他引：2       下载免费PDF全文

朱勤文  王方正 《地球科学》1997,22(6):585-588

定量计算了湘南中新生代多种类型玄武岩的矿物－熔浆平衡条件和岩浆粘度、密度、上升速度等岩浆物理参数，识别出了三类原生玄武岩浆，橄榄拉斑武岩浆、白榴碧玄岩浆、碧玄岩浆、根据玄武岩的地质岩石学的地球化学特征，及岩浆起源条件，深部地质和地球物理等方面资料的综合分析，认为本区玄武岩是大陆岩石圈深部热扰动的产物。  相似文献   

新疆北部晚古生代埃达克岩、富铌玄武岩组合：古亚洲洋板块南向俯冲的证据   总被引：50，自引：0，他引：50  

张海祥  牛贺才  Hiroaki Sato  单强  于学元  Jun'ichi Ito  张旗 《高校地质学报》2004,10(1):106-113

地球化学研究结果表明，新疆北部富蕴县境内的晚古生代下泥盆统托让格库都克组的安山质岩石具有与埃达克岩非常相似的地球化学特征，它们具有较高的Al2O3，Na2O和Sr含量以及Sr/Y比值；明显亏损重稀土和Y，它们的MORB标准化微量元素蛛网图表现为明显的Nb，Ta负异常和Sr正异常，同时强烈亏损高场强元素。与埃达克岩共生的玄武岩的地球化学特征则与富铌玄武岩一致，表现为Si过饱和及富Na的特征，同时具有较高的Nb，TiO2和P2O5含量，并富集高场强元素。由于埃达克岩和富铌玄武岩的形成均与板块俯冲有关，因此，它们的存在表明，古亚洲洋在早-中泥盆世向南(哈萨克斯坦-准噶尔板块)发生了一次洋壳俯冲作用。  相似文献   

柴达木盆地新生代不同层次构造特征   总被引：8，自引：1，他引：8       下载免费PDF全文

郑孟林李明杰  曹春潮张军勇段书府  陈元中沈亚 管俊亚 《地质学报》2004,78(1):26-35

应用柴达木盆地地震、非地震资料进行综合解释研究发现,新生代盆地深、浅层构造存在较大差异,盆地沉积在不同时期受到不同构造格局的控制。古近系受近东西向构造控制,新近系受北西向构造控制,显示了柴达木盆地新生代为不同时期受不同方向构造控制的大型叠合盆地。盆地地层深、浅层构造变形特征不同,深层表现为陡倾的逆冲断裂构造,以断块构造为主要特征;中浅层表现为滑脱褶皱与滑脱断裂构造;地表在背斜核部发育斜列展布的正断层构造。盆地经历了多旋回沉积和多方式的后期改造,不同的构造组合形成了不同的储油气构造模式,认识这一点对于盆地深层的油气勘探,特别是寻找隐蔽油气藏具有重要意义。  相似文献   

Crystal morphologies in pillow basalts: implications for mid-ocean ridge processes     

Franois Faure  Pierre Schiano 《Earth and Planetary Science Letters》2004,220(3-4):331-344

We present the results of a detailed petrological study of a sparsely phyric basalt (MAPCO CH98-DR11) dredged along the Mid-Atlantic Ridge (30°41′N). The sample contains microphenocrysts of olivine that display four different rapid-growth morphologies. Comparison of these morphologies with those obtained in dynamic crystallization experiments allows us to constrain the thermal history of the sample. The dendritic morphology (swallowtail, chain and lattice olivine) is directly related to the final quenching during magma–seawater interaction. In contrast, the three other morphologies, namely the complex polyhedral crystal, the closed hopper and the complex swallowtail morphology result from several cycles of cooling–heating (corresponding to a maximum degree of undercooling of 20–25°C) during crystal growth. These thermal variations occurred before eruption and are interpreted to be the result of turbulent convection in a small magmatic body beneath the ridge. The results suggest that the Mid-Atlantic Ridge is underlain by a mush zone that releases batches of liquid during tectonic segregation. Aphyric basalts are emitted during eruptions controlled by the tectonic activity, whereas phyric basalts correspond to small fractions of magma from the mush zone mobilized by reinjections of primitive magmas.  相似文献   

Magmatic effects of the lunar late heavy bombardment     

Linda T Elkins-Tanton 《Earth and Planetary Science Letters》2004,222(1):17-27

Large volumes of mare basalts are present on the surface of the moon, located preferentially in large impact basins. Mechanisms relating impact basins and mare basalt eruptions have previously been suggested: lunar impacts removed low-density material that may have inhibited eruption, and created cracks for fluid flow [Icarus 139 (1999) 246], and lunar basins have long been described as catchments for magma (e.g., [Rev. Geophys. Space Phys. 18 (1980) 107] and references therein). We present a new model for melt creation under near side lunar basins that is triggered by the impacts themselves. Magma can be produced in two stages. First, crater excavation depressurizes underlying material such that it may melt in-situ. Second, the cratered lithosphere rises isostatically, warping isotherms at the lithosphere-asthenosphere boundary which may initiate convection, in which adiabatic melting can occur. The first stage produces by far the largest volume of melt, but convective melting can continue for up to 350 Ma. We propose that giant impacts account for a large portion of the volume and longevity of mare basalt volcanism, as well as for several compositional groups, including high alumina, high titanium, KREEP-rich, and picritic magmas.  相似文献   

~(40)Ar/~(39)Ar dating of shear deformation of the Xianshuihe fault zone in west Sichuan and its tectonic significance   总被引：6，自引：1，他引：6  

ZHANG Yueqiao  CHEN Wen  & YANG Nong . Institute of Geomechanics  Chinese Academy of Geological Sciences  Beijing  China  . Institute of Geology  Chinese Academy of Geological Sciences  Beijing  China  . Institute of Geology  Geophysics  Chinese Academy of Sciences  Beijing  China 《中国科学D辑(英文版)》2004,47(9)

TheNW-SEstrikingXianshuihefaultzoneslicesthesoutheasternTibetanPlateauandconnectssoutheastwardwiththeAnninghe-Zemuhe-Xiaojiangfaultzone,whichformahuge,activesinistralstrike-slipfaultzone(fig.1).ThisfaultzoneisanimportantseismicfaultineastTibet[1-5].EarthquakegeologystudiesandoffsetpatternsofyounggeologicalfeatureshaveshownthatlateQuaternarysinistralsliprateoftheXianshuihefaultzonereaches13mm/a[1,2].TheXianshuhefaultzoneconsistsoftwomainbranches,theDaofufaultbranchinthewestandtheXianshuih…  相似文献