| 大兴安岭吉峰科马提岩Sm-Nd等时线年龄测定 |
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| 关键词:komatiite Sm-Nd isochron age Da Hinggan Ling |
| 基金项目:地质调查项目“六十林场幅和阿里河幅1∶20万填图” |
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| Dating of Sm-Nd Isochron Ages of the Jifeng Komatiites from the Da Hinggan Ling |
| The Jifeng komatiites are situated in the north Da Hinggan Ling. Their geological and geochemical feature indicate that the komatiite series consists of the ultramafic komatiite,basaltic komatiite,tholeiite and gabbro.The REE patterns of the komatiite is similar to chondrite.The eight samples composed of komatiite,tholeiite and gabbro yield a reasonable good isochron age of ( 1727± 74.7)Ma(2 σ ) with I Nd =0.510725±0.0000798, ε Nd ( t )=6.94±1.56.Their Nd model ages mainly range from 1 589 Ma to 1 799 Ma.Such a case shows the Jifeng komatiites derived from the depleted theosphere mantle in the early Middle Proterozoic. This crustal accretion event would be associated with the Songnen Massif splitting from the southorn continental margin of the Xibailiya Massif. |
| HU Dao-gong,LI Hong-wen,LIU Xu-guang,YU Rong-wen.2003.Dating of Sm-Nd Isochron Ages of the Jifeng Komatiites from the Da Hinggan Ling[J].Acta Geoscientica Sinica,24(5):405-408. |
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