摘要
Asuiteof1.84–1.92Gametamaficdykeswithintheparagneisssuite（khondalite）oftheQuanjimassifinNWChina,hasbeenchoseninthisstudyforfurtherunderstandingthetectonicevolutionandpossiblelinkstotheglobalColumbiasupercontinent.Occurrenceandfieldrelationssuggestthattheywereformedcoevallywithapreviousstudied1.83–1.85Gametamaficdykeswarms.Whole-rockmajorandtraceelementalgeochemistrysuggestsprecursormagmaoftheamphibolitesbeinggeneratedfromavolcanicarc-relatedtectonicsettingratherthanaback-arcenvironmentwherethemetamaficdykeswarmswereemplaced.ThemetamaficdykesshowenrichmentofLREEandstronglynegativeanomaliesforTa-Nb,Zr-HfandTi,havehighSiO2（49.3wt.%–52.5wt.%）butlowMgO（6.40wt.%–7.76wt.%）contentsandMg#（Mg#=[100×（MgO/40.3）]/[MgO/40.3+FeO/71.8]）values（45.7–52.1）,suggestingevolvedprecursormagma.ThehighvaluesofLa/Ta（22.2–42.8）andLa/Nb（1.71–2.47）,mildlynegativeεNd（t）values（-2.51–0.15）,withdepletedmantlemodelages（TDM）of2.45–2.84Ga,suggestthattheirprecursormagmaswerepossiblyderivedfromasubduction-relatedfluidmetasomatizedArcheansub-continentallithosphericmantle.Thisstudyprovidesfurtherevidenceforoceanicplatesubductionprevailingbeforeoraround1.85Ga,whichconfirmsaprolongedsubduction-accretion-collisionhistoryintheNWChinawhichispossiblylinkedtotheassemblyoftheColumbiasupercontinent.
出版日期
2016年04月14日（中国Betway体育网页登陆平台首次上网日期，不代表论文的发表时间）
