The discovery of Nanqiao highly depleted N-MORB and geological significance
The discovery of Nanqiao highly depleted N-MORB and geological significance
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发表时间：
2003
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通讯作者：
Zhou Jin-cheng
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作者：
Zhou Jin-cheng
采用单颗粒锆石蒸发法测定了位于赣西北古九岭岛弧向西延沿着的湖南南桥玄武岩的207 Pb/206 Pb年龄。数据产生的锆石结晶年龄为1？玄武岩为271±2 Ma。玄武岩和闪长岩具有高度亏损的地球化学特征：K2 O值很低，不相容的HFSE和REE丰度大多低于N-MORB（少数接近后者），eNd（1？271 Ma）的平均值为6.86 ~ 8.98，反映了典型的N-MORB地球化学特征。该玄武岩可能代表了沿着古俯冲带分布的洋壳残留物，可作为古九岭岛弧的新证据。
With single-zircon evaporation technique, the authors determined 207Pb/ 206Pb age of Nanqiao basalt in Hunan, which is located along the westward extension of ancient Jiuling island arc in northwest Jiangxi. The data yield a zircon crystallization age of 1?271±2 Ma for the basalt. The basalt and diabase show highly depleted geochemical features: K 2O values are very low, abundances of their incompatible HFSE and REE are mostly lower than those of N-MORB (with a few close to the latter), and e Nd(1?271 Ma)values vary from 6.86 to 8.98, suggesting typical N-MORB geochemical characteristics. This basalt may represent a relict of the ocean crust distributed along an ancient subduction zone and can serve as new evidence for ancient Jiuling island arc.