西沙群岛生物碳酸盐的成因和沉积:来自活体仙掌藻的证据

A recent island survey reveals that the Xuande Atoll and the Yongle Atoll in the Xisha Islands can be classified into one of two systems: the depleted atoll system and growth atoll system; the survey also indicates that the decreased area of several shoals is an unbearable burden for the Xisha Islands, of which the largest island area is 2.13 km2 and the minimum elevation is 1.4 m. According to a survey on the ecological characteristics of Halimeda in the Laolongtou breaker zone of Shidao Island in the Xisha Islands, the green and white living Halimeda are collected,the isotopic ages of 14 C contained in the Halimeda are shown to be 27 years and 55 years, respectively, and carbonate mainly occurs in five types, i.e., luster, segment, sand, sand grain, and marl in the formation. The Halimeda segments mainly provide the carbonate sediments of long-term biogenic deposits in the reef environment and the annual productivity per area is 60–100 g/m2; the characteristics of the microstructure of the Halimeda are analyzed, the aragonite raphide carbonate is deposited and enriched in the cortexes, medullas and cysts, and the Halimeda generally contain major elements such as C, O, Ca, Cl, Mg, K, Na, S and Al, and are rich in trace elements such as tellurium(Te), rhodium(Rh) and strontium. It is believed that the Halimeda grow slowly,including the biotic community of reef corals in the reef areas, thus they possess an environmental remediation capacity, but it takes much time to remedy the environment, and it is necessary to make the law to protect the diversity and vulnerability of the Xisha marine ecology, the ecology of the reef community and the island environment in a scientific way. As indicated in the survey, under the background of global warming and sea-level rise, the discovery of large amounts of Halimeda in the Laolongtou sea area is significant for the natural increase of the depleted atoll system of the Xuande Atoll, while the Halimeda segments represent the primary form of the fossil Halimeda, of which the species can be identified and preserved in great numbers under geological conditions. The Miocene was discovered in large amounts in the Xichen-1 well, therefore the study on the characteristics and mechanism of Halimeda carbonate sediments plays a pivotal role in the formation and construction of organic reefs in the South China Sea as well as oil and gas exploration.     

青岛青山湾-垭口变沉积岩岩石地球化学特征及其物质来源

青岛青山湾—垭口出露一套浅变质的海相陆缘碎屑沉积岩,上覆岩浆锆石的LA-ICP-MS U-Pb年龄为(118.9±3.3)Ma,成熟度较低,与中新生代造山带砂岩类似。稀土元素球粒陨石化标准配分曲线均为轻稀土明显富集的右倾型,表明,研究区碎屑岩具有相同的物源区和构造背景,与活动陆缘的稀土元素配分曲线非常接近。Ce具弱的负异常,指示碎屑岩为大陆边缘海相成因,(La/Ce)N(PAAS)表明陆缘碎屑物质对该区碎屑岩有明显的贡献。主微量元素构造环境判别图解表明,研究区碎屑岩具有活动陆缘和大陆岛弧的特征,经历了相对简单的沉积演化过程;结合稀土元素配分曲线的特征,该区碎屑岩更可能是活动大陆边缘沉积形成。主微量元素分析揭示研究区碎屑岩物源富长英质岩石,镁铁质岩石作为物源也参与到成岩过程中。     

Ferroan dolomites in Miocene sediments of the Xisha Islands and their genetic model

Carbonate rocks are important reservoirs for global petroleum exploration.The largest oilfield in the South China Sea,Liuhua 11-1,is distributed in the massive carbonate reef area of the Zhujiang(Pearl)River Mouth Basin.Previous studies showed that one 802.17-m-long core from well Xichen-1 in the South China Sea mainly consisted of white and light gray-white organic reefs.Recently,a Miocene whole core(161.9 m long)of well Xiyong-2,near well Xichen-1,was found to contain six layers of yellowish brown,light yellowish gray,iron black,or light yellowish gray-white organic reefs.Scanning electron microscope images of these layers reveal a typical ferroan dolomite rich in Fe(up to 29%),with the high concentrations of Mn,Cu,W,Zn,Cr,Ni,and Co.Systematic X-ray powder diffraction analysis yields a 1.9–6.1 match in phase ratio with ankerite,5.4–26.9 with dolomite,and zero with calcite,which indicate that the samples can be classified as ferroan dolomite.The iron and heavy metals are inferred to be originated from multiple volcanic eruptions of Gaojianshi Island in the Dongdao Atoll during the middle-late Miocene.These elements were dissolved in seawater,likely as a sol,and carried to Yongxing Island in the Xuande Atoll by sea currents and tides enhanced by prevailing winds,and deposited as a part of the sedimentation process in the study area.The ferroan dolomite has Sr content of (125–285)×10~(-6),which is lower than the accepted Sr boundary value of dolomite.This finding suggests that dolomitization occurred during large-scale global glacial regression in the late Miocene.The isolated Xisha carbonate platform,exposed to air,underwent freshwater leaching and dolomitization induced by mixed water,and caused the extensive Fe-Mg exchange along the organic reef profile to form ankerite and ferroan dolomite.These results may help to understand paleoceanographic environmental changes in the South China Sea during the Miocene.     

国际天然气水合物调查研究现状及其主要技术构成

本在研究大量国外献（含2000年6月日本东京“2000年西太平洋地球理会议”）资料的基础上，统计了迄今为止国际天然气水合物的发现成果，对涉及天然气水合物研究和调查的工作进行了简要回顾，划分其为五个研究工作阶段和五个调查工作阶段，并对一些重要国家尤其是对我国周边国家或地区进行天然气水合物调查和研究工作的现状作了简要介绍，通过分析天然气水合物分布与产出状况的11个重特征，归纳总结了国际天然气水合物调查综合评价的地球物理资料采集，处理及其解释，资源量计算，实物样品采集等三大主要技术的基本内容和要求，指出了高投入的前提下，坚持勘测方法的综合性，高技术性，创新性和有效性，将是取得了实质性成果的关键之所在。     

中国海域及邻区含油气盆地生物礁的对比研究

本文阐述了中国海域及邻区含油气盆地生物礁形成环境,分布、时代、与发育演化特征,进而提出三种成礁模式。指出在东海,渤海湾盆地存在发现礁油气田的可能性及工作建议。     

区别于DSDP-ODP的深海保压保温天然气水合物钻探取心技术

到目前为止，任何深海天然气水合物原位岩心样品的钻探、取心技术都离不开ODP(大洋钻探计划)或DSDP(深海钻探计划)专用船舶钻探技术，该技术主要通过从工作母船上连接几百到几千米钻杆到海底，实现500—1000m的钻探，再通过不同类型PCS(保压取心器)与PTCS(保压保温取心器)取心工具实现样品采集。重要特点是投入经费巨大。新型保压保温取心钻具是将钻具直接固定在深海海底，实现样品的原位保真采集，针对国内外两类着底式天然气水合物钻探、取心技术进行了分析，对于深海浅表层天然气水合物原位样品采集作业反映了创新的思维、技术模式、设计方案与科学方法     

德国联邦地学研究中心与全德天然气水合物研究

简要介绍了德国联邦地学研究中心及全德天然气水合物调查研究现状与成果,特别是对“太阳号”在“水合物海脊”和SO177-1航次在中国南海等的科学调查及研究成果进行了介绍。     

含油气盆地裂变径迹研究进展与固体核裂变径迹学——第九届全国固体核裂变径迹学术研讨会的启示

简要介绍了第九届全国固体核裂变径迹学术研讨会的概况,根据会议交流成果重点阐述了含油气盆地裂变径迹的研究成果和进展。     

台西盆地新生界油气地质勘探与开发

台西盆地是我国投入工作量较少和在盆地西部(海峡中心线以西)油气勘探工作程度较低的地区；但是在盆地东部(包括海峡中心线以东和台湾陆地地区)已经有相当的油气发现。通过对海峡两岸油气地质与周边区域地质构造的调查研究和二维地震剖面分析表明，台西盆地是直接遭受菲律宾海板块俯冲作用和台湾地体独特弧陆碰撞构造作用影响的含油气盆地。碰撞岛孤前锋与岛弧带地震活动频繁，严重破坏了盆地原型的地质构造特征。台西盆地早期为断陷盆地性质，晚期为典型岛孤后盆地性质，构造区划为东西两个坳陷带发育四凹两凸。中新生代沉积盆地表现为典型下部断陷型和上部坳陷型盆地结构，最大沉积厚度8000～10000m，沉积主洼形态较好，晚—早第三纪是盆地主要的勘探目的层系。     

东海陆架盆地早期沉积体系及其资源远景评价意义

根据东海四轮对外招标和近期部分工作成果,对东海陆架盆地新生代早期与前第三系含油气系统存在的可能性及其油气资源远景评价意义进行了初步分析.推测西湖-基隆(台北)凹陷带新生代盆地早期——古新统(T04-T06)可能发育裂谷早期湖相或滨海湖相沉积体系,与已经钻探证实的长江-丽水(瓯江)凹陷带构成“二坳夹一隆”的沉积格局,认为该河湖沉积体系与前第三系含油气系统为陆架盆地区提供了更为广阔的油气资源远景评价和勘探空间.