简介:<正>ONSOUTHERNSTRETCHOPTHES-NTECTONICBELT,CHINAChenGuanghaoandWeiZhoulin(ChangshaInstituteofGeotectonic,AcademiaSinica,Changsha,410013,Hunan,China)S-Ntectonicbelt,southstretching,boundingbeltItcanbeinferredfromthegeophysicaldata,linearstructures,tectonicevolu-tionhistoryandmetallogenythattheS-NtectonicBeltstretchesfurthersouthinadifferentdi-rectionandmannerafterinterceptedbytheRedRiverFault,Thestretchingsegmentistheim-portanttectonicboundaryinIndo-AsiaandassiminlatestheS-Ntectonicbeltwithsomediffer-ences.
简介:TheJiamusimcdianmassifislocatcdaboutlittlcXinganlingtoLaoycling,casternHeilongjiangProvince.Beinginaccordwiththediwathcory,thcJiamusipalaco-mcdianmassifdevclopspre-geosyn-clinlarchacansialiccrust.KhondalitescricsinthcJiXidistrictmaybcrcputcdasrcprcscntivc,isotopicageofwbichis25OOMa.ThcrcarethcDongfc
简介:这研究在Balong提供n链烷和Holocene黄土的花粉记录()镇,Dulan()县,Qinghai()省,和环境变化从同意很好的两个记录重建了。过去的气候变化的三个阶段被n链烷和花粉代理的变化译解。在5370一BP前,气候温暖干燥却稍微潮湿,相应于Mid-Holocene气候的最佳;53703830一BP,气候或者变化了在之间温暖干燥稍微潮湿、温暖干燥,从Mid-Holocene气候的最佳显示转变到迟了的Holocene冷时期;在3830一BP以后,气候主要是温暖干燥的。温暖的凉爽、极其干燥的气候被n链烷和花粉代理在30402600一BP期间记录,建议环境演变为荒芜或咸的湖,根据在西方的周王朝的冷、高度经常的自然灾难时期(ca。29962721一BP)在中国。
简介:ObjectiveThenearlyparallelN–S-trendingriftsinsouthernTibetrepresenttheE–WextensionoftheTibetPlateau.MostdatawhichconstrainedtheageoftheextensionaldeformationcomefromisotopicdatingofthedikesprobablyrelatedtotheactivityofthenearlyN–Sfaultingandmicasfromhydrothermalactivityandthelowtemperaturethermochronologyofplateauuplift.Previous
简介:KarstrocksfromtheHuanglongFormationexposedatthemarginoftheEasternSichuanBasincanbedividedintofourtypes:slightlycorroded,moderatelycorrodedporous,intenselycorrodedbrecciatedandintenselycorrodedandreplacedsecondarycalcickarsticrocks.Thecarbon,oxygenandstrontiumisotopecompositionsofthevariouskarstrocksareanalyzedsystematicallyandcomparedtorockswithoutkarstcorrosion.Theresultsindicatethat(1)theHuanglongFormationintheeasternSichuanBasinwasarestrictedbaysuppliedandcontrolledbyfreshwaterinwhichmudmicriteandmud-dolomicriteexhibitlowδ13Candδ18Ovaluesandhigh87Sr/86Srratios;(2)alltypesofkarsticrocksinthepaleokarstreservoirsoftheHuanglongFormationintheresearchareaareaffectedbyatmosphericfreshwaterwiththeδ13Candδ18Ovaluesand87Sr/86Srratiosintheoriginalformationapproachingthoseofatmosphericfreshwater,whichreflectsancienthydrologicalconditions,fluidproperties,isotopicsourceandthefractionationeffect;(3)theintenselycorrodedandreplacedsecondarylimestoneisaffectedbyavarietyofdiageneticfluids,oftenreflectedbyδ13Candδ18Ovalues,whilethe87Sr/86Srratiosexhibitthestrongdegreeofthecorrosion;(4)aftercomparingthe87Sr/86Srratiosofeachtypeofkarstrock,thediageneticfluidsaredeterminedtobemainlyatmosphericfreshwater,anddependingonthestrengthofcorrosion,andthelow87Sr/86Srratiofluidsinthelayerwillparticipateinthekarstprocess.Thecarbon,oxygen,andstrontiumisotopesofdifferentkarsticreservoirscanprovidemeaningfulgeochemicalinformationforforecastingandevaluatingthedevelopmentanddistributionrulesoftheHuanglongFormationatthemarginoftheeasternSichuanBasinintimeandspace.更多还原
简介:新疆哈密东天山构造岩浆带位于尾亚-罗布庄磁力高带上的喀拉塔格磁场小区,该带发育幅值在200~300nT的正磁场区,封闭磁异常对应于石炭纪石英闪长岩或隐伏基性侵入岩体。钳子山C07-2磁异常为该区带高磁异常,最高幅值2340nT。经钻探验证,打出3层低品位含铜钛磁铁矿,总厚119m。据81个化学样分析,TFe约3.6%~28.80%,平均品位13.5%,TiO21.31%~2.33%。ZK0701-10/5层(111~113m)见有2m厚具工业品位的铜矿体和磁铁矿体,分析结果为Cu0.4%,TFe28.8%。该钻探成果为在哈密玉西地区寻找岩浆型钛磁铁矿提供了有力依据。
简介:在华南的Dajiangbian形成是统治siliciclastic的沉积继任,低档变态在卡赛西亚·布洛克的西方的边缘上扔了,并且被glaciogenicdiamictite(Sizhoushan形成)盖住。Sizhoushanglaciogenic阶层能被归因于Jiangkou冰川(Sturtian冰川)他们在华南与Jiangkou阶层分享stratigraphic和lithological类似的事件。在整个Dajiangbian形成的上面的部分的一些碳酸盐,燧石和页岩单位为碳酸盐碳同位素被取样(13Ccarb)和器官的碳同位素(13Corg)分析。geochemical的一个范围索引包括氧同位素(18O)并且Mn/Sr(Fe/Sr)比率建议主要的碳同位素价值在上面的Dajiangbian形成被保存。上面的Dajiangbian形成表演13C向上减少向的-0.1,的carb到-5.4。我们建议否定13在Sizhoushandiamictite下面的C旅行是有Pre-SturtianIslay13Ccarb异例并且与全球Neoproterozoic同位素地层学允许关联。我们发现碳酸盐和上面的Dajiangbian形成的器官的碳同位素数据被联合,与13Ccarb-13C在多重大陆上观察的org模式。
简介:ThetransitionzonebetweentheEastAsiaandCentralAsiacrustobodlesisnotonlyadiwaregion,butalsoagigantictectono-metallogenicbeltinAsia.IttrendsN-S,liesbetweenlong.100°-107°Eandlat.14°-62°N,hasalengthof4600kmandfurtherextendssouthwardandnorthward.Themainfeaturesofthebeltareasfollows:(1)Thebc1tcon8istsofotc