云南兰坪中排李子坪铅锌矿矿床成因

铅锌矿产于下白垩统景星组下段泥质粉砂岩、钙质砂岩和中侏罗统花开左组上段砂岩夹薄层泥灰岩介壳灰岩中,脉状、透镜状、层状、似层状等产出。NNE向断裂的交叉夹持部位的旁侧派生次级断裂及层间破碎带是主要容矿构造,矿床成因为沉积-中低温热液改造构造控矿型。     

南极纳拉海峡固定冰生长、 结构、 盐度和氧同位素组成

采用第19次中国南极科考采集的冰芯样品、 数据, 基于海冰的"冻结日"记录, 使用海冰一维热力学模型来计算纳拉海峡固定冰的生长厚度. 考虑气象条件以及冰情观测结果, 将该模型的计算海冰厚度和实测厚度进行比较发现, 在纳拉海峡存在着多年生长的海冰. 对采集于南极洲中山站附近纳拉海峡的固定冰冰芯样品进行结构、 盐度和稳定氧同位素(δ~(18)O)分析, 获取了海冰的结构和盐度剖面特征、 冰芯雪冰、 附加冰的含量、 雪冰中的雪以及全部冰芯中雪所占的百分比. 结果表明: 样品冰芯具有典型的海冰特征结构, 如柱状冰水平方向的C轴以及上部粒状冰层和下部柱状冰层结构特征, 部分柱状冰中间存在着粒状冰夹层; 盐度和δ~(18)O剖面也显示了多年冰生长的证据. 海冰的结构和氧同位素特征表明, 纳拉海峡固定冰的生长主要受热力学过程控制, 其结果和2000年1月至2003年2月人工冰情观测结果一致, 观测中没有发现冰脊、 叠置等动力过程. 附加冰在冰芯中所占的比例平均为5.01%. 使用不同的同位素标准来区分雪冰层, 估计研究区域平均有多达16.4%～37.9%的雪冰, 海冰粒状层中雪的部分约占全部冰厚度的0.8%～23.5%.     

贵州龙里高山草原泥炭沉积年代、速率及其有机碳同位素记录

通过对贵州龙里高山草原泥炭进行加速器(AMS)14C测年和有机碳的测定,获得泥炭层底部0.90 m和0.55 m处年龄分别为(7 933±33)a B.P.和(7 733±28)a B.P.,计算出泥炭层堆积速率为1.75 mm/a。获得泥炭层δ13C为-28.9‰～-26.6‰,平均为-27.8‰,说明植被以C3植物为主,与现在坪台沼泽上苔藓繁盛相似。结合其他地区的气候记录推断,研究区泥炭发育于相对温暖湿润的气候环境,是全新世大暖期的第一个暖湿期形成的产物。     

Geochemical Features and Metallogenic Prediction of the Caixiashan‐Weiquan Area in the East Tianshan Region

The Caixiashan-Weiquan area is an important ore concentration area in the eastern Tianshan metallogenic belt. Firstly, this paper studies geochemical features of 1564 samples of 1:200000 stream sediments of the Matoutan mapsheet, where the Caixiashan and Weiquan deposits are located. Processing, analysis and explanation of exploration geochemical data play an important role in the procedure of finding the ore, which are related to whether the measured elements content of geochemical samples can effectively guide the work of mineral exploration. As a highly nonlinear dynamical system, the neural network is more analogous to the human brains in terms of principles and features compared with conventional geochemical approaches. It can adapt itself to the environment, sum up laws, complete pattern recognition. Secondly, the authors used the Kohonen neural network to classify all samples based on 10 mineralization elements of stream sediment samples in order to determine possible mineral ores, reduce the scope of ore targets and study indicator elements of the ninth group of samples, which is the mostly closest to the deposit. The results show that the neural network can delineate metallogenic prospective areas and is effective in the discovery of deep geochemical information.     

Re–Os and U–Pb Geochronology of the Erlihe Pb–Zn Deposit, Qinling Orogenic Belt, Central China, and Constraints on Its Deposit Genesis

The Erlihe Pb–Zn deposit is an important mine of the Pb–Zn metallogenic zone in the South Qinling Orogen. It has been considered a sedimentary exhalative deposit in previous investigations because the ore body occurs concordantly at the transitional location of an upright fold. Re and Os isotopic analyses for paragenetic pyrites with sphalerite and galena from the ore body have been used to determine the timing of mineralization and to trace the source of metallogenic materials. The Re–Os isotopic data of four pyrite samples construct an isochron, yielding a weighted average age of 226±17 Ma (mean square weighted deviation=1.7), which is considered the main mineralization age. A dioritic porphyrite vein sample, showing weaker mineralization, was also dated using the SHRIMP zircon U–Pb isotopic method to constrain the youngest metallogenic age of the ore deposit, because it distributes along a group of tensional joints cutting not only the upright fold in the deposit field, but also the main ore bodies. The dioritic porphyrite sample yields a weighted mean 206Pb/238U age of 221±3 Ma, which is slightly younger than the Re–Os isotopic isochron age of the pyrites, considered as the upper age limit of the mineralization, namely the ending age of the mineralization. The Os isotopic compositions of sulfide minerals distribute within a range between Os isotopic compositions of the crust and the mantle, indicating that the ore deposit can be derived from magma-related fluid, and the metallogenic materials are most likely derived from the mixing source of the crust and the mantle. The Erlihe Pb–Zn deposit and associated dioritic porphyrite vein, important records of Qinling tectonic–magmatism–mineralization activities, were formed during the Triassic collisional orogeny processes.     

全球碳循环研究中的δ13C方法及其进展

随着分析技术的进步,δ13C观测在全球碳循环研究中越来越受到重视。在讨论关于碳循环中δ13C的Suess效应、分布特征和同位素分馏等基本概念的基础上,结合现有的观测事实,介绍应用δ13C辨别碳的源汇问题的方法,通过比较不同KeelingPlot方法分析该方法在研究大气CO2背景特征中的意义。着重讨论δ13C在研究大气C...     

示波极谱法测量电锌液中微量镍

提出在丁二酮肟-亚硝酸钠-氨水-氯化铵体系中,准确测定电锌液中微量镍的新方法:克服原子吸收光谱法测定微量镍回收率偏低问题。     

芦苇、菖蒲和水葱对水体中Zn2+的富集效应研究

采用水培方法,在不同ZnCl2浓度(0mg/L、50mg/L、100mg/L、300mg/L、800mg/L、1500mg/L和2500mg/L)处理的水体中,对湿地植物芦苇(Phragmites australis)、菖蒲(Acorus calamus)和水葱(Scirpus tabernaemontani)进行培养,研究植物的不同部位对Zn2+的积累能力。结果表明,在相同ZnCl2浓度处理下的水体中,水葱、菖蒲和芦苇体内的平均Zn2+积累浓度存在差异,菖蒲体内的Zn2+积累浓度最高。在不同ZnCl2浓度处理下的水体中,水葱体内的平均Zn2+积累浓度在ZnCl2浓度为1500mg/L时最高,为31050.84mg/kg(植物地上部分为10206.67mg/kg,地下部分为20844.17mg/kg);菖蒲和芦苇体内的平均Zn2+积累浓度则在ZnCl2浓度为2500mg/L时最高,分别为54130.67mg/kg(地上部分为16774.00mg/kg,地下部分为37356.67mg/kg)和25423.34mg/kg(地上部分为4506.67mg/kg,地下部分为20916.67mg/kg)。这3种植物都可以作为利用植物修复重金属污染水体的遴选物种。其中,菖蒲对Zn2+的吸收能力明显高于水葱和芦苇。     

The origin of the Maozu carbonate-hosted Pb–Zn deposit,southwest China: Constrained by C–O–S–Pb isotopic compositions and Sm–Nd isotopic age

The Maozu Pb–Zn deposit, located on the western margin of the Yangtze Block, southwest China, is a typical carbonate-hosted deposit in the Sichuan–Yunnan–Guizhou Pb–Zn metallogenic province with Pb + Zn reserves of about 2.0 million tonnes grading 4.15 wt.% Pb and 7.25 wt.% Zn. Its ore bodies are hosted in Sinian (635–541 Ma) Dengying Formation dolostone and show stratiform, vein and irregular textures. Ores are composed of sphalerite, galena, pyrite, calcite, dolomite, quartz and fluorite with massive, banded, disseminated and veined structures. The C–O–Sm–Nd isotopic compositions of hydrothermal calcites and S–Pb isotopic compositions of sulfides were analyzed to constrain the origin of the Maozu deposit. δ¹³C_PDB and δ¹⁸O_SMOW values of hydrothermal calcites range from −3.7‰ to −2.0‰ and +13.8‰ to +17.5‰, respectively, and plot near the marine carbonate rocks field in a plot of δ¹³C_PDB vs. δ¹⁸O_SMOW, with a negative correlation. It suggests that CO₂ in the hydrothermal fluids was mainly originated from marine carbonate rocks, with limited influence from sedimentary organic matter. δ³⁴S_CDT values of sulfides range from +9.9‰ to +19.2‰, similar to that of Cambrian to Triassic seawater sulfate (+15‰ to +35‰) and evaporate (+15‰ to +30‰) in the Cambrian to Triassic sedimentary strata. It suggests that reduced sulfur was derived from evaporate in sedimentary strata by thermo chemical sulfate reduction. Sulfides have low radiogenic Pb isotope compositions (²⁰⁶Pb/²⁰⁴Pb = 18.129–18.375, ²⁰⁷Pb/²⁰⁴Pb = 15.640–15.686 and ²⁰⁸Pb/²⁰⁴Pb = 38.220–38.577) that plot in the field between upper crust and the orogenic belt evolution curve in the plot of ²⁰⁷Pb/²⁰⁴Pb vs. ²⁰⁶Pb/²⁰⁴Pb, and similar to that of age corrected Proterozoic basement rocks (Dongchuan and Kunyang Groups). This indicates that ore-forming metals were mainly derived from basement rocks. Hydrothermal calcite yields a Sm–Nd isotopic age of 196 ± 13 Ma, possibly reflecting the timing of Pb–Zn mineralization in the SYG province, younger than the Permian Emeishan mantle plume (∼260 Ma). All data combined suggests that hydrothermal fluids circulated through basement rocks where they picked up metals and migrated to surface, mixed with reduced sulfur-bearing fluids and precipitated metals. Ore genesis of the Maozu deposit is different from known magmatic–hydrothermal, Sedimentary Exhalative or Mississippi Valley-types, which maybe represent a unique ore deposit type, named as the SYG-type.     

（∈y，∈yVqδ）-模糊n-序超群

把模糊集理论应用到n-序超群,在交换n-序超群中引入了（∈y,∈yVqδ）模糊n-序子超群和（∈y,∈yVqδ）模糊n-序可逆子超群的概念,并研究了其性质。