简介:ThepresenceofthereversalsofthegeomagneticfieldwithintheBrunhesisindicatedbypaleomagneticstuidesonCenozoicvolcanicrocksintheLeizhouPeninsula,loessstrataandQuaternarymarinesedimentsinthePearlRiverMouthbasininChina.Theseregionalreversalsoccuredat0.58±0.13Ma,0.45Maand0.47—0.48MarespectivelyaccordingtotheresultsofK-Arisotopicdatingandclimatostratigraphicandbiostratigraphicanalyses.ThereversalsequivalenttotheEmperorEventissuggested.ThereversalsrevealedindifferentregionswithvariouslithologiccharactersinChinaprovethattheEmperorEventisaglobalreversaleventratherthanageomagneticexcursion,anditsconfirmationwillpermitaprecisedefinitionoftheMiddle/LatePleistoceneboundary.
简介:由使用SHRIMPU-Pb和单个锆石逐步的蒸发方法,作者从东方Hebei为granitoids获得了一些结果省。Yuhuzhaihyperthenetonalitic花岗石被形成2550妈以前,Qingyangshugabbroic片麻岩2536妈,Luecao附近的theYinmahegranodioritic片麻岩,Lulong县,2533妈,gabbro-dioritic片麻岩nearLongwan,Qianxi县,2518-2515妈,在Zunhua2515的Qiuhuayutrondjemitic片麻岩妈,在Zunhua2495妈的theXiaoguanzhuangtonalitic片麻岩,和在Qianxi县2492Ma的Cuizhangzi片麻岩。这些geochronilogical数据尽管多样,在作文,类型和起源表明那,在东方Hebei省的花岗石的片麻岩是emplaced并且在magmatic的一个相当短的时期结晶活动。在这小调子差距的片麻岩的如此的大数量的形成建议它是在Neoarchean的结束的一个批评外壳生长阶段。各种各样的类型的事实thatgranitoids同时发生了暗示一在plating(披风羽毛)下面大规模活动,它当时为外壳生长负责。
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简介:揭示发生到在Bangong-Nujiang缝术地区之中被抓紧的Nyainrongmicrocontinent的侏罗记tectonothermal事件,标明日期的40Ar/39Ar在microcontinent在地下室orthogneiss和侏罗记granitc片麻岩上被执行。在加热阶段,四件样品展出了扁平的高原年龄,与Tp在166176妈的范围集中了的价值;isochron年龄Ti在165175妈的范围被集中,并且他们的相应年龄是在许可的范围以内一致。年龄应该Amdo片麻岩和在侏罗记的magmatic岩石的冷却炮兵阵地的最后的变丑的时代是代表性的。geochronological研究证明了microcontinent的最后的变丑水晶的地下室并且冷却中生代大规模tectonothermal事件发生在晚中间的侏罗记。在中间的侏罗记,Nyainrongmicrocontinent经历了强壮的构造运动。为microcontinent与同位素地球化学与geochronological结合,tectonothermal事件的原因应该被归因于在Nyainrongmicrocontinent和南方卡恩格唐·布洛克追随者之间的碰撞向北方Bangong-Nujiang的subduction海洋的外壳。
简介:Geologicmarksrelatedtoextraterrestrialimpactevents,suchasimpactsplitgravels,impactbrecciatelayers,impactdikes,microirghizites,microtektites,especiallymeteoriticresidues,werediscoveredontheboundarybetweenSinian/CambrianatTianmenshanofWesternHunan,whichmaypossiblydemonstratethatanextraterrestrialimpacteventhaseveroccurredthereontheS/Cboundary.