珠江三角洲平原区土壤Pb元素地球化学特征及其影响因素研究     

郭思雨  侯青叶  宗庆霞  唐志敏  韦彬  庞世琦 《现代地质》2019,33(3):514-524

以珠江三角洲平原为研究区域,对其7个区县102件水稻根系土样品进行土壤理化参数及Pb形态分析,探讨在第四系分布区土壤Pb全量及Pb活动态含量的特征及影响因素。结果表明:全部供试土壤样品中Pb元素平均含量为46.47mg/kg,略高于广东省土壤Pb含量背景值(36mg/kg),表现出一定的累积趋势。研究区自西北陆相沉积区至南部海陆交互相沉积区,元素含量增高。Pb元素主要以残渣态和铁锰氧化物形态赋存在土壤中,迁移能力弱。影响土壤Pb全量的因素主要有Al2O3、K2O、Tl、Mo;影响土壤Pb活动态的因素有Pb全量、pH、有机质、CEC、P、TFe2O3、Mn;其中,p H是控制Pb元素活动性的最主要因素。  相似文献   

云南澜沧老厂多金属矿床矿石类型及其成因探讨     

王磊  李高权  李洪江  陈品鸿  蔡昌厚  杨大省 《地质与资源》2019,28(6):535-542

云南澜沧老厂是三江成矿带南段最重要的铅锌铜钼多金属矿床之一.根据不同的赋矿特征、含矿岩性、矿石构造及成矿元素将澜沧老厂多金属矿床矿石类型系统地划分为铅锌硫化矿石、铅锌氧化矿石、颗粒状含铜黄铁矿石、块状含铜黄铁矿石、夕卡岩型矿石及斑岩型钼矿石6种类型.矿体产状、微量元素地球化学、年代学证据均表明铅锌硫化矿石、颗粒状含铜黄铁矿石及块状含铜黄铁矿石为火山喷流沉积型成因（VMS型）,而铅锌氧化矿石、夕卡岩型矿石及斑岩型钼矿石为斑岩热液型成因.其中,铅锌硫化矿石、颗粒状含铜黄铁矿石及块状含铜黄铁矿石的主控矿因素为地层;铅锌氧化矿石为构造;夕卡岩型矿石为岩性;斑岩型钼矿石为岩体.  相似文献   

KIC 4762887: A near-contact binary or an ellipsoidal variable star?     

《New Astronomy》2021

  相似文献   

Photometric study of five kepler contact binaries     

《New Astronomy》2020

A lot of data in time domain were obtained by the Kepler mission, including many contact binaries. Long-term observation lets us obtain more information about the short time scale variation in their light curves or in their orbital periods. Unfortunately, the exposure time is too long (most of them are 30 minutes). Hence, many variations in light curves are smoothed. To avoid this problem, we analyzed some Kepler contact systems with both long-cadence mode and short-cadence mode data. Using the latest version of the Wilson-Devinney code, we obtained the physical parameters of a batch of contact binaries and find out four targets(KIC 5123176, KIC 5296877, KIC 8496820, KIC 9776718) have low mass ratios (q  <  0.25) and one target (KIC 7950962) has a mass ratio very close to unit.  相似文献   

云南省新平县哀牢山地区富硒土壤成因及其影响因素研究   总被引：1，自引：0，他引：1  

黄钊  陈政  薛传东  刀艳  许胜超  代达龙  吴松 《现代地质》2020,34(3):609-617

以云南省新平县者竜—戛洒地区1∶5万土地质量地球化学调查评价结果为基础,对该地区富硒土壤的成因及其影响因素进行分析,结果表明,研究区土壤硒平均含量为0.38 mg/kg,高于全国土壤硒平均含量0.29 mg/kg,按0.4 mg/kg相似文献   

滇中禄丰地区中元古代早期球颗玄武岩的锆石U-Pb年龄、地球化学特征及其大地构造意义     

刘军平  孙柏东  王晓峰  刘伟  马进华  关学卿  宋冬虎  吕勃烨 《地质论评》2020,66(1):35-51

在1∶5万区域地质调查的基础上,在禄丰地区东川群黑山组新发现了球颗玄武岩及凝灰岩夹层。采用LA-ICP-MS技术测得球颗玄武岩和凝灰质板岩中锆石U-Pb加权平均年龄分别为1678±10 Ma和1572±19 Ma,表明黑山组沉积时代为中元古代早期;其中球颗玄武岩SiO_2含量介于40.83%～52.56%,δEu正异常,大离子亲石元素Rb、Ba和高场强元素Nb、Ta、Th等强不相容元素相对富集,全岩地球化学显示为大陆板内低钛拉斑海相玄武岩,形成于伸展的构造环境,可能为Columbia超大陆裂解的产物。本次的发现,为准确地标定东川群时代、层序及大地构造属性提供新的参考依据,也为重塑整个滇中前寒武纪地层格架提供时代约束。  相似文献   

昌宁-孟连结合带奥陶纪洋岛玄武岩的识别及其构造意义——来自地球化学和锆石U-Pb年龄的证据   总被引：2，自引：0，他引：2  

孙载波  曾文涛  周坤  吴嘉琳  李龚健  黄亮  赵江泰 《地质通报》2017,36(10):1760-1771

西南三江昌宁-孟连构造带传统被认为是晚古生代古特提斯洋的缝合带。在该构造带中段铜厂街蛇绿混杂岩东侧勐勇—芒红一带,新识别出一套近南北向展布的灰绿色气孔-杏仁状玄武岩、安山玄武岩和硅质岩、浅变质泥质粉砂岩组成的火山-沉积岩系。对杏仁状玄武岩样品进行LA-ICP-MS锆石U-Pb定年,获得其~(206)Pb/~(238)U年龄加权平均值为449.3±8.4Ma(MSWD=3.5),表明该套火山岩喷发于奥陶纪。元素地球化学特征表现为富铝(12.11%~15.04%)、富钠(K_2O/N_2O=0.03~0.44)、高Mg~#值(45.9~61.7),同时,该套火山岩中MgO=6.78%~12.34%,平均为9.43%,Cr=58.6×10~(-6)~636×10~(-6),平均为310.3×10~(-6),Ni=57.4×10~(-6)~410×10~(-6),平均为202.1×10~(-6),Nb=18.9×10~(-6)~32.8×10~(-6),平均为25.06×10~(-6),具有轻稀土元素强烈富集的"直线状"稀土元素配分模式,(La/Yb)_N=5.25,(Ce/Yb)_N=4.42,(Ce/Sm)_N=1.68,稀土元素总量随全碱含量增大有升高的趋势,表明其为亚速尔型洋岛。总体上,该套火山岩具碱性OIB(洋岛玄武岩)的特征,可能是大洋板内热点前部熔融的产物。亚速尔型洋岛玄武岩的出现代表了特提斯洋盆内洋岛发育早期阶段的物质记录,为重新认识滇西南昌宁—孟连地区特提斯主洋盆开阔多岛洋的格局提供了丰富的岩石学依据。  相似文献   

Removal of heavy metals from contaminated water using ethylenediamine-modified green seaweed (Caulerpa serrulata)     

《Physics and Chemistry of the Earth》2012

The demand for clean water is on the increase as the population increases. One of the ways to address the water shortage is to treat the polluted water through removal of the contaminants. The use of adsorbents for pollutant removal is one of the promising methods. Seaweed is an aquatic plant and its sorption ability for selected metals in water was investigated in this study. We report the performance of the seaweed (Caulerpa serrulata) before and after modification with ethylenediamine (EDA), on adsorption of copper, lead and cadmium in aqueous solution. The adsorption capacities for Cu, Cd and Pb were 5.27 mg g⁻¹, 2.12 mg g⁻¹ and 2.16 mg g⁻¹, respectively, with the EDA-modified seaweed, and 3.29 mg g⁻¹, 4.57 mg g⁻¹ and 1.06 mg g⁻¹, with the unmodified weed, respectively. The pH for maximum adsorption was found to be within the range of pH 4–pH 6. In a separate investigation, it was found that 0.1 g of dried seaweed leached 20 mg of dissolved organic carbon (DOC) using 100 ml of distilled-deionised water. The resulting solution was green. The leaching phenomenon contributes to secondary pollution. Modification of the seaweed with EDA reduced the DOC content by half (50%) and also removed the green colouration. Kinetic studies showed that the adsorbent was able to take up to 95% of the metals (in synthetic standard solutions) in less than 10 min. The adsorbed metals were then stripped using a solution of 0.5 M HNO₃ indicating that the adsorbent can be regenerated. In addition, the study revealed that modification improved the thermal stability of the adsorbent such that even when the temperature was raised to 1000 °C, more than 80% (compared to <50% for unmodified weed) of the modified adsorbent was not degraded, indicating that modification had a significant influence on the thermal stability of seaweed. The modified seaweed has been shown to have great potential for the removal of metals and DOC in polluted water. The modified adsorbent can therefore be applied for the removal of metals in polluted waters hence suitable for treatment of water for domestic consumption at a point of use.  相似文献   

Dating the giant Zhuxi W–Cu deposit (Taqian–Fuchun Ore Belt) in South China using molybdenite Re–Os and muscovite Ar–Ar system     

《Ore Geology Reviews》2017

The recently discovered Zhuxi W–Cu ore deposit is located within the Taqian–Fuchun Ore Belt in the southeastern edge of the Yangtze Block, South China. Its inferred tungsten resources, based on new exploration data, are more than 280 Mt by 2016. At least three paragenetic stages of skarn formation and ore deposition have been recognized: prograde skarn stage; retrograde stage; and hydrothermal sulfide stage. Secondly, greisenization, marmorization and hornfels formation are also observed. Scheelite and chalcopyrite are the dominant metal minerals in the Zhuxi deposit and their formation was associated with the emplacement of granite stocks and porphyry dykes intruded into the surrounding Carboniferous carbonate sediments (Huanglong and Chuanshan formations) and the Neoproterozoic slate and phyllites. The scheelite was mostly precipitated during the retrograde stage, whereas the chalcopyrite was widely precipitated during the hydrothermal sulfide stage. A muscovite ⁴⁰Ar/³⁹Ar plateau age of about 150 Ma is interpreted as the time of tungsten mineralization and molybdenite Re–Os model ages ranging from 145.9 ± 2.0 Ma to 148.7 ± 2.2 Ma (for the subsequent hydrothermal sulfide stage of activity) as the time of the copper mineralization. Our new molybdenite Re–Os and muscovite ⁴⁰Ar/³⁹Ar dating results, along with previous zircon U–Pb age data, indicate that the hydrothermal activity from the retrograde stage to the last hydrothermal sulfide stage lasted up to 5 Myr, from 150.6 ± 1.5 to 145.9 ± 1 Ma, and is approximately coeval or slightly later than the emplacement of the associated granite porphyry and biotite granite. The new ages reported here confirm that the Zhuxi tungsten deposit represents one of the Mesozoic magmatic–hydrothermal mineralization events that took place in South China in a setting of lithospheric extension during the Late Jurassic (160–150 Ma). It is suggested that mantle material played a role in producing the Zhuxi W–Cu mineralization and associated magmatism.  相似文献   

滇西镇康水头山Pb-Zn矿床成矿流体及矿质来源探讨——H、O、S、Pb同位素地球化学证据   总被引：2，自引：1，他引：1  

邓明国  赵剑星  刘凤祥  余海军  孙柏东  刘飞  李仕斌 《岩石学报》2017,33(7):2001-2017

滇西镇康水头山Pb-Zn矿床是保山地块镇康Pb-Zn-Fe-Cu多金属矿集区内又一重要找矿成果。矿体呈似层状、透镜状产于上寒武统保山组大理岩化灰岩中,呈NEE向顺层产出,矿石矿物主要为闪锌矿和方铅矿,偶见黄铜矿和黄铁矿等;脉石矿物主要有白云石、绿泥石、方解石、石英和绢云母等。本文基于对矿床地质特征的详细研究,结合矿床H、O、S、Pb同位素组成,对其成矿流体和矿质来源进行了探讨,同时与毗邻的芦子园超大型Pb-Zn-Fe-Cu多金属矿床进行了对比。研究表明:该矿床石英的δD值介于-101.1‰~-93.3‰之间,均值为-96.85‰(n=4),δ~(18)O_(H_2O)值为3.37‰~3.77‰之间,均值为3.57‰(n=4),表明成矿流体早期以原生岩浆水为主,有大气降水的混入。矿床金属硫化物的δ~(34)S值均为正值,介于4.1‰~12.2‰,均值为8.23‰(n=10),与旁侧的芦子园矿床δ~(34)S值(8.9‰~12‰)较为接近。该矿床可划分出三个成矿阶段,阶段Ⅱ为以闪锌矿和方铅矿为主的主要成矿阶段(δ~(34)S主要集中在4.1‰~6.2‰之间),其δ~(34)S均值可近似代表成矿热液中的δ~(34)S∑S值,即δ~(34)S∑S≈δ~(34)S均值=6.56‰(n=7),闪锌矿和方铅矿δ~(34)S值有部分重叠,但总体上具有δ~(34)S闪锌矿δ~(34)S方铅矿以及不同颜色闪锌矿之间δ~(34)S深棕色闪锌矿δ~(34)S棕褐色闪锌矿δ~(34)S浅棕色闪锌矿的分布特征,暗示硫同位素在硫化物间的分馏达到平衡,表明S同位素组成较为稳定,显示水头山矿床具有深部壳源岩浆成因的特征。矿床金属硫化物的Pb同位素分析显示,Pb同位素组成非常集中(~(206)Pb/~(204)Pb=18.3408~18.4483,均值为18.3815,~(207)Pb/~(204)Pb=15.8337~15.9440,均值为15.8745,~(208)Pb/~(204)Pb=38.8224~39.4391,均值为38.9941,n=10),投点主要分布在上地壳演化线上方,表明其Pb主要来自于以岩浆作用为主的上地壳物质。本文认为矿区深部壳源岩浆热液是水头山矿床最重要的成矿流体与矿质来源,流体的混合作用是矿床金属元素沉淀和富集的重要机制,矿床具有低温、后生成矿特征,推测矿床的形成与燕山晚期的岩浆热液作用有关。  相似文献