Hercynian-Indosinian Sedimento-Tectonic Evolution of the Nanpanjiang Basin

Following the orogeny in the Early Palaeozoic, the tectonic evolution of the Nanpanjiang basin in the Hercynian-Indosinian stage constituted a complete Wilson Cycle, made up of the stages of early rifting (D-P1), late rifting and passive margin developement (P2-T1), and peripheral foreland basin developement (T2-T3). The REE data of the initial Early Triassic basalts from the southern part of the basin has verified the existence of the oceanic crust once in the basinal evolution. The basin developed into a foreland one in the Middle-Late Triassic, indicating that the Yangtze plate once collided with the Indo-Sinian plate along the Black River fracture zone.     

Earthquake-Generating Structure During the Period of the 1992 Sichuan Lima Earthquake Sequence

In this paper,a test or alternative scheme for studying large earthquake sequences through the study of small earthquake sequences is suggested,and a small earthquake sequence,the Lima earthquake sequence for which analogue records have been turned into digital data,is used here.In order to provide the deep construction background and the spatial distribution of structure for generating earthquakes,the P-wave and S-wave layered velocity models in this area are obtained by using mine explosion and earthquake observed records; then,the hypocenter locations and focal depths of the Lima earthquake sequence are determined adopting the velocity models given above and using a location method with numerical properties for a microseismic monitoring network(Zhao et al.,1994)and a new method for determining focal depth from data of a local seismographic network(Zhao,1992); finally,based on this,the variation of quality factor Q of the crustal medium during the period of the sequence is estimated.The obtained resul     

Carbon and Strontium Isotopes of Late Palaeozoic Marine Carbonates in the Upper Yangtze Platform,Southwest China

238 marine carbonate samples were collected from seven sedimentary sections ofthe entire late Palaeozoic (Permian, Carboniferous and Devonian) in the Upper Yangtze Plat-form, southwest China. Based on the absence of cathodoluminescence and very low Mn (gener-ally<50 ppm) contents of the samples, it is thought that they contain information on the orig-inal sea water geochemistry. The results of isotopic analyses of these samples are presented interms of δ~(13)C and ~(87)Sr/~(86)Sr ratios versus geological time. The strontium data, consistent withother similar data based on samples from North America, Europe, Africa and other areas inAsia, support the notion of a global consistency in strontium isotope composition of marinecarbonates. The strontium data exhibit three intervals of relatively low ~(87)Sr/~(86)Sr ratios in thelate Middle Devonian to early Late Devonian, Early Carboniferous and Early Permian, corre-sponding to global eustatic high sea level stands. The lowest ~(87)Sr/~(86)Sr ratio recorded in theLate Permian was probably caused by substantial basalt eruptions in the Upper Yangtze Plat-form at the time. Three corresponding periods of relatively high δ~(13)C values at roughly the samethe intervals were caused by a relatively high rate of accumulation of organic carbon duringsea level rises at these times. The deposition of coal was probably responsible for the increaseof sea water δ~(13)C at other times. The δ~(13)C values drop dramatically near theDevonian/Carboniferous, Carboniferous/Permian and Permian/Triassic boundaries, con-sistent with other similar data, which further support the notion that geological time boundariesare associated with mass extinction and subsequent rejuvenation.     

川西白马地区地表地球化学油气勘探方法的探索与实践

川西白马地区在开展前期试验和环境调查的基础上，选定了土壤吸附戏（Ｃ１－Ｃ５），后生碳酸盐（△Ｃ）、会相态汞、二价铁和电导率等五类九种化探指标这些指标的异常形态一般呈半环状或断续的条带状；各种化探异常在平面上的分布具相似性或相嵌性；所有指标的异常与工区内沙溪庙组底面主要构造高部位的平面位置吻合较好。圈定了九个化探远景区，在白马庙和松华镇两个远景区所钻的五口井，化探预测与钻探结果的符合率达７５％。实践     

“源控论”再认识——以四川盆地天然气勘探为例

烃源作为成藏的首要条件,没有陆相、海相之分、没有地域之别,也没有油藏、气藏的不同。在海相过成熟碳酸盐岩干气区由系烃源层、煤系烃源层形成的烃源,制约着气藏的形成与展布。     

地震救助生命搜索与定位技术研究进展

生命搜索是地震紧急救援中最重要的问题，由于时间紧迫、环境条件恶劣也是最困难的问题。先进的技术与装备是提高救助成功率，最大限度减轻人员伤亡的技术保障。本文简要介绍了利用国内外目前较为成熟的相关技术，研制开发光学探生仪、声波／振动探生仪、红外热像仪3种先进、轻便、高效、实用的地震救助现场生命搜索与定位技术设备，以及利用系统工程学原理和现代管理理论，开展地震灾害现场生命搜索与救援支持系统的研究，从而初步建立地震救助生命搜索定位技术系统的基本情况。     

四川西部现代热泉型金矿化的发现和初步研究

四川西部现代热泉分布广泛，但以往对于其含金性没有研究资料。本文报道了对四川西部巴塘县热坑一带、理塘县热水塘一带及康定县木格错一带现代热泉及其水热活动产物中含金性初步调查的结果，发现热水本身携带有金，泉华堆积物中钙质部分含金较低、铁硅质部分含金较高，以强烈硅化的蚀变围岩含金最高，整体矿化水平与云南腾冲热泉型金矿相似。建议在三江地区对现代热泉的含矿性进行专门调查，并注意对深部矿化情况的调查研究。     

搜索理论与建筑物评估和标记问题的讨论

简述了救援支持系统的含义、搜索理论的发展及其在倒塌建筑物救援中的应用前景；分析了我国现有倒塌建筑物评估的现状，认为应当在适当时机开展这方面的研究；重点讨论了建筑物评估和标记，认为目前我国应当借鉴国外救援行动有关的建筑物评估与标记方法；讨论了建筑物倒塌救援的搜索方法和程序；介绍了国外建筑物倒塌救援标记的使用方法。     

川滇菱形块体顺时针转动的构造学与古地磁学证据

川滇菱形块体内部受NE向丽江 -小金河断裂的切割 ,可进一步划分为川西北次级块体和滇中次级块体等南北 2个部分 ;各次级块体东边界断裂有规律地左旋滑动、西边界断裂的右旋滑动及其滑动速率值的差异 ,反映出新生代时期各次级块体作向SE的水平滑移叠加绕垂直轴顺时针转动的复合运动。其中 ,川西北次级块体SE向的水平滑移速率 5mm/a ,顺时针转动角速度 1 4°/Ma ;滇中次级块体SE向的水平滑移速率 3 5mm/a ,顺时针转动角速度约 1 5°/Ma。在滇中次级块体内部姚安、大姚、永仁、昆明北马街等地采集到约 90个古新世地层的定向样品 ,通过交变退磁和热退磁获得了它们各自的剩磁矢量 (实验磁偏角和磁倾角 ) ,由实测磁偏角与期望磁偏角相比可知川滇地区滇中次级块体中新世早期以来的顺时针转动累积量可达 30°～ 4 8°。次级块体的整体转动与块边活动断裂的左旋滑动符合左旋走滑断裂作用区块体作顺时针转动的运动学模式     

福州盆地的地震环境与主要断层潜在地震的最大震级评价

综合探查表明 ,福州盆地的主要断层均无全新世活动。通过区域地壳动力学与地震构造背景分析、地震活动水平统计对比等 ,综合判定了福州盆地的地震环境及主要断层潜在地震的最大震级。结果表明 :福州盆地位于台湾动力触角对大陆作用的弱影响区 ,但靠近强、弱影响区的过渡边界 ,处于有、无≥ 6级强震区的过渡地带。与福建—粤东北沿海发生过强震的地段相比 ,福州盆地及附近主要断裂的最晚活动时代偏老 ,壳内的低速层不显著。另外 ,在福建及邻区的 12个地震构造单元中 ,福州盆地单元的地震活动水平最低。该盆地西缘和南缘的闽候 -南屿断层和五虎山北麓断层是具有发生中等地震潜势的相对危险断层段 ,潜在地震的最大震级估值为MS6 .0和 5 .6