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1.
《International Geology Review》2012,54(2):151-160
The fact that there is little relation between zones of faulting and pyrite ore deposits is presented as a major argument against many older theories of the formation of such deposits. The author, having made close studies of Soviet deposits, notably in the Urals, finds that there is only fragmentary data to support a direct pyrite-to-faulting correspondence while there is some evidence of metasomatism of a broader and more long-standing nature. In attempting to establish some relation between acidic granitoid bodies, volcanic extrusives and pyrite mineralization, he discards the usual theories in favor of one which associates pyrite bodies with small brachyanticlinal uplifts and leans toward the scheme: phase 1, rocks (or magmas) producing ore-bearing solutions, →phase 2, rocks through which these solutions travel,→ phase 3, rocks which capture the solutions. The latter two phases are interbeds of volcanogenic-sedimentary rocks, in the author's opinion. The author leaves “open” the obvious association of pyrite bodies with quartz albitophyres and basic extrusive formations. He also suggests that there is some connection between original deep magma chambers (of acidic lavas) and ore-bearing solutions. Frequent reference is made to the pyrite deposits of Shasta County, California, as well as major deposits in Canada and Norway.—A. Eustus 相似文献
2.
Based on research on the “Xinyu-type” Sinian iron deposits in Jiangxi Province and metamorphosed iron deposits in Jiangkou and Qidong of Hunan, Sanjiang and Yingyangguan of Guangxi, Longchuan of Guangdong and some other areas in Fujian, the authors have come to the following conclusions:
- The metamorphosed late Precambrian iron ores widespread in south China may be roughly assigned to two ore belts, namely the Yiyang-Xinyu (Jiangxi)-Jiangkou(Hunan)-Sanjiang (Guangxi) ore belt or simply the north ore belt, and the Songzheng(Fujian)-Shicheng (Jiangxi)-Bailing (Longchuan of Guangdong)-Yingyangguan (Guangxi) ore belt or the south ore belt. Tectonically, the former lies along the southern margin of the “Jangnan Old Land”, while the latter along the northwestern border of the “Cathaysian Old Land”.
- Iron deposits of this type occur exclusively in the same interglacial horizon of the Sinian Glaciation in south China. Above and below the ore bed there lie the glacial till-bearing volcanic-sedimentary layers.
- Based on sedimentary features, the iron formations can be divided into four types: silica-iron-basalt formation, silica-iron-clastic rock formation, silica-iron-tuff formation and silica-iron-carbonate rock formation, which progressively grade into each other.
- Iron ores were formed at the late stage of late Proterozoic rifting in neritic environments, with their distribution governed by the rift valleys on the margins of the “Jiangnan Old Land” and “Cathaysian Old Land”. Consequently, intense mafic volcanism as well as weathering and denudation of palaeocontinent during rifting provided material sources for the formation of iron deposits. Meanwhile, warm and humid stationary neritic environment during the south China great glacial period constitutes favorable palaeoclimatologic and palaeogeographic conditions for the deposition of iron ores.
- The iron formations have undergone regional metamorphism of greenschist-amphibolite facies.
3.
《International Geology Review》2012,54(8):1401-1407
Sinitsin's approach to the mercury-antimony mineralization of the Tien Shan and Alay was through a systematic study of the tectonics and geomorphological evolution of the area. In affirming an upper Paleozoic age for the mercury mineralization, Sinitsin stressed the study of Paleozoic structure and sedimentation. The principal factors controlling the origin, nature and distribution of ore deposits such as the combination of facies, folding, and the position of mineralization channels are determined by the tectonic development of the housing structure, beginning with the sedimentation period. Sinitsin believed that the historical approach is the only Way to attack the most intricate and controversial problems in geology, including those of mineralization and ore deposits distribution. Chapter I gives a brief survey of the Precambrian outcrops and the influence of pre-Paleozoic trends on Paleozoic and younger structures., Chapter II contains the bulk of the data on tectonic development on the Paleozoic of West Tien Shan and Alay and shows that the ore zones are located along the junction of older and younger major structures, largely within the first. Chapter III deals with Mesozoic structures of the Fergana Mountains. Chapter V, “Arrangement of the Principal Structural Elements,” considers first the problem of the relationship among Paleozoic structures of the Tien Shan and Alay; second, the problem posed by the Talas -Fergana fault: and third, relations between Alay and the Pamirs. Chapter VI presents a summary and conclusions and opens with an original genetic classification of folded structure in the province under study. First order folds, represented by anticlinoria tens of kilometers across, usually coincide with troughs of the later geosynclinal stages. First order structures have deep plutonic roots. Second order folds are anticlines and synclines measuring a few kilometers across. Third order folds, fen to hundreds of meters across, usually are local features. First order folded structures often are separated by marginal faults which are of prime importance in mineralization control. — C. E. Sears. 相似文献
4.
The dilemma of the Jiaodong gold deposits: Are they unique? 总被引：2，自引：0，他引：2
The ca. 126e120 Ma Au deposits of the Jiaodong Peninsula, eastern China, define the country＇s largest gold province with an overall endowment estimated as＆gt;3000 t Au. The vein and disseminated ores are hosted by NE-to NNE-trending brittle normal faults that parallel the margins of ca. 165e150 Ma, deeply emplaced, lower crustal melt granites. The deposits are sited along the faults for many tens of kilometers and the larger orebodies are associated with dilatational jogs. Country rocks to the granites are Pre-cambrian high-grade metamorphic rocks located on both sides of a Triassic suture between the North and South China blocks. During early Mesozoic convergent deformation, the ore-hosting structures developed as ductile thrust faults that were subsequently reactivated during Early Cretaceous ＂Yan-shanian＂intracontinental extensional deformation and associated gold formation. 〈br〉 Classification of the gold deposits remains problematic. Many features resemble those typical of orogenic Au including the linear structural distribution of the deposits, mineralization style, ore and alteration assemblages, and ore fluid chemistry. However, Phanerozoic orogenic Au deposits are formed by prograde metamorphism of accreted oceanic rocks in Cordilleran-style orogens. The Jiaodong de-posits, in contrast, formed within two Precambrian blocks approximately 2 billion years after devolati-lization of the country rocks, and thus require a model that involves alternative fluid and metal sources for the ores. A widespread suite of ca. 130e123 Ma granodiorites overlaps temporally with the ores, but shows a poor spatial association with the deposits. Furthermore, the deposit distribution and mineral-ization style is atypical of ores formed from nearby magmas. The ore concentration requires fluid focusing during some type of sub-crustal thermal event, which could be broadly related to a combination of coeval lithospheric thinning, asthenospheric upwelling, paleo-Pacific plate subduction, and seismicity along the continental-scale Tan-Lu fault. Possible ore genesis scenarios include those where ore fluids were produced directly by the metamorphism of oceanic lithosphere and overlying sediment on the subducting paleo-Pacific slab, or by devolatilization of an enriched mantle wedge above the slab. Both the sulfur and gold could be sourced from either the oceanic sediments or the serpentinized mantle. A better understanding of the architecture of the paleo-Pacific slab during Early Cretaceous below the eastern margin of China is essential to determination of the validity of possible models. 相似文献
5.
庐枞盆地中发育一些大中型硫铁矿床,曾长期被认为是与次火山岩有关的中低温热液成因。本文从矿床层控特点、矿体形态产状、矿石沉积组构、矿物组合及其生成顺序、矿化分带、包裹体及同位素地球化学等诸方面,证明它们具显著的火山喷气沉积成因特征,并受到后期热液叠加改造。提出了大鲍庄式陆相火山喷气沉积-热液叠加改造型硫铁矿的成矿模式。 相似文献
6.
多重水力断裂的分形扩张 总被引：6，自引：2，他引：4
应用复杂性理论对于赣南脉钨矿床的著名“五层楼”式形态垂直分带进行研究 ,获得如下结果。 (1 )赣南脉钨矿床的“五层楼”式形态垂直分带是“多重水力断裂分形扩张”的结果。脉钨矿床的控矿多重断裂是一种以水力断裂为主导的热致与流体驱动断裂构造。脉钨矿床的自组织临界性是多重分形扩张之源 ,而中观破裂尖端周围流体静力学应力场梯度最大区则是分形扩张的驱动力。多重水力断裂的发生和发展是一种分形扩张过程 ,其演化服从串级“崩塌间断平衡”的时空分形生长动力学 ,与地震的Omori余震律相类似。 (2 )脉钨矿床“三环一帽”式的成矿地球化学分带是一种多组分成矿溶液的渗滤、溶解沉淀波结构 ,是成矿反应扩散系统中化学波的时空同步化传播而形成的目标斑图 ,是近平衡地质介质内 ,通过外界的“短暂局部激发”、继之以构造、岩浆和成矿脉动作用等“局部中断”而形成的径向对称、嵌套球状、远离平衡的局域化耗散结构 ,即脉动型自孤子。 (3)赣南脉钨矿床是近平衡区域地质背景中远离平衡的局域化耗散结构。赣南钨矿集区是复合自孤子的群集体。它们是在构造、岩浆多期次脉动条件下 ,来自①矿源层部分熔融的“区域提纯”、②岩浆期后成矿热液输运反应和③含钨地层、岩石淋滤交代的成矿物质 ,通过岩浆和热液孤 相似文献
7.
《International Geology Review》2012,54(8):664-693
This article surveys the geographical distribution of metal ores, grouped into six categories: iron, manganese, chromium, silver-lead-zinc, copper and tin. The author reviews the occurrence of these ores throughout the world, and their association primarily with broad geotectonic zones. The essential information is encompassed in six maps. Legends explain the classification of the deposits by age (metallogenic eras), type and paragenetic associations of minerals. The symbols for these various classifications of ores are superimposed on maps showing the zones of Precambrian (cratonal), Paleozoic, Mesozoic and Cenozoic folding. The particular interest of this paper is that the author has made this survey as a preliminary to dividing the earth's surface into metallogenic provinces (of which he distinguishes 21), giving a brief discussion of each and showing its connection to areas of different ages and geotectonic structures. The ultimate aim is to construct “prognostic maps”, or maps drawn on such a basis that they may be used to predict the occurrence of a given ore or ores in a given region. — Paul T. Broneer 相似文献
8.
The relationship between major structural lineaments and locations of ore deposits in Iran has been investigated using geospatial data. In the course of lineament extraction, satellite images, aeromagnetic data, digital elevation model (DEM) and structural maps were processed and the lineaments and large-scale faults were identified. The extracted lineaments, based on subjective assessment, from each dataset were imported into GIS software and the “lineament map of Iran” was prepared by data integration. The analysis for selecting significant lineament was mainly based on fault correlated lineament and lineament with field map fractures, which was sets as benchmarks for compiling a final output map. Four major regional lineament trends of N–S, E–W, NW–SE and NE–SW were identified in the data of all images, which are corresponded to the structural zones and the major fault systems of Iran. The mineral deposits (active and abandoned) and mineral indications database compiled are based on the published maps, papers, reports and the ore deposits data files of Geological Survey of Iran. Integrating the output of these two datasets by GIS software resulted in the “Combined Map of Lineaments and Gold, Copper, Lead, Zinc and Iron Deposits of Iran”. The number and distance of ore deposits toward the lineaments were processed by the counting and cumulative methods in the GIS software's. Approximately, over 90% of the ore deposits of Iran are located in the central part of the lineaments (15 km on each side) which are concordant with a definition of large lineament. About 50% of these mineral deposits are closer than 5 km to the lineaments. There are significant correlations between lineament density and intersections with ore deposits occurrences. The observed associations at this scale are informative in establishing exploration strategy and decreasing exploration risks for detailed work on ore deposit scale. 相似文献
9.
产于太古宙中深变质岩中的金矿床在我国华北东北地区分布很广,成矿时代主要靠同位素年龄及其与后期岩浆活动的关系来确定。夹皮沟金矿是该型矿床中工作较多且有代表性的一个矿床,对其成矿时代有前寒武纪（Ar、Pt）成矿、显生宙（海西、海西一印支、燕山）成矿及前寒武纪十显生亩成矿等不同认识。本文根据矿脉与海西期花岗闪长岩及脉岩的关系,以及含金石英包裹体Rb－sr等时线年龄资料,认为成矿属海西期或海西一印支期,可能有燕山期的叠加。由于石英含过剩氩,故所得元古宙Ar－Ar、K－Ar表面年龄无地质意义,锆石可能具继承性,其太古宙年龄不能肯定为成矿时代。该矿是否有前寒武纪成矿期尚待进一步工作。 相似文献
10.
I.S. Zagorčev 《Precambrian Research》1974,1(2):139-156
The Precambrian basement of Bulgaria consists of two sharply defined units: the Upper Precambrian—Lower Paleozoic (?) Diabase-phyllitoid (Vlasina) complex, characterized by greenschist facies metamorphism, and the high-grade (amphibolite facies) basement (Thracian massif), subdivided into Rhodopian and pre-Rhodopian complexes. According to the style and dominant fold trend five Precambrian structural zones are defined within the Thracian massif: Ograzhden Anticlinorium; Sredna Gora Anticlinorium; Rhodope Anticlinorium; Pirin structural zone; Upper Thracian structural zone.The pre-Rhodopian development (4 major fold phases in amphibolite facie metamorphic conditions) resulted in formation of a grate-shape structure with centrifugal vergence, and smooth curvature of the dominant trend. The consecutively formed Rhodopian complex was folded following a simple “dome-and-basin” interference pattern, in amphibolite facies conditions, and uplift tendencies for the peripheral anticlinoria. The structure was complicated by torsion in the Pirin zone, and by setting up of the first (“ancestral”) fault zones along the junction lines between the separate Precambrian structural zones. After erosion the Diabase-phyllitoid complex covered the periphery of the Thracian massif and incorporated fragments of it as cores of positive structures. The Precambrian structural plan has been largely inherited by later (Hercynian and Alpine) tectonics. 相似文献
11.
有关本区矿床成因先后有同生沉积、低温超低温热液、沉积改造等不同看法。本文根据宏观、微观资料的初步分析认为,本区铅锌矿床属于后成深循环热卤水成因——后成层控矿床。本文将对这一问题进行讨论。 相似文献
12.
扬子区震旦纪地层序列和南、北方震旦系对比 总被引：18，自引：7，他引：18
198 2年“晚前寒武纪地层分类命名会议”决议“震旦系是青白口系之上的晚元古代最上部的一个年代地层单位 ,以三峡地区的剖面为代表 ,暂以莲沱组底界为底界”。但从区域性对比和同位素年代地层学分析 ,莲沱组底至黄陵花岗岩的侵蚀面之间有约 10 0 Ma的沉积缺失 ,莲沱组和南沱组也不能代表 75 0～ 6 6 0 Ma间的沉积历史。峡东地区震旦系下部地层不完整是显而易见的。本文赞同修订震旦系的含义 ,以下冰碛层 (古城组或铁丝坳组 )之底为震旦系的底界 ,年龄为 70 0 Ma。朝鲜飞浪洞组可与古城组、大塘坡组和南沱组对比 ,祥原系及辽南、徐淮地区的相当地层属“南华冰期”前的沉积地层。建议震旦系之下至青白口系顶 (85 0 Ma)之间建立辽南系 ,从而完善我国晚元古代年代地层框架 相似文献
13.
Dr. Harald Dill 《International Journal of Earth Sciences》1983,72(3):955-980
Most of the U occurrences situated at the western edge of the Bohemian Massif show in their upper parts secondary U minerals. The immigration (P, V, As and Se) from the country rocks and the ore body, via saprolite and paleosoils into the secondary ore minerals is investigated. The P content is suggested to be closely related to hydromorphic paleosoils. From those intermediate stages it may have been brought into the upper parts of the vein structures. No laterogenic impoverishment in the wall rocks with respect to phosphorus or apatite could be determined. The arsenic distributions is also governed as at other sulfide deposits by underlying sulfides and reducing conditions of a primary hypogene ore zone, whereas vanadium content in U secondary minerals is closely related to the enclosing country rocks. Granites, on account of their low content in mafic minerals, have low V contents in U secondary minerals. Besides the Schwarzach Area, U ore mineralisations from other U occurrences have been investigated. Some of the U deposits are certainly of “per ascensum” origin and their secondary U mineralisation can well be interpreted as having been derived from the underlying primary “black ores”. However, some mineralisations cannot be classified with certainty as being “per ascensum”. They include some properties pointing to “per ascensum” (e. g. sulfide association) as well as characteristics typical for “per descensum” (small depth, large amounts of U-VI minerals). The mode of formation may in some cases be as follows: Variscan or Alpine ore mineralisations of no economic significance may have formed a reducing environment and caused U to be concentrated. Younger redistribution processes influenced by modern tectonics (uplifting) and the fluviatile drainage pattern have taken place and in some cases destroyed the primary deposits or enhanced the ore mineralisation. These processes roughly resemble those described from sandstone — hosted roll front deposits. 相似文献
14.
长江中下游地区层状铜矿床基本特征及成因 总被引：1，自引：0，他引：1
阐述了长江中下游 (包括赣北地区 )主要的铜矿成因类型暨沉积—海底喷流沉积层状铜 (S,Au,Ag)矿床 ,并对层状铜矿床的成因进行分析 ,指出其找矿方向 相似文献
15.
16.
作者按照涂光炽教授的分类将福建省层控铅锌矿床划分为4种类型。本文对它们的地质特征、微量元素和硫、铅同位素组成的特征作了较详细的阐述,对矿床的矿质来源作了初步的探讨。 相似文献
17.
伊宁吐拉苏火山盆地构造与金矿成矿关系 总被引：10，自引：4，他引：6
伊宁吐拉苏火山盆地发育在前寒武纪和加里东基底上,盖层主要由早石炭世陆相火山岩组成。基底与盖层中的断裂、褶皱构造特征有显著差异。火山构造单元划有火山喷发带、火山构造带、火山机体三级。构造演化经历了基底和火山盆地形成及剥蚀三个阶段。金矿产于大哈拉军山组。认为三级控矿构造与三级火山构造相对应,分别控制着金矿带、金矿田、金矿床（点）的展布和产出。 相似文献
18.
《International Geology Review》2012,54(4):638-641
Rare earth mineralization, in the form of xenotime and monazite, occurs along tear faults at an unidentified locality in the Precambrian terrane of European part U. S. S. R. The petrographic and geologic relationships of the last rocks appear to reflect Mg-Fe metasomatism followed by metasomatisrn. The rare earth mineralization appears to have accompanied the K metasomatism. Chemical analyses are presented for one xenotime and two monazites; emission and X-ray spectroscopic analyses are presented for the xenotime. — R.V. Dietrich. 相似文献
19.
Typomorphic features of placer gold in the eastern Siberian Platform were studied to determine its genesis. It was established
that this region contains abundant alluvial bar placers, which were formed mainly by the erosion of gold reservoirs of different
ages. Discovery of gold with the points of eolian reworking in the Quaternary sediments allows us to predict the eolian gold
placers in individual areas of the northeastern and central parts of the eastern Siberian Platform. Identification of two
types of gold on the basis of typomorphic features in the Cenozoic deposits indicates that placer gold was mainly derived
from the Precambrian sources spatially confined to the exposure of ancient basement, as well as from local ore occurrences
related to the Mesozoic tectonomagmatic activation. Thus, two main stages of ore formation (Precambrian and Mesozoic), were
substantiated for the first time in the eastern Siberian Platform. 相似文献
20.
四、胶东群的地质时代,各岩组时序及基底构造问题沈阳地矿所余汉茂1983年在栖霞桃村至十八盘一带,采选了胶东群化山组地层中锆石试样5个,送北京铀矿地质研究所作铀—钍—铅同位素年龄测定,其结果见表3。表3之锆石年龄为一致年龄。作Pb—Pb等时线,得年龄值为2662.5±21.9 22.3百万年(见图16)。作阿仑斯—韦瑟里尔(两阶段)一致曲线模式图(见图17),得上交点年龄2675±17.2 9.6百万年,数据点集中在上段,铅略有丢失,但不影响Pb-Pb等时线。两者年龄在误差范围内一致,下交点误差大,无地质意义。故胶东群化山组的成岩年龄为2675±17.2 9.6百万年。 相似文献