摘要
MesozoicophiolitescropoutdiscontinuouslyintheIndo-MyanmarRangesinNEIndiaandMyanmar,andrepresenttheremnantsoftheNeotethyanoceaniclithosphere(Senguptaetal.,1990;Mitchell,1993).TheseophiolitesintheIndo-MyanmarRangesarethesoutherncontinuationoftheNeotethyanophiolitesoccurringalongtheYarlungZangboSutureZone(YZSZ)insouthernTibetfarthernorthwest(Mitchell,1993;FareeduddinandDilek,2015),asindicatedbytheircoevalcrystallizationagesandgeochemicalcompositions(Yangetal.,2012;Liuetal.,2016).TheKalaymyoophioliteislocatedinthecentralpartoftheeasternIndo-MyanmarRanges(Fig.1).compositionoftheseophiolitesfromthecentralTibetanPlateau(CTP)isdominatedbyMORBsandminorOIBsandadistinctlackofIATsandBONs,whichisinconsistentwithmostophiolitesworldwide(RobinsonandZhou,2008;Zhangetal.,2008).Butthegenerationandtectonicnatureoftheseophiolitesarestillcontroversial.*TheKalaymyoperidotitesconsistmainlyofharzburgites,whichshowtypicalporphyroclasticorcoarse-grainedequigranulartextures.Theyarecomposedofolivine(Fo=89.8–90.5),orthopyroxene(En86-91Wo1-4Fs8-10;Mg#=89.6–91.9),clinopyroxene(En46-49Wo47-50Fs3-5;Mg#=90.9–93.6)andspinel(Mg#=67.1–78.9;Cr#=13.5–31.5),andhaverelativelyhomogeneouswhole-rockcompositionswithMg#sof90.1–90.8andSiO2(41.5–43.65wt.%),Al2O3(1.66–2.66wt.%)andCaO(1.45–2.67wt.%)contents.TheydisplayLightRareEarthElement(LREE)-depletedchondrite-normalizedREEpatternswith(La/Yb)CN=0.04–0.21and(Gd/Yb)CN=0.40–0.84,andshowaslightenrichmentfromPrtoLawith(La/Pr)CNintherangeof0.98–2.36.TheKalaymyoperidotitesarecharacterizedbyPd-enrichedchondrite-normalizedPGEpatternswithsuperchondritic(Pd/Ir)CNratios(1.15–2.36).TheircalculatedoxygenfugacitiesrangebetweenQFM–0.57andQFM+0.90.ThesemineralogicalandgeochemicalfeaturescollectivelysuggestthattheKalaymyoperidotitesrepresentresidualuppermantlerocksafterlowtomoderatedegrees(5–1
出版日期
2017年07月25日（中国期刊网平台首次上网日期，不代表论文的发表时间）
