云南东川播卡-拖布卡地区含金石英脉的^40Ar／^39Ar年龄及其地质意义

东川播卡-拖布卡地区金矿是云南中部"康滇地轴"中、新元古界昆阳群岩石中发现的第一个金矿,位于接近三江褶皱带的扬子地块西缘.原生金矿化为含金黄铁矿石英脉、细脉、网脉和浸染状石英黄铁矿.四个不同产状的典型含金石英脉的石英的阶段加热40Ar/39Ar年龄谱为马鞍形,坪年龄值范围为59.93±0.21～42.38±0.32 Ma,最小视年龄范围59.30±4.30～41.90±1.8 Ma,与计算坪年龄加热阶段相应数据的40Ar-39Ar等时线年龄范围59.34±0.17～41.25±0.10 Ma,三者基本一致.等时线年龄计算的相关系数大于0.998,40Ar/3 6Ar初始值范围为293.17±1.40～295.2±0.43,与尼尔值一致.石英形成后没有受到后期地质作用.石英样品的坪年龄没有受到过剩氩和氩丢失的影响,可以作为石英和金矿的年龄.金矿形成于新生代第三纪古新世和始新世初的陆内拉张地质构造环境中.     

Some parameters in arctic sea ice dynamics from an expedition in the summer of 2003

1Introduction Seaiceoccupiesthemainpartofthesurfaceof theArcticOcean.ThefocusoftheSecondChineseNa- tionalArcticResearchExpedition(CHINAE-2003) wastounderstandthevariationsofarcticmarineenvi- ronmentsandtheseaiceeffectsontheclimatechanges ofglobalextent,inmiddleandlowerlatitudesareas, especiallyinChina.Therefore,thejointsea-ice-airob- servationforseaicestudieswasoneofthekeypro- jectsinCHINARE-2003.Theinvestigatedareacov- ered3000kmfromsouthtonorthand900kmfrom westtoeast.Seventemporali…     

Arctic sea ice distribution in summer based on aerial photos

1Introduction TheArcticOceanisoneoftheimportantcold sourcesontheearth,whichaffectsglobalclimateand oceancirculationseriously.Itsinteractionwithglobal climatesystemisrepresentedbyseaice,whichisthe mainfeatureonthesurfaceoftheArcticOcean(Aa- gaard,etal.,1989).Firstly,seaiceplaysapivotalrole intheheatandmassbalanceonthesurfaceoftheArc- ticOcean.Seaicenotonlyobstructstheheatexchange betweenatmosphereandocean,butalsoreflectsthe mostofthelocalsolarradiationbacktotheatmo- spherebecauseofitshighalb…     

Sea ice thickness and concentration in Arctic obtaining from remote sensing images

1　Introduction TheArcticOceanisoneoftheimportantcoldregionsontheearth,whichcanaffect globalclimateandoceancirculationseriously.Itsinteractionwiththeglobalclimatesystem isrepresentedbyseaice,whichisthemainfeatureonthesurfaceoftheArcticOcean(Aa gaardandCarmack1989).First,seaiceplaysapivotalroleintheheatandmassbalance onthesurfaceoftheArcticOcean.Seaicenotonlyobstructstheheatexchangebetweenat mosphereandocean,butalsoreflectsmostsolarradiationbacktotheatmospherebecause ofitshighalbedo(Gre…     

Recently Ratified and Proposed Cambrian Global Standard Stratotype-section and Points

This paper briefly summarizes an officially ratified Global Standard Stratotype-section and Point (GSSP) and a proposed GSSP for global stages of the Cambrian System. The Luoyixi section near Luoyixi town, Guzhang, northwestern Hunan is ratified as the boundary stratotype for the base of the global Guzhangian Stage, which is the upmost stage of an unnamed series termed provisionally as Cambrian Series 3. The GSSP position lies 121.3 m above the base of the Huaqiao Formation in the section, coinciding with the first appearance of the cosmopolitan agnostoid trilobite Lejopyge leavigata. The Duibian B section at Duibian village, Jiangshan, western Zhejiang, is proposed as the boundary stratotype for the base of the proposed global Jiangshanian Stage that is the second stage of the Furongian Series. The proposed GSSP position lies 108.12 m above the base of the Huayansi Formation in the section, coinciding with the first appearance of the cosmopolitan agnostoid trilobite Agnostotes orientalius. This horizon is also with the first appearance of the cosmopolitan polymerid trilobite Irvingella angustilimbata.     

青海德尔尼硫化物矿床成因的新认识

通过对青海德尔尼硫化物矿床的产出部位、成矿环境、矿石矿物的组合、主要化学元素的成份及同位素测试数据等分析研究,认为该矿床具有裂谷成矿机制的特征,成因类型应属裂谷型层控矿床。     

滩间山金矿矿床成因初步探讨

本文通过对滩间山矿区地层、构造及岩浆岩与成矿关系的研究,认为中元古界万洞沟群是金的矿源层;成矿构造具有多期次、多阶段活动的特点,矿体受单一及复合型式的构造控制;华力西期侵入体对成矿作用仅体现于为矿床的形成与再造提供热源。矿质在弱酸—中偏碱性溶液中,主要呈硫络合物的形式搬运、并在还原条件下成矿。特别指出,含磷质物地层是区内重要的岩金找矿标志之一。     

昆仑山口西Ms8.1地震的地壳变形特征

利用全球定位系统1991－2001年及震后4期GPS观测数据。获得了2001年11月14日昆仑山口西地震（Ms8.1)的同震和震后形变运动图像，跨破裂带GPS网最近两点测得的最大同震形变为1.9m左右，而震后4个月断层蠕滑引起的变形约为80mm，破裂带两侧震后变形幅度具有非对称性。南侧震后变形基本是北侧的2－3倍。研究结果显示破裂带南盘在震后向偏东方向有明显移动，预示本次地震后能量的重新分配与积累，根据近几十年以来东昆仑断裂带的大地震由西向东扩展的特点，未来地震有向东迁移的可能。