共查询到19条相似文献，搜索用时 171 毫秒
1.
区内砂金矿大都分布在嘉陵江、涪江、白龙江和汉水的河床、河漫滩及Ⅰ级阶地内。在河道由开阔趋向狭窄或由狭窄突变为开阔地段、河流转弯的凸岸（堆积岸）弧形拐弯偏向上游地段、支沟与主河道文汇处靠下游等地段砂金相对富集。砂金主要富集在松散沉积层近底部的含泥砂砾层中。区内砂金矿的成因类型分为冲积型河床砂金矿、冲积型河漫滩砂金矿和冲积型阶地砂金矿三种。成矿时代为全新世早期。形成砂金矿必须具备两个条件：一是必须有砂金矿质来源，即必须有含金地质体的存在；二是有适宜的外营力作用、良好的地貌条件和有利的新构造运动，两者缺一不可。据此划出琵琶寺一河口和刘家坪-椒园里两个找矿远景区。 相似文献
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内蒙中生代卓资山拗陷盆地,目前已发现埋藏砂金矿点十余处,大多数已剥蚀成帽状残山或剥蚀台地。在埋藏砂金矿附近的洼地、沟谷中发育有品位富,颗粒粗、易采、易选的近代砂金矿(图1)。阐明本区埋藏砂金矿的成因类型、矿床特征、成矿条件、找矿标志与近代砂金矿的关系,对于了解该区近代砂金矿的成矿特征和规律,指导埋藏砂金矿和近代砂金矿的普查找矿以及群众采金都是很有意义的。 相似文献
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藏北地区砂金矿成因类型及富集特征 总被引：1，自引：0，他引：1
藏北地区的水系绝大多数为内流水系，地形坡度变化大、冰川发育、新构造运动强烈、导致该区砂金矿的成因类型的多样性和复杂性，多数为复成因类型的砂金矿，即冲－洪积矿金矿，冰川、冰水沉积砂金矿、湖滨砂金矿、坡残积砂金矿。砂金虽沿现代河谷展布，但与现代河床无关。许多砂金矿偏离现代河床数米，有些砂金矿富集在现代河床两则的高帮上。本文所总结的砂金成因类型和富集特征，对指导藏北地区的砂金找矿勘查工作具有现实的指导意义。 相似文献
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梧桐河-都鲁河流域是我国主要砂金富集区之一.区内以流水成因河漫滩砂金矿和阶地砂金矿为主.砂金矿的分布,明显地受矿质来源、新构造运动、水动力条件和沉积环境的控制.砂金矿体多呈带状、条带状赋存于河谷堆积物的底部,在矿体中经常出现一至几个富矿地段.砂金粒度为0.03-3.5mm.区内砂金矿的找矿前景好,主要找矿标志是旧采金迹、金矿化异常区和老变质岩分布区.根据砂金矿的分布和富集规律,可在五号山、小梧桐河北支沟、西梧桐河二支沟一带寻找岩金矿. 相似文献
6.
随着砂金矿勘探工作的普遍深入,现有的砂金矿钻探工艺、设备还较落后,满足不了生产实际的需要。现结合龙江－I型及130型钻机在永冻地层的应用情况,探讨永冻地层砂金矿钻探工艺及设备问题。 相似文献
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苏联砂金矿床的主要地质－工业类型可分为：化学风化壳砂矿、弱分异堆积层的洪－冲积砂矿和洪－坡积砂矿、冲积砂矿、大陆古海岸线的滨海砂矿、工艺成因砂矿、其中冲积砂矿的工业价值最大，关于砂金矿的原生补给源、主要的有金－石英建造、金－硫化物－石英建造、金－硫化物建造、金－冰长石－石英建造，与它们有关的矿砂规模各不相同，其中金－石英建造的意义最大。砂金矿发育区的分类在砂矿的预测找矿中占有主导地位，在苏联可分为：老地盾和原地台砂金矿区，前中生代褶皱带砂金矿区、中生代褶皱区的砂金矿区、构造岩浆活化区的砂金矿区。对于砂金矿的地貌构造位置，可分为隆起区、稳定地貌区和坳陷区。坳陷区中的成矿后坳陷对成矿意义最大。 相似文献
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前言 由于寻找砂金矿有周期短、成本低、收效快的特点。所以目前找砂金矿的队伍愈来愈多,砂金找矿在整个金矿找矿中所占的比例越来越大。物探方法几乎能运用于地质普查勘探工作的全过程,而在砂金矿中的作用和效果也是不可忽视的。它不单能直接找矿,而且通过确定地质构造及其形态,利用矿体赋存部位与构造的空间联系,也能间接指 相似文献
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本文根据岳口砂金矿的探井资料,提出了砂金矿金粒再生加大的化学成因模式。及其在“锈板—碳板”中迁移、沉淀富集的机理。诚然,本区砂金矿金的迁移和沉淀富集作用机理不是单一的,也许有多种因素导致金的富集。尽管各含金层中都会存在同生沉淀富集的金粒,但形成砂金矿富矿层的主要机理是表生作用地球化学的机械搬运和化学沉淀再富集。 相似文献
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苏联砂金矿床的主要地质-工业类型可分为:化学风化壳砂矿、弱分异堆积层的洪-冲积砂矿和洪-坡积砂矿、冲积砂矿、大陆古海岸线的滨海砂矿、工艺成因砂矿,其中冲积砂矿的工业价值最大。关于砂金矿的原生补给源,主要的有金-石英建造、金-硫化物-石英建造、金-硫化物建造,金-冰长石-石英建造。与它们有关的砂矿规模各不相同,其中金-石英建造的意义最大,砂金矿发育区的分类在砂矿的预测找矿中占有主导地位,在苏联可分为:老地盾和原地台砂金矿区、前中生代褶皱带砂金矿区、中生代褶皱区的砂金矿区、构造岩浆活化区的砂金矿区,对于砂金矿的地貌构造位置,可分为隆起区、稳定地貌区和坳陷区,坳陷区中的成矿后坳陷对成矿意义最大。 相似文献
11.
Yu. I. Goldfarb 《Geology of Ore Deposits》2007,49(4):241-270
The comprehensive study of alluvial gold placers, fluvial sediments, and river valleys allowed division of these placers into subtypes, categories, and varieties on the basis of genetic principles. The comparison of observation results with reconstructions of placer-forming fluvial processes demonstrates the distinct dependence of all basic properties of placers on the dynamics of their formation, i.e., on the hydraulic size of gold grains, the dimensions of streams, and the phase of the elementary erosion cycle (PEC). Four PECs are distinguished: erosion, abrasion, equilibrium, and aggradation. A lithodynamic alluvial complex (LDAC) of the same name corresponds to each PEC. Any fractions of free gold can be transported by streams, and the mode of transportation depends on the PEC. Placers of eight dynamic categories, brush, erosion, perluvial, apron, bar, equilibrium, aggradational, and gravitational, are syngenetic to certain lithofacies belonging to different LDACs. The first four categories are combined into the channel-line subtype, which embraces all traditional placers. The nontraditional bar and equilibrium (beach subtype) and aggradational and gravitational categories (representing two subtypes of the same name (?)) are so far poorly studied but may be regarded as highly promising. The size, morphology, thickness, structure, and localization of placers; average and modal values of size and roundness of gold grains; degree of their sorting and concentration; three-dimensional distribution of gold; composition of alluvium; relationships of placers with alluvium and the gutter, river valleys of various sizes, and types of morphostructures; and other features are distinct for placers pertaining to specific categories and make up natural groups individualized for each category. The correlation of placer properties in each category makes these properties predictable at the early stages of geological exploration and enhances the efficiency of forecasting and prospecting. In high-grade gold clusters, closely spaced placers group into composite deposits. The subdivision of these placers into categories makes it possible to apply rational methods and tools of exploration and mining of placers; to estimate the character, volume, and location of previous losses of gold; and to select targets for their remining. The dynamic analysis of recently formed and ancient placers is helpful for implementation of panning and interpretation of the results obtained in the context of prospecting for gold. The proposed classification may be used not only in the study of stream gold but also in the exploration of some other placer deposits. 相似文献
12.
砂金成矿地质条件：砂金物质来源于含金丰度较高的建平群以及具金矿化的构造破碎带和火山岩型金矿床（点）;有利的新构造运动,地壳缓慢差异上升,剥蚀作用大于堆积作用,使含金地质体长期处于地表氧化带遭受充分地风化破碎作用,使金容易从含金地质体中解离出来;本区为干燥、多风、少雨气候条件,不易形成冲积型大型砂金矿。建平群出露区、凌源-北票-阜新断裂带两侧、含金多金属硫化物矿床（点）的氧化带、原生金矿床（点）分布区以及山前、山间、洪积扇、支谷的中上游或源头是寻找残积、坡积、洪积和细各砂金矿的有利地区。 相似文献
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论述了辽东地区砂金矿控矿因素,揭示了砂金矿矿规律,并指出了在具备物源,气候,水动力,地貌,等条件下,形成一个有工业意义的砂金矿床,对其含金层必须要有一定适宜的封存条件。 相似文献
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呼伦贝尔盟北部地区由于新构造运动含金地质体长期风化剥蚀，促使金的活化。河流及其2－3级支流发育，流域广，水流充足，有利于砂金矿的迁移、富集。现代的乐山丘陵、宽阔沟谷有利于砂金的保存。该区已发现数十个砂金矿，多为河谷型，主要含金层为含粘土砂层或砂砾层。砂金富集与河谷地貌关系密切，河床弯曲的凸岸、变异部位、关门咀、迎门山等地貌是砂金富集有利部位。该区金直接来源于加里东和华力西花岗岩。结合金的来源、矿床的分布特征和富集规律，指出了该区今后砂金找矿方向。 相似文献
16.
L. V. Eirish 《Russian Journal of Pacific Geology》2008,2(5):454-463
The intensity of placer formation is controlled by many factors, mainly by the erosion level of orebearing structures. Their deep erosion and long-term denudation resulted in the formation of numerous, often large placers with fine gold, which lost their relation with bedrocks and were derived mainly by rewashing of loose deposits from the depressions adjacent to the ore-bearing orogens. These placers are developed in many gold-bearing areas: Dambuki, Sutara, Erik, and others. Rich placers with coarse gold of high fineness were formed via erosion of gold mineralization that was previously metamorphosed by post-ore granitoids (Niman and Kerbi regions, Central Sikhote Alin). 相似文献
17.
Bibhuranjan Nayak 《Journal of the Geological Society of India》2011,78(4):345-348
Although sporadic mining of placer gold from river beds is not uncommon in India, there is no documented literature on the
occurrence of gold in the beach placer sand deposits of the country. While characterizing the heavy minerals of the Chavakkad-Ponnani
(CP) beach placer sands along the North Kerala coast, the association of gold with the pyriboles in these sands has been observed.
A native gold grain of about 25 μm was seen to occur as an inclusion within an amphibole of hornblendic composition. The pyriboles
of the CP deposit are angular to sub-angular indicating a nearby provenance that may be in the upstream reaches of the Ponnani
River in the districts of Malappuram and Palakkad or further north in the auriferous tracts of the Wynad-Nilambur or Attapadi
regions. It is argued that the occurrence of native gold in CP deposit is not a freak occurrence and that it warrants thorough
investigation of all the pyribole-ilmenite-rich placers to examine the possible presence of gold and its abundance in the
beach placers of northern Kerala coast. 相似文献
18.
Dave Craw 《Ore Geology Reviews》2010,37(3-4):224-235
The giant gold placer system on the Otago Schist of southern New Zealand was derived from Mesozoic orogenic gold deposits in the underlying schist basement. The core of the schist basement was exhumed in the middle Cretaceous, coeval with the accumulation of the oldest preserved nonmarine sedimentary rocks in the area (ca 112 Ma). Those sedimentary rocks contain quartz clasts, with distinctive ductile deformation textures, that were derived from structural zones in, or adjacent to, major orogenic gold deposits. Quartz textures in these structural zones are readily distinguishable from the rest of the schist belt, and hence provide a fingerprint for erosion of gold. The earliest sedimentary rocks on the margins of the gold-bearing schist belt are immature, and were derived from unoxidised outcrops in areas of high relief. Gold was not liberated from unoxidised basement rocks during erosion, and was removed from the system without placer concentration. Placer concentration did not begin until about 20 million years later, when oxidative alteration of gold deposits had facilitated gold grain size enhancement from micron scale (primary) to millimetre scale (secondary). Subsequent erosion and recycling of gold in the early Cenozoic, and again in the late Cenozoic, caused additional concentration of gold in progressively younger deposits. The Klondike giant placer goldfield of Canada had a similar geological history to the Otago placer field, and Klondike placer accumulation occurred in the late Cenozoic, at least 70 million years after Mesozoic exhumation of orogenic gold. The giant placer deposit on the western slopes of the Sierra Nevada in California occurs in Eocene and younger sedimentary rocks, at least 40 million years younger than the timing of major exhumation of the source rocks. Circum-Pacific giant gold placers formed under entirely different tectonic regimes from the emplacement of their source orogenic deposits, and these giant placer deposits do not form in foreland basins associated with convergent orogens. Formation of giant placers requires less active erosion and more subdued topography than the collisional orogenic activity that accompanied emplacement of source gold deposits in basement rocks, as well as oxidative alteration of the primary deposits to liberate gold from sulfide minerals and enhance secondary gold grain size. 相似文献
19.
辽南碧流河中上游砂金矿地质特征及成矿地质条件 总被引：1，自引：0，他引：1
辽南碧流河中上游砂金矿位于营口—宽甸台拱与复州台陷的交接部位。砂金主要赋存于碧流河及其支谷水系第四系全新统砂砾石层的底部,砂金矿体平行河谷呈层状分布;矿体埋藏浅,砂金粒度中粗,易采选;属冲洪积型谷底砂金矿。本区砂金主要来源于岩金矿和含金地层,成矿物质丰沛,成矿地质条件优越,是辽南砂金成矿的远景区。 相似文献