• 责任者：Wang Yongfeng (State Key Laboratory of Geological Processes and Mineral Resources ; China University of Geoscienees ; Wuhan 430074 ; China) ; Zhang Junfeng
• 刊名：Acta Petrologica et Mineralogica
• 出版年：2013
• 卷期：32(5)
• 关键词：岩石圈地幔 ; lithospheric mantle ; 斜方辉石 ; orthopyroxene
• 页码：p.604-612
• 图表：5 illus., 39 refs.
• 分类号：0700
• issnNo：ISSN1000-6524
• isbnNo：CN11-1966/P

     An electronic backscattered diffraction （EBSD） study of the sieve-textured reaction rim between or- thopyroxene and basalt in the Hannuoba mantle xenoliths was conducted in Damaping area, Hebei Province. Some conclusions have been rearched： （1） The reaction rim has a complex multi-layer structure composed of a basalt layer, an olivine-rich layer and an intergrowth layer of olivine and clinopyroxene; （2） The Mg# of the o- livine grains in the reaction rim increases toward the orthopyroxene grain while the Mg# of the clinopyroxene grains in the reaction rim remains stable; （3） There is a well-defined crystallographic topotactic relationship be- tween orthopyroxene and clinopyroxene, i.e., （100）opx//（100）cpx, （010）opx//（010）cpx, （001）opx//（001）cpx; （4） The crystallographic distribution of olivine grains is nearly at random and shows no relationship with orthopy- roxene and clinopyroxene. This sieve-textured reaction rim can be interpreted as the result of a multistage reac- tion process. In the first step, the orthopyroxene reacts with the melt to form clinopyroxene which made the re- action melt more silicic. As the melt gets saturated with silica, olivine precipitates from the reaction melt. Com- paring to the reaction between a silica-saturated melt and a peridotite, the reaction between a silica-tmderstaturated melt and a peridotite is probably easier to proceed due to the formation of sieve-textured reaction rims. The sieve-textured reaction rims provide a feasible channel for the migration of the melt along otherwise closed grain boundaries at high pressure, weaken the surrounding peridotite through the reduction of mineral grain size, and maintain a continuous erosion and destruction of the peridotite during the upward migration of the melt. This process may lead to a quick rejuvenation of lithospheric mantle.