Far beyond the Gulf: the implications of warfare for Asian labour migration

The implications of the Gulf War are assessed for the countries in Asia that send labor migrants to the Middle East. "This paper seeks to examine the effects of...the loss of remittances (and related issues, including return migration), primarily in terms of the long-term implications of the War for the future of contract labour migration in the Asian region...."     

GPS技术在山区石油地震勘探测量中的应用

针对GPS技术在山区石油地震勘探测量中的工作方式,结合2007年度南盘江一桂中地区二维地震大剖面资料采集应用GPS的工程实例,介绍GPS技术应用的新进展。通过GPS静态测量和应用RTK技术放样物理点,从测前准备、数据处理、精度分析等方面,阐述提高作业精度、有效进行质量控制的方法,旨在最大限度地发挥GPS技术在山区施工中的作用。     

汶川地震山地灾害遥感快速提取及其分布特点分析

针对泥石流滑坡灾害体特有的物质组成与活动特点,通过比较分析其在不同遥感影像的光谱特征差异,选择ETM+影像作为主要数据源,提取湿度指数与绿度指数,利用ETM+的穗帽变换、影像差值增强、密度分割和掩膜技术建立了泥石流滑坡山地灾害快速提取模型,并用于汶川地震.通过灾害体的提取,分析了本次地震山地次生灾害的分布规律,利用空间叠加进行了成因的分析.本次地震山地灾害具有如下特点:(1)沿主要地表破裂带分布;(2)山地灾害主要出现在8度-9度地震烈度区,随着烈度的降低,山地灾害的总面积也相应的减少;(3)山地灾害主要发生在海拔高度1000-2500m的地带;(4)主要发生在坡度20°-50°之间的边坡上;(5)地震及余震期间以崩塌滑坡滚石为主,后期以泥石流滑坡为主;(6)具有河流左右两岸呈不对称分布等特点.结果表明,利用ETM+影像建立基于湿度指数与绿度指数的快速提取模型,对于大规模泥石流滑坡提取效果较好,进行大区域山地灾害的遥感快速提取是可行的.     

东海陆坡及邻近槽底天然气水合物成藏条件分析及前景

在西太平洋边缘海中,东海是唯一没有获得天然气水合物样品的边缘海。利用已有的地震资料、海底温度资料等,从沉积物来源、沉积地层厚度、烃源岩条件、沉积速率、海底温度—压力条件等方面对东海水合物成藏条件进行了分析。认为冲绳海槽沉积物源丰富,沉积厚度大,且发育烃源岩地层。冲绳海槽较高的沉积速率主要分布于冲绳海槽槽底沉积中心,以及西部陆坡连接海底峡谷底部的三角洲区域。根据冲绳海槽实测的海底温度数据,整个冲绳海槽地区600m以深的范围都能够满足水合物发育的温度、压力条件。以温度梯度为30℃/km计算,冲绳海槽中水合物稳定域的最大厚度为650m。冲绳海槽盆地中普遍发育的底辟构造、背斜构造等局部构造,以及网格状断裂系统,为烃类气流体的向上及侧向运移创造了有利条件,成为天然气水合物发育的有利区带。根据已经发现的BSR特征来看,东海地区天然气水合物前景广阔。     

对北秦岭太阳寺矿集区金矿成矿特征的初步认识

甘肃省天水冯家场—两当太阳寺一带,是近年来资源评价和矿产勘查的重点,是秦岭-大别成矿省北秦岭成矿带中重要的矿化集中区。文章在分析区域构造背景的基础上,对该区成矿特征进行了初步总结,选择典型矿床进行了介绍,初次把该区命名为太阳寺矿集区,这将对该区矿产勘查工作部署,深入研究矿集区成矿规律具有参考意义。     

Geochemistry of the Mian-Lue ophiolites in the Qinling Mountains, central China: Constraints on the evolution of the Qinling orogenic belt and collision of the North and South China Cratons

The Anzishan ophiolite, a typical ophiolitic block of early Carboniferous age in the Mian-Lue suture zone of the Qinling Mountains, central China, consists of amphibolites/metabasalts, gabbros and gabbroic cumulates. All of these rocks, as well as those in the Hunshuiguan-Zhuangke (HZ) block, have compositions similar to normal MORB and back-arc basin basalts (BABB) with high ε_Nd(t) values, indicating that they were derived from a depleted mantle source. The Mian-Lue suture zone also contains blocks of other lithologies, e.g., rift volcanic rocks in the Heigouxia block and arc volcanic rocks in the Sanchazi block. Although they are in fault contact with each other, the presence of these different blocks in the Mian-Lue suture zone may represent a complete Wilson cycle, from initial rifting to open ocean basin to final subduction and continent-continent collision, during the late Paleozoic-early Triassic. In this region, the North and South China Cratons were separated by Paleo-Tethys at least until the early Carboniferous, and final amalgamation of both cratons along the Qinling orogenic belt took place in the Triassic.     

陕西小秦岭华阳川韧性剪切带的特征 及其区域构造意义

陕西小秦岭华阳川韧性剪切带发育在新太古界太华群之中,野外调研和显微构造观察结果表明,该韧性剪切带是由构造片岩、眼球状片麻岩组成的深层次韧性剪切带,具有逆冲兼左行走滑的斜冲特征。对韧性剪切带构造片岩黑云母进行^40Ar／^39Ar同位素定年,获得坪年龄为419M±0．6Ma,反等时线年龄为417Ma±0．8Ma。认为华阳川韧性剪切带及其相应的小秦岭区域主导构造变形是发生于419Ma左右的秦岭加里东事件的结果。     

Sedimentary characteristics of terrigenous debris at site MD05-2905 in the northeastern part of the South China Sea since 36 ka and evolution of the East Asian monsoon

Sediments with high sedimentation rate at site MD05-2905 in the Northeastern slope of the South China Sea provide unique materials for a high-resolution study on the paleoenvironment. Based on precise dating of AMS ¹⁴C, grain size analysis of terrigenous debris at core MD05-2905 was conducted after organic matter, biological carbonate and biogenic opal were removed. The results show that 15.5–63.5 μm coarse grain size ingredients may indicate East Asian winter monsoon changes and that 2–9 μm fine grain size ingredients may be used as a proxy of evolution of the East Asian summer monsoon. The results of grain size analysis, which suggest East Asian monsoon intensity, reveal that a winter monsoon dominated the glacial regime and a summer monsoon dominated the Holocene regime. It was also shown that the summer monsoon increased gradually, experienced several abrupt changes and reached a culmination in the early Holocene (11200–8500 a B.P.) since 36 ka. Controlled by precession periodicity, it may be related with the amount of solar radiation at the highest stage, which needs further study. __________ Translated from Advances in Earth Science, 2007, 22(10): 1012–1018 [译自: 地球科学进展]     

东秦岭中部奥陶系-志留系界线地层及腕足动物群

东秦岭中部晚奥陶世和早志留世地层分布较广,化石较丰富,尤其是腕足类,分为寺岗组、石燕河组、刘家坡组和张湾组。曾庆銮等(1993)根据腕足类及其群落的更替,把石燕河组和刘家坡组归於早志留世,因而引起较大争论。本文据岩性将寺岗组和石燕河组分别改称为石燕河组下段和上段,并据腕足类化石认为石燕河组和刘家坡组应归於晚奥陶世、张湾组为早志留世;另据上述地层生物群落的特征及群落的更替,认为从石燕河组到刘家坡组,以及刘家坡组至张湾组恰好反映了全球冰期引起的晚奥陶世海退和早志留世冰期结束引起的海侵,故本区奥陶系-志留系界线宜划在刘家坡组和张湾组之间。     

RATIONAL UTILIZATION OF MOUNTAIN SOILS IN SOUTHEAST QINGHAI-XIZANG (TIBETAN)PLATEAU

ISoil-fo~gEnvironmentandMainSoilTrocsThesoLItheastQinghai-Xizang(Tibetan)PlateauwheretheHengduanMoUnains,eastempartoftheThmalayanandNyainqentanglhamoUnainsarelocatedextendsfrom25'to34"Nand92'to1O5'Ewithanareaof5OO,OOOkm',oraboutone-fiffooftheentireQinghai-XiZangPlateau.ItisatransitionalzoneofdeePdisseCtedmoUntainseXtendingsoutheastWardpenpherallowlandsandwichedin-betWeenSichuanBasinandcentralYunnanPlateau.Whletheterrainofthesmponinclinestosoutheast,thealtitudeofthevaIleysraises…