CAJ | 학술논문

本文以北秦岭造山带华北陆块南缘被动陆缘火山裂谷(大洋?)盆地、早古生代岛弧-弧后盆地和晚古生代岛弧-蛇绿杂岩等构造相带为研究重点,综合利用同位素年代学、古生物年代学、岩石学、岩石地球化学和同位素地球化学等实测数据,系统研究和探讨了北秦岭造山带被动陆缘大洋扩张向俯冲增生造山转换的时限.研究显示:华北陆块南缘由晚新元古代大洋扩张作用转化为板块俯冲作用的转换时限为早奥陶世,约472Ma左右.北秦岭造山带在古生代期间至少存在两期板块俯冲增生造山作用,时代上向南变新,空间上向南向洋内迁移.两次俯冲增生造山作用分别构筑了北秦岭造山带早古生代岛弧-弧后盆地和晚古生代岛弧-俯冲杂岩两条构造相带.
본문이북진령조산대화북륙괴남연피동륙연화산렬곡(대양?)분지、조고생대도호-호후분지화만고생대도호-사록잡암등구조상대위연구중점,종합이용동위소년대학、고생물년대학、암석학、암석지구화학화동위소지구화학등실측수거,계통연구화탐토료북진령조산대피동륙연대양확장향부충증생조산전환적시한.연구현시:화북륙괴남연유만신원고대대양확장작용전화위판괴부충작용적전환시한위조오도세,약472Ma좌우.북진령조산대재고생대기간지소존재량기판괴부충증생조산작용,시대상향남변신,공간상향남향양내천이.량차부충증생조산작용분별구축료북진령조산대조고생대도호-호후분지화만고생대도호-부충잡암량조구조상대.
This study examines the tectonic affinities and geochronology of three tectonic facies in the north Qinling orogenic belt, the volcanic rift or oceanic basin on the south margin of the north China block, early Paleozoic island arc-backarc basin assembledge, and late Palezoic island arc-subduction-related opiolitic melange, respectively, using integrated field observations, biochronologic, geochemical, isotopic, SHRIMP and LA-ICP-Ms zircon U-Pb analyses. The results in the study show that transformation from sea-floor spreading on the south margin of the north China block to subduction resulting in the arc-basin system occuured in the early Ordovician, ca 472±11 Ma, and there were two events of subduction-accretion orogeny developed in the north Qinling orogenic belt during the Paleozoic. Subduction migrated southward to the ocean from the early to late Paleozoic.