Temporal and vertical distribution of microphytobenthos biomass in mangrove sediments of Zhujiang (Pearl River) Estuary

Being a primary producer, Microphytobenthos (MPB) play an important role in the benthic ecosystem of mangrove swamps. The temporal and vertical distribution of MPB biomass, expressed as chlorophyll a (Chla), was investigated in mangrove swamps on the Qi’ao island and the Futian Mangrove Nature Reserve, Guangdong Province, South China. Both locations are situated in the Zhujiang (Pearl River) Estuary. For each location, bi-monthly sampling was carried out at four sites during low tide period. Except one site on the Qi’ao Island, which was in Phragmites australis marsh, all sites were in mangrove swamps. The Chl a concentration in surface (0-1 cm) sediment ranged from 0.2 μg/cm 3 to 8.3 μg/cm3 in the Qi’ao Island and from 2.1 μg/cm3 to 15.6 μg/cm3 in the Futian Mangrove Reserve. The peak Chl a concentration occurred in winter or early spring, while the lowest Chl a concentration, with a value of about one quarter of the peak, was observed in summer or early autumn. The vertical distribution of Chl a concentration exhibited an exponential decline with depth, which indicated a muddy sediment with high organic matter, and the slope of the curve was positively related to Chl a concentration in the surface sediment. The MPB biomass of the Qi’ao Island was significantly lower than that of the Futian Mangrove Reserve. Our results suggest that the overlaying water quality might influence the MPB biomass in surface sediments.     

基于GHSOM网络的南海风场时空变化特征分析

基于1979—2018年欧洲中期天气预报中心(ECMWF)近海面10 m风场资料,采用增长型分层自组织映射(GHSOM)神经网络方法,对南海海表面风场(SSW)的季节变化和年际异常变化进行了分析,结果表明：(1)GHSOM网络训练原始风场数据第一层结果揭示了4个特征模态,高度概括了南海近海面风场的季节变化特征;第二层结果提取了风场的月变化特征。(2)GHSOM网络训练异常风场数据第一层结果揭示了4类异常风场特征模态：反气旋式异常、气旋式异常、西南风异常和东北风异常模态。其中反气旋式异常和气旋式异常模态呈现出不对称现象,即反气旋式异常风场的振幅大于气旋式异常风场;且这两个模态与ENSO事件密切相关,它们的时间序列与Niño 3.4指数序列存在显著的延迟相关。同时,东北风异常风场模态的发生频率大于西南风异常模态。向下扩展的第二层结果揭露了异常风场模态更多的细节特征。     

黔西南泥堡—包谷地卡林型金矿田热液矿物地球化学特征及其地质意义

黔西南泥堡—包谷地卡林型金矿田以泥堡特大型金矿床为主体,兼具一系列小型金矿床和新发现的金矿点.笔者等在矿田内系统采集了与成矿密切相关的石英、方解石、萤石和辉锑矿样品,分析微量元素和稳定同位素地球化学特征,探讨成矿流体性质及来源.分析结果显示,石英、方解石和萤石整体上富集As、Sb、Li、Sr、W等元素,其中As、Sb成...     

Emplacement age and PGE geochemistry of lamprophyres in the Laowangzhai gold deposit,Yunnan, SW China

Widely-distributed lamprophyres in the Laowangzhai gold deposit were associated closely with gold ores. Phlogopite⁴⁰Ar/³⁹Ar dating suggests that the emplacement age of lamprophyric magma ranges from (30.8±0.4) to (34.3±0.2) Ma, and gold mineralization took place at (26.4±0.2) Ma. PGE geochemical tracing indicates that gold in the gold deposit did not come from the primitive lamprophyric magma. The tempo-spatial paragenesis between lamprophyres and mesothermal gold deposits along the Jinsha-Red River belt may be attributed to the fact that they formed in the same tectonic setting.

     

南极泰勒谷及罗斯岛地区火山岩微量元素地球化学

南极泰勒谷及罗斯岛地区火山岩的微量元素地球化学研究表明,它们可以分为两大类,博尼湖南岸、克雷克特山和鸟角的碧玄岩或碱玄岩是地幔平衡部分熔融作用的结果;罗德角和伊万思角的安粗岩是岩浆分离结晶作用的结果,其母岩浆相当于本区的碧玄岩。５个采样地区火山岩具有相同的地幔来源,地幔源区为轻稀土富集型,并富集重稀土元素。     

金沙江-红河构造带北段囊谦盆地新生代高钾岩石40Ar/39Ar年代学研究

9个黑云母样品高精度~(40)Ar/~(39)Ar法定年结果表明,囊谦盆地高钾岩浆的活动年限为37.1~37.8Ma。高钾岩石在地质背景和岩石类型上与青藏东缘发现的两类高钾岩系中的早期高钾岩浆岩具有可比性,它们可能形成于相同的构造背景。结合前人的同位素年代学研究资料,金沙江-红河构造带南、北段高钾岩浆活动的时间分别为40~24Ma和40~33Ma,南、北段高钾岩浆活动时间的差异可能指示陆内俯冲作用时限的差异。     

The Kuroshio near the Luzon Strait and circulation in the northern South China Sea during August and September 1994

Wind data from NCEP and hydrographic data obtained from August 28 to September 10, 1994 have been used to compute circulation in the northern South China Sea and near Luzon Strait using three-dimensional diagnostic models with a modified inverse method. The numerical results are as follows: the main Kuroshio is located above 400 m levels near Taiwan’s eastern coast and above 800 m levels away from it. Near Luzon Strait above 400 m levels a branch of the Kuroshio joins with a part of the northward current, which comes from an area west of Luzon’s western coast and intrudes northwestward, then it branchs into western and eastern parts near 20°30′ N. The eastern part flows northward into an area east of Taiwan, while its western part continues to intrude northwestward, flowing through an area southwest of Taiwan. Net westward intruded volume transport through longitude Section AB at 121°00′ E from 19°00′ N to 21° 43′ N is about 3.5 × 10⁶ m³s⁻¹ in a layer above 400 m levels. The anticyclonic eddies W1 and W3 exist above 700 m levels east of Dongsha Islands and below 200 m levels in the eastern part of the region, respectively. The circulation in the middle region is dominated mainly by a basin-scale cyclonic gyre, and consists of three cyclonic eddies. Strong upwelling occurs in the middle region. The joint effect of baroclinity and relief and interaction between wind stress and relief both are important for real forcing of flow across contours of fH ⁻¹ in effecting the circulation pattern.     

发挥地勘行业技术优势为河南大农业发展战略服务

河南是农业和矿业大省,农业地质可以为我省农业发展做出新贡献,且已取得了明显实效,如钾镁肥开发等。发挥地勘行业的技术优势,可以开展以下四个方面的工作:1.开展农业地质生态环境遥感综合调查评价,为农业生产布局服务;2.开展农用矿物肥料开发研究,致力于提高农产品的品质;3.加大天然矿物饲料开发力度,提高畜产品的品质;4.开展缺水地区地下水资源调查。在我省农业地质刚起步的现阶段,应重点培育该学科并提倡多学科联合攻关,营建适应科技创新的新机制。     

黔西南大丫口地区金矿找矿标志及找矿预测研究

大丫口地区位于黔西南卡林型金矿矿集区内,大地构造位处扬子地台西南缘与华南加里东褶皱带西缘两大构造单元的过渡地带,北西向与泥堡大型金矿床相连,南东向与戈塘金矿床相邻。目前已发现区内金矿（化）主要有两种产出类型：一是赋存于茅口组上与覆龙潭组底部一套由区域性构造作用形成的、并经热液蚀变的构造蚀变岩体（SBT）中的层控型,二是产于断层破碎带或两盘牵引膝褶带内的断控型。本文初步总结了该区的找矿标志,开展了找矿预测。     

黔西南泥堡—包谷地卡林型金矿田热液矿物地球化学特征及其地质意义

黔西南泥堡—包谷地卡林型金矿田以泥堡特大型金矿床为主体,兼具一系列小型金矿床和新发现金矿点。本文在矿田内系统采集了与成矿密切相关的石英、方解石、萤石和辉锑矿样品,分析微量元素和稳定同位素地球化学特征,探讨成矿流体性质及来源。分析结果显示,石英、方解石和萤石整体上富集As、Sb、Li、Sr、W等元素,其中As、Sb成矿元素继承了成矿流体的特征;Sb成矿元素与Bi、W、Mo、Co、Ni等亲岩浆元素相关性较好,显示成矿与岩浆活动有关。方解石、萤石显示MREE富集,方解石具有显著的Eu正异常,反映了成矿流体在矿物沉淀时的稀土配分特征,并且处于相对酸性和还原的状态。石英δDV-SMOW、δ18OV-SMOW和δ13CV-PDB分别为-76‰~-55.7‰（均值-64.9‰）、16.5‰~24.5‰（均值21.1‰）、-14.3‰~-7.0‰（均值-10.9‰）,辉锑矿δ34SV-CDT值为-0.4‰、-0.6‰和1.9‰,方解石δ13CV-PDB和δ18OV-SMOW分别为-6.5‰~-2.5‰（均值-4.5‰）、16.2‰~22.4‰（均值18.7‰）。综合研究区内分析和收集的C、H、O和S同位素结果,表明成矿流体可能主要来源于岩浆流体,并有部分地层水加入。结合区域地球物理和年代学资料,认为黔西南卡林型金矿成矿可能与深部岩浆活动有关,而与区域上出露的基性—超基性岩浆岩没有直接的成因联系。