Late Triassic Intraoceanic Arc Aystem within Neotethys: Evidence from Cumulate Hornblende Gabbro in Gangdese Belt, South Tibet

在线阅读 下载PDF 导出详情
摘要 TheNeotethysplaysanimportantroleinshapingtheGangdesemagmaticbelt,southernTibet.However,theinitialtimeofspreadingandsubductionoftheNeotethysremainscontentious.Inthisstudy,asuiteoflateTriassiccumulatehornblendegabbrowasidentifiedinthesouthernmarginoftheGangdesemagmaticbelt.Thegabbroexhibitscumulatestructure,withhornblendeandplagioclaseastheprimarymineralphases.Isotopicdataindicateahydrousmagmasourcederivedfromadepletedmantlewedgethathasbeenmodifiedbyslabdehydration.Geochemicaldiscriminationssuggestthatthegabbrowasformedinanintraoceanicarcsetting,withcrystallizationagesofca.220-213Ma.Hornblende,hornblendelagioclaseandilmenitethermometersrevealthatthecrystallizationtemperatureof900-750°Cforthegabbro.Hornblendeandhornblende-plagioclasegeobarometersyieldanemplacementdepthatca.14.5-19.5km.ThisgabbroconstitutesalineofevidenceforanintraoceanicarcmagmatismthatiscoevalwiththecounterpartsinthesouthernTurkey,revealinganintraoceanicsubductionsystemwithintheNeotethysfromwesttoeastintheLateTriassicandthattheoceanizationoftheNeotethyswasmuchearlierthanpreviousexpectation.
机构地区 不详
出处 《地质学报:英文版》 2017年S1期
关键词
出版日期 2017年01月17日(中国期刊网平台首次上网日期,不代表论文的发表时间)
  • 相关文献