| 山东铁铜沟橄榄岩的水含量:华北克拉通早白垩世富水岩石圈的分布 |
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| 引用本文： | 夏群科,程徽,刘佳.山东铁铜沟橄榄岩的水含量:华北克拉通早白垩世富水岩石圈的分布[J].地球科学,2017,42(6):853-861. |
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| 作者姓名： | 夏群科 程徽 刘佳 |
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| 作者单位： | 1.中国科学技术大学地球和空间科学学院，安徽 合肥 230026 |
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| 基金项目： | 国家自然科学基金项目41472057 |
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| 摘 要： | 已有研究表明，华北克拉通东部的山东费县岩石圈地幔在克拉通破坏峰期(早白垩世)时是高度富水的，其中橄榄石的H2O含量＞180×10-6；而同期克拉通西部的太行山符山地区岩石圈地幔具有贫水特征，其中橄榄石的H2O含量为~10×10-6.这表明西向俯冲的古太平洋板块造成了华北东部早白垩世岩石圈地幔的富水特征，为克拉通破坏提供了力学前提.为了解古太平洋板块俯冲的影响范围，对介于费县和符山之间的山东铁铜沟地区早白垩世高镁闪长岩中的橄榄岩捕掳体进行了含水性分析，橄榄石的原始H2O含量(6×10-6~24×10-6，平均值为(15±7)×10-6)与符山地区相当，暗示太平洋板块俯冲造成的岩石圈富水效应可能仅局限在华北最东部，这和最东部地区克拉通破坏程度最高是一致的.
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| 关 键 词： | 水含量 橄榄岩 早白垩世 铁铜沟 克拉通破坏 岩石学 地球化学 |
| 收稿时间： | 2017-05-10 |
The Distribution of the Early Cretaceous Hydrous Lithospheric Mantle in the North China Craton: Constraints from Water Content in Peridotites of Tietonggou |
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| Abstract: | Previous studies show that the Early Cretaceous lithospheric mantle beneath Feixian (Shandong Province) in the eastern part of the North China Craton (NCC) was highly hydrous ( > 1 000×10-6, H2O wt.), in which the H2O content of olivine was > 180×10-6. Meanwhile the Early Cretaceous lithospheric mantle beneath Fushan (Shanxi Province) in the western part of the NCC was relatively dry, in which the H2O content of olivine was ~10×10-6. This contrast demonstrates that the hydration of the Early Cretaceous lithospheric mantle of eastern NCC was probably due to the westward subduction of the Pacific plate, and this high water content had significantly reduced the viscosity of the lithospheric mantle and provided a prerequisite for the destruction of the NCC. To explore the distribution of hydrous lithospheric mantle in the NCC, we measured the H2O content of the peridotite xenoliths hosted by the Early Cretaceous high-magnesium diorites of Tietonggou (Shandong Province) that is located between Feixian and Fushan.The H2O content of olivine in the Tietonggou peridotites is (6-24)×10-6 (average (15±7)×10-6) and comparable with that of the Fushan olivine, suggesting that the Early Cretaceous hydrous lithospheric mantle caused by the westward subduction of the Pacific plate was likely limited to the most eastern part of the NCC. |
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