浅析激电法在建阳市井后钼矿区的找矿效果     

吕士炳 《福建地质》2009,28(4):296-301

建阳井后钼矿在新一轮矿产远景调查的矿点检查时开展了物探工作,发现激电异常,结合矿区成矿地质特征,推断其是隐伏钼矿（化）体引起的矿致异常,经工程验证得以证实。该区激电异常是深部找矿的有效标志。  相似文献   

刚果（布）主要矿产及地质特征     

李如满  刘峰  段焕春 《矿产与地质》2009,23(6):578-583

在结合刚果（布）1／100万区域矿产地质调查资料的基础上,对该国的主要矿产及地质特征进行了分析．结合区域地质矿产概况将该国的金属矿产分为12个矿带,归为3大类：结晶基底和绿岩带中的铁矿、金矿、钨锡铌钽及稀土矿,碳酸盐岩地层中的低温热液铜铅锌矿,构造、岩体、地层共同控制的多金属矿。根据分析结果对成矿规律进行了初步总结：绿岩带和重熔花岗岩及其相互作用形成了铁矿、金矿及钨锡铌钽等相关矿产;中生代的构造活动形成了碳酸盐岩地层中的低温热液铜铅锌矿;中元古代岩浆活动及中生代的构造活动促使了南部构造、岩体、地层共同控制的多金属矿带的形成。在对成矿规律认识的基础上对找矿潜力作了分析,认为该国所有金属矿产绝大部分为风化矿产和冲积砂矿,矿点多,但原生矿少,寻找原生矿的空间大;勘探和开采程度极低,矿业开发前景巨大．总的说来,以该国作为长期的矿业开发基地,具有战略意义。  相似文献   

库车前陆冲断带盐构造区平衡剖面研究   总被引：1，自引：0，他引：1  

余一欣  王鹏万 《海相油气地质》2009,14(1)

通过计算库车前陆冲断带古近系库姆格列木组含盐层系初始沉积厚度,并以此作为地质约束条件,采用分层复原法对该区地质剖面进行平衡复原。复原结果表明,库车前陆冲断带南北向总缩短量为18~31km,缩短率为16%~34%。其中新生代变形强度最大,缩短率接近15%。新生代最强烈的构造变形又是发生在库车组开始沉积后的喜马拉雅运动晚期,该时期缩短量已超过新生代缩短量的80%,缩短速率达到2.43mm/a。  相似文献   

西非被动大陆边缘含油气盐盆地构造背景及油气地质特征分析   总被引：5，自引：3，他引：2  

刘祚冬  李江海 《海相油气地质》2009,14(3):46-52

西非被动边缘含油气盐盆地包括西非安哥拉—喀麦隆段的加蓬盆地、下刚果盆地、宽扎盆地等。认为这些盐盆地从构造、沉积相、油气分布上都具有垂向上的分段性。盆地演化受控于石炭纪末泛大陆裂解及随后南大西洋的张开。盆地演化划分为前裂谷阶段(J3前)、同裂谷阶段(J3—K1)、过渡阶段(K1)和后裂谷阶段(K2—Q)。由于Tristan热点活动以及热带干旱气候的相互作用,过渡阶段发育厚层阿普特阶盐层,将盆地分为盐上、盐下两套油气系统,控制了油气纵向上的分布。盐盆地以上侏罗统—下白垩统特富湖相Ⅰ型烃源岩、森诺曼阶—赛诺统缺氧环境下形成的Ⅱ型海相烃源岩为主要源岩;大型深水浊积扇体为储层,油气通过同生断层及盐窗等疏导通道运聚至构造圈闭、盐层顺层滑脱引起的拱张圈闭以及一些岩性圈闭中,这些有利的成藏条件相匹配形成了巨大规模油田。  相似文献   

首次在白云鄂博铁矿发现的矿物种述评     

徐金沙  李国武  沈敢富 《地质学报》2012,86(5):842-848

上世纪后半叶,在白云鄂博铁矿究竟首次发现的矿物种是多少?对此,地质学家们有不同的说法,大体上有15、19、4和16种之异。本着客观、平允的立场,作者的统计是9种新矿物。迄今,该矿业已发现的新矿物共计有14种之多。在对这些新矿物稍加评述的基础上,初步总结了白云鄂博铁矿新矿物研究的经验、教训。顺便展望其新矿物发现前景。  相似文献   

Offshore Occurrences of Heavy-Mineral Placers,Northwest Galicia,Spain     

Malcolm Richard Gent  Mario Menéndez Alvarez  Jesús José María García Iglesias  Javier TaraÑo Álvarez 《Marine Georesources & Geotechnology》2013,31(1-2):39-59

ABSTRACT

Results of offshore water-jet sediment sampling demonstrate the potential for interstadial placer deposits of industrial minerals in the shore-face to inner-shelf of Cape Ortegal, NW Spain. Placer deposition is interpreted to have occurred during glacial interstadials since the Last Glacial Maximum, and deposits sampled at 24 to 42 m. BSL were formed during the Younger Dryas, and subsequently preserved as a result of very rapid rising sea-levels. The sediments are almost entirely terrestrially derived with a particularly high heavy mineral content (Sp. Gr. >2.9), of more than 75% in all samples. Reworked garnet from earlier-sedimentary deposits constitutes an important fraction of the placer deposits identified but is generally absent in other sediments. Indications of the presence of +5 m-thick paleo-placer deposits with sections include:

• Placer garnet + spinel grades increase with depth in those sediments at 24 to 42 m BSL to the ocean-floor.

• The d50 of sediments with background grades decrease with depth while those of placer deposits do not display any significant trend.

• Garnets in non-mineralized sediments are almost entirely angular, whereas in placer enriched sediments they vary in form from well-rounded to angular. Some grains in the latter display surface morphologies typical of reworked sediment while none of the former do.

Sediments deposited during glacial interstadials at depths of up to 130 m BSL may represent important, undeveloped exploration targets for offshore placer deposits of industrial minerals. Industrial mineral exploration should extend the depths of investigations to those corresponding to major interstadial periods.  相似文献   

浙江桃花岛碱性和普陀山铝质A型花岗岩副矿物对比研究   总被引：1，自引：0，他引：1  

谢磊  王汝成  王德滋  邱检生 《高校地质学报》2005,11(3):390-403

浙江舟山群岛的桃花岛和普陀山分别出露有大片中国东部沿海典型的燕山期碱性和铝质A型花岗岩,二者的岩石化学和主要造岩矿物存在明显差别。利用电子探针进行的测试分析表明,它们在副矿物组合及副矿物特征方面的差异也很显著：桃花岛碱性A型花岗岩中副矿物组合为富钍锆石、褐帘石、硅钛铈矿、钛磁铁矿和富锰钛铁矿;普陀山铝质A型花岗岩中的副矿物组合为贫钍锆石、富钍独居石、磁铁矿、金红石和红钛锰矿。二者更可从单颗粒矿物（特别是锆石）的成份和内部结构上加以区分。这些副矿物上的差异暗示了两类A型花岗岩的源区成分、结晶环境和物理化学特征存在明显不同：（1）碱性A型花岗岩的源岩相对较多地包含了来自较深部的地幔组分岩浆;（2）碱性A型花岗岩形成的温度相对较高,而铝质A型花岗岩结晶阶段的氧逸度较高;（3）碱度和磷活度的差异也是导致一些副矿物种类结晶差异的关键因素。  相似文献   

Sediment dynamics in the Eurasian Arctic Ocean during the last deglaciation — The clay mineral group smectite perspective   总被引：1，自引：0，他引：1  

Christoph Vogt  Jochen Knies   《Marine Geology》2008,250(3-4):211-222

This study focuses on sedimentological investigations of sediment cores recovered during the international Arctic′91, expeditions with the German research ice breaker RV “Polarstern” to the European sector of the Arctic Ocean. Here, we deduce the last glacial/interglacial changes in transport mechanism and sedimentation from the clay mineral group smectite. We choose the smectites as an example of how sediment mineralogy can be linked with particular source regions (the Kara and Laptev seas), distinct transport mechanism (sea ice and surface currents) and sedimentation processes. Smectite contents in Arctic sediments discussed for two time slices, including the Last Glacial Maximum (LGM), and the last deglaciation (Termination I), reveal the highest variability subsequent to the retreat of the Eurasian ice sheets. Our results show that smectite anomalies in the Eurasian Basin are associated with distinct meltwater pulses and occurred around 13.5–13.0 ¹⁴C ka B.P. Compelling evidence is provided that these anomalies are deduced from sea-ice entrained sediments from the eastern Kara Sea that entered the Arctic Ocean after ice-sheet break-up and eventually flooding of the Kara Sea. We propose that smectite anomalies in sediments of the eastern Arctic Ocean can be utilized to identify deglacial events and to help decipher configurations of the Eurasian ice sheets. The identification of smectite maxima along the modern sea-ice edge in the Eurasian Basin further indicates biologically enhanced sedimentation from melting sea ice allowing the reconstruction of seasonally open water in the region. Hence, considering the poor preservation conditions of primary paleoceanographic proxies in the Arctic Ocean, the clay mineral contents, particularly the smectite group, may be one alternative tool for paleoclimatic reconstruction in the Eurasian Basin.  相似文献   

On the unusual holocene carbonate sediment in lake Nam Co, central Tibet     

Minghui Li  Shichang Kang  Liping Zhu  Feiyue Wang  Junbo Wang  Chaolu Yi  Xiaomin Fang  Manping Xie 《山地科学学报》2009,6(4):346-353

In lacustrine sediments, aragonite is a widespread mineral, whereas monohydrocalcite is a rare carbonate mineral. In the cold and high-attitude Xizang （Tibetan） Plateau, where aragonite has been commonly found in lacustrine sediments, there is no aragonite, but low-Mg calcite, monohydrocalcite and trace dolomite. The lake receives solutes primarily from surface runoffs and remains fairly constant water chemistry for a long time. The total CaCO3 percentage in sediments could be controlled by evaporation and inflow of detrital materials. The absence of aragonite is unusual when compared to other lacustrine sediments from the Tibetan Plateau. This could be due to low Ca/Mg ratio, low salinity, low Mg and Ca concentration. Monohydrocalcite might precipitate from the lake water mediated by biological activities. Low-Mg calcite originated from minor ostracoda shell and the precipitation of lake water with biological activities.  相似文献   

大连湾近海表层沉积物矿物组合分布特征及其物源环境     

李艳  李安春  万世明  徐方建  李传顺  池野 《海洋地质与第四纪地质》2009,(4)

对大连湾、大窑湾外近海表层沉积物进行了黏土矿物X射线衍射分析以及轻矿物的分离和鉴定,根据其组合分布特征,探讨了该区沉积物中黏土矿物和轻矿物的来源,并对沉积环境及其主控因素进行了初步分析。结果表明:研究区黏土矿物主要由伊利石(59%)、蒙皂石(20%)、绿泥石(16%)和高岭石(5%)组成,研究区西部伊利石较高,而东部绿泥石较高,蒙皂石有向湾内富集的趋势。轻矿物由斜长石(45%)、石英(34%)、钾长石(10%)、绿泥石(8%)、白云母(2%)和方解石(0.4%)组成,呈东西向条带状分布,与沉积物粒度分布特征较为一致。矿物分布受潮流、地形影响明显,研究区北部近岸水下岸坡区,水动力条件较强,沉积物粒度较粗,矿物组合以长石、石英富集为特征;向南水深增加,东部为一水下台地,矿物组合以白云母、绿泥石含量高为特征;研究区南部水深增加,又出现一水下岸坡,其下地形趋于平坦,因受出入渤海的潮流和进入渤海的黄海暖流的影响,水动力条件最强,沉积物粒度较粗,长石含量最高,轻矿物含量高。研究区潮流、地形对矿物组成、组合和含量具有控制作用。北部水下岸坡及以内近岸浅水区沉积物粒度较粗,轻矿物含量低,石英、长石含量高,物质主要来自沿岸侵蚀及...  相似文献