A Three—Stage Metallogenic Model for Gold Deposits in Metamorphosed Microclastic Rocks   总被引：1，自引：0，他引：1  

王秀璋  程景平等 《中国地球化学学报》1996,15(3):258-264

Gld deposits occurring in metamorphosed microcelastic rocks are distributed extensively at home and abroad.Some deposits of this type are of superlarge tonnage.The formation of gold deposits in metamorphosed microclastic rocks involves three stages:the sedimentary stage,the regionally metamorphic stage,and the ore-forming stage.At the first stage,microclastic sedimentary source rocks were developed in a relatively semi-enclosed reducing sea basin and were enriched in carbon,sulfur and gold.At the second stage,the gold adsorbed on organic matter and clay minerals was relesed and poorly concentrated during the destruction of organic matter and the depletion of clay minerals by regional metamorphism with increase temperature and pressure.At the third stage,a tectono-hydrothermal event took place.As a result,gold was leached from metamorphosed microclastic rocks,transported to ore depositional locus and/or mixed with gold of other sources in the course of migration,and finally precipitared as ores.Gold deposits of this type were eventually formed at the third stage,and they also can be classified as the orogenic belt type and the activation zone type.The gold deposits occurring in metamorphosed microcalastic rocks are the products of reworking processes and the influence of magmatism should be taken into consideration in some cases.  相似文献   

清流南部地区的滑脱构造     

揭育金  韦德光 《福建地质》1996,15(4):208-213

清流南部及邻区广泛存在的加里乐、印支期滑脱构造应是该区造山作用的一个重要方面，它们的形成，发展与分隔闽西北，闽西南两大构造单元的南平－宁化北东东向构造－岩浆带密切相关。  相似文献   

大别-郯庐-苏鲁造山带复合旋转拼贴作用   总被引：29，自引：0，他引：29  

肖文交  周烑秀  杨振宇  赵西西 《地球科学进展》2000,15(2):147-153

郯庐断裂带的成生演化与含超高压变质带(UHP)的大别及苏鲁造山带存在较密切的时空关系。郯庐断裂带所在的构造位置应是晚二叠世华北与扬子地块碰撞时的根带。UHP岩石的折返过程可能发生于华北、扬子地块的大角度旋转、拼合过程中。在华北与扬子地块的造山后期或者造山期后的构造变形中所记录的构造形迹经晚中生代以来的中国东部构造变形叠加而逐渐呈现复杂的构造组合,所谓“郯庐断裂带”的走滑平移即其中的一种运动方式。华北与扬子地块碰撞造山作用与陆内变形最终造就了大别—郯庐—苏鲁复合造山带。  相似文献   

秦岭造山带(陕西部分)中新生代陆内造山及与矿产关系     

罗乾周  代新宇  李新林  周小康  杜少喜  陈高潮  张俊良 《陕西地质》2007,25(2):25-30

印支运动后的秦岭造山带受古亚洲构造域、环太平洋构造域和特题斯三大构造域联合作用,发生了强烈的陆内造山,奠定了该区条块相间构造岩片系统的基本构造格架,控制了本区斑岩型钼矿和众多热液型多金属矿产的最终成矿作用和矿带展布。  相似文献   

东昆仑德尔尼矿床中矿床(体)的叠加成矿作用研究   总被引：2，自引：5，他引：2  

宋忠宝  王轩  任有祥  栗亚芝  王凯  陈向阳  陈博  王升勤  高永宝  李丽 《西北地质》2007,40(4):1-6

德尔尼大型钴铜矿床是一个以海底喷流-沉积成矿为主体,以后期叠加成矿为特色的复合成矿作用的矿床。其叠加成矿作用,则以钴矿(化)体的"套鞋状"产出和磁黄铁矿的"薄层外壳"为标志,以赋矿超基性岩与工业矿体接触处发生的蚀变作用、星点状磁铁矿的消失或净化,以及镍元素带入为支撑点体现出来的,它昭示了超基性岩体在叠加成矿过程中对德尔尼矿床成矿作用的某种贡献。  相似文献   

上海地区勘察阶段估算高层住宅沉降量的实用方法     

赵榆 《上海国土资源》2007,(1):40-44

勘察设计阶段估算基础沉降量时通常采用等代实体基础的分层总和法,但由此计算出的最终沉降量一般与实测值差别较大。这一差别就会导致勘察和设计工作过于保守,造成不必要的浪费。实际工作中学术界对此也做了大量的工作,分析了产生误差的原因,也提出了使计算结果更为准确的计算方法。但鉴于勘察阶段对沉降量计算的要求,以及等代实体基础的分层总和法积累多年的经验,本文考虑在不改变计算方法的前提下,提出一个实用简便的方法计算沉降:对经验附加应力赋予一个调整系数,使计算所得的最终沉降量更接近实测值。  相似文献   

Types, Evolution and Pool-Controlling Significance of Pool Fluid Sources in Superimposed Basins： A Case Study from Paleozoic and Mesozoic in South China   总被引：2，自引：0，他引：2  

徐思煌梅廉夫  袁彩萍马永生 郭彤楼 《中国地质大学学报(英文版)》2007,18(1):49-59

Having multiple tectonic evolution stages, South China belongs to a superimposed basin in nature. Most marine gas pools became secondary pools. The pool fluid sources serve as the principal pool-controlling factors. On the basis of eight typical petroleum pools, the type, evolution in time-space, and the controlling of petroleum distribution of pool fluid sources are comprehensively analyzed. The main types of pool fluid sources include hydrocarbon, generated primarily and secondly from source rocks, gas cracked from crude oil, gas dissolved in water, inorganic gas, and mixed gases. In terms of evolution, the primary hydrocarbon was predominant prior to Indosinian; during Indosinian to Yen- shanian the secondary gas includes gas cracked from crude oil, gas generated secondarily, gas dissolved in water, and inorganic gas dominated; during Yenshanian to Himalayan the most fluid sources were mixed gases. Controlled by pool fluid sources, the pools with mixed gas sources distributed mainly in Upper Yangtze block, especially Sichuan (四川) basin; the pools with primary hydrocarbon sources distributed in paleo-uplifts such as Jiangnan (江南), but most of these pools became fossil pools; the pools with secondary hydrocarbon source distributed in the areas covered by Cretaceous and Eogene in Middle-Lower Yangtze blocks, and Chuxiong (楚雄), Shiwandashan (十万大山), and Nanpanjiang (南盘江) basins; the pools with inorganic gas source mainly formed and distributed in tensional structure areas.  相似文献   

构造叠加晕法在预测金矿区深部盲矿中的应用效果   总被引：6，自引：5，他引：6  

李惠  张国义  王支农  张文华 《物探与化探》2003,27(6):438-440

在原生晕分带理论的基础上,根据不同成矿阶段的元素组合、不同成矿阶段矿体的轴向分带及其在空间上的叠加特点,建立起一种预测盲矿的新模式---构造叠加晕模式.构造叠加晕法在一些金矿区深部及其外围预测盲矿已取得了显着效果.  相似文献   

塔里木西北缘北西向古隆起的存在及油气勘探前景   总被引：8，自引：0，他引：8  

杨庚 《新疆地质》2003,21(2):157-162

塔里木西北缘柯坪逆冲带为天山和塔里木盆地在中新生代盆山耦合过程中形成，为印度板块和欧亚板块碰撞影响最显的地区之一．柯坪地区存在两种方向的构造，即NE向逆冲推覆构造和NW向的走滑构造及潜伏构造．在NE逆冲带的走向上，推覆构造变形样式从南向北，以寒武纪蒸发岩作为主要的滑动拆离面——薄皮逆冲，到北部地区卷入元古界结晶基底的逆冲推覆构造．根据变形时代分析，NW向构造为长期发育的巴楚隆起，形成时代为中生代早期，近NE向的柯坪逆冲构造形成于新生代，同时也形成NW向的走滑构造．早期形成的巴楚隆起构造南北两侧发育的阿瓦提盆地和塔里木盆地西南为生油区，巴楚隆起为油气运移指向区．  相似文献   

Recent developments in study of the typical superimposed basins and petroleum accumulation in China:Exemplified by the Tarim Basin     

JIN Zhijun  WANG Qingchen 《中国科学D辑(英文版)》2004,47(Z2)

Most of petroliferous sedimentary basins in China have experienced multiple phases of tectonic evolution and deposition, and are characterized by tectonic and depositional superimposition. The term "superimposed basin" is suggested to describe those basins which consist of two or more simple prototype basins superimposing vertically and/or coalescing laterally. The characteristics of petroliferous superimposed basins are "multiple stages of basin forming and reworking, multiple layers of source rocks, multiple periods of hydrocarbon generation and expulsion, multiple periods of petroleum migration-accumulation-escape". Therefore,applying the wave process analysis method to studying the process of basin formation, hydrocarbon generation, and reservoir formation, and then establishing theory of "petroleum accumulation system" is helpful to enhancing petroleum exploration efficiency in superimposed basins.This paper will, based on case study in the Tarim basin, report the major developments in studying basin formation, hydrocarbon generation and petroleum accumulation. In study of basin formation, (1) geophysical comprehensive profiles reveal that the Tarim plate has been subducted beneath the Tianshan orogenic belt with an interfinger structure and that the deep structure in the eastern section of the Tianshan orogenic belt is different from that in the western section. (2) The vertical variation in debris and geochemical composition reveals the nature and Mesozoic-Cenozoic evolution history of the Kuqa Depression. (3) Field investigation and paleostress reconstruction show that the Kuqa Depression has undergone gravity-driven extension in sedimentary cover when the Tianshan uplifted vertically. In hydrocarbon generation study, new developments include (1) setting environmental index to judge high grade source rocks in marine carbonates, and (2) establishing the lower limit of the organic carbon content for effective carbonate source rocks. In petroleum accumulation study, (1) methods of determining paleopressure and paleotemperature of forming fluid inclusions have been established. (2) The petroleum source analysis has indicated that the crude oil in the Lunnan and Tahe oilfields are derived from the source rocks of the Middle and Upper Ordovician. (3) Three generations of oil inclusions from the Lunnan oilfield have been recognized and dated.  相似文献