Porosity–permeability relationships in Miocene carbonate platforms and slopes seaward of the Great Barrier Reef, Australia (ODP Leg 194, Marion Plateau)     

STEPHEN N. EHRENBERG  GREGOR P. EBERLI†  GREGOR BAECHLE† 《Sedimentology》2006,53(6):1289-1318

  相似文献   

Petrology and Geochemistry of West Philippine Basin Basalts and Early Palau-Kyushu Arc Volcanic Clasts from ODP Leg 195, Site 1201D: Implications for the Early History of the Izu-Bonin-Mariana Arc   总被引：3，自引：0，他引：3  

SAVOV  IVAN P.; HICKEY-VARGAS  ROSEMARY; D'ANTONIO  MASSIMO; RYAN  JEFFREY G.; SPADEA  PIERA 《Journal of Petrology》2006,47(2):277-299

Site 1201D of Ocean Drilling Program Leg 195 recovered basalticand volcaniclastic units from the West Philippine Basin thatdocument the earliest history of the Izu–Bonin–Marianaconvergent margin. The stratigraphic section recovered at Site1201D includes 90 m of pillow basalts, representing the WestPhilippine Basin basement, overlain by 459 m of volcaniclasticturbidites that formed from detritus shed from the Eocene–Oligoceneproto-Izu–Bonin–Mariana island arc. Basement basaltsare normal mid-ocean ridge basalt (N-MORB), based on their abundancesof immobile trace elements, although fluid-mobile elements areenriched, similar to back-arc basin basalts (BABB). Sr, Nd,Pb and Hf isotopic compositions of the basement basalts aresimilar to those of basalts from other West Philippine Basinlocations, and show an overall Indian Ocean MORB signature,marked by high ²⁰⁸Pb/²⁰⁴Pb for a given ²⁰⁶Pb/²⁰⁴Pb and high¹⁷⁶Hf/¹⁷⁷Hf for a given ¹⁴³Nd/¹⁴⁴Nd. Trace element and isotopicdifferences between the basement and overlying arc-derived volcaniclasticsare best explained by the addition of subducted sediment orsediment melt, together with hydrous fluids from subducted oceaniccrust, into the mantle source of the arc lavas. In contrastto tectonic models suggesting that a mantle hotspot was a sourceof heat for the early Izu–Bonin–Mariana arc magmatism,the geochemical data do not support an enriched, ocean islandbasalt (OIB)-like source for either the basement basalts orthe arc volcanic section. KEY WORDS: back-arc basalts; Izu–Bonin–Marianas; Philippine Sea; subduction initiation; Ocean Drilling Program Leg 195  相似文献   

电子政务综合分析与评价平台建设初探     

董春  刘纪平  康风光 《测绘科学》2007,32(Z1):88-90

本文立足于政府部门决策分析的科学化和智能化,突破电子政务局限于办公自动化和政府上网等操作层面的研究,提出了在数据库管理系统及数据钻取与挖掘工具、模型库管理系统、知识库管理系统技术支撑下建立起来的电子政务综合分析与评价平台的框架结构和技术体系,该平台综合了GIS的空间分析与数据挖掘功能、空间统计功能、经典统计分析功能以及数学分析功能,能够对政务信息数据库进行多方位、深层次的数据分析与综合评价,最终对政府提供科学决策依据。  相似文献   

Organic geochemistry of Deep Sea Drilling Project sediments from the Gulf of Calofornia—hydrothermal effects on unconsolidated diatom ooze     

Bernd R.T. Simoneit  R.P. Philp  P.D. Jenden  E.M. Galimov 《Organic Geochemistry》1984,7(3-4)

The effects of intrusive thermal stress have been studied on a number of Pleistocene sediment samples obtained from Leg 64 of the DSDP-IPOD program in the Gulf of California. Samples were selected from Sites 477, 478 and 481 where the organic matter was subjected to thermal stress from sill intrusions. For comparison purposes, samples from Sites 474 and 479 were selected as representative of unaltered material.The GC and GC-MS data show that lipids of the thermally unaltered samples were derived from microbial and terrestrial higher-plant detritus. Samples from sill proximities were found to contain thermally-derived distillates and those adjacent to sills contained essentially no lipids. Curie point pyrolysis combined with GC and GC-MS was used to show that kerogens from the unaltered samples reflected their predominantly autochthonous microbial origin. Pyrograms of the altered kerogens were much less complex than the unaltered samples, reflecting the thermal effects. The kerogens adjacent to the sills produce little or no pyrolysis products since these intrusions into unconsolidated, wet sediments resulted in in situ pyrolysis of the organic matter.Examination of the kerogens by ESR showed that spin density and line width pass through a maximum during the course of alteration but ESR g-values show no correlation with maturity. Stable carbon isotope (δ¹³C) values of kerogens decrease by 1–1.5‰ near the sills at Sites 477 and 481 and the atomic N/C decreases slightly with proximity to a smaller sill at Site 478. Differences in maturation behavior between Site 477 and 481 and Site 478 are attributed to dissimilarities in thermal stress and to chemical and isotopic heterogeneity of Guaymas Basin protokerogen.  相似文献   

IVSA模型在双来源自动站小时降水数据实时拼接中的应用     

刘一鸣 《气象》2015,41(11):1398-1407

利用2012年5月1日至7月31日全国自动气象站两种来源实时上传资料中的“非缺测不一致”小时降水数据,详查了问题的产生原因,为在实时拼接过程中高效判断数据正确性,提出较小尺度时间序列求证比对模型（IVSA）：当同一时间同一台站的两种来源小时降水值发生不一致时,首先在较小时间尺度（分钟级）序列上使用内部一致性检查方法分别求证小时降水的正确性;当各自在较小时间尺度序列均无法证伪时,将单元出错概率引入两分钟降水序列的比对过程,并据此竞优遴选得出较为可靠的小时降水数据。指出：（1）产生非缺测不一致问题的原因主要有生成报文时观测数据不全、报文处理环节不一致、台站信息不正确三类。（2）使用2012年5月1360组实例形成IVSA模型参数后,模型在2012年6—7月的4017组非缺测不一致数据中取得了99.65%的判断准确率。通过IVSA模型,非缺测不一致的小时降水数据取舍问题可在分钟降水序列比对中找出答案。  相似文献   

辽宁省夏季多模式降水预报检验及晴雨预报技术研究     

聂安祺  李得勤  滕方达  陆井龙  王当 《气象与环境学报》2020,36(5):10-17

利用辽宁省291个国家气象观测站的降水资料,对2019年夏季（6-9月）8种模式降水预报及中央气象台格点降水预报进行了检验评估和比较,并采用消空方法进行晴雨预报技术研究。结果表明：2019年,EC模式具有最优的暴雨预报性能,而日本模式暴雨TS评分最高;中尺度模式对于局地性暴雨和短时强降水具有较好的预报潜力,性能较好的是GRAPES_MESO模式和睿图东北3 km模式;全球模式对24 h暴雨的预报频率比实况偏低30%,3 h强降水则偏低60%,中尺度模式对24 h暴雨的预报频率比实况偏高30%,3 h强降水则偏低20%。由于对小量级降水存在较多空报,各模式原始预报的晴雨预报大多呈现空报偏多的情况;使用小量级降水剔除的消空策略能够明显提高晴雨准确率,消空之后EC模式具有最优的晴雨预报性能。分别使用24 h和3 h累计降水量优化消空策略,发现分别取1.0 mm和0.8 mm的阈值进行消空可以使24 h晴雨准确率提高15.58%,3 h晴雨准确率提高10%-30%。  相似文献   

中国大陆科学钻探工程主孔3000～3500 m花岗质片麻岩地球化学性质及其成因机制   总被引：1，自引：0，他引：1  

周开富刘福来  许志琴李天福杨经绥  薛怀民叶建国 《地质学报》2006,80(12):1851-1866

中国大陆科学钻探工程主孔(CCSD-MH)3000~3500m深度范围内的岩心揭示的主要岩石类型以正、副片麻岩为主,夹少量的榴辉岩、片岩及斜长角闪岩等。正片麻岩可进一步划分为钾长花岗质片麻岩和二长花岗质片麻岩。地球化学研究表明,花岗质片麻岩的SiO2含量普遍高,为73.56%~79.01%,Al2O3含量为10.49%~13.75%;TiO2、Fe2O3、FeO、MnO和MgO的含量明显偏低,其中Fe2O3为0.26%~2.56%,FeO为0.09%~1.13%,MgO为0.01%~0.63%;岩石明显富含Na2O、K2O,强烈贫钙,Na2O K2O的含量为6.20%~9.15%,K2O的含量为1.26%~5.67%,CaO的含量为0.08%~1.59%。花岗质片麻岩在洋脊玄武岩标准化蛛网图上都表现出强烈富集大离子亲石元素(K、Rb、Th)的特点,高场强元素Ti、Ta和Nb表现为明显的负异常,而Hf和Zr则为明显正异常。3000~3500m花岗质片麻岩的原岩具A型花岗岩的特征,形成于大陆裂谷环境,记录了Rodinia超大陆裂解时苏鲁地区的花岗岩浆事件,表明新元古代晚期扬子板块北缘的构造属性为大陆裂谷环境。  相似文献   

Numerical study on mode curvature for damage detection of a drilling riser using transfer matrix technique     

《Applied Ocean Research》2017

In order to prevent marine pipeline accidents caused by corrosion defect, crack or loose contact, the technique of non-destructive testing or examination (NDT or NDE) becomes great important in the flied of structural health monitoring (SHM) in ocean engineering. The objective of this study is to propose a numerical method to localize and size the structure damage of a drilling riser. One theoretical development is a simple and effective algorithm used for ocean risers’ mode extraction and damage detection based on the transfer matrix technique. The merits of the developed method are that damage of risers with different boundary conditions and variable cross-sections can be localized and sized. Additionally, the relationships between damage locations and modes are discussed by comparing mode shape difference, mode curvature and mode curvature difference. Numerical results show that mode curvature values of damaged elements have little influence on those of intact elements. Based on this fact, a damage index method is developed to evaluate damage severities and explore the influence of single and multiple damage severities on damage indexes. More importantly, the outcomes are verified to be accurate enough to indicate the feasibility and reliability of the numerical method by the standard FEM package.  相似文献   

国内外海洋调查船现状对比分析          下载免费PDF全文

孟庆龙  李守宏  孙雅哲  杨维维 《海洋开发与管理》2017,34(11):26-31

海洋调查船是专门进行海洋调查研究的工具,研究内容囊括了海洋气象、水声、物理、化学、生物、地质和水文等诸多学科,是我国海洋强国战略以及"一带一路"顺利实施的重要保障。海洋调查船按照使用的目的分为综合调查船、渔业调查船和极地调查船等。文章在各类调查船中分别选取了国内外具有代表性的船舶进行对比分析,总结了国内各类型调查船的优势和不足,对我国各类调查船的发展方向具有较好的借鉴意义。同时,文章根据对国内外调查船调查能力的对比,提出了我国调查船发展的建议:(1)完善调查船类型;(2)提高各类型船舶调查能力;(3)增加相应类型船舶数量,达到我国海洋调查需求;(4)推动海洋调查仪器设备的国产化进程;(5)加强国家海洋调查船队运行管理职能。  相似文献   

GRAPES-GEPS环流集合预报的分类释用方法研究与检验     

罗月琳  高丽  陈权亮  蔡宏珂  任宏利 《气象学报》2021,79(4):646-658

集合预报在数值天气预报体系中具有重要地位,因此如何有效提取集合样本信息以提高集合预报技巧一直是一个重要课题.基于中国全球集合预报业务系统(GRAPES-GEPS)的500?hPa高度场集合资料开展对环流集合预报的分类释用方法研究,并对集合聚类预报结果进行了检验分析.通过在传统Ward聚类法中引入动态聚类的"手肘法"方案...  相似文献