阿尔金山东段拉配泉地区区域物化探异常分布规律及找矿方向     

赵更新  毛德宝张燕 《地质通报》2007,26(8):1021-1028

在分析阿尔金区域地质和物化探异常资料的基础上,对阿尔金东段的构造特点和不同地层、岩石建造的成矿元素分布分配进行了分析和讨论,重点研究了阿尔金东段区域地球化学异常的分布规律和特点,分析和推断了引起Cu、Pb、Zn、Au、Ag等异常密集区带的地质因素,讨论了地球化学异常和区域成矿问题。认为阿尔金东段成矿潜力较大,并初步探讨了找矿方向。  相似文献   

西藏边坝-洛隆地区下白垩统边坝组的建立及其意义   总被引：1，自引：0，他引：1  

田立富  朱才伐  向树元  泽仁扎西  陈洁 《沉积与特提斯地质》2007,27(4):11-16

边坝组是新建立的一个岩石地层单位。该组与下伏下白垩统多尼组呈整合接触,与上覆上白垩统宗给组呈角度不整合接触关系。岩性以紫红色深灰色粉砂质泥岩夹薄层白云岩为特征,深灰色薄层粉砂质泥岩中产丰富的双壳类化石Trigonioides(Diversitrigonioides)xizangensis-Pleuromya spitiensis组合。边坝组的建立完善了该地区下白垩统地层系统,对冈底斯北缘弧后前陆盆地白垩纪岩相古地理研究具有重要意义。  相似文献   

东天山秋格明塔什黄山韧性剪切带变形特征分析     

杨兴科  张连昌  姬金生  曾章仁  陶洪祥 《地球科学与环境学报》1998,20(3):42

东天山秋黄韧性剪切带位于新疆东部两大板块碰撞接合地带,东西延长逾６００ｋｍ,由石炭系组成,规模巨大,分带明显,宏微观变形标志清晰,石英Ｃ轴组构呈点极密型,分为四期变形,序列演化明显,应变测量属平面单剪,剪切位移量达７５ｋｍ以上,存在脆韧性变形转换,变形时代为海西中晚期,强弱应变相间排列的标度不变性特征明显,变形机制属地壳中深层次塑性流变和韧性剪切,与板块间的俯冲碰撞构造演化密切相关。控制着金铜矿分布。  相似文献   

湘赣边地区走滑断裂带致矿异常的结构样式及分形特征   总被引：4，自引：1，他引：3  

李先福  李建威  傅昭仁  王学平 《地球科学》1998,23(2):11

湘赣边地区构造岩浆带是环太平洋成矿带内最重要的高值地质矿产异常区,其中ＮＮＥ向走滑断裂明显地控制了岩浆－断陷盆地和铀及钨、锡、铅、锌、锑等的成矿作用．在区域地质环境研究的基础上,根据典型矿田（床）控矿构造分析成果,将走滑断裂带内局部性致矿地质异常归纳为：帚尾式致矿异常,棋盘格式致矿异常、辫状结环式致矿异常和拉分盆缘式致矿异常．重点讨论了各类异常的结构样式和分维特点．  相似文献   

中国东部新生代碱性玄武岩中的流体组成及其碳,氧同位素地球化学特征   总被引：16，自引：2，他引：14  

张铭杰  王先彬 《地球化学》1998,27(5):452-457

利用热分解质谱法测定了中国东部新生代碱性玄武岩中流体挥发分的组成,并对不同温度段释放出的ＣＯ２气体测定了Ｃ,Ｏ同位素值,流体组成和ＣＯ２的Ｃ,Ｏ同位素值表明中国东部上地幔源区的不均一性,与其中所含幔源岩捕体相比,碱性玄武岩浆发育在相对氧化的环境中,并有外来流体组分的加入。  相似文献   

云南宁蒗地区喜山期斑岩体岩石化学特征与成矿性及其岩浆来源探讨   总被引：1，自引：0，他引：1  

胡受权  郭文平 《岩石矿物学杂志》1998,17(2):136-144

宁蒗地区喜山期斑岩带受近现北向的包都－波罗弧形断裂带控制,由壳幔混源型岩浆浆被动侵位耐成,总结上呈向北逐渐倾伏的趋势。该斑岩带斑岩属钙碱性系列、中酸性岩类。通过对该斑岩带各斑岩体（群）地质特征、岩石化学特征的综合分析,表明其为含铜斑岩或铜（钼）斑岩,具良好的成矿前景。  相似文献   

云南宁蒗地区喜山期斑岩体岩石化学特征与成矿性及其岩浆来源探讨   总被引：1，自引：0，他引：1  

胡受权  郭文平 《岩石矿物学杂志》1998,(2)

宁蒗地区喜山期斑岩带受近南北向的包都－波罗弧形断裂带控制,由壳幔混源型岩浆被动侵位而成,总体上呈向北逐渐倾伏的趋势。该斑岩带斑岩属钙碱性系列、中酸性岩类。通过对该斑岩带各斑岩体（群）地质特征、岩石化学特征的综合分析,表明其为含铜斑岩或铜（钼）斑岩,具良好的成矿前景。  相似文献   

滇西怒江断裂带新构造特征   总被引：9，自引：0，他引：9       下载免费PDF全文

李京昌 《地震地质》1998,20(4):25-320

怒江断裂带从走向上可以分为南北走向段和北东走向段,其喜马拉雅期的构造变形以右行剪切为主导。右行剪切的变形历史可以分为早期压剪变形和晚期张剪变形两个大的阶段。这两期变形各自在南北走向段和北东走向段表现出不同的特点。总之,怒江断裂带喜马拉雅期构造变形具有时空不均一性的特点  相似文献   

Silicate and carbonate weathering in the drainage basins of the Ganga-Ghaghara-Indus head waters: Contributions to major ion and Sr isotope geochemistry   总被引：1，自引：0，他引：1  

S. Krishnaswami  Sunil K. Singh 《Journal of Earth System Science》1998,107(4):283-291

The role of silicate and carbonate weathering in contributing to the major cation and Sr isotope geochemistry of the headwaters of the Ganga-Ghaghara-Indus system is investigated from the available data. The contributions from silicate weathering are determined from the composition of granites/ gneisses, soil profiles developed from them and from the chemistry of rivers flowing predominantly through silicate terrains. The chemistry of Precambrian carbonate outcrops of the Lesser Himalaya provided the data base to assess the supply from carbonate weathering. Mass balance calculations indicate that on an average ∼ 77% (Na + K) and ∼ 17% (Ca + Mg) in these rivers is of silicate origin. The silicate Sr component in these waters average ∼40% and in most cases it exceeds the carbonate Sr. The observations that (i) the⁸⁷Sr/⁸⁶Sr and Sr/Ca in the granites/gneisses bracket the values measured in the head waters; (ii) there is a strong positive correlation between⁸⁷Sr/⁸⁶Sr of the rivers and the silicate derived cations in them, suggest that silicate weathering is a major source for the highly radiogenic Sr isotope composition of these source waters. The generally low⁸⁷Sr/⁸⁶Sr (< 0.720) and Sr/Ca (∼ 0.2 nM/ μM) in the Precambrian carbonate outcrops rules them out as a major source of Sr and⁸⁷Sr/⁸⁶Sr in the headwaters on a basin-wide scale, however, the high⁸⁷Sr/⁸⁶Sr (∼ 0.85) in a few of these carbonates suggests that they can be important for particular streams. The analysis of⁸⁷Sr/⁸⁶Sr and Ca/Sr data of the source waters show that they diverge from a low⁸⁷Sr/⁸⁶Sr and low Ca/Sr end member. The high Ca/Sr of the Precambrian carbonates precludes them from being this end member, other possible candidates being Tethyan carbonates and Sr rich evaporite phases such as gypsum and celestite. The results of this study should find application in estimating the present-day silicate and carbonate weathering rates in the Himalaya and associated CO₂ consumption rates and their global significance.  相似文献   

Geologic and tectonic evolution of the Himalaya before and after the India-Asia collision     

Kewal K. Sharma 《Journal of Earth System Science》1998,107(4):265-282

The geology and tectonics of the Himalaya has been reviewed in the light of new data and recent studies by the author. The data suggest that the Lesser Himalayan Gneissic Basement (LHGB) represents the northern extension of the Bundelkhand craton, Northern Indian shield and the large scale granite magmatism in the LHGB towards the end of the Palæoproterozoic Wangtu Orogeny, stabilized the early crust in this region between 2-1.9 Ga. The region witnessed rapid uplift and development of the Lesser Himalayan rift basin, wherein the cyclic sedimentation continued during the Palæoproterozoic and Mesoproterozoic. The Tethys basin with the Vaikrita rocks at its base is suggested to have developed as a younger rift basin (～ 900 Ma ago) to the north of the Lesser Himalayan basin, floored by the LHGB. The southward shifting of the Lesser Himalayan basin marked by the deposition of Jaunsar-Simla and Blaini-Krol-Tal cycles in a confined basin, the changes in the sedimentation pattern in the Tethys basin during late Precambrian-Cambrian, deformation and the large scale granite activity (～ 500 ± 50 Ma), suggests a strong possibility of late Precambrian-Cambrian Kinnar Kailas Orogeny in the Himalaya. From the records of the oceanic crust of the Neo-Tethys basin, subduction, arc growth and collision, well documented from the Indus-Tsangpo suture zone north of the Tethys basin, it is evident that the Himalayan region has been growing gradually since Proterozoic, with a northward shift of the depocentre induced by N-S directed alternating compression and extension. During the Himalayan collision scenario, the 10–12km thick unconsolidated sedimentary pile of the Tethys basin (TSS), trapped between the subducting continental crust of the Indian plate and the southward thrusting of the oceanic crust of the Neo-Tethys and the arc components of the Indus-Tangpo collision zone, got considerably thickened through large scale folding and intra-formational thrusting, and moved southward as the Kashmir Thrust Sheet along the Panjal Thrust. This brought about early phase (M1) Barrovian type metamorphism of underlying Vaikrita rocks. With the continued northward push of the Indian Plate, the Vaikrita rocks suffered maximum compression, deformation and remobilization, and exhumed rapidly as the Higher Himalayan Crystallines (HHC) during Oligo-Miocene, inducing gravity gliding of its Tethyan sedimentary cover. Further, it is the continental crust of the LHGB that is suggested to have underthrust the Himalaya and southern Tibet, its cover rocks stacked as thrust slices formed the Himalayan mountain and its decollement surface reflected as the Main Himalayan Thrust (MHT), in the INDEPTH profile.  相似文献