Characteristics of Upper Mantle Activity in the South China Sea Region and the Indochina Mantle Plume

According to computed results of the mantle traction field beneath the lithosphere based on satellite-modelled gravity anomalies of different degrees, it has been revealed that the three types of mantle convection on different scales existing in the South China Sea region is the key factor controlling the geodynamics. The mantle convection models on large and middle scales have been proved by natural seismic S-wave tomographic data and interpreted by using the present mantle plume concept In consideration of other relevant geological and geophysical data, the authors put emphasis on discussing the expression form, origin and age of the Indochina mantle plume and its important effect on the conversion of organic matter and hydrocarbon accumulation in Cenozoic basins.     

Micro-area Chemical Composition and Preserved P-T Evolution Trace of Phengite in Albite Gneiss from the Donghai Ultrahigh-Pressure Metamorphic Area, East China

Study of micro-area chemical compositions indicates that phengite in albite gneiss from hole ZK2304 of the Donghai region has evident compositional zoning. SiO2 and tetrahedrally coordinated Si contents decrease, and Al2O3, AlIV and AlVI contents increase gradually from core to rim. However, K2O, MgO and FeO contents basically remain unchanged from core to rim. According to P-T estimates obtained from geothermometers and barometers, combined with previous experimental data, the core belt (micro-area I) of phengite was formed at T=637-672℃ and P=1.55-1.73 GPa, and the transitional belt (micro-area II) of the phengite were formed at r=594-654℃ and P=1.35-1.45 GPa. Towards the rim belt (micro-area III), the temperature decreased slightly, but the pressure decreased rapidly with r=542-630℃ and P=1.12-1.19 GPa. The P-T evolution path recorded by the compositional zoning of phengite is characterized by significant near-isothermal decompression, revealing that the gneiss has. undergone high-pressure-ultrahi     

Geological Features of the Eastern Sector of the Bangong Co-Nujiang River Suture Zone: Tethyan Evolution

According to an analysis of the geological features in the eastern sector of the Bangong Co-Nujiang River suture zone, the Tethyan evolution can be divided into three stages. (1) The Embryo-Tethyan stage (Pz1): An immature volcanic arc developed in Taniantaweng (Tanen Taunggyi) Range, indicating the existence of an Embryo-Tethyan ocean. (2) The Palaeo-Tethyan stage (C-T2): During the Carboniferous the northern side of the Taniantaweng Range was the main domain of the Pa-laeo-Tethyan ocean, in which developed flysch sediments intercalated with bimodal volcanic rocks and oceanic tholeiite, and Pemian-Early Triassic arc granites were superimposed on the Taniantaweng magmatic arc; on the southern side the Dengqen-Nujiang zone started secondary extension during the Carboniferous, in which the Nujiang ophiolite developed, and the Palaeo-Tethyan ocean closed before the Middle Triassic. (3) The Neo-Tethyan stage (T3-E): During the Late Triassic the Dengqen zone developed into a relatively matural ocean basin, i     

Evidence of the Pan-Lake Stage in the Period of 40-28 ka B.P. on the Qinghai-Tibet Plateau

The Qinghai-Tibet plateau is one of major saline lake regions in China, where saline lakes are widespread and constitute an important object of researches on the palaeoclimatic change in the region. On the basis of comprehensive investigations of the evolution of the lake's surface and sediments on the plateau, the authors have further demonstrated the existence of a pan-lake stage (river and lake flooding stage) on the Qinghai-Tibet plateau during the period of about 40+-28 ka B.P. and analyzed the palaeoclimatic characteristics of the pan-lake period and relationships between the ancient monsoons and the uplift of the plateau since the beginning of the Quaternary.     

新疆罗布泊K1孔磁性地层及古纬度初析

Ｋ１孔位于罗布泊“耳轮”构造的北缘。磁性地层初步研究得知,在孔深６１～６２ｍ处为界,以上为布容正向极性时（Ｂｒ）,以下为松山反向极性时（Ｍａ）。在孔底９７～１００ｍ处的正向极性偏移应属Ｃｏｂｂ Ｍｏｕｎｔａｉｎｓ事件,对照Ｓ．Ｃ．Ｃａｎｄｅ和Ｄ．Ｖ．Ｋｅｎｋ修定的古地磁极性年表,氏地层的年代为１．２Ｍａ,归属早更新世中期。中更新世地层厚５０余米,晚更新世地层厚１０ｍ左右,全新世地层厚度小于５ｍ。根     

石嘴山一矿地质构造的控气性分析

通过分析地质构造与煤层瓦斯含量,涌出量及煤与瓦斯突出之间的关系。总结出地质构造控气（煤层瓦斯）的四种类型及地质构造分级控突（煤与瓦斯突出）的三种形式,对矿井开展斯预测与防治有指导作用。     

正确处理地勘队伍经济发展与改革、稳定之关系的做法与体会

江苏省地质勘查院在改革过程中 ,针对自身的特点 ,以领导班子建设、提高职工素质、做好离退休人员工作、妥善处理某些热点问题入手 ,创建一个适合经济发展的稳定局面。在此基础上 ,立足市场 ,对院内机构进行调整 ,在增加新的经济增长点、扩大市场占有份额、优化资源配置、加强管理等方面做了大量工作 ,促进了经济的发展。同时通过实现技术与劳务分离、精干队伍、确保地质勘查工作的投入 ,以加强综合地质研究 ,参与国家地质勘查领域的竞争 ,开创了地勘工作的新局面。     

Fault System, Diapirism and Oil (Gas) Migrationin the Yinggehai Basin, South China Sea

1. Introduction In recent years, growing attention has been focused on diapirs because of their significance to hydrocarbon accumulation in basins (Barber & Brown, 1988; Martin Hovland et al., 1989; Law et al., 1989; Collier et al., 1990; Lewis et al., 1994; Carmelo Monaco et al., 1996; Hieke et al., 1996; Hieke et al., 1996; Lewis et al., 1996; Limonov et al., 1996; Gallardo & Blackwell, 1999). With more and more effort devoted to the studies of the northern continental marginal basins …     

A New Differentiation Operator for Seismic Wave Equation

1. Introduction The pseudospcetral (PS) method was employed in the calculations for fluid dynamics (Orszag, 1972). The method has also been employed widely in the simulations of acoustic wave and elastic wave equations because of its high accuracy and efficiency in use of the computer memory compared with the other discrete numerical method (Kosloff and Kosloff, 1982; Fornberg, 1987; Reshef et al., 1988). The time differentiation in the PS method is generally performed by using a second or…