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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
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BRYAN KRAPEZ 《Sedimentology》1985,32(2):223-234
Five local varieties of the Ventersdorp Contact placer at the East Driefontein Gold Mine, Carletonville, are distinguished by clast-type assemblage, reflecting discrete provenances. The placer further comprises six lithofacies which are not restricted to specific provenance-varieties. The six lithofacies are: massive, matrix-supported conglomerate (facies Gms): massive, or crudely bedded, clast-supported conglomerate (facies Gm); channel-based conglomerate (facies Gt); single clast layers (facies Glag); horizontally stratified sandstone (facies Sh); and trough cross-stratified sandstone (facies St). Facies Gms represents debris-flow deposits, whereas the other facies are stream deposits. Lithofacies and provenance-varieties are complexly interrelated in local environments, which are themselves complexly related to geomorphic elements of a degradation surface. The maximum thickness of the placer is 7 m. The placer was deposited on a hard, i.e. non-alluvial, bedrock surface, suggesting that it is a pediment mantle. It owes its preservation to a capping of conformably overlying basalts. Economic gold mineralization is present in all the conglomerate facies and all the provenance-varieties. Gold concentrations are high in gravel-bar deposits and channel fills but are not restricted to these environments. A major feature of gold concentration is its variability between provenance-controlled varieties. The gold concentration of a specific primary source is interpreted to be a major control on gold concentration in the final deposit. The origin of the placer as a pediment mantle, and its subsequent preservation by lava-flows, suggests that there was little potential for selective reworking of heavy minerals. Nevertheless, the Ventersdorp Contact placer on the Carletonville Goldfield is one of the richest gold placers in the Witwatersrand Basin. 相似文献
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布鲁嘎里河砂金矿产于兴华渡口群下兴华组和晋宁期花岗岩分布区。研究区为低山丘陵,经长期风化剥蚀和堆积形成了一系列侵蚀堆积地貌。第四纪松散物覆盖在下兴华组地层和花岗岩之上。目前已圈定２条矿体。矿体连续性好,平面上呈条带状,多为粒状,板状,片状,ＮＥ,ＮＷ向断裂不但控制区内的地貌形态,也为砂金的形成提供了有利地质条件。砂金分布区应该是原生金矿（化）的集中区,在普勘勘探砂金的同时更要注意寻找原生金矿,在兴 相似文献
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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
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浅谈冲积型砂金矿床成矿模式——以陕西月河砂金矿床为例 总被引：2，自引：0，他引：2
本文通过对砂金矿床形成过程的分析认为:在地壳局部下沉过程中,砂金在水等强应力作用下,与砾石、砂一起进入沉积盆地,形成砂金的中间储存体;随着地壳的间歇性上升,在蛇曲河流的作用下由于砂金与砾石的运动规律相仿,故和砾面一起被保留在河流冲刷面上的河床滞留砾石沉积中。当地壳多次间歇性上升后,使砂金中间储存体中分散的砂金集中富集在河床滞留砾石层中,从而形成砂金矿床。 相似文献
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辽东半岛自晚白垩世以来,长期处于抬升剥蚀阶段,地形向准平原化,自晚更新世起发生多次海侵、海退作用,在黄海沿岸形成断续的滨海平原;数个滨海平原中以东沟滨海平原准平原化最好。其第四纪沉积物最全,厚度大,砂金成矿条件最好,对辽东半岛黄海沿岸砂金的供源条件、成矿环境的研究,并与国外特大型滨海砂金矿床的成矿地质条件对比认为,东沟滨海平原具有形成大型特大型滨海砂金矿床的成矿地质条件,此外,东沟平原从丘陵到浅海具有沟谷砂金、河床砂金、滨海砂金、浅海砂金的成矿条件,砂金潜在远景较大。 相似文献
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我国砂金点多面广,很多江河水系都有砂金.为实现黄金生产发展的规划目标,当前加强砂金地质工作,对我国发展黄金生产建设具有重要现实意义. 相似文献
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朋友砂金矿床位于秘鲁南部亚马逊盆地中,具有典型的热带雨林气候和独特的水文地质特征.第四系松散堆积层发育完全,厚度大.圣母河砂金矿的富集有明显规律性,其与水文地质条件及物质来源相关,这种成矿规律性可用一模型来描述,该模型适用于具有金矿成矿物质来源的热带河流冲积型砂金矿床.合理的找矿方法是热带雨林地区砂金矿床定位评价的关键. 相似文献
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砂金水化学成矿因素探讨 总被引：1，自引：1，他引：1
通过从砂金矿和原生金矿中自然金在粒度、形态、成色等方面特征对比，两类矿床中自然金成色的关系研究以及砂金过采区再生产意义的分析，对砂金水化学成矿因素进行了初步探讨金在表生条件下可以活化、迁移、再生富集成矿，砂金的水化学成矿作用在诸种成矿因素中占有重要地位。 相似文献
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金仓砂金矿是吉林省延边地区著名的第四纪砂金矿床。其砂金含矿层中砾岩多呈棱角状,砂金粒度及形态沿河流流向分异现象不明显,砂金的连生矿物、伴生重砂矿物、成色、微量元素、稀土元素、铅及硫同位素、气液包裹体成分特征均可和矿区内原生金矿化对比。据此,初步从为金仓河砂金主要来源于金仓河谷中、上游底部基岩含金蚀变破碎带中的原生金。 相似文献
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陇南地区白龙江下游冯坪子位于西秦岭复杂构造带中,广泛发育碧口群绿片岩系,为含金初始矿源岩,第四纪以来,白龙江流域长期隆起剥蚀,对矿金运移富集提供了良好的地质环境,断陷带、构造谷负向部位成为砂金储集场所,冯坪子河漫滩采样分析结果表明,深度增加金品位增高,3.5～5m,7.5～11m为金富集段。 相似文献
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研究区位于胶东半岛西北部，具有丰富的岩金和砂金资源，是我国目前重要的黄金产地。作者应用沉积学和水动学的理论和方法，重点研究了该地区现代河流的沉积学特征、砂金聚集规律及其形成的水动力条件，认为河流砂金的聚集是一个与机械成矿作用密切相关的动态过程，与特定的河流水动力条件有关，其中横向环境的底流对于形成河谷台阶状缓坡倾斜面及砂金聚集具有重要意义。 相似文献
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黑龙江省北部风化壳的形成及其对砂金成矿的作用 总被引：2，自引：0，他引：2
黑龙江省北部风化壳的形成及其对砂金成矿的作用宋长春张宝林（中国科学院长春地理研究所，长春１３００２１）关键词风化壳砂金次生长大储集体黑龙江省北部地区第三纪准平原化过程形成了广布的风化壳，在部分区段风化壳中储集有大量的金质，表现出明显的金及伴生元素地球... 相似文献