中扬子区寒武纪层序地层研究

笔者建立了中扬子区寒武系层序地层格架，研究了中扬子区层序界面和体系域特点，分析了中扬子区层序样式的基本类型及其特征。共划分出2个二级层序、14个三级层序。寒武系下统划分了1个二级层序(SS3)、6个三级层序(SQ1—SQ6)，平均延时约5．0Ma；体系域颜色普遍较深，泥质含量较高，是一套良好的烃源岩。寒武系中上统划分出1个二级层序(SS4)、8个三级层序(SQ7—SQ14)，平均延时约2．9Ma；体系域颜色普遍较浅，云质含量较高，是一套良好的储集层。总体上H型样式为主，T型样式和TH型样式数量相当，反映寒武纪水体中等。二级层序体系域和三级层序体系域都表现出明显的南北向差异性。     

广东大亚湾底质重金属分布特征与环境质量评价

大亚湾是粤东的大型海湾，毗邻深港，其环境质量现状及发展趋势颇受关注。对大亚湾海域45个表层站位、1口浅钻及2个柱状样重金属元素Hg、As、Cd、Cu、Pb、Cr、Zn进行分析，并对底质环境质量进行定量评价。其结果：①大亚湾海域Hg、As、Cu的污染指数Pi值均小于1．0，超标率为0，表明全区未受这些因子污染；②Cd、Zn、Pb、Cr的污染指数Pi值部分大于1．0，表明受到这些因子不同程度的污染，其中Pb的超标率最高，达93．3％，污染指数Pi值为0．83～2．25，为良好—中等污染，总体为轻微污染；Zn的超标率为76．9％，pf值为0．25～2．63，变化较大，总体为轻微污染；Cd的超标率为60．0％，Pi值为0．50～1．78，良好—轻微污染；Cr的超标率为17．8％，Pi值为0，49～1．90，良好—轻微污染；③综合污染指数为1．08～2．21，平均1．37，表明本区均不同程度地受重金属污染，总体属轻微污染，其中范和港污染最为严重，SQI值多在1．5以上，其次为中央列岛附近海域。湾口和澳头—霞涌近岸海域污染较轻。从钻孔及柱状样的重金属含量分布来看，在表层没有明显增多的趋势。     

浅论新疆海相火山热水沉积矿床的分带及其找矿意义

新疆海相火山热水沉积矿床，一般在时间上没有明显的集中生长期。空间上依附于活动大陆边缘火山岛弧带，它在区域上和矿床本身具有矿种转化、类型转换、配套与分带特征。以块状氧化物、块状碳酸盐和块状硫化物转换序次来研究该类矿床。利用铁木尔特铅锌矿上部铅锌下部铜金，预须开普台铁矿上铁下铜；莫托沙拉铁锰矿上锰下铁中间铅锌重晶石等矿种转化规律和由块状氧化物和块状碳酸盐向块状硫化物成生过渡特点，预测诸如蒙库铁矿、赤龙峰火山盆地中铁矿和喀喇昆仑山各铁矿床(点)外围与深部转换、发展成为铜金矿的成矿前景。     

China''''s First Exploration of Chukchi Sea and Its Adjacent Waters in the ArcticA Study on Lead Geochemistry of Atmospheric Aerosol

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鄂尔多斯盆地奥陶系马家沟组溶斑形成机理

鄂尔多斯盆地中部气田奥陶系马家沟组属蒸发边缘海相地层,其风化壳是中部气田的主要产气层段。该层中广泛发育毫米级、厘米级的溶斑,这些溶斑的产状、大小、成分以及溶孔内的充填物十分复杂,有的具多期充填,充填物为石膏、石英、方解石、白云石、高岭石、黄铁矿等多种矿物。溶斑中下半部残留的岩石经溶蚀后的白云石晶粒形成的渗流砂示底构造十分明显。研究表明,溶斑的形成不仅具有适宜的岩相古地理环境和其复杂的生成演化史,而且与原始沉积以及不同地史阶段的岩溶作用相关。     

冲绳海槽南部沉积层序的粒度特征

对取自冲绳海槽南部的A2 3孔经前处理后的沉积物样品进行了粒度测试,探讨了陆源沉积层序的粒度特征。沉积物平均粒径、分选系数、偏态、峰态等粒度参数的变化显示出A2 3孔的沉积层序以 4 0 0cm为界可分为上、下两段,下段各参数稳定,代表了比较稳定的水动力条件的沉积环境;上段则波动较大,小规模浊流沉积频繁发育,暗示了不稳定的沉积环境。浊流层内粗粒与细粒组分含量及粒度分布的变化具有明显的规律性。通过分析A2 3孔陆源沉积层序的各沉积参数特征,认为冲绳海槽南部的沉积环境和动力在时间尺度上有较大的变化,东海陆架物质向南部海槽的输运可能是以峡谷为通道的重力作用引起的床底沉积作用为主。另外,对陆源碎屑和全样粒度结果的对比,显示了前处理方法对于海洋沉积物粒度分析的重要性.     

A review of the physics and ecological implications of the thermal bar circulation

Following recent applications of numerical modelling and remote sensing to the thermal bar phenomenon, this paper seeks to review the current state of knowledge on the effect of its circulation on lacustrine plankton ecosystems. After summarising the literature on thermal bar hydrodynamics, a thorough review is made of all plankton observations taken in the presence of a thermal bar. Two distinct plankton growth regimes are found, one with production favoured throughout the inshore region and another with a maximum in plankton biomass near the position of the thermal bar. Possible explanations for the observed distributions are then discussed, with reference to numerical modelling studies, and the scope for future study of this interdisciplinary topic is outlined.     

岳西菖蒲地区超高压变质带内的构造地层序列与叠加褶皱型式

以大别造山带南部菖蒲地区为解剖区,结合区域地质调查分析,建立了包括浅变质岩层、超高压变质岩片在内的构造地层序列—岩片组合。对其组成特征、界面性质、形成时代、变形序列等,进行了较系统阐明,并对叠加褶皱型式及形成机制进行了讨论。     

Simulation of marine boundary layer characteristics using a 1-D PBL model over the Bay of Bengal during BOBMEX-99

The characteristic features of the marine boundary layer (MBL) over the Bay of Bengal during the southwest monsoon and the factors influencing it are investigated. The Bay of Bengal and Monsoon Experiment (BOBMEX) carried out during July–August 1999 is the first observational experiment under the Indian Climate Research Programme (ICRP). A very high-resolution data in the vertical was obtained during this experiment, which was used to study the MBL characteristics off the east coast of India in the north and south Bay of Bengal. Spells of active and suppressed convection over the Bay were observed, of which, three representative convective episodes were considered for the study. For this purpose a one-dimensional multi-level PBL model with a TKE-ε closure scheme was used. The soundings, viz., the vertical profiles of temperature, humidity, zonal and meridional component of wind, obtained onboard ORV Sagar Kanya and from coastal stations along the east coast are used for the study. The temporal evolution of turbulent kinetic energy, marine boundary layer height (MBLH), sensible and latent heat fluxes and drag coefficient of momentum are simulated for different epochs of monsoon and monsoon depressions during BOBMEX-99.The model also generates the vertical profiles of potential temperature, specific humidity, zonal and meridional wind. These simulated values compared reasonably well with the observations available from BOBMEX.     

Sedimentary Facies Architectures of Third-Order Sequences from Early to Middle Triassic in Nanpanjiang Basin

There are complex and regular changes on sedimentary facies from the Early to the Middle Triassic in the Nanpanjiang basin. After the obvious drowned event of carbonate platforms in the transitional period between Permian and Triassic, carbonate platforms have evolved into the ramp type from the rimmed-shelf type. The differentiation of sedimentary facies becomes dearer in space, which are marked by the changes from an attached platform to a turbidity basin and several isolated platforms in the basin. The striking characteristics are the development of oolitic banks on isolated platforms in Nanning and Jingxi and the reef- and bank-limestones in the margin of the attached platform in the Early Triassic. Despite the difference of the time-span and the architectnre of fades succession of third-order sedimentary sequences, the process of the third-order relative sea-level changes reflected by the sedimentary facies succession of the third-order sequences is generally synchronous. Therefore, six third-order sequences could be discerned in the strata from the Early to the Middle Triassic in the Nanpanjiang basin. Using two types of facies changing surfaces and two types of diachronisms in stratigraphic records as the key elements, the sedimentary facies architectures of the third-order sequences that represent sequence stratigraphic frameworks from the Early to the Middle Triassic in the Nanpanjiang basin could be constructed.