上海志留纪、奥陶纪地层新发现化石及其地层意义

在开展上海岩石地层清理工作中，对以往留存地层断代疑点的地层补做了采样、分析鉴定工作。在志留纪、奥陶纪地层中发现孢粉、牙形刺及腹足类化石，对所属地层时代的厘定起了关键作用。     

新疆中天山干沟一带蛇绿混杂岩和志留纪前陆盆地的发现及其意义

托克逊县干沟一带出露有早古生代蛇绿混杂岩和志留纪前陆盆地沉积。其时空配置表明,新疆中天山北缘早古生代大洋在奥陶纪曾发生大规模的向北消减,志留纪因前陆和岛弧的碰撞而形成前陆盆地,充填序列揭示了碰撞造山作用过程。对碎屑岩中陆源锆石同位素测年表明其最新物源的年龄不小于461Ma。而侵入该前陆盆地碎屑岩的花岗闪长岩中火成锆石的同位素测年数据为(386.1±4.1)Ma,限定了前陆盆地的上限。前陆盆地的终结标志着碰撞造山作用的结束。     

Reservoir Potential of Silurian Carbonate Mud Mounds in the Southern Sichuan Basin, Central China

Lower Silurian mud mounds of the Shinuilan Formation, located in the southern Sichuan Basin, China, have developed in open shelf settings in deeper water than shallow-water reef-bearing limestones that occur in the region. An integration of the outcrop, drill data and seismic profiles show that contemporaneous faults have controlled the boundary and distribution of the sedimentary facies of Lower Silurian rocks in the southern Sichuan Basin. Mounds appear to have developed in the topographic lows formed by synsedimentary faulting, on the sheff of the Yangtze Platform. Average mound thickness is 20 m, maximum 35 m. Mounds are composed mainly of micrite, possibly microbially bound, and are overlain by shales. Mound tops are preferentially dolomitized, with the Mg^2＋ source probably from the clay content of the mound-top carbonate. Microfacies analysis and reconstruction of the diagenetic history reveal that the mound tops have higher porosity, and are gas targets; in contrast, mound cores and limbs show pores filled by three generations of calcite cement, and therefore have a low gas potential.     

奥陶纪末集群灭绝后腕足动物复苏的主要源泉--论先驱型生物的分类

先驱型、幸存型和复活型生物是地质历史中生物集群灭绝后宏演化早期阶段(复苏期)的源泉.研究华南奥陶纪末集群灭绝前后的腕足动物表明,先驱型生物因拥有非凡的演化新质而有预适应能力,在功能形态、生态和生理上具有成功的幸存机制,在适应环境变化的能力、类型的多样性、分类单元和个体数量等方面,都明显超过了另两种类型:它们是新时期生物演化的主要源泉和大量新兴类型的祖先.在先驱型生物中,进一步识别幸存-先驱型、灾变-先驱型和复活-先驱型有重要的研究意义.复活-先驱型多样性最大,适应环境能力最强,居群最繁盛,在新的生物宏演化过程中作用最大.     

奥陶纪末集群灭绝后腕足动物复苏的主要源泉

先驱型、幸存型和复活型生物是地质历史中生物集群灭绝后宏演化早期阶段(复苏期)的源泉．研究华南奥陶纪末集群灭绝前后的腕足动物表明,先驱型生物因拥有非凡的演化新质而有预适应能力,在功能形态、生态和生理上具有成功的幸存机制,在适应环境变化的能力、类型的多样性、分类单元和个体数量等方面,都明显超过了另两种类型它们是新时期生物演化的主要源泉和大量新兴类型的祖先．在先驱型生物中,进一步识别幸存-先驱型、灾变-先驱型和复活-先驱型有重要的研究意义．复活-先驱型多样性最大,适应环境能力最强,居群最繁盛,在新的生物宏演化过程中作用最大．     

四川盆地南北缘志留纪生物礁成岩作用及储层特征

四川盆地南北缘志留纪生物礁发育、类型多样,有点礁、灰泥丘、层状礁等。它们曾经历了多种成岩作用,其中主要有胶结作用、溶蚀作用、硅化作用以及白云化作用。由于构造运动简单,本区生物礁的成岩作用演化过程是从早期的海底成岩作用,经短时的大气淡水作用就进入埋藏成岩作用阶段,最后达表生暴露阶段。生物礁的原生孔隙以格架孔、体腔孔为主,并发育有不规则窗格孔、粒间孔及晶间孔等,次生孔隙为后期溶孔及溶缝。由于胶结作用发育,使本区生物礁的储集意义减小。     

9th International Symposium on the Ordovician System, 7th International Graptolite Conference ＆ Field Meeting of the International Subcommission on Silurian Stratigraphy

The “9th International Symposium on the Ordovician System, 7th International Graptolite Conference & Field Meeting of the International Subcommission on Silurian Stratigraphy” commenced on August 12,2003, by receiving in San Juan City to all participants of the pre-symposia field trip through the Precordillera of Mendoza and San Juan provinces, western Argentina. On August 13, the field trip began with the purpose to show significant Lower Paleozoic outcrops from diverse settings of the Precordillera geological province. This fivedays excursion was led by Drs. S. H. Peralta.     

志留纪以来的云开地块

桂南－粤西的云开地块,位于特提斯构造带和环太平洋构造带的交汇处。其变质基底仅出露于两广边境的云开大山地区,但古生代海相沉积盖层分布广泛,甚至跨越北部湾。地块北缘的古生代深水沉积带,也延展到越南东北沿海地区。云开地块的范围,可能西起红河三角洲,东达珠江三角洲。晚古生代时,它可能为地处南纬低纬度海域的碳酸盐台地。古南海于中晚二叠世开始张开,使云开地块北移,与大明山地体碰撞,形成云开北缘的造山带。中晚三叠世,古南海的进一步扩张和桂西－越北的古特提斯向南消减,又形成晚二叠世造山带以北的印支期岩浆弧和磨拉石。也是东古特提斯闭合过程的重要部分。新生代早期南海张开前,古南海北侧的南沙地块可能和云开地块相接,总面积可能超过50万km2,在东南亚地质演化中起重要作用。     

西南天山超高压变质带中志留纪岛弧火山岩岩片及其构造意义

西南天山造山带位于伊犁-中天山板块和塔里木板块之间,普遍被认为是古南天山洋闭合,塔里木板块和伊犁-中天山板块碰撞造山的产物.在西南天山含榴辉岩高压-超高压变质带中,我们在哈布腾苏和科普尔特2个地区识别出这一套基性-酸性火山岩.在哈布腾苏剖面,该套火山岩以酸性岩为主,在野外作为构造岩片与高压-超高压榴辉岩与蓝片岩相间产出...     

某地水铝英石

The major concern of this paper is with allophane(m Al2O3.n SiO2.p H2O),a colloid mineral from a certain locality in China,which is surperfaeial in origin and may be used as an indicator to eluvial deposits enriched in Cu,U,V,Detailed studies have been carried out on its features,the forming environments,the factors governing its enrichment,and mineral associations by means of field investigation,microscopie identification,chemical analysis and DTA technique.