Chemical and Isotopic Characters of the Water and Suspended Particulate Materials in the Yellow River and Their Geological and Environmental Implications   总被引：1，自引：0，他引：1  

DING Tiping  GAO Jianfei  TIAN Shihong  WANG Huaibai  LI Ming  WANG Chengyu  LUO Xurong  HANG Dan 《《地质学报》英文版》2016,90(1):285-351

The chemical and isotopic characteristics of the water and suspended particulate materials(SPM)in the Yellow River were investigated on the samples collected from 29 hydrological monitoring stations in the mainstem and several major tributaries during 2004 to 2007.TheδD andδ~(18)O values of the Yellow River water vary in large ranges from-32‰to-91‰and from-3.1‰to-12.5‰,respectively.The characters of H and O isotope variations indicate that the major sources of the Yellow River water are meteoric water and snow melting water,and water cycle in the Yellow River basin is affected strongly by evaporation process and human activity.The average SPM content(9.635g/L)of the Yellow River is the highest among the world large rivers.Compared with the Yangtze River,the Yellow River SPM has much lower clay content and significantly higher contents of clastic silicates and carbonates.In comparison to the upper crust rocks,the Yellow River SPM contains less SiO_2,CaO,K_2O and Na_2O,but more TFe_2O_3,Co,Ni,Cu,Zn,Pb and Cd.The abnormal high Cd contents found in some sample may be related to local industrial activity.The REE contents and distribution pattern of the Yellow River SPM are very close to the average value of the global shale.The averageδ~(30)Si_(SPM)in the Yellow River(-0.11‰)is slightly higher than the average value(-0.22‰)of the Yangtze River SPM.The major factors controlling theδ~(30)Si_(SPM)of the Yellow River are the soil supply,the isotopic composition of the soil and the climate conditions.The TDS in the Yellow River are the highest among those of world large rivers.Fair correlations are observed among Cl~-,Na~+,K~+,and Mg~(2+)contents of the Yellow River water,indicating the effect of evaporation.The Ca~(2+)and Sr~(2+)concentrations show good correlation to the SO_4~(2-)concentration rather than HCO_3~-concentration,reflecting its origin from evaporates.The NO_3~-contents are affected by farmland fertilization.The Cu,Zn and Cd contents in dissolved load of the Yellow River water are all higher than those of average world large rivers,reflecting the effect of human activity.The dissolved load in the Yellow River water generally shows a REE distribution pattern parallel to those for the Yangtze River and the Xijiang River.Theδ~(30)Si values of the dissolved silicon vary in a range from 0.4‰to 2.9‰,averaging1.34‰.The major processes controlling the D_(Si)andδ~(30)Si_(Diss)of the Yellow River water are the weathering process of silicate rocks,growth of phytolith in plants,evaporation,dissolution of phytolith in soil,growth of fresh water diatom,adsorption and desorption of aqueous monosilicic acid on iron oxide and human activities.The averageδ~(30)Si_(Diss)value of the Yellow River is significantly lower than that of the Nile River,Yangtze River and Siberia rivers,but higher than those of other rivers,reflecting their differences in chemical weathering and biological activity.Theδ~(34)S_(SO4)values of the Yellow River water range from-3.8‰to 14.1‰,averaging 7.97‰.There is some correlation between SO_4~(2-)content andδ~(34)S_(SO4).The factors controlling theδ~(34)S_(SO4)of the Yellow River water are the SO_4 in the meteoric water,the SO_4 from gypsum or anhydrite in evaporite rocks,oxidation and dissolution of sulfides in the mineral deposits,magmatic rocks and sedimentary rocks,the sulfate reduction and precipitation process and the sulfate from fertilizer.The~(87)Sr/~(86)Sr ratios of all samplesrange from 0.71041 to 0.71237,averaging 0.71128.The variations in the~(87)Sr/~(86)Sr ratio and Sr concentration of river water are primarily caused by mixing of waters of various origins with different~(87)Sr/~(86)Sr ratios and Sr contents resulting from water-rock interaction with different rock types.  相似文献   

中国利用树轮资料重建干湿变化研究进展   总被引：1，自引：0，他引：1  

王亚军  李明启 《地理科学进展》2016,35(11):1397-1410

树木年轮资料定年准确、分辨率高、连续性强,已成为研究过去全球变化的重要信息来源之一。中国树轮与干湿变化研究,样点分布广泛,研究树种较多,重建尺度较长。基于树轮宽度、密度和同位素等各种代用指标,在分析树木径向生长对干湿变化响应、重建历史时期干湿变化等方面取得很大进展。一般来说,在干旱半干旱区的低海拔区域,水分条件,尤其是春季、秋季和年湿润状况,是树木径向生长的重要影响因素。森林上限、相对冷湿区域以及亚热带气候区,树木生长与降水的相关性偏弱。在时间尺度上,基于树轮重建的长于1000年甚至超过2000年的干湿变化序列已有多条,主要分布在青藏高原地区。目前最长年表已达4500年,最长降水序列为3500年。本文通过对部分树轮成果的简要概括,以期为树轮采样和干湿变化重建提供借鉴与帮助。  相似文献   

兴凯湖花岗杂岩体的锆石U——Pb 年龄及其地质意义   总被引：3，自引：0，他引：3  

杨浩  张彦龙  陈会军  葛文春 《世界地质》2012,31(4):621-630

佳木斯地块东南缘的兴凯湖花岗杂岩体主要由花岗闪长岩、二长花岗岩和正长花岗岩组成,其锆石的LA-ICP-MS U-Pb 测年结果显示,杨田寨南山岩体形成于257 ± 2 Ma,双子山岩体形成于215 ～212 Ma; 花岗岩的时空展布表明,两期花岗质岩浆的就位可能分别与古亚洲洋板块的俯冲作用和后造山伸展进程密切相关。结合本区和黑龙江东部其他花岗质岩石的年龄,揭示了佳木斯地块和兴凯地块在早古生代、二叠纪及三叠纪共同经历了三期大规模岩浆活动,暗示两者具有相同的构造属性,共同组成了同一陆块。  相似文献   

江南造山带东部旌德高Sr/Y花岗闪长岩的形成机制及其构造意义   总被引：1，自引：0，他引：1  

周洁 《地质学报》2014,88(1):53-62

旌德岩体是江南造山带东部一个典型的高Sr/Y岩体。锆石的原位U-Pb定年表明,该岩体侵位于141±1Ma。岩体由花岗闪长岩和二长花岗岩组成。岩体中黑云母为镁质黑云母。斜长石为奥长石、中长石。全岩地球化学表明,高的SiO2（66.01% ~ 70.87%）,Al2O3（14.91% ~16.24%）,全碱（K2O+Na2O = 6.64% ~ 8.01%）,K2O/Na2O变化范围在0.78～1.04,Sr（189×10-6 ~ 452×10-6）,和LREE;低的HREE和HFSE含量,Eu有轻微的负异常到弱的正异常（δEu＝0.81~1.18）。岩体具有高的Sr/Y（23 ~ 66）值和(La/Yb)N（13 ~ 58）值,且MgO、Cr、Ni含量较低。相对较高的εNd(t)＝‒12.92~‒6.28,二阶段模式年龄 tDM2 = 1.4~1.9Ga,岩体中发育有岩浆混合成因的暗色包体,指示有幔源岩浆参与。交代的岩石圈地幔发生部分熔融,岩浆底侵到壳幔过渡带附近,导致下地壳发生部分熔融形成了旌德岩体,且发生了岩浆混合作用。  相似文献   

藏北羌塘中西部红脊山地区晚古生代蛇绿岩地球化学特征及构造意义   总被引：2，自引：0，他引：2  

邓明荣  董永胜  张修政  张乐  许王  柳佳成 《地质通报》2014,33(11):1740-1749

以变质玄武岩为研究对象,对红脊山蛇绿岩进行了详细的岩石学和地球化学研究。结果表明,玄武岩主量元素含量与典型的N-MORB非常相似,稀土元素总量较低,具有轻稀土元素略亏损的近平坦左倾型配分型式,Eu异常不显著(δEu=1.05~1.16)。微量元素蛛网图总体也与N-MORB相似,表明变质基性岩源于N-MORB型亏损地幔源区。与典型的大洋中脊玄武岩相比,微量元素蛛网图显示出部分大离子亲石元素明显富集和部分高场强元素明显亏损的特征,尤其是Nb的亏损较为明显(Nb=1.67×10-6~2.26×10-6,平均值为1.97×10-6),表明本区玄武岩受俯冲带物质的影响,很可能形成于俯冲带之上的弧后盆地次级扩张的大地构造背景,属SSZ型蛇绿岩范畴,为特提斯大洋岩石圈在俯冲过程中引发弧后盆地次级扩张的产物。本研究为龙木错—双湖—澜沧江板块缝合带中西段的构造演化研究提供了重要依据。  相似文献   

鄂尔多斯盆地西缘汝箕沟大岭－鼓鼓台玄武岩锆石U-Pb定年及其构造意义   总被引：4，自引：0，他引：4  

杨华  付金华  欧阳征健  孙六一  马占荣 《地球学报》2010,31(2):229-236

利用显微镜、地球化学、ELA-ICPMS定年等技术, 对鄂尔多斯盆地西缘汝箕沟大岭－鼓鼓台玄武岩及其样品中的锆石进行了内部结构、元素组成分析和原位定年。汝箕沟大岭－鼓鼓台玄武岩为典型的大陆拉斑玄武岩, 所获得的锆石年龄分别为1966±15 Ma、344±22 Ma和241±7 Ma, 其中1966±15 Ma为继承锆石年龄, 344±22 Ma为岩浆第一次分离结晶年龄, 而241±7 Ma代表了玄武质岩浆最后喷出时的锆石结晶年龄。可见, 中晚三叠世盆地西缘北部贺兰山地区处于区域挤压背景下的局部伸展环境, 可能为一小型裂谷盆地。  相似文献   

内蒙古白云鄂博地区基底岩石锆石年代学及对构造背景的指示   总被引：12，自引：7，他引：5  

范宏瑞  杨奎锋  胡芳芳  王凯怡  翟明国 《岩石学报》2010,26(5):1342-1350

白云鄂博地区的克拉通基底岩石主要由糜棱岩化花岗片麻岩(2588±15Ma),正长岩、花岗闪长岩(2018±15Ma)和黑云母花岗片麻岩、含石榴石蓝晶石花岗片麻岩(～1890Ma)等组成,白云鄂博超大型稀土矿床就位于华北克拉通太古代基底之上。太古代克拉通基底在早元古代中晚期(2.0Ga)又经历了一次强烈的碰撞造山运动,造成了闪长质与花岗质岩浆侵位,以及1.9Ga片麻岩相变质事件。  相似文献   

西藏首例独立钼矿——冈底斯沙让大型斑岩钼矿的发现及其意义   总被引：19，自引：3，他引：19  

秦克章李光明  赵俊兴李金祥  薛国强严 刚 粟登奎 肖 波 陈 雷 范 新 《中国地质》2008,35(6):1101-1112

近年来西藏冈底斯斑岩成矿带找矿取得了一系列重大突破．迄今冈底斯带上的斑岩-矽卡岩铜钼矿床蚀变及矿化年龄主要集中在30～12Ma,形成于印度与亚洲大陆晚碰撞伸展环境或陆内后碰撞造山挤压向伸展走滑转换的过渡环境．但是与碰撞背景有关的独立斑岩钼矿还未见报道。笔者通过对沙让钼矿的多次考察和钻孔岩心的系统观察编录,主成矿岩体为花岗斑岩,强烈蚀变地段可达9km^2。根据矿床的含矿斑岩（花岗斑岩）、热液蚀变类型及分带、脉系与矿化特征,认为沙让钼矿应归为独立的斑岩钼矿,产于碰撞环境的主碰撞阶段（55Ma）。并基于与同类矿床蚀变矿化范同、强度的对比和TEM、激电探测,矿化延伸可达800m深度．成矿条件优越．具有很大的找矿潜力。沙让独立斑岩型钼矿类型的确立将进一步丰富冈底斯这一巨型斑岩成矿带的成矿谱系．具有重要的区域找矿意义和研究价值．  相似文献   

Mesozoic molybdenum deposits in the east Qinling–Dabie orogenic belt: Characteristics and tectonic settings     

J.W. Mao  F. Pirajno  J.F. Xiang  J.J. Gao  H.S. Ye  Y.F. Li  B.J. Guo 《Ore Geology Reviews》2011,43(1):264-293

The East Qinling–Dabie orogenic belt accommodates the largest Mo ore district in the world. It contains 8.43 Mt of proven Mo metal reserves which accounts for 66% of the total proven Chinese Mo reserves. The Mo ore district includes 24 deposits and 12 occurrences, with four major types of Mo mineral systems, i.e., porphyry, porphyry-skarn, skarn and hydrothermal veins. The latter can be further subdivided into quartz vein and carbonatite vein types. Although Mo mineralization in the belt began in the Paleoproterozoic (1680 ± 24 to 2044 ± 14 Ma), all economically significant deposits were formed during the Mesozoic. Re/Os dating of molybdenite has shown that there are three episodes of Mo mineralization, i.e., Late Triassic (233–221 Ma), Late Jurassic to Early Cretaceous (148–138 Ma) and Early to middle Cretaceous (131–112 Ma).Late Triassic Mo deposits developed as molybdenite–quartz veins and carbonatite vein types. Stable isotope systematics (C, O, S) and high contents of Re and Sr indicate that the carbonatite Mo veins are mantle-derived. Porphyry and porphyry–skarn Mo mineral deposits were formed in the Late Jurassic to Early Cretaceous and Early to middle Cretaceous. The Late Jurassic to Early Cretaceous granite porphyries that are associated with the Mo deposits usually occupy less than 1.5 km² at the surface and are situated in the East Qinling area, far west of China's continental margin. On the other hand, the Early to middle Cretaceous batholiths and granite porphyries, , with associated Mo deposits are located in the Dabieshan area and eastern part of the East Qinling area. The Late Jurassic to Early Creataceous granitoids and related Mo deposits possibly formed in a back-arc extensional setting of the Eurasian continental margin, which was probably triggered by the oblique subduction of the Izanagi plate. The Early to middle Cretaceous batholiths and granite porphyries are linked to the tectonic regime of lithospheric thinning, asthenospheric upwelling and partial melting of the crust, induced by a change in Izanagi Plate motion parallel to the continent margin.In the East Qinling–Dabie belt there are vein type Pb–Zn–Ag deposits surrounding porphyry and/or porphyry–skarn Mo (W) deposits, forming well defined ore clusters. The same spatial arrangement (i.e., porphyry Mo stockworks and outlying Pb–Zn–Ag ore veins) is also observed at the deposit scale. Thus, Mo porphyry stockworks and distal polymetallic veins belong to the same ore system and may reflect an outward temperature decrease from the highly fractionated granite plutons. Both, porphyry stockworks and polymetallic veins, can be used as vectors for further prospecting.  相似文献   

青海祁连山冻土区天然气水合物的气源条件及其指示意义   总被引：1，自引：0，他引：1  

卢振权  祝有海  张永勤  刘晖  王婷 《矿床地质》2013,32(5):1035-1044

祁连山木里冻土区天然气水合物的气源条件还不清楚,这直接影响到下一步的勘查方向。文章试图以DK-2天然气水合物钻孔为例,从天然气水合物及其相关气体组成与同位素特征入手,对比分析天然气水合物产出层段的泥岩、油页岩、煤、油气显示等有机地球化学特征,探讨该区天然气水合物的气源条件及其对天然气水合物勘查的指示意义。该区天然气水合物所在层段的泥岩、油页岩、煤的有机质丰度、类型、热演化程度等参数显示,它们不能成为天然气水合物的主要气源岩层;结合天然气水合物及相关气体组成与同位素特征,判断该区天然气水合物的气体来源可能主要为深部石油(原油)伴生气或深部气源岩层的成熟-过成熟气;该区油气显示现象与天然气水合物密切伴生,或可作为天然气水合物的指示标志。  相似文献