墨西哥湾GC238区冷泉碳酸盐岩的微结构与石化微生物特征

采于墨西哥湾GC238海底天然气渗漏区浅表层的冷泉碳酸盐岩呈结核状产出,由方解石微晶和胶结物及少量的黄铁矿构成。胶结物由直径为0.1～0.5 m的方解石化的球体、卵形体、棒状体组成,充填于方解石晶体之间。冷泉碳酸盐岩结核下表面发育有由方解石化的球体、卵形体、棒状体组成的薄层,其中的一些球状集合体（约5 m）断面显示发育有核和外壳的层圈结构。黄铁矿呈草莓状,也具有相似的层圈结构。这种层状结构与活体古细菌被硫酸盐还原细菌包裹的层圈结构相似。样品中所保存的球体、卵形体、棒状体及其所组成的层圈结构可能是石化的甲烷氧化古细菌和硫酸盐还原细菌。     

墨西哥湾GC238区冷泉碳酸盐岩的微结构与石化微生物特征

采于墨西哥湾GC238海底天然气渗漏区浅表层的冷泉碳酸盐岩呈结核状产出,由方解石微晶和胶结物及少量的黄铁矿构成。胶结物由直径为0.1～0.5m的方解石化的球体、卵形体、棒状体组成,充填于方解石晶体之间。冷泉碳酸盐岩结核下表面发育有由方解石化的球体、卵形体、棒状体组成的薄层,其中的一些球状集合体(约5m)断面显示发育有核和外壳的层圈结构。黄铁矿呈草莓状,也具有相似的层圈结构。这种层状结构与活体古细菌被硫酸盐还原细菌包裹的层圈结构相似。样品中所保存的球体、卵形体、棒状体及其所组成的层圈结构可能是石化的甲烷氧化古细菌和硫酸盐还原细菌。     

南海北部冷泉碳酸盐岩和石化微生物细菌及地质意义

通过对2002年广州海洋地质调查局在南海北部海域拖网采集的碳酸盐岩样品进行岩石、矿物、微量元素和同位素特征的研究,证实在南海水合物远景区发育有冷泉碳酸盐岩。冷泉碳酸盐岩形态类似于烟囱,主要由方解石、伊利石、石英、黄铁矿和一种未知的矿物组成。保存了很可能是石化的甲烷氧化和硫酸盐还原细菌。碳酸盐岩矿物的δ^13CPDB为-51.24‰～-51．757‰。碳酸盐岩矿物的页岩标准化稀土元素配分模式具无Ce和Eu异常、微弱的轻稀土亏损和中稀土富集特征,表明形成于还原的缺氧环境,显示了冷泉碳酸盐岩的特征,指示在南海北部水合物远景分布区内冷泉活动的近海底可能发育有水合物。     

南海神狐海域富Fe碳酸盐岩烟囱矿物学和地球化学的研究

<正>冷泉碳酸盐岩广泛分布在世界各地的主动或被动大陆边缘,它是冷泉区渗漏的甲烷与海水中硫酸根离子发生甲烷厌氧氧化和硫酸盐细菌还原作用的产物,详细记录海底流体的渗漏情况。因此,利用冷泉碳酸盐岩中的矿物组成、元素含量以及C、O、Fe同位素特征示踪碳酸盐的沉淀氧化还原环境、海底流体来源及其流体活动、探讨天然气水合物存在的可能性具有非常重要的作用。南海北部陆坡是天然气水合物发育的理想场所,已发现水合物发育的地质、地球化学和生物证据。2007年,广州海洋地质调查局在神狐海域     

西藏岗巴地区晚白垩世冷泉碳酸盐岩地球化学特征及其对流体来源及沉积环境的示踪

冷泉碳酸盐岩是海底冷泉流体活动的重要标志,其地球化学特征记录了过去流体活动的信息。西藏岗巴地区晚白垩世沉积地层中发育有冷泉碳酸盐岩,为了探究其形成的流体来源及沉积环境,开展了野外观察、岩石学、矿物学、地球化学研究。该区岗巴剖面冷泉碳酸盐岩以结核状产于灰黑色页岩中,碳酸盐矿物主要为泥微晶方解石,含少量草莓状黄铁矿,δ13CV-PDB为-17.0‰~-7.2‰,表明碳源可能与甲烷渗漏冷泉活动有关。稀土元素分布模式呈中稀土富集特征,经La校正后显示无Ce异常,指示了冷泉碳酸盐岩形成于弱缺氧的沉积环境中。西藏岗巴地区碳酸盐岩结核的发现及其地质地球化学特征是该地区晚白垩世冷泉甲烷渗漏活动发育的有力证据,对古冷泉流体来源及沉积环境特征的探讨将为恢复古冷泉活动提供重要线索。     

南海北部烟囱状碳酸盐岩记录的冷泉流体活动演化特征研究

冷泉碳酸盐岩是冷泉渗漏活动的重要产物之一,它记录了冷泉流体的来源、其活动演化特征和沉积环境等。通过对南海北部东沙海域Site3站位采集的三个烟囱状冷泉碳酸盐岩的矿物成分、碳氧同位素及碳酸盐岩中黄铁矿硫同位素的研究,确定了冷泉渗漏可能的流体来源,结合烟囱状碳酸盐岩独特的形貌特征,探讨了研究区冷泉流体的活动演化特征。烟囱A为环状,外环直径16 cm,中央流体通道直径5 cm;烟囱B呈底部直径8 cm的实心锥形;烟囱C也为环状,外环直径20 cm,中央流体通道直径12 cm。三个烟囱都具有较负的碳同位素组成(δ~(13)CVPDB值低至–55.7‰)和较正的氧同位素组成(δ~(18)OVPDB值高达5.4‰)特征。研究认为,甲烷是该海域冷泉渗漏流体的主要烃类来源,其中沉淀烟囱C的冷泉流体中很可能存在水合物分解释放流体的加入。三个烟囱状碳酸盐岩的外层相比于内层,普遍具有δ~(13)C值高、δ~(18)O值低、δ~(34)S值高的特征,认为这是由于烟囱状碳酸盐岩从外至内形成过程中沉积空间逐渐受到限制导致流体渗漏强度增强而造成的。综上所述,烟囱状冷泉碳酸盐岩因其独特的形态结构,是冷泉流体渗漏特征在时间和空间上变化的优良记录者。     

海底天然气渗漏系统微生物作用及冷泉碳酸盐岩的特征

海底天然气渗漏系统是全球海洋环境中广泛分布的自然现象。部分渗漏天然气通过细菌作用转变为二氧化碳,同时海水硫酸盐被还原为硫化氢, 与孔隙水中的钙和铁结合而沉淀冷泉碳酸盐岩。冷泉碳酸盐岩的常见矿物有微晶方解石、文石、白云石和黄铁矿。冷泉碳酸盐岩常发育一些特殊的组构, 如黄铁矿环带结核、溶蚀面、平底晶洞、凝块和向下生长的叠层石组构等。碳酸盐岩特别负的δ13C值指示碳来源于生物成因的甲烷, 而18O富集可能与天然气水合物的分解有关。冷泉碳酸盐岩中黄铁矿的δ34S值低于海水的, 这指示硫来源于微生物还原的海水硫。冷泉碳酸盐岩中的生物标志化合物及其极负的δ13C值指示微生物的生命代谢活动。     

华北地台中元古代碳酸盐岩中的微生物成因构造及其生烃潜力

华北地台中元古界主要由环潮坪石英砂岩、浅海碳酸盐岩和浅海—泻湖相暗色页岩3种沉积相组合构成,以陆表海浅水碳酸盐岩占主导。碳酸盐岩中除含有丰富的微古植物、宏观藻类和微生物建隆外,还发育大量的微生物成因构造(MISS)和微生物诱发的碳酸盐沉淀(MMCP)。微生物席和MISS构造在高于庄组上部(约1.6 Ga)和雾迷山组下部(约1.45 Ga)碳酸盐岩中尤为发育,表明活跃的微生物活动和高有机质产量。在石化微生物席中,发现有丝状、球状细菌化石和草莓状黄铁矿;围岩中发现有针状文石、花瓣状重晶石、放射状菱铁矿、铁白云石和葡萄状碳酸盐胶结物等多种自生碳酸盐矿物,指示甲烷厌氧氧化(AOM)导致的自生碳酸盐沉淀。中元古代的温暖气候和海洋分层、缺氧、硫化条件有利于微生物的高生产量和高有机质埋藏率。气隆构造和核形石状碳酸盐结核反映浅埋藏条件下活跃的成烷作用和甲烷排放,围岩和MMCP中富沥青质。华北地台中元古界富微生物席碳酸盐岩有良好的生烃潜力,有可能形成重要的烃源岩。据微生物席、MISS构造及MMCP的研究,初步估算华北地台中元古代碳酸盐岩的概略生烃潜力约为10×108t石油当量。     

南海北部甲烷渗漏系统环境变化的碳、氧同位素记录

冷泉碳酸盐岩记录了甲烷渗漏活动和流体组分随时间的变化过程,对示踪冷泉系统沉积环境变化具有非常重要的意义.对南海北部获取的冷泉碳酸盐岩进行了碳、氧同位素剖面研究,并对南海北部冷泉碳酸盐岩的碳、氧同位素变化范围进行了统计分析.研究结果及已发表的δ13C和δ18O剖面数据表明,南海北部冷泉碳酸盐岩剖面的δ13C和δ18O之间普遍存在相关性,相关系数R2最高可达0.933 1.经统计,南海北部冷泉碳酸盐岩样品δ13C和δ18O均具有较大的变化范围,其最大变化分别为34.50×10-3和5.89%(Vienna Pee Dee Belemnite,V-PDB).冷泉碳酸盐岩δ13C和δ18O的相关性特征可能指示了初始流体的变化、后期矿物形成/重结晶作用、渗漏系统较为复杂或者成岩作用等环境变化信息.对不同碳酸盐岩样品来说,δ13C的变化主要由海水的参与程度决定,而δ18O的变化可能与温度和Mg元素参与方解石沉淀的程度有关.      

Citrobacter freundii 作用下球状碳酸盐矿物的形态演化过程研究

不少微生物都具有形成球状碳酸盐矿物的能力。对形成过程的动态跟踪研究是了解球状碳酸盐矿物形成机理的关键。利用光学显微镜和电子显微镜对Citrobacter freundii作用下球状碳酸盐矿物的形成过程进行了跟踪研究。结果表明,纳米晶体在有机物质的包裹下逐渐聚集,最终生长为具有辐射状内部结构和菱形表面纹理的球状构造。在球状构造形成之前,矿物集合体经历了花形、哑铃形、花菜形、纺锤形以及类似于十字形的多种过渡形态。对最初、过渡和最终形态进行总结,有助于理解微生物作用下的球状碳酸盐矿物形成机理,为识别微生物活动在沉积环境中遗留的痕迹提供更多有用的信息。以往的研究极少涉及Citrobacter freundii诱导碳酸盐矿物的形成。研究结果将丰富微生物促进球状碳酸盐矿化的研究内容。     

Unity of the national and the international in the socio-cultural development of the peoples of the USSR

International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen.     

Report of the restudy of the defined global stratotype of the base of the Silurian System

The Global Stratotype Section and Point （GSSP） for the base of the Silurian System was defined in 1985. Since that time, a number of researchers have suggested that this section has serious deficiencies for use as a GSSP. As a result, in 2000, the Subcommission on Silurian Stratigraphy （SSS） proposed undertaking a formal restu@ of this GSSP, which was subsequently approved by the International Commission of Stratigraphy （ICS）. The result of this restudy was the formal proposal that the current GSSP, at 1.6 m above the base of the Birkhill Shale, at Dob＇s Linn, Scotland, should be maintained as the same locality and stratigraphic level, but the bios- tratigraphical definition of the boundary should be revised. The previously defined, basal Silurian grapto- lite zone, the Parakidograptus acuminatus Zone, should be subdivided into a lower Akidograptus ascensus Zone and a higher E acuminatus Zone. The base of the A. ascensus Zone, marked by the first appearance of A. ascensus, should be regarded as the biostratigraphic mark for the base of the Silurian. This proposal has now been formally approved by the SSS and ICS, and ratified by International Union of Geological Sciences. This is the first GSSP to undergo formal restudy and redefini- tion, and the proposal also included a recommended procedure for restudy of GSSPs.     

Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth

It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T ₃ = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″.     

东濮凹陷北部沙河街组三段中亚段沉积环境分析

东濮凹陷北部沙三中亚段广泛发育盐岩和烃源岩,这两个看似不能共存的物质却在这里互层共生。该时期研究区沉积特征为多盐韵律与多层烃源岩互层共生、连续沉积,单个盐韵律厚度从几米到十几米,烃源岩有机质丰度高、类型好。平面上,两者在湖盆沉积沉降中心共生;垂向上,高有机质丰度、好干酪根类型与高盐度地层具有较好的对应关系。因而成为恢复古气候和古环境的重要研究对象。通过岩石学、古生物学以及Sr/Ba、B/Ga、(V+Ni+Mn)、Fe/Mn、Sr/Cu、Mg/Ca、V/(V+Ni)、稀土元素含量和氯同位素等方法对凹陷北部沙三中亚段的沉积环境进行研究。结果表明,凹陷北部沙三中亚段为深水沉积的还原环境,古盐度较高,达到半咸水-咸水沉积;微量元素和孢粉化石特征表明研究区沙三中亚段为温暖潮湿的环境。     

The Tendencies of the Development of the Mineral-Resources Sector at the Turn of the Century

Important tendencies in development of the world mineral-resources sector at the beginning of the 21st century were an increase in production and consumption of mineral materials differentiated by types of metals and nonmetallic mineral raw materials, by countries and regions, as well as the concentration of the production of mineral raw materials in a small number of countries, and a reduction in industrial reserves of minerals in the world economy, even at the current stage of their extraction. These tendencies should be taken into account in working out a strategy for development of the Russian mineral raw-material base.     

Causes of the famine among the rural population of the Sahelian zone of the Sudan

Taking the example of W Sudan, an analysis of the climatic incidents leading to the two recent famine disasters is made. On this natural background, the human side is investigated. Focus is directed towards the fragile economic structure of the famine-prone population groups. An early-warning system for famine in the Sahelian Zone is proposed taking grain production and storage, livestock development and the relationship between the prices of livestock and grain as major indicators.     

郯庐断裂南段研究进展与断裂性质讨论

据1：5万区域地质调查和专题研究资料，就郯庐断裂带是否南延与消失的原因，其与大别—苏鲁造山带交截形成的假位错效应，以及与中新生代沉积盆地形成演化的关系等作了新的阐述。在此基础上，讨论了郯庐断裂带是否为巨大的左行平移断层或转换断层。认为郯庐断裂带可能是在“古郯庐带”的基础上于早侏罗世重新活动、白垩纪强烈活动的地堑型枢纽断裂带。     

The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads

In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning.