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1.
在黑龙江东部鸡西盆地下白垩统穆棱组鸡D7井679.19 m井段,首次发现了一含金古砂矿层,其中所含重砂矿物有:自然金、自生独居石、碎屑独居石、磷钇矿、锆石、方铅矿、闪锌矿、金红石、钛铁矿、磷灰石、黑云母、绿泥石、黄铁矿、黄铜矿、白钛石、榍石、褐铁矿、赤铁矿、磁铁矿、铁锰矿、勃姆石、氧化铀矿、自然铜和自然铜-锌金属等.矿层厚度约为4.14 m,在砂岩薄片中目估重砂体积分数为10%～24%.含金古砂矿层的发现为金的来源提供了新线索.该古砂矿层疑似海岸带沉积环境中形成,如能证实则该矿床远景可观,笔者提出用磁化率测井的方法圈定隐伏古砂矿的建议.此外,由于发现莓状黄铁矿、自然铜-锌金属和自生独居石等,认为古砂矿是在有利于生物成矿作用的沉积环境中形成. 相似文献
2.
对含有稀有元素的矿床进行调查研究的最终目的,是要作出该矿床的远景评价或工业评价。根据稀有元素在自然界的赋存情况,一般将稀有元素划分成下面两大类: 1.能够形成独立矿床的稀有元素,如Be,Li,Nb,Ta,Zr,TR,U,Th……等,其矿床如花岗伟晶岩型的铍矿床、钽矿床、砂矿型的锆英石(Zr)砂矿及独居石砂矿(TR Th)。 相似文献
3.
通过对津巴布韦奇拉色卡矿区金刚石古砂矿的地质特征、矿层特征、赋矿规律等的研究,建立了该区矿床勘查模型。研究表明,该区构造上处于太古宙津巴布韦克拉通东部边缘,西部紧邻林波波造山带、莫桑比克造山带,而林波波带为重要的金刚石产地,该区处于金刚石古砂矿成矿的有利位置;矿层赋存于中元古代乌肯多群砂砾岩组沉积岩中。该区金刚石古砂矿为沉积型金刚石古砂矿类型,属滨海环境沉积建造。在中元古代,原生矿中的金刚石被风化剥蚀出来,经流水的搬运,在滨海地区沉积,固结形成金刚石古砂矿床。津巴布韦奇拉色卡矿区金刚石古砂矿的发现及研究对指导中国境内寻找金刚石古砂矿具有重要的意义。 相似文献
4.
广东(大陆部分)滨海砂矿成矿地质条件及分布规律 总被引：1，自引：0，他引：1
广东大陆海岸线漫长,滨海砂矿资源丰富,大、小矿床(点)90处.本省滨海砂矿独居石、磷钇矿、锆英石、钛铁矿和金红石的储量,在全国同类型矿床中名列首位,是我国上述矿产的重要产区.六十年代以来,前人曾对本区滨海砂矿的地质特征、分布规律和找矿方法进行过总结.我队从 相似文献
5.
摘要: 通过研究江苏邳州花山子古锆砂矿的成矿地质背景、矿区地质特征、矿石类型、矿物组成、化学成分和放射性异常特征,借鉴现代锆砂矿成矿机制,进一步探讨花山子古锆砂矿的地质特征及找矿方向。花山子古锆砂矿是沉积砂矿床类型,赋存于中寒武世徐庄组中上部粉砂岩中,放射性元素钍含量高于一般粉砂岩钍含量,是古锆砂矿重要的找矿标志。徐庄组主要分布在徐州北部地区,汴塘耿庄、大泉焦庄和台儿庄高山等地区具有较好的找矿前景。 相似文献
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南海及邻域具有多样的地形地貌和丰富的物源,为海洋固体矿产资源的形成和分布提供了物质来源和堆积环境。为系统查明南海及邻域砂矿资源分布情况,本文通过对南海及邻域2606个站位表层沉积物样品进行粒度测试、碎屑矿物鉴定,以及重矿物的品位计算,分析了南海及邻域有用矿物砂矿资源以及建筑用砂资源分布特征并预测了远景区,总结了砂矿成矿模式。结果表明,南海及邻域具有远景的矿种主要有锆石、钛铁矿、金红石、锐钛矿、独居石和石榴子石等;重矿物高品位矿点主要集中在南海东北陆架、菲律宾海盆、南部陆架,重矿物异常区主要位于周缘陆架浅水区以及越东外陆架浅水海域、菲律宾海盆。锆石品位异常区的范围最大,达到工业品位的面积也最大;其次是磁铁矿、钛铁矿、独居石的异常区;锐钛矿、金红石异常区的面积相当;石榴子石品位异常范围最小。根据砂矿的分布规律、大地构造背景、成矿条件以及成矿元素特征,圈定了24个有用重矿物砂矿成矿远景区和6个成矿带。沉积物中砂（0. 063~2 mm）含量大于50%的建筑用砂的远景区9个,主要分布于海南岛西南面到台湾海峡南部一线以北海域,其次为南海南部礼乐滩、万安滩、曾母暗沙附近海域,其余海域极为罕见。基于南海砂矿资源分布特征,初步建立了近岸型、潮流砂脊型、古河道埋藏型、峡口型、陆架坡折带型等五种砂矿成矿模式,为海砂资源进一步勘查提供方向和建议。 相似文献
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目前稀有元素对发展我国尖端工业起着重要作用。其中的钛主要用于冶金工业,而锆英石、独居石的用途更为广泛,可用于制造各种高溫合金、特殊光学仪器、耐高溫和高压的絕緣材料以及防止原子射綫等。在锆砂矿中除锆外,还可能富集钛铁矿、钶铁矿、独居石、磷钇矿、金紅石等稀有元素。因此应該 相似文献
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福建近海砂矿资源极为丰富，目前已发现各类近海砂矿10余种，初步探明具有工业价值的有回填用砂（建筑用砂）、石英砂（型砂、玻璃砂、标准砂等）和稀有、稀土砂（锆石、钛铁矿、金红石、独居石和磷钇等）9个矿种，各类矿床（点）42个，成因类型有海积、风积、冲洪积和洪积等。近海砂矿主要分布在闽江口及其以南近海地区，是福建极为重要的矿产资源。 相似文献
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沉积物中重矿物分布受物源区、构造抬升与剥蚀作用、古地貌以及沉积古气候、古环境等多种因素影响,因此沉积重砂矿物的研究可应用于物源区、沉积环境的分析,阐明构造旋回与沉积作用的响应关系。本文通过对塔中地区中1井等6口探井上泥盆统东河砂岩和志留系柯坪塔格组砂岩中重砂矿物分析,提出了塔中东河砂岩重砂矿物主要来自稳定的基底再沉积及花岗岩来源,但受近源的基性火山岩及岩浆期后热液作用影响较大;志留系下砂岩重砂矿物主要来自下覆碳酸盐岩、花岗岩和搬运再沉积物,总体形成于稳定的、多物源的构造-沉积环境,物源方向可能是东南至西北方向。 相似文献
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围绕堆石料单粒强度尺寸效应的颗粒流模拟方法展开研究。首先,基于FISH二次开发建立了堆石料的随机不规则单粒模型,充分考虑堆石料的形状特征和破碎现象;然后,建立了堆石料单粒强度尺寸效应的等效模拟方法,以单粒强度随其粒径的变化规律为基础,推导了堆石料模型中细观黏结强度与堆石料等效粒径的负指数经验公式;其次,基于建立的数值模型对堆石料的室内单粒压缩试验进行仿真模拟,验证数值模型的正确性和合理性,并对较大粒径堆石料的单粒强度进行模拟预测,突出数值试验的优势;最后,基于建立的数值模型对相同粒径不同形状特征堆石料的单粒强度分布特征进行模拟研究。研究结果表明：（1）堆石料内部缺陷含量和尺寸随粒径增加对其单粒强度所产生的尺寸效应,可通过堆石料模型中细观强度参数随粒径折减进行等效模拟;（2）形状特征对堆石料的破裂机制具有重要影响,方形颗粒为压剪破裂,单粒强度较高,而随机不规则颗粒和圆形颗粒为拉剪或劈裂,单粒强度相对较低;（3）拉剪或劈裂条件下,堆石料形状越不规则,其单粒强度的离散程度越高,反之则离散程度越低。相关研究成果可为进一步研究荷载作用下堆石体内各粒径段堆石料的破碎量奠定基础,从而更加真实地反映堆石体的级配演化规律。 相似文献
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Observations of collisions of saltating grains with a granular bed from high-speed cine-film 总被引：6，自引：0，他引：6
High-speed photography was used to record saltating sand grains colliding with a horizontal, noncohesive bed of similarly sized grains. Impacting grain/bed interaction is discussed in general. The process, as observed from the films, is then described in terms of the apparent bed contact length (ABCL) and various parameters of the impacting grains and any ejected grains. Examples are given of typical behaviour of bed grains in response to impacting grains of different sizes. Saltating grains that are large in comparison to the bed grains they encounter at collision can churn up the surface layers of soils and sediments, so that previously buried grains become available for entrainment. This process is discussed in relation to the potential release of dust particles into the airflow. 相似文献
13.
为了区分农作物与野生草类的淀粉粒形态,对现代粟（Setariaitalica）、黍（Panicummiliaceum）和狗尾草（Setariaviridis）的淀粉粒形态进行了比较。观察结果表明,粟的淀粉粒以圆球形单粒为主,脐点位于中央,大部分由脐点向外有1～3条放射线,表面光滑,淀粉粒平均长度约19m。黍的淀粉粒以多角形单粒为主,脐点位于中央,但很多淀粉粒的脐点不是很明显。在一些脐点形成1～3条射线,表面光滑,淀粉粒平均长度约为19m。狗尾草淀粉粒以卵形为主,脐点位于中央,表面可见层纹,边缘凹凸不平且常有裂隙形成,淀粉粒平均长度约为18m。研究证明,利用粟、黍和狗尾草的淀粉粒形态特征,可以有效地对考古遗存中的这几种禾本科植物遗迹进行区分。 相似文献
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Micron-sized soil grains from the Luna 20 mission are the most lightly irradiated we have examined, in contrast to micron-sized grains from the Luna 16 soil, which are the most heavily irradiated. Radiation damage in micron-sized grains is inversely correlated with albedo of the soil. The absence of angular, amorphous grains in Luna 20 supports our previous contention that such grains in Luna 16 were produced by intense radiation damage. 相似文献
15.
近年,考古学家发现坚果类植物在农业起源中曾占有很重要的地位。为了对考古器物上附着的淀粉粒进行鉴定,我们对中国北方现代主要坚果类栗属（Castanea）中的板栗（C.mollisima）、栎属（Quercus）中的槲树（Q.dentata）、槲栎（Q.aliena）、麻栎（Q.acutissima）、栓皮栎（Q.viriabilis）、蒙古栎（Q.mongolicus）和胡桃属（Juglans）中的胡桃楸（J.mandshurica）共7个样品进行了淀粉粒形态对比分析,以求为建立北方坚果类淀粉粒的鉴定标准积累资料。实验结果发现,除胡桃楸未发现淀粉物质以外,其他6个样品的淀粉粒不仅可以与其他科、属进行区分,甚至在一定程度上还可以进行种间的区分。板栗的脐点是闭合的,有层纹,无裂隙; 麻栎脐点是偏心的; 槲树栓皮栎的淀粉粒近乎80％都具有裂隙特征,但栓皮栎的淀粉粒中会出现横裂隙和相当数量的星形裂隙而只有槲树的淀粉粒才具有相当数量的纵向裂隙; 蒙古栎的淀粉也大多具有裂隙（70％）而且纵向型裂隙占主要地位,但是蒙古栎淀粉粒表面有细密的放射线; 60％的槲栎淀粉粒不具有裂隙特征。所有样品的淀粉粒均由大小不一的各种卵圆形组成,而且6个样品的长轴最大值（约20μm）和6个样品的平均值（约10μm）都非常接近。 相似文献
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对来自中国北方不同区域的9个粟（Setaria italica）样品及其野生祖本青狗尾草（Setaria viridis）的7个样品,9个黍（Panicum miliaceum）样品及其近缘野生种糠稷（Panicum bisulcatum）和野黍（Eriochloa villosa）样本各 1个,共27个样品进行了淀粉粒分析。针对每个样品,统计100～200颗淀粉粒粒径数据,100颗形态特征数据,在此基础上初步明确了5种植物淀粉粒如下判别特征: 1）5种淀粉粒中,除野黍淀粉粒为小粒径（X=4.8±0.8μm）的椭球形和球形外,其余4种淀粉粒都以多面体为主,球形或近球形为辅,脐点居中开放,黍、粟、青狗尾草和糠稷淀粉的平均粒径分别为X=7.3±1.4μm,X=9.9±2.3μm,X=7.7±1.4μm和X=6.9±1.2μm。2）粒径大于12μm的淀粉粒一般不是黍的淀粉粒。3）粒径大于14μm的淀粉粒99.9％来自粟。3）粒径小于11μm的淀粉粒,如果超过40％的淀粉粒表面无裂隙,极有可能为黍属的淀粉粒; 如果有超过30％的淀粉粒表面具有裂隙,则非常有可能来自狗尾草属。4）近乎45％的粟淀粉粒粒径处于11～14μm,而只有约4％的青狗尾草淀粉粒粒径位于这一区间。如果粒径在11～14μm的淀粉粒含量超过获得淀粉粒总量的4％,则其中很可能包含有粟的淀粉粒。以上标准在鉴定时还需要综合考虑。高粱（Sorghum bicolor）与薏米（Coix chinensis）在粒径和形态上与狗尾草属和黍属有部分重合,但大部分高粱的淀粉粒具有层纹,薏米则有30％的粒径大于14μm,与粟只有5％的淀粉粒位于这一粒径范围有很大的区别。通过研究发现,在现阶段,典型黍亚科（Panicoideae）种类淀粉形态在统计上的区别是明显的,但仅依靠少量颗粒特征进行区分是困难的,如何把现代淀粉特征准确应用到考古样品的鉴定中,还有待更多的淀粉埋藏学研究。目前,针对粟、黍及其野生近缘种的鉴别,植硅体分析的效果明显好于淀粉粒分析。 相似文献
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From their birth as condensates in the outflows of oxygen-rich evolved stars, processing in interstellar space, and incorporation into disks around new stars, amorphous silicates predominate in most astrophysical environments. Amorphous silicates were a major building block of our Solar System and are prominent in infrared spectra of comets. Anhydrous interplanetary dust particles (IDPs) thought to derive from comets contain abundant amorphous silicates known as GEMS (glass with embedded metal and sulfides) grains. GEMS grains have been proposed to be isotopically and chemically homogenized interstellar amorphous silicate dust. We evaluated this hypothesis through coordinated chemical and isotopic analyses of GEMS grains in a suite of IDPs to constrain their origins. GEMS grains show order of magnitude variations in Mg, Fe, Ca, and S abundances. GEMS grains do not match the average element abundances inferred for ISM dust containing on average, too little Mg, Fe, and Ca, and too much S. GEMS grains have complementary compositions to the crystalline components in IDPs suggesting that they formed from the same reservoir. We did not observe any unequivocal microstructural or chemical evidence that GEMS grains experienced prolonged exposure to radiation.We identified four GEMS grains having O isotopic compositions that point to origins in red giant branch or asymptotic giant branch stars and supernovae. Based on their O isotopic compositions, we estimate that 1-6% of GEMS grains are surviving circumstellar grains. The remaining 94-99% of GEMS grains have O isotopic compositions that are indistinguishable from terrestrial materials and carbonaceous chondrites. These isotopically solar GEMS grains either formed in the Solar System or were completely homogenized in the interstellar medium (ISM). However, the chemical compositions of GEMS grains are extremely heterogeneous and seem to rule out this possibility. Based on their solar isotopic compositions and their non-solar elemental compositions we propose that most GEMS grains formed in the nebula as late-stage non-equilibrium condensates. 相似文献
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Mohamed F. Raslan 《Resource Geology》2009,59(1):99-105
Uraniferous iron grains occur in some radioactive granite plutons in the Eastern Desert of Egypt. Modal analysis of these grains indicates that weight abundance of uraniferous grains amounts to 17.50%, 18.00% and 26.00% of the total accessory heavy minerals of the uranium-mineralized samples of Gabal Gattar, El Missikat and El Erediya, respectively. These grains are mainly restricted to shear zones associated with strong hematitization, and occur either as fracture fillings or as interstitial grains among the main rock-forming minerals. Uraniferous iron grains are mainly composed of uranophane and β-uranophane coated and stained with limonite. These grains represent the main radioactive minerals in addition to the bright canary yellow to yellow uranophane and β-uranophane mineral grains. The data obtained on scanning electron microscopy and electron microprobe analysis confirm the abundance of iron in the darker colored varieties with respect to the light colored varieties. This mode of occurrence of the uranium minerals requires special consideration during mineral processing by physical means. 相似文献
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Two types of garnet porphyroblast occur in the Schneeberg Complex of the Italian Alps. Type 1 porphyroblasts form ellipsoidal pods with a centre consisting of unstrained quartz, decussate mica and small garnet grains, and a margin containing large garnet grains. Orientation contrast imaging using the scanning electron microscope shows that the larger marginal garnet grains comprise a number of orientation subdomains. Individual garnet grains without subdomains are small (< 50 µm), faceted and idioblastic, and have simple zoning profiles with Ca‐rich cores and Ca‐poor rims. Subdomains of larger garnet grains are similar in size to the individual, small garnet grains. Type 2 porphyroblasts comprise only ellipsoidal garnet, with small subdomains in the centre and larger subdomains at the margin. Each subdomain has its own Ca high, Ca dropping towards subdomain boundaries. Garnet grains, with or without subdomains, all have the same Ca‐poor composition at rims in contact with other minerals. The compositional zonation patterns are best explained by simultaneous, multiple nucleation, followed by growth and amalgamation of individual garnet grains. The range of individual garnet and garnet subdomain sizes can be explained by a faster growth rate at the porphyroblast margin than in the centre. The difference between Type 1 and Type 2 porphyroblasts is probably related to the growth rate differential across the porphyroblast. Electron backscatter diffraction shows that small, individual garnet grains are randomly oriented. Large marginal garnet grains and subdomain‐bearing garnet grains have a strong preferred orientation, clustering around a single garnet orientation. Misorientations across subdomain boundaries are small and misorientation axes are randomly oriented with respect to crystallographic orientations. The only explanation that fits the observational data is that individual garnet grains rotated towards coincident orientations once they came into contact with each other. This process was driven by the reduction of subdomain boundary energy associated with misorientation loss. Rotation of garnet grains was accommodated by diffusion in the subdomain boundary and diffusional creep and rigid body rotation of other minerals (quartz and mica) around the garnet. An analytical model, in which the kinetics of garnet rotation are controlled by the rheology of surrounding quartz, suggests that, at the conditions of metamorphism, the rotation required to give a strong preferred orientation can occur on a similar time‐scale to that of porphyroblast growth. 相似文献