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早中生代的扬子大陆向华北大陆的深俯冲碰撞作用以及中、新生代的华北东部岩石圈减薄作用是国际大陆动力学问题研究的两个热点。然而,把它们有机联系起来,探讨深部岩石圈演化动力学过程的研究还很少。报道了中国大陆科学钻探先导孔(CCSD-PP1)橄榄岩的矿物岩石化学分析结果。这些橄榄岩亏损玄武质组分(如低w(CaO+Al2O3)、高Mg#等),并经历了中元古代来自软流圈的碳酸岩熔体的交代作用和早中生代的超高压再平衡过程。结合已发表的华北捕虏体橄榄岩资料,对这一橄榄岩的原始地幔属性进行了分析。发现CCSD-PP1橄榄岩与华北古老岩石圈地幔组成相似,是早中生代来自华北岩石圈的构造侵入体。早中生代华北岩石圈的伸展减薄与苏鲁超高压变质岩石的折返提供了早期软流圈物质上涌的构造体制。
The deep subduction collision of the Early Mesozoic Yangtze continent to the North China continent and the lithospheric thinning of the Meso-Cenozoic North China are two hotspots in the study of the dynamics of the interior continent. However, there is little research on the dynamics of deep lithosphere evolution by organically connecting them. This paper reports the results of mineralogy and petrochemistry of the CCSD-PP1 peridotite in the Chinese mainland. These peridotites are depleted in basaltic components such as low-w (CaO + Al2O3), high Mg #, etc.) and underwent the metasomatism of Mesoproterozoic carbonate melt derived from the asthenosphere and the EHV rebalance process. Based on the published data of the North China xenoliths, the original mantle properties of this peridotite are analyzed. It is found that CCSD-PP1 peridotites are similar in composition to the ancient lithospheric mantle in North China and are tectonic intrusions from the North China lithosphere in the early Mesozoic. The early Mesozoic extensional thinning of the North China lithosphere and the reentry of the Sulu ultrahigh-pressure metamorphic rocks provide the structural system for the early asthenospheric upwelling.