利用GIS和多维数据库技术实现长江口海域环境时空数据分析

基于GIS和多维数据库技术,依据海洋环境数据的特征,建立了长江口及邻近海域海洋环境的时空多维数据模型,研究了海洋环境数据的时空分析方法。依据2003、2004和2006年多航次的现场调查和分析数据,完善了海洋环境时空多维数据模型,对长江口海域环境时空多维海量数据进行了加工处理与可视化分析,并利用ArcGIS软件平台实现了数据的共享与发布,为岸滩蚀退的遏制和河口三角洲环境的综合治理提供了科学的数据基础。     

大西洋中脊TAG热液活动区海底热液沉积物的硫同位素组成及其？…

对１９８８年取自大西洋中脊ＴＡＧ热液活动区的海底表层热液沉积物中３６件硫化物样品进行了硫同位素组成分析。结合ＯＤＰＬｅｇ１５８的近期成果,对ＴＡＧ区热液沉积物的硫同位素组成及其时空演变、硫源、硫同位素偏重的原因和硫的演化进行了探讨,得出如下结论：（１）ＴＡＧ区表层热液喾物的δ＾３４Ｓ值从２．９‰－７．６‰变化,均值为５．９８‰,与其它洋中论脊热液合活动区相比明显偏重,（２）从海底表层区到蚀变玄武岩     

长江口及其邻近海域表层沉积物粒度划分及变化规律研究

对长江口及其邻近海域30个站位的表层沉积物粒度进行了粒级划分,在此基础上探讨了各粒级的变化规律。结果表明研究区表层沉积物最高含量粒级——粉砂(粒径4-63μm,含量大于50%)并非组成沉积物的主体粒级,<16μm的细粉砂及黏土粒级才是研究区的主体粒级,含量在50%-80%之间,能代表粒径频率分布的中心趋向和平均搬运动能情况。16μm是研究区沉积物粒度性质的一个分界点。通过对表层沉积物粒级的研究还发现研究区沉积物粒度粒级含量变化具有明显的规律性:4-8μm,8-16μm细粉砂粒级百分含量的变化规律与<1μm,1-2μm,2-4μm粒级(细分的黏土粒级)完全一致,与>16μm的各粒级之间不相关或呈强的负相关关系;16-32μm、32-63μm粗粉砂粒级含量的变化规律与63-125μm,125-250μm,>250μm粒级(细分的砂粒级)的变化规律呈弱相关或弱负相关关系,与<16μm的各粒级的变化规律不相关。对沉积物粒度的不同组分研究有助于对沉积动力环境和元素的“粒度效应”等问题进行深入探讨。     

琼东南盆地陵南低凸起深水钻井岩心的稀土元素地球化学特征及其意义

A geochemical analysis of rare-earth elements(REEs) in 97 samples collected from the core of deep-water Well LS-A located at the Lingnan Low Uplift Area of the Qiongdongnan Basin is conducted, with the purpose of revealing the changes of sedimentary source and environment in the study region since Oligocene and evaluating the response of geochemical characteristics of REEs to the tectonic evolution. In the core samples, both ∑REE and ∑LREE(LREE is short for light-group REEs) fluctuate in a relatively wide range, while ∑HREE(HREE is short for heavy-group REEs) maintains a relatively stable level. With the stratigraphic chronology becoming newer, both ∑REE and ∑LREE show a gradually rising trend overall. The ∑REE of the core is relatively high from the bottom of Yacheng Formation(at a well depth of 4 207 m) to the top of Ledong Formation, and the REEs show partitioning characteristics of the enrichment of LREE, the stable content of HREE, and the negative anomaly of Eu to varying degrees. Overall the geochemical characteristics of REEs are relatively approximate to those of China's neritic sediments and loess, with significant "continental orientation". The ∑REE of the core is relatively low in the lower part of Yacheng Formation(at a well depth of 4 207–4 330 m), as shown by the REEs partitioning characteristics of the depletion of LREE, the relative enrichment of HREE, and the positive anomaly of Eu; the geochemical characteristics of REEs are approximate to those of oceanic crust and basalt overall, indicating that the provenance is primarily composed of volcanic eruption matters. As shown by the analyses based on sequence stratigraphy and mineralogy, the provenance in study region in the early Oligocene mainly resulted from the volcanic materials of the peripheral uplift areas; the continental margin materials from the north contributed only insignificantly; the provenance developed to a certain extent in the late Oligocene. Since the Miocene, the provenance has ceaselessly expanded from proximal to distal realm, embodying a characteristic of multi-source sedimentation. In the core strata with 31.5, 28.4, 25.5, 23, and 16 Ma from today, the geochemical parameters of REEs and Th/Sc ratio have significant saltation, embodying the tectonic movement events in the evolution of the Qiongdongnan Basin. In the tectonic evolution history of the South China Sea, the South China Sea Movement(34–25 Ma BP, early expansion of the South China Sea), Baiyun Movement(23 Ma BP), late expansion movement(23.5–16.5 Ma BP), expansion-settlement transition, and other important events are all clearly recorded by the geochemical characteristics of REEs in the core.     

大西洋中脊TAG热浪区硫化物中流体包裹体的He-Ne-Ar同位素组成

对大西洋中脊ＴＡＧ（Ｔｒａｎｓ－Ａｔｌａｎｔｉｃ Ｇｅｏｔｒａｖｅｒｓｅ）热液区硫化物中流体包裹体的 Ｈｅ, Ｎｅ和 Ａｒ同位素组成进行了测定,流体包裹体的~3Ｈｅ／~4Ｈｅ比值为 ２．２～１３．３ Ｒａ,均值 为７．２Ｒａ,与该区喷口热液流体（~３Ｈｅ／~４Ｈｅ＝７．５～８．２Ｒａ）和ＭＯＲＢ（~３Ｈｅ／~４Ｈｅ＝６～１１Ｒａ）相比, 其变化范围明显较大．~（２０）Ｎｅ／~（２２）Ｎｅ比值为 １０．２～１１．４,明显高于大气值（９．８）．而~（４０）Ａｒ／~（３６）Ａｒ比 值的变化范围从２８７到 ３５９,接近大气值（２９５．５）．这些结果表明,热液硫化物中流体包 裹体的稀有气体是地幔和海水端员混合的产物,热液流体捕获的地慢源稀有气体中有 部分可能来自下地幔,且流体包裹体中的Ｈｅ主要来自上地慢,Ｎｅ和Ａｒ主要来自海水．     

冲绳海槽岩浆活动研究进展及思考

冲绳海槽以其特有的构造地质环境吸引着众多地质学者的关注。针对冲绳海槽地区岩浆作用过程的研究是其中的核心内容之一。本文综述了近年来冲绳海槽岩浆源区物质特征、岩浆形成演化过程及其控制机制等方面研究取得的主要成果,并在此基础上指出了目前冲绳海槽岩浆活动研究工作中存在的科学问题,提出利用铀系不平衡方法研究冲绳海槽岩浆活动的新思路,同时探讨了今后一段时间内的研究方向应该集中在以下四个方面: ①菲律宾板块俯冲的脱水过程对冲绳海槽岩浆活动的作用;②俯冲过程中深海沉积物对冲绳海槽岩浆的贡献;③冲绳海槽岩浆熔融的控制因素;④冲绳海槽火山活动和海底热液活动的成因关系。     

上新世以来南海海水表层温度（SST）的变化

The reconstruction of sea surface temperature(SST) is a key issue in research on paleoceanography. The recently related studies are mainly concentrated on the Quaternary. The skeletons of a typical species of benthonic foraminifer(Amphistegina radiata) in the top 0–375.30 m interval of Well "Xike-1" reef core, Shidao Island, the Xisha Islands, are uniformly selected. The ratios of magnesium to calcium concentrations and other indicators are analyzed by an electron microprobe analysis(EMPA) with the purpose of estimating the paleo-SSTs since the Pliocene and further investigating the periodic change law of paleoclimate in the South China Sea(SCS).Meanwhile, the geologic significance of paleoclimatic events in the SCS is discussed with global perspectives. The results indicate that the paleo-SSTs reconstructed by the ratios of magnesium to calcium concentrations in the SCS show a general periodic trend of "high–low–high–low" in values changes since the Pliocene. By comparison,the fluctuations of reconstructed paleo-SSTs are much stronger in the Quaternary. Moreover, the variations of the ratios of magnesium to calcium concentrations in the A. radiata skeletons have recorded a series of major paleoclimatic events since the Pliocene, of which the Quaternary glaciation events and the Arctic ice cap forming events during the late Pliocene are more significant. Thus, using the changes of the ratios of magnesium to calcium concentrations in the A. radiata skeletons from Well "Xike-1" reef core to reflect the relative changes of paleo-SSTs is a relatively feasible and reliable way in the SCS, which is also proved by the correlation of drilling cores characteristics in this area.     

渗透率对沉积物覆盖洋壳内热液循环的影响

上部洋壳内的热液对流是一个普遍存在的, 而且非常重要的地质过程. 在简单的平面边界条件下, 渗透率强烈地影响着热液循环的形态、对流体的大小及流体速度场. 通过使用高级数值模拟方法, 系统地研究了不同地层渗透率结构、地层非均质性、裂缝带及侵入体影响下的热液对流. 其中, 地质模型由沉积物、高渗基岩层、低渗基岩层三部分组成. 当高渗基岩层内的渗透率大于10倍的沉积物内渗透率时, 高渗层内发生对流现象. 热液循环的形态及流体流速受地层渗透率结构、高渗层内渗透率变化、裂缝带及冷却侵入体的强烈影响. 而地层非均质性(垂向与横向渗透率比值为1.5)对热液循环的影响相对较弱. 基岩内裂缝带是影响流场的最重要因素; 局部侵入体的影响范围只局限于其上方的对流强度, 而对区域规模的流动影响较小. 因此, 热液循环的关键因素是良好的渗透带(通道)及长期的热源, 而不包括流体来源.     

冲绳海槽浮岩岩浆活动模式浅析

本文根据部冲绳海槽的地下结构、地温场特征、以及浮岩中斑晶矿物的结晶温度和榴辉岩的熔融相关系等，综合分析了冲绳海槽酸性浮岩岩浆的活动模式。提出：在冲绳海槽中部和东部地下１５ｋｍ以下的地幔物质部分熔融、产生橄榄拉斑玄武质岩浆，而在海槽中部地壳一结构层中（７－１５ｋｍ）熔融产生少量安山质岩浆。因此，在冲绳海槽地下存在有双层岩浆房结构，并且二者之间中部有岩浆通道。来自地幔的拉斑玄武质岩资源下部地壳中一方面     

现代海底热液沉积物中硫化物集合体和其单矿的之间的硫同位素关系 …

硫化物集合体的硫同位素比值介于其单矿物中硫同位素比值的最大和最小值之间。当｜σ２－σ１｜〈△时,－σ（１＋２）与矿折中硫同位素组成最大和最小值的距离均小于△。当｜σ２－σ１｜〉△时,σ（１＋２）与σ１和σ２的距离有可能大于△。对现代海底热液沉积物来讲,排除了生舶和有机质的影响后,直接测定其硫化物集合体的硫同位素比值进行同位素示踪研究是可行的。