新疆乌恰萨热克铜矿北矿带库孜贡苏组沉积相、古流向、物源区及其找矿意义——来自砾石统计分析的证据   总被引：1，自引：1，他引：0  

陆俊吉  胡煜昭  江小均  乔欣 《地质通报》2016,35(6):963-970

萨热克盆地库孜贡苏组是萨热克铜矿的赋矿层位,开展沉积相、物源区及古流向研究对隐伏铜矿的勘探具有重要意义。选取萨热克铜矿北矿带库孜贡苏组地表矿化最好的砾岩展开砾石统计分析,结果表明,偏斜度显示砾岩为冲积扇相沉积,砾石叠瓦状和砂岩斜层理产状统计显示古流向为北北东向;砾石成分主要为石英、石英砂岩、砂岩,石英岩等;粒度分布呈宽峰态或尖峰态;物源区为元古宇长城系阿克苏群变质岩剥蚀区;物源补给分为主河流补给和支河流补给2种方式。冲积扇相、古流向、物源区分析确定了矿体的范围、最优的勘探线布置方位和潜在的找矿靶区,具有很好的勘探意义。  相似文献   

Analysis of phenotypic and genetic parameters for growthrelated traits in the half smooth tongue sole, <Emphasis Type="Italic">Cynoglossus semilaevis</Emphasis>     

刘峰  李仰真  杜民  邵长伟  陈松林 《中国海洋湖沼学报》2016,34(1):163-169

Phenotypic and genetic parameters for growth-related traits in the half-smooth tongue sole, Cynoglossus semilaevis, were estimated in 22 full-sib families produced by normal and neo-male breeding stocks. As phenotypic males with female genotypes, neo-males are harmful in C. semilaevis aquaculture because they reduce overall production. The present study evaluated the difference in the growth-related traits: total length (TL), body weight (BW) and square root of body weight (SQ_BW) at the age of 570 days between normal and neo-male offspring (neo-males used as male parents). The difference in the proportion of females between normal and neo-male offspring was also assessed. Based on the linear mixed model, restricted maximum likelihood (REML) and best linear unbiased prediction (BLUP) were used to estimate various (co)variance components and estimated breeding values (EBVs) of growth-related traits. As a result, all the mean values of the three studied traits were significantly larger in normal offspring than in neo-male offspring. Additionally, the female proportion was significantly larger in normal offspring than in neo-male offspring. Heritability was 0.128±0.066 2 for TL, 0.128±0.065 5 for BW and 0.132±0.062 9 for SQ_BW, all of which were low level heritabilities. The correlation coefficients of EBVs and phenotypic values of the target traits were 0.516 for TL, 0.524 for BW and 0.506 for SQ_BW, all of which were highly significant (P <0.01). Genetic correlations among TL, BW and SQ_BW were positive high (0.921–0.969) and higher than those of phenotype (0.711–0.748), both of which had low standard errors (0.063–0.123 for genotype, and 0.010–0.018 for phenotype). Compared with normal offspring, neo-male offspring have lower breeding values for each studied trait through EBVs comparison. Therefore, neo-male offspring should not be used as broodstock in a C. semilaevis breeding programs.  相似文献   

The morphological characteristics of gully systems and watersheds in Dry-Hot Valley,SW China     

Zhen Xu  Fachao Qin  Bin Zhang  Qingchun Deng  Hui Liu  Jie Jin  Liangtao Shi 《中国地球化学学报》2018,37(6):854-866

Gully systems and watersheds are geomorphic units with clear boundaries that are relatively independent of basin landscapes and play an important role in natural geography. In order to explore the morphological characteristics of gully systems and watersheds in the Dry-Hot Valley [South West (SW) China], gullies are interpreted from online Google images with high resolution and watersheds are extracted from digital elevation model at a scale of 1:50,000. The results show that: (1) There are 17,382 gullies (with a total area of 1141.66 km²) and 42 watersheds in the study area. (2) The average gully density of the study area (D) is 4.29 km/km², gully frequency (F) is 14.39 gullies/km², the branching ratio (B) is 5.13, the length ratio (L) is 3.12, and the coefficient of the main and tributary gullies (M) is 0.06. The degree of gully erosion is strong to extremely strong, the main development intensity of gully erosion ranges from intense to moderate, and the type of gully system is tributary. (3) The watershed areas (A) are between 0.39 and 96.43 km², the relief ratio (R) is from 0.10 to 0.19, the circularity ratio (C) is from 0.30 to 0.83, the texture ratio (T) is from 0.82 to 39.35, and the dominant geomorphological texture type is fine. (4) There is a quantitative relationship between F and D:F?=?0.624D² (R?=0.84) and T is closely related to D, F, M (R²?>?0.7). A, R and C are related to M (R²?>?0.5). The development of gully systems is the result of coupling effects between multiple factors. In this area, the degree of erosion and the condition of the main and tributary gullies can be controlled by the degree of topographic breakage in the watershed, which provides some theoretical basis for the evaluation of gully erosion by the latter. In addition, the scale, relief, and shape have a significant impact on the locations of the main and tributary gullies. For tributary gullies, attention should be paid to the interception and control of runoff and sediment in the small confluence branches in order to prevent gully expansion and head advance. These features can inform the development of targeted measures for the control of soil erosion.  相似文献   

Geochemical and Petrological Studies on the Early Carboniferous Sidingheishan Mafic–Ultramafic Iintrusion in the Southern Margin of the Central Asian Orogenic Belt, NW China     

SUN Tao  QIAN Zhuangzhi  THAKURTA Joyashish  YANG Shenghong  XU Gang  DUAN Jun  GAO Bo  WANG Jing 《《地质学报》英文版》2018,92(3):952-971

The Sidingheishan mafic-ultramafic intrusion is located in the eastern part of the Northern Tianshan Mountain, along the southern margin of the Central Asian Orogenic Belt in northern Xinjiang autonomous region of China. The Sidingheishan intrusion is mainly composed of wehrlite, olivine websterite, olivine gabbro, gabbro and hornblende gabbro. At least two pulses of magma were involved in the formation of the intrusion. The first pulse of magma produced an olivine-free unit and the second pulse produced an olivine-bearing unit. The magmas intruded the Devonian granites and granodiorites.An age of 351.4±5.8 Ma(Early Carboniferous) for the Sidingheishan intrusion has been determined by U-Pb SHRIMP analysis of zircon grains separated from the olivine gabbro unit. A U-Pb age of 359.2±6.4 Ma from the gabbro unit has been obtained by LA-ICP-MS. Olivine of the Sidingheishan intrusion reaches 82.52 mole% Fo and 1414 ppm Ni. On the basis of olivine-liquid equilibria, it has been calculated that the MgO and FeO included in the parental magma of a wehrlite sample were approximately10.43 wt% and 13.14 wt%, respectively. The Sidingheishan intrusive rocks are characterized by moderate enrichments in Th and Sm, slight enrichments in light REE, and depletions in Nb, Ta, Zr and Hf. The ε_(Nd)(t) values in the rock units vary from +6.70 to +9.64, and initial ~(87)Sr/~(86)Sr ratios range between 0.7035 and0.7042. Initial ~(206)Pb/~(204)Pb, ~(207)Pb/~(204)Pb and ~(208)Pb/~(204)Pb values fall in the ranges of 17.23-17.91,15.45-15.54 and 37.54-38.09 respectively. These characteristics are collectively similar to the Heishan intrusion and the Early Carboniferous subduction related volcanic rocks in the Santanghu Basin, North Tianshan and Beishan area. The low(La/Gd)_(PM) values between 0.26 and 1.77 indicate that the magma of the Sidingheishan intrusion was most likely derived from a depleted spinel-peridotite mantle.(Th/Nb)_(PM)ratios from 0.59 to 20.25 indicate contamination of the parental magma in the upper crust.Crystallization modeling methods suggest that the parental magma of the Sidingheishan intrusion was generated by flush melting of the asthenosphere and subsequently there was about 10 vol%contamination from a granitic melt. This was followed by about 5 vol% assimilation of upper crustal rocks. Thus, the high-Mg basaltic parental magma of Sidingheishan intrusion is interpreted to have formed from partial melting of the asthenosphere during the break-off of a subducted slab.  相似文献   

40Ar‐39Ar Dating of the Mahuaping W‐Be deposit,Northwestern Yunnnan Province,China, and its Geological Significance     

JIA Fudong  ZHANG Changqing  LIU Huan  HUA Zhixin  KONG Zhigang  MENG Xuyang 《《地质学报》英文版》2018,92(2):864-865

正Objective Located near the intersection of Yangtze craton,TibetSanjiang orogen and Songpan-Ganzi orogen of Northwest Yunnan Province,the Mahuaping deposit is a unique large-scale tungsten-beryllium-fluorite ore deposit ever discovered in this area.In recent years,many studies have been carried out in Sanjiang Tethyan metallogenic belt and  相似文献   

干湿循环作用下红土抗剪强度与微结构关系研究          下载免费PDF全文

张祖莲  梁谏杰  黄英  邱观贵  袁强 《水文地质工程地质》2018,(3):78-85

针对云南红土型水库因水位升降引起库岸土体干湿循环的客观实际,研究干湿循环作用下库岸红土抗剪强度与其微结构的变化规律,揭示二者之间的内在联系,为研究红土型库岸失稳提供依据。通过红土试样的干湿循环试验,模拟水库蓄水和库水位反复升降引起的库岸红土干湿循环作用。结果表明:（1）在一定初始干密度条件下,红土的黏聚力、内摩擦角和抗剪强度均随干湿循环次数的增加而非线性减小,但在干湿循环次数约10次时趋于稳定。（2）干湿循环作用导致红土微结构发生变化。当初始干密度分别为1.2,1.3,1.4 g/cm3、干湿循环次数达10次时,试样红土颗粒数量降幅依次为45.4%,38.2%,35.7%;孔隙率增幅依次为52.6%,45.9%,40.4%;孔隙面积增幅依次为64.4%,58.2%,50.8%。（3）在干湿循环作用下,红土黏聚力与红土颗粒的定向度和平均圆形度呈正相关关系,相关系数R分别为0.985和0.923。内摩擦角与孔隙率和孔隙面积呈反相关关系,相关系数R分别为-0.936和-0.912。干湿循环作用导致红土微结构的改变,从而引起红土宏观力学性质的变化。  相似文献   

滇西芦子园远程矽卡岩Pb-Zn-Fe(Cu)多金属矿床流体包裹体初探及矿床成因探讨   总被引：4，自引：4，他引：0  

邓明国  陈伟  王学武  刘凤祥  管申进  卢映祥  余海军  赵发 《岩石学报》2018,34(5):1239-1257

滇西镇康芦子园是"三江"成矿带保山地块内迄今发现的唯一超大型Pb-Zn-Fe(Cu)多金属矿床,是区内系列同类层控热液铅锌矿床的典型代表。矿体呈似层状、脉状及透镜状产于寒武系碳酸盐岩建造的矽卡岩和大理岩层间破碎带,矿石构造以条带状、浸染状和脉状-网脉状为主要特征;围岩蚀变复杂、分带明显,由下至上依次为石榴子石-透辉石-透闪石-阳起石化带→绿泥石-绿帘石-阳起石-蔷薇辉石化带→碳酸盐-大理岩化带。矿床成矿流体从早期到晚期经历了多个矿化阶段。本文选取了该矿床早矽卡岩阶段、晚矽卡岩阶段、石英硫化物阶段和石英碳酸盐阶段的多种脉石矿物及闪锌矿进行了系统的流体包裹体研究。结果显示,早矽卡岩阶段发育微溶CO_2富液相和纯液相水溶液包裹体,并含大量K~+、Na~+、Ca~(2+)、F~-和Cl~-和少量SO_4~(2-),气相成分主要为H_2O、CO_2及少量CH_4和N_2,包裹体均一温度为233.6~315.6℃,盐度为10.6%~17.6%NaCleqv;晚矽卡岩阶段发育含CO_2和子矿物三相包裹体,均一温度214.9~388.0℃,盐度5.9%~16.4%NaCleqv;石英硫化物阶段发育含CO_2的水溶液包裹体,气相成分为CH_4、H_2O和少量CO_2,均一温度150.0~285.0℃,盐度为2.5%~13.8%NaCleqv;石英碳酸盐阶段为单一成分的水溶液包裹体,均一温度为105.0~187.5℃,盐度为0.5%~12.3%NaCleqv。结合H-O同位素研究表明,成矿流体最初来源于具中高温、中高盐度、高K、Na,富CO_2、Cl、F等特征的深部岩浆热液,在石英硫化物阶段开始有大气降水混入,演化为中阶段中低温、低盐度、贫CO_2的热液流体,至成矿晚阶段转化为以大气降水占主导。该矿床成矿环境的改变、流体混合以及流体的沸腾作用可能是导致成矿物质富集沉淀的重要机制。综合矿床地质特征、成矿流体包裹体和HO同位素研究认为,该矿床为与陆陆碰撞造山和深部隐伏岩体有关的远程矽卡岩成矿系统。  相似文献   

新疆四顶黑山花岗岩体锆石LA-ICP-MS U-Pb年龄及地质意义          下载免费PDF全文

王静  王学武  邓明国  孙涛 《地质找矿论丛》2018,33(3):365-374

新疆东天山位于中亚造山带南缘,天山—兴安造山系北天山造山带东段,发育大量泥盆纪—石炭纪花岗岩,其形成过程多与觉罗塔格洋的俯冲作用有关。四顶黑山花岗岩体位于东天山觉罗塔格构造岩浆带的东端,岩体在地表呈不规则状产出,侵位于元古界片岩-变火山岩、奥陶系变玄武岩和泥盆系雀儿山群火山岩;主要岩石类型为花岗岩和花岗闪长岩。花岗岩的LA-ICP-MS锆石U-Pb年龄为380.4 Ma±3.7 Ma,表明岩体形成于晚泥盆世。岩石表现出高硅(w(SiO_2)=64.87%~74.71%)、高碱(w(K_2O)=3.35%~4.68%,w(Na_2O)=2.26%~3.85%)、富铝(w(Al_2O_3)=11.82%~14.13%)和低MgO(w(MgO)=0.56%~2.12%)、CaO(w(CaO)=1.68%~3.74%)、TiO_2(w(TiO_2)=0.26%~0.57%)、P_2O_5(w(P_2O5)=0.01%~0.19%)特征,A/CNK=0.83~1.00;富集Ba、K、La、Ce、Nd,亏损Th、Nb、Ta、Sr、Ti,铕负异常较明显(δEu=0.70~0.73);具有岛弧型花岗岩特征。四顶黑山花岗岩体形成于岛弧环境,属于觉罗塔格洋向南俯冲过程中的产物。四顶黑山花岗岩体两侧的镁铁-超镁铁质岩体的形成时代应晚于晚泥盆世。  相似文献   

滇西澜沧岩群碎屑锆石U-Pb定年及其地质意义   总被引：1，自引：0，他引：1       下载免费PDF全文

徐云飞  丛峰  刘军平  孙柏东  黄晓明 《沉积与特提斯地质》2018,38(2):103-112

虽然前人对澜沧岩群做了大量的研究,但缺乏同位素年代学方面的研究。此次研究针对澜沧江南段菖蒲塘-大田山地区澜沧岩群绢白云母石英片岩进行碎屑锆石U-Pb定年,为澜沧岩群的形成时代增添年代学证据。极大多数(129粒)锆石阴极发光(CL)图像显示其有明显的结晶振荡环带,指示其为岩浆成因的碎屑锆石,129粒碎屑锆石具有多组峰值年龄,最年轻一组年龄加权平均值为452±26Ma,表明澜沧岩群最早沉积时限不早于452±26Ma;极少数(1粒)锆石具弱阴极发光,缺乏内部结构特点,认为其为变质重结晶锆石,变质结晶锆石U-Pb年龄为255±3Ma,与前人研究所得澜沧岩群变质时代基本吻合。综合分析,澜沧岩群的沉积时限不早于452±26Ma,在二叠纪末期可能发生变质作用。  相似文献   

小冰期时中国南方地区降水模式的差异研究   总被引：1，自引：0，他引：1  

肖思雅  李廷勇  陈朝军  黄冉  王涛  吴尧  徐玉珍  邱海英  黄洋阳  李俊云 《地质论评》2021,67(1):56-67

小冰期是过去一千年中全球气候变化的重要事件之一。关于小冰期时中国季风区和西风影响区气候变化的对比研究众多,但是缺乏中国南方地区降水模式时空差异的研究,难以了解中国南方地区降水变化规律。为了系统地了解小冰期时中国南方地区降水的复杂性,本文将中国南方地区划分为东南—华南沿海地区、中部地区以及西南地区三个区域,总共选取了19条高分辨率的古气候记录进行对比研究,主要有以下几点认识:(1)相对于中世纪暖期而言,小冰期期间中国南方东南—华南沿海地区的气候偏湿,这可能与雨带在中国南方的滞留时间延长和沿海地区受台风的影响增强有关。(2)中国中部地区秦岭南麓和神农架高山林区在小冰期时期主要呈"冷湿"的模式,差异在于秦岭南麓区域主要在小冰期中后期偏湿,这与中部其他区域偏"冷干"的模式不同。这种区域差异可能是由于地形地势和大气环流的复杂性导致。(3)中国西南地区受印度夏季风和东亚夏季风的共同影响,且该区域地形复杂,其气候变化在小冰期时期存在更加明显的空间差异,没有呈现出比较一致的降水模式。与小冰期期间的降水变化不同的是,近30年东南—华南沿海地区除了台湾和雷州半岛,其他区域降水明显减少,可能受气温和人类活动等因素的影响。通过结合高分辨率的古气候记录,我们系统分析了中国南方小冰期的干湿模式在时空上的差异及其可能的影响因子,这对于认识小冰期时中国南方不同区域降水的复杂性及未来旱涝灾害的防控具有一定意义。  相似文献