Zircon SHRIMP geochronology of the Xinkailing-Kele complex in the northwestern Lesser Xing＇an Range, and its geological implications

Located in the eastern portion of the Xing'an-Mongolian Orogenic Belt (XMOB), the Xinkailing-Kele complex has previously been considered to be Precambrian metamorphic rocks, mainly according to its relatively high metamorphic grade. Our filed observation, however, revealed that the complex is composed mainly of metamorphic rocks (Kele complex), tectono-schists ("Xinkailing Group"), and granitoids (Xinkailing granitic complex). Dating on these rocks using advanced SHRIMP zircon U-Pb technique indicates that: (1) Biotite-plagioclase gneiss from the Kele complex has a protolith age of 337±7 Ma (2σ) and a metamorphic age of 216±3 Ma (2σ); (2) the tectono-schist of the "Xinkailing Group" gave a magmatic age of 292±6 Ma (2σ), indicative of felsic volcanic protolith of the schist formed in late Paleozoic time; and (3) the Menluhedingzi and Lengchuan granites of the Xinkailing granitic complex were emplaced at 167±4 (2σ) and 164±4 Ma (2σ), respectively. These results suggest that the Xinkailing-Kele complex is not Precambrian metamorphic rocks and the so-called Precambrian "Nenji-ang Block" does essentially not exist. In combination with regional geological data, we propose that the Kele metamorphic complex is likely related to a collisional tectonism that took place in Triassic time, as indicted by its metamorphic age of 216±3 Ma. The Xinkailing granitic complex was em-placed along the collisional zone during Mid-Jurassic time, likely in a post-orogenic or anorogenic setting.     

SHRIMP U-Pb zircon age of the Jinchuan ultramafic intrusion and its geological significance

The Jinchuan ultramafic intrusion is located in the Longshoushan Uplift on the southwestern margin of the Alxa Block, to the north of the Northern Qilian Orogenic Belt (Fig.1). It is broadly dyke-like, and was intruded into a Paleoproterozoic sequence of migmatites, gneisses and marbles (Baijiazhuizi Formation). The intrusion is northwest-elongated, -6500 m long and 20-527 m wide, and     

铜尾矿资源化的现状和展望

文章阐述了铜尾矿造成的危害,对当前我国的铜尾矿利用情况进行了总结,提出了在目前条件下合理利用 铜尾矿的措施。     

用蛇纹石尾矿制备氧化镁和二氧化硅的工艺研究

对利用蛇纹石尾矿制取MgO和SiO2的工艺进行了探讨．实验证明，合适的工艺条件为：矿粒度小于80目，盐酸浓度为6mol／L，酸解温度为60℃左右，酸解时间约2～2．5h，产品MgO的收率为80％～85％，SiO2的收率为80％左右．     

凡口铅锌矿尾矿的综合利用

通过对凡口铅锌矿尾矿的综合利用现状调查与分析，结合我国当今尾矿回收利用的新技术，提出了一种适合凡口铅锌矿尾矿综合利用的新方法，通过对尾矿中有价金属的再选、对 0．019mm的尾矿进行采空区的充填、将-0.019mm的尾矿用于制地面砖和水泥熟料，最后采用堆土复垦方法处理，最终可达到无尾矿矿山的目标。     

马兰庄铁矿尾矿复垦实践

介绍了马兰庄铁矿尾矿复垦工艺，复垦土地、水质及土壤分析，土壤、农作物有害元素含量测定，农作物种植试验等。实践证明马兰庄铁矿尾矿复垦，技术上可行，社会效益显著。     

西藏南迦巴瓦峰地区发现高压麻粒岩

在西藏南迦巴瓦峰的西侧,沿雅鲁藏布江右岸,出露大片麻粒岩相片麻岩,其中含大量基性麻粒岩包体,特别是在直白东沟,我们发现了一些高压基性麻粒岩包体,与麻粒岩一起构成一个高压麻粒岩带,该带的西北紧邻雅鲁藏布江蛇绿岩带,向东南变为角闪岩相和绿片岩相岩石,构成了一个较完整的下地壳剖面.高压基性麻粒岩包体为透镜状,单个透镜体大小从几十厘米到几米不等,其长轴及内部面理与围岩片麻理一致.包体核心较新鲜,由近等量的粉红色石榴子石和绿色辉石组成,石榴子石和辉石有时呈条带状相间出     

铜尾矿对熟料烧成高温液相的影响

应用ＤＴＡ和收缩膨胀曲线测定，研究了铜尾矿对水泥熟料烧成中高温液相出现温度的影响，结果表明：铜尾矿作为矿化剂的一种，能降低液相出现温度，并当与氟、硫复合作用时，效果更加显著，能有效地促进水泥熟料的烧成。     

Multi-stage evolution of gneiss from North Dabie： evidence from zircon U-Pb chronology

TTG gneiss is a common rock to outcrop in the northern part of the Dabie orogen, a few of which are closely associated with eclogites that experienced the Triassic ultrahigh pressure metamorphism. Although they were thermally metamorphosed by a large-scale magma activity in this region at the Early Cretaceous, it is unclear whether or not they are also affected by the Triassic metamorphism during continental subduction and exhumation. In order to resolve this issue, SHRIMP zircon U-Pb dating was carried out for the host gneiss of eclogites in North Dabie. The results show that cores from the gneiss have an age of 746~.31 Ma, consistent with the protolith ages of granitic gneisses in the Dabie orogen. Zircon overgrowing with different U and Th concentrations give concordant ages of 212~21 and 120~11 Ma, respectively. Th/U ratios of overgrown zircons are both lower than 0.1, suggesting a metamorphic genesis. The present resuits suggest that the gneiss in North Dabie has the similar protolith ages of Neoproterozoic to those granitic gneisses elsewhere in the Dabie orogen, and experienced not only the Triassic metamorphism but also the thermal metamorphism due to the Early Cretaceous magmatism. This provides an important insight into the geodynamic evolution of gneissic rocks in the Dabie orogen.     

铝土矿浮选尾矿的FeCl3改性及对铬(VI)吸附的机理研究

铝土矿浮选尾矿经FeCl3改性后,对铬酸根离子的吸附能力大大提高.随着改性尾矿用量和吸附时间的增加,以及溶液pH值的降低,改性尾矿对铬酸根的吸附能力提高,铬酸根的去除率最大可达95.22%.铝土矿浮选尾矿经铁盐改性后,Fe(OH)2 和Fe(OH)2 在矿物表面产生了吸附,使得改性后尾矿的比表面积和等电点增大,铁含量增加,并在红外光谱图中1 432 cm-1处出现新的羟基峰.改性尾矿吸附铬酸根离子后,其比表面积和零电点降低,X衍射图中铁矿物峰值强度降低,红外光谱图中铁的羟基峰消失,证明对铬酸根离子的吸附主要是通过改性尾矿表面吸附的羟基铁离子与铬酸根离子产生反应的结果.图6,表3,参9.