A study on benthic community structure in west of the Taiwan Strait and near the Taiwan Shoals

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Main Controlling Factors on Hydrocarbon Accumulation and Distribution in Marine Sedimentary Sequences in South China

Multiple source rock assemblages were deposited in the sedimentary provinces in South China in geologic history,and some of them were destructed by and some survived against multiple tectonic movements.Therefore,multiple sources,mixed sources,and uneven distribution of sources occurred in the marine sedimentary basins in South China during the late stage of hydrocarbon pooling.Epidiagenesis of the marine carbonate reservoirs and its modification to reservoir poroperm characteristics determined the formation and the scale of natural gas pools.The exploration practices show that the large to medium gas fields mainly occur in areas with high-quality reservoirs.Detailed study of the paleo-oil accumulations and typical oil and gas reservoirs reveals that the basins experienced multiphase superimposition and modification,leading to the distribution of the Paleozoic paleo-oil accumulations and bitumen in the peripheral areas.The phenomenon that oil and gas production concentrates in the Sichuan basin indicates that the overall sealing conditions of a basin determine the oil/gas potentials and the scale of oil and gas production.This is a critical factor controlling the accumulation and distribution of gas in the marine sequences in South China.The early oil and gas pools in the Yangtze platform left billions of bitumen in the peripheral areas due to the destruction of seals.Since the Himalayan,"late-generation and late-accumulation" gas pools represented by the gas pools in the Sichuan (四川) basin were formed in the marine sedimentary sequences in South China as a result of the change of the sealing conditions.Current gas discoveries appear to be "paleo-generation and paleo-accumulation" gas pools but actually are "late-generation and late-accumulation" gas pools.These patterns of hydrocarbon pooling clearly depict themselves in western Sichuan basin and Weiyuan (威远)gas field.It is revealed that the gas pools in the Sichuan basin were mainly formed as a result of hydrocarbon phase change (thermal cracking of oil to gas),miscible migration,and dynamic equilibration since the Himalayan.A large number of gas pools were formed in the Himalayan and the gas pools in the marine sequences are characterized by late pooling; this kind of gas fields/pools are controlled by:(1) effectiveness of modification and superimposition of the marine basins,(2) effectiveness of the source rocks,(3) effectiveness of the overall preservation conditions,and (4) effectiveness of plays.     

垣曲盆地最高阶地风尘堆积形成时代及其构造意义

对垣曲盆地原土坪阶地剖面进行了详细的沉积学和磁性地层学研究,结果表明,原土坪剖面地层自下而上由水下河湖相-漫滩相-风尘堆积构成,整个剖面记录了一个水位下降、由水下沉积环境转变为气下环境的连续堆积过程。剖面地层记录的1.84～1.62MaB.P.期间由河湖相沉积环境转变为典型风尘堆积的沉积转型及风尘堆积反映出的1.21MaB.P.前后古气候变化事件是对青藏高原青藏运动C幕和昆黄运动的区域沉积响应。开始于1.62MaB.P.的典型风尘堆积底界年龄代表了该级阶地的形成时代,表明该段黄河至少在此时已经形成。     

基于本体的地理信息服务查询组件设计

介绍了一种基于本体的服务发现组件设计方法,将基于本体的元数据和基于本体的查询结合起来,提高了基于OGC标准的网络地理服务发现的查询效率和准确性.     

云南东川因民铜矿金矿化特征及成因初探

因民铜矿发育两种金矿化类型:一是铜矿的伴生金;二是热液构造蚀变岩型。化探样品分析结果显示,金矿化主要赋存于金箔箐断层上、下盘的角砾状蚀变岩内,空间上受岩性和断裂构造的双重控制。邻区拖布卡金矿的成矿地质背景与本区相似,在成矿地质年代上作以类比推测,认为喜马拉雅期是主成矿期。另外通过对光片镜下和化探原生晕样聚类分析研究,发现构造蚀变岩型金矿化具明显的多期多阶段性及热液特征。     

塔里木盆地塔中低凸起地层水化学特征对不整合的响应

对塔中低凸起地层水化学特征与不整合之间关系的研究结果表明,地层水化学特征对不整合具有很好的响应。在遭受强烈抬升和剥蚀、之间形成不整合的奥陶系和志留系,以及紧靠不整合面附近的石炭系CⅢ油组,其地层水具有矿化度、Cl-含量、K Na 含量和r(Cl-Na)/rMg值相对较小,而HCO3-含量、rNa/rCl值和rSO42-×100/rCl值相对较大的特点,反映出地质历史时期大气降水的影响。在志留系与石炭系之间以及志留系与奥陶系之间的不整合面附近,地层水的矿化度、r(Cl-Na)/rMg值和B3 含量变小,而rNa/rCl值和rSO24-×100/rCl值变大,具有典型的遭受大气淋滤的地层水化学基本特征。     

藏东八宿地区泛非期花岗岩锆石SHRIMP U-Pb定年

卡穷细粒黑云母碱长花岗岩出露于藏东八宿县同卡地区,是藏东地区首次发现的泛非期花岗岩.卡穷微陆块呈岩片状夹持于班公湖-怒江缝合带内,卡穷岩群构成卡穷微陆块的主体,卡穷岩群是由花岗岩、花岗片麻岩、黑云斜长片麻岩、大理岩、黑云斜长变粒岩、退变榴辉岩等组成的构造地质体.卡穷细粒黑云母碱长花岗岩获得的锆石SHRIMPU-Pb年龄为507Ma±10Ma,为泛非事件的岩浆活动记录,进一步证实班公湖-怒江板块缝合带以南是泛非期基底,为解决青藏高原南部的构造演化问题提供了新资料.     

藏东吉塘地区冈瓦纳相冰海杂砾岩的特征及其意义

察雅县吉塘镇澜沧江以西的酉西和泄巴发现冰海杂砾岩,是藏东地区班公湖－怒江缝合带以东首次发现的冈瓦纳相沉积岩,基本特征与青藏高原南部的冈瓦纳相冰海杂砾岩相同,而吉塘镇澜沧江以东的石炭纪—二叠纪地层与古生物则是典型扬子型的。冰海杂砾岩的分布范围大致代表冈瓦纳大陆塔尔切尔冰期影响的空间,并具有时代对比价值。这些资料可能说明一个事实,藏东地区石炭纪—二叠纪冈瓦纳大陆的东部边界为北澜沧江断裂带。     

应用GPS数据与重力数据确定大地水准面

作为GPS/重力边值问题理论及方法的应用,在对GPS/重力方法确定(似)大地水准面的原理进行简要介绍与分析的基础上,利用收集到的N区的600个GPS/重力数据和48个高精度GPS水准数据,计算出该区域的(似)大地水准面。通过拟合法和系统差直接改正法进行的精度分析表明,应用GPS/重力数据结合水准方法确定的该地区(似)大地水准面的精度达到厘米级精度。     

非均匀月壤介质的被动微波辐射传输模拟

基于非均匀月壤物理模型和辐射传输方程,模拟月壤介质中的微波辐射传输特性,探讨频率、月壤厚度等与月表亮温的关系。结果表明:在低频段,月壤微波辐射亮温的动态变化范围较大,可探测的月壤厚度大,3 GHz时的最大可探测月壤厚度达12.4 m;在高频段对应的可探测月壤厚度较小,特别是从50GHz往后的频率段内,最大可探测月壤厚度均小于2 m。不同频率的亮温-厚度变化曲线没有交叉点,且频率越高,所能探测的月壤厚度越小。根据模拟结果,建立了月壤厚度与亮温的查找表。基于查找表,利用单个波段的亮温数据即可得到月壤厚度信息。