Covariations in oceanic dimethyl sulfide,its oxidation products and rain acidity at Amsterdam Island in the Southern Indian Ocean

Simultaneous measurements of rain acidity and dimethyl sulfide (DMS) at the ocean surface and in the atmosphere were performed at Amsterdam Island over a 4 year period. During the last 2 years, measurements of sulfur dioxide (SO₂) in the atmosphere and of methane sulfonic acid (MSA) and non-sea-salt-sulfate (nss-SO₄ ^2-) in rainwater were also performed. Covariations are observed between the oceanic and atmospheric DMS concentrations, atmospheric SO₂ concentrations, wet deposition of MSA, nss-SO₄ ^2-, and rain acidity. A comparable summer to winter ratio of DMS and SO₂ in the atmosphere and MSA in precipitation were also observed. From the chemical composition of precipitation we estimate that DMS oxidation products contribute approximately 40% of the rain acidity. If we consider the acidity in excess, then DMS oxidation products contribute about 55%.     

湖南仁里稀有金属矿田36号伟晶岩地球化学特征、成矿时代及其意义

位于幕阜山岩体西南缘的仁里稀有金属矿田是近年来华南地区新发现的一处重要花岗伟晶岩型稀有金属矿产地,铌钽矿体赋存于岩体内外接触带伟晶岩中,具有明显成矿分带性.文章选取仁里矿床岩体内接触带36号伟晶岩脉为研究对象,开展伟晶岩的地球化学及云母Ar-Ar年代学研究,探讨其与花岗岩围岩成因关系及岩体内接触带伟晶岩的成岩成矿时代,以丰富仁里矿田稀有金属成矿作用研究.研究表明,36号伟晶岩具高硅(w(SiO2)为72.87％～76.21％)、高铝(w(Al2O3)为13.69％～15.14％)、低钙镁铁、相对富碱(w(Na2O+K2O)为6.59％～8.33％)、(高钾)钙碱性及过铝质特征;微量元素总体富集Nb、Ta、Hf、U等高场强元素(HFSE),相对亏损Ba、Sr等离子亲石元素(LILE);稀土元素总量(ΣREE)13.95×10-6～71.63×10-6,轻稀土元素富集,重稀土元素亏损,具壳源特征.白云母Ar-Ar坪年龄为早白垩世(136.6±1.4)Ma,成矿作用发生于仁里矿田稀有金属大规模成矿的早阶段.地球化学及矿物学特征显示,36号伟晶岩与花岗岩围岩具有良好的演化关系,结合野外观察现象及成岩年龄,认为36号伟晶岩为花岗质岩浆侵位后残余岩浆结晶分异的产物,母岩为中粗粒片麻状黑云母二长花岗岩.     

基于多源数据约束的成矿动力学模拟——以宁芜盆地钟姑矿田典型矿床为例

数据驱动是大数据分析的特点之一。成矿过程的数值模拟即采用数据驱动方式,在基本的物理化学方程及地质模型基础上,通过定量的手段,模拟不同阶段、不同条件下成矿系统的演化过程,从而能够更深入、直观的讨论各种地质要素对成矿系统的影响,验证已有的成矿理论,获得新的认识。姑山铁矿床和杨庄铁矿床是宁芜火山岩盆地钟姑矿田内的典型矿床。前人研究显示,杨庄铁矿床为典型的充填-接触交代型热液矿床,而姑山铁矿床目前在成因上仍存在争议,存在岩浆成因和热液成因等多种观点。为了更好的对比和了解姑山铁矿床和杨庄铁矿床的成因及成矿过程,本文基于多源数据的综合解译剖面,采用力-热耦合数值模拟方法对与热液矿床密切相关的扩容空间的形成机制和特点开展研究。模拟结果显示,姑山铁矿床和杨庄铁矿床可能分属不同的成因类型;随着岩体的逐渐冷却,杨庄铁矿床内岩体和地层接触带会出现明显的扩容空间,可为成矿流体的汇聚及矿质的沉淀提供良好的条件,有利于热液矿床的形成;而姑山铁矿床内岩体和地层接触带只有局部区域出现扩容空间,同时体应变数值较小且形态变化大,并不利于大规模的流体汇聚及矿质的沉淀,姑山铁矿床可能主要为岩浆成因,并受少量热液的叠加改造。     

湖南仁里稀有金属矿田206号锂辉石伟晶岩脉地球化学特征及成矿时代

湖南仁里稀有金属矿田是中国近年来新发现的一处重要的花岗伟晶岩型铌、钽、锂等稀有金属矿产地,文章针对矿田含锂伟晶岩地球化学特征、成矿时代及其与花岗岩的关系,选取传梓源锂铌钽矿床内规模最大的206号锂辉石伟晶岩脉开展地球化学和白云母Ar-Ar定年工作,并与区内其他伟晶岩、花岗岩的地球化学特征、成岩时代对比分析.传梓源206号锂辉石伟晶岩属高分异稀有金属伟晶岩,形成时代为(135.4±1.4)Ma,岩石地球化学表现为高硅、高铝、低钙、相对富碱、钙碱性及过铝质特征;稀土元素总量很低,以轻稀土元素为主;微量元素富集Cs、Rb、U、Ta、Nb、Zr、Hf,相对亏损Ba、Ti,Zr/Hf、Nb/Ta比值低且集中.幕阜山地区稀有金属成矿可分为2期:第1期稀有金属成矿时代约145 Ma,与燕山早期岩浆活动有关;第2期稀有金属成矿时代135～125 Ma,为主成矿期,该期稀有金属伟晶岩与燕山晚期的二云母二长花岗岩存在成因联系,两者为同源岩浆连续结晶分异过程中不同阶段的产物.稀有金属富集成矿经历了岩浆-热液两阶段作用,Be、Nb、Ta、Li、Rb、Cs等稀有元素的富集多发生于岩浆结晶分异晚期,热液作用使Ta、Li、Rb、Cs再次富集.     

On the inclusion of ground-based gravity measurements to the calibration process of a global rainfall-discharge reservoir model: case of the Durzon karst system (Larzac, southern France)

This work examines the relevance of the inclusion of ground-based gravity data in the calibration process of a global rainfall-discharge reservoir model. The analysis is performed for the Durzon karst system (Larzac, France). The first part of the study focuses on the hydrological interpretation of the ground-based gravity measurements. The second part of the study investigates further the information content of the gravity data with respect to water storage dynamics modelling. The gravity-derived information is found unable to either reduce equifinality of the single-objective, discharge-based model calibration process or enhance model performance through assimilation.     

Middle Devonian-Tournaisian rocks and biota on Hainan Island, South China

On the basis of new paleontological data,the sequence and distributions of the Middle Devonian-Tournaisian rocks on Hainan Island have been sorted out for the first time.The Devonian rocks include the Middle Devonian Jinbo Formation and the Upper Devonian Changjiang Formation,which are distributed in northwestern Hainan Island.The Jinbo Formation is represented by631 m of littoral facies deposits,and was intruded by the Yanshanian granite in the base.The presence of chitinozoans Eisenackitina caster,Funsochitina pilosa,and Lagenochitina amottensis indicates the Givetian in age.The Changjiang Formation is made up of 140 m of neritic facies rocks,and contains the Famennian conodonts Palmatolepis gracilis sigmoidalis,Polygnathus germanus,and corals Cystophrentis kalaohoensis.The Devonian-Tournaisian transition beds,the lower part of the Jishi Formation,are composed of 61–129 m sandstone and siltstone,with gastropods Euomphalus spp.and brachiopods,and marked by conglomerate with the underlying Devonian rocks.The middle-upper part of the Tournaisian Jishi Formation consists of 100–251 m clastic and carbonate rocks,containing abundant corals Pseudoularinia irregularis,conodonts Siphonodella isosticha,trilobites Weberiphillipsia linguiformis,and brachiopods.On the basis of the occurrence of Xinanosprifer flabellum and Homotoma sp.,the Nanhao Formation in southern Hainan Island is now regarded as the Lower Silurian,instead of the previously designated Lower Carboniferous.It is confirmed that no Carboniferous rocks occurred in the area south to the Gancheng-Wanning Fault.     

地震行业地面骨干网与应急卫星通信网互联路由设计方案的探讨

本文介绍了地震行业地面骨干网与应急卫星通信网的运行现状及互联存在的路由问题,讨论了实现两网互联的路由设计目标和策略,根据OSPF协议与BGP协议的特点和适用范围,提出了统一互联的接入方法,以及联合使用OSPF和BGP协议解决两网互联路由问题的具体方案,经网络仿真平台测试证明,该方案切实可行,效果良好。     

Hydrological characteristics of karstic groundwater in the northeast Viet Nam as studied by isotopic techniques

The stable water isotopic composition (δ²H and δ¹⁸Ο), tritium (³H) activity, dissolved organic carbon, alkalinity, as well as the composition of carbon 13 (δ¹³C) in dissolved inorganic carbon (DIC) of 36 water samples taken from 16 resurgences in the northeast provinces of Viet Nam in the dry (Mar 2008) and rainy (June 2008) seasons were analyzed to elucidate hydrological characteristics of the karstic aquifers in the area. The stable water isotopic composition of the water samples collected clearly demonstrated that the karstic groundwater in the region was recharged from the local meteorological water. The tritium activity in the samples was found to be in between 3 and 4 TU, falling in the range of the ³H activity in the local precipitation and thus meaning that the traveling of recharge water to the resurgences was very short. Concentrated and diffuse allogenic recharges seem to be important sources of karstic groundwater in the study region. Water in the karstic aquifers could be classified into three types as: (a) water from karstic areas with dense vegetation cover that causes DIC be depleted in carbon 13 (¹³δ<?12‰ vs. Pee Dee Belemnite standard of Vienna, VPDB); (b) water from karstic areas with poor vegetation cover that originates DIC with carbon 13 composition ranging from ?11 to ?12‰; and (c) surface water from lakes, springs and rivers that has DIC with enriched carbon 13 (δ¹³C >?10‰). This implies that there are several sources of carbon dioxide contributing to the DIC in water of the karstic aquifers in the study region. Among other potential sources, the atmospheric CO₂, CO₂ from carbonate rock dissolution, biomineralization of soil organic matters and plant roots respiration seem to be important sources of the DIC in the waters of this region. The results show high vulnerability towards anthropogenic contaminants of karstic groundwater in the study region.     

Performance of a multi-RCM ensemble for South Eastern South America

The ability of four regional climate models to reproduce the present-day South American climate is examined with emphasis on La Plata Basin. Models were integrated for the period 1991–2000 with initial and lateral boundary conditions from ERA-40 Reanalysis. The ensemble sea level pressure, maximum and minimum temperatures and precipitation are evaluated in terms of seasonal means and extreme indices based on a percentile approach. Dispersion among the individual models and uncertainties when comparing the ensemble mean with different climatologies are also discussed. The ensemble mean is warmer than the observations in South Eastern South America (SESA), especially for minimum winter temperatures with errors increasing in magnitude towards the tails of the distributions. The ensemble mean reproduces the broad spatial pattern of precipitation, but overestimates the convective precipitation in the tropics and the orographic precipitation along the Andes and over the Brazilian Highlands, and underestimates the precipitation near the monsoon core region. The models overestimate the number of wet days and underestimate the daily intensity of rainfall for both seasons suggesting a premature triggering of convection. The skill of models to simulate the intensity of convective precipitation in summer in SESA and the variability associated with heavy precipitation events (the upper quartile daily precipitation) is far from satisfactory. Owing to the sparseness of the observing network, ensemble and observations uncertainties in seasonal means are comparable for some regions and seasons.     

一种四维绘图软件Vis5d使用要点简述

Vis5D是美国威士康星-麦迪逊大学空间科学与工程中心(SSEC)研制的可视化系统,主要有Bill Hibbard 和Johan Kellum 完成.Vis5D能够直观而清晰地显示3维立体图形,适用于中尺度研究结果,尤其是云物理结构研究.本文介绍了Vis5D的安装过程以及数据文件转换为v5d格式的方法,并以GRAPES数值模式输出产品为例进行了初步的可视化试验.