华北早白垩世岩石圈地幔水含量的区域分布特征及其对克拉通破坏的动力因素的制约

The North China Craton (NCC) had undergone multi-stage subduction of oceanic plates from the south, north and east sides since the early Paleozoic; these events may have caused the strong hydration of the NCC lithospheric mantle and provided a prerequisite for the destruction of the NCC. But it remains unclear which subduction had contributed most to the hydration. This project will measure the water contents of the mantle xenoliths and xenocrysts hosted by the high-magnesium diorites and lithospheric mantle-derived basalts of the early Cretaceous when is the peak time of the NCC destruction, to reveal regional distribution of water in the early Cretaceous NCC lithospheric mantle and provide new constraints on the main dynamic factor in the destruction of the NCC.

华北克拉通东部自古生代以来经历的多期、多方向海洋板块的俯冲加水可能造成了克拉通岩石圈地幔的弱化，为克拉通破坏提供了力学前提。但是起主导作用的俯冲事件尚未得到明确的限定。本项目将系统分析华北克拉通破坏峰期- - 早白垩世- - 岩石圈地幔来源的玄武岩以及高镁闪长岩中岩石捕掳体和矿物捕掳晶的结构水含量，了解华北早白垩世岩石圈地幔水含量的区域分布特征，为认识华北克拉通破坏的主要动力因素提供新的制约。

华北克拉通东部自古生代以来经历的多期、多方向海洋板块的俯冲加水可能造成了克拉通岩石圈地幔的弱化，为克拉通破坏提供了力学前提。但是起主导作用的俯冲事件.尚未得到明确的限定。.本项目系统分析了华北克拉通破坏峰期（早白垩世）岩石圈地幔物质的水含量，配合其它元素和同位素数据的信息，得到如下结果：（1）华北早白垩世岩石圈地幔普遍表现出富集特征；（2）华北东部的早白垩世岩石圈地幔普遍具有比软流圈高得多的水含量，而重力梯度带西部则表现出贫水的特征。.这些结果显示，太平洋板块的西向俯冲造成了华北东部岩石圈的富水特征及其所带来的低黏滞度，这是华北东部被破坏的力学前提。