简介:本文重点研究了大别山潜山,牌楼地区榴辉岩P-T-t轨迹,探讨了大别山地区榴辉岩成因,认为榴辉岩原岩主要是碱性玄武岩,少部分洋脊拉斑玄武岩岩浆早期结晶分异堆晶岩及部分钙质沉积岩。它们在华北与杨子板块碰撞时(260±30Ma),地壳向下俯冲到40-60km处,温度550°-830°C,压力1.1-2.1GPa的条件下形成的。在构造抬升过程中,榴辉岩产生了角闪岩相、绿片岩相退变质作用,角闪岩相温压条件:460°-570℃,0.4-0.7GPa。流体包裹体研究表明:流体包体成分主要为NaCl-H_2O,H_2O,NaCl-CO_2-H_2O体系,变质作用过程从早至晚由氧化向还原环境转化。熔融包体的发现表明:榴辉岩形成具有局部深熔作用。从榴辉岩产状、岩石化学、地球化学特征表明本地区榴辉岩不是一种成因,同时具有B类、C类榴辉岩特征。
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简介:WhileattendanceatpreviousIGC'swasremarkable,themorethan7,000earthscientists,exhibitorsandguestswhometinFlorenceforthe32^ndInternationalGeologicalCongresssetanall-timerecordasthehighestnumberofparticipants.Theycamefrom120countriesand75%werenotItalian.Thisproportionofforeignattendeeswasthelargestever;inlinewithatrendofincreasingnonlocalparticipation,ittestifiestothevitalityandinternationalcharacteroftheIGCs.
简介:矿化蚀变信息提取是遥感找矿的重要手段之一。AdvancedLandImager(ALI)遥感图像信噪比高达100~200,且有较高的波谱分辩率,能够区分具有标示性波谱特征的岩矿。以美国Cuprite地区ALI遥感图像为例,通过数字处理、最小噪声分离变换(MNF),分离和均衡数据中的噪声。然后提取纯净像元(PPI),输入到N维可视化器中开发端元组分光谱,并与波谱库中的波谱进行比对分析。将提取的端元作为样本,进行数据集合评估,最后进行蚀变信息的提取。结果表明,ALI遥感数据由于其波段多,波谱空间分辨率高,经过MNF-PPI后的三维散点图端元提取,能够识别更微弱的岩矿信息。
简介:ThereareobviousdifferencesinthemineralassemblageandmetamorphicP-TconditionsbetweentheeclogitesfromthenorthernandsouthernpartsoftheeasternDabieMountains.ThosefromthenorthernpartofthemountainsaredevelopedinAlpineperidotiteandgneiss.Theyhaveamineralassemblageofgarnet+diopsidewithnoquartz,andwereformedattemperaturesof600℃-740℃.Thosefromthesouthernpartaredevelopedingneissandmarble.Theyconsistofgarnet+omphacite+lessquartzandweremetamorphosedattemperaturesintherangeof650°-800℃.Thesedifferencessuggestthattheformermaybeformedduringthemetamorphismofthedeepsubductedoceaniccrust,whereasthelattermaybegeneticallyrelatedtothesubductionofthecontinentalcrustinthisarea.