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

发布时间：2018-05-30 03:35

本文选题：水含量 + 橄榄岩　；参考：《地球科学》2017年06期

【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H_2O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H_2O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H_2O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.
[Abstract]:Studies have shown that the lithospheric mantle in Fexian County, Shandong Province, in the eastern part of the North China Craton was highly water-rich during the craton failure peak (early Cretaceous). The H _ 2O content of olivine is 180 脳 10 ~ (-6) ~ (-1), while that of olivine is 10 脳 10 ~ (10) ~ (-6) ~ (th) in the lithospheric mantle in the western part of the craton of Taihang Mountain, where the H _ 2O content of olivine is 10 脳 10 ~ (-6) ~ (-6). This indicates that the westward subduction of the paleo-Pacific plate resulted in the water-rich characteristics of the early Cretaceous lithospheric mantle in the eastern part of North China, which provided a mechanical premise for the cratonic failure. In order to understand the influence of the paleo-Pacific plate subduction, the peridotite captivates in the early Cretaceous high-mafic diorite in the Tieconggou area, Shandong Province, between Fexian and Wushan are analyzed. The original H _ 2O content of olivine is 6 脳 10 ~ (-10) ~ (-6), with an average value of 15 卤7 脳 10 ~ (10) ~ (-6), which suggests that the lithospheric water-rich effect caused by Pacific plate subduction may be confined to the eastern part of North China, which is consistent with the highest degree of craton failure in the easternmost region.
【作者单位】：中国科学技术大学地球和空间科学学院;浙江大学地球科学学院;
【基金】：国家自然科学基金项目(No.41472057)
【分类号】：P534.53;P588.125

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