对“也谈铙钹寨超镁铁岩体的成因和构造类型的归属问题”一文评论的答疑  

Reply to Comments on"Origin and structural nature of Raobozhai ultamafic rock:A discussion"

作　　者：王希斌[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037

出　　处：《岩石学报》2006年第12期3084-3089,共6页Acta Petrologica Sinica

摘　　要：张旗先生的《评论》和他之前的工作没有提供饶钹寨岩体的"地幔交代作用"的证据;地幔交代作用不能作为判别地幔岩为大陆地幔和大洋地幔属性的标志,因为两者均可能发生地幔交代作用。根据铙钹寨岩体原岩为强烈亏损的方辉橄榄岩(和二辉橄榄岩),伴有豆荚状铬铁矿及瘤状矿石和铬尖晶石成分具有蛇绿岩地幔岩属性(双峰分布)而非大陆地幔橄榄岩特征,认为该岩体带有蛇绿岩成员的某些特征,并认为该岩体经历了角闪岩相-麻粒岩相的变质作用。我们对《评论》中列举的所谓大陆地幔橄榄岩中也产有豆荚状铬铁矿的诸多例子给予了剖析,指出《评论》犯有基本概念的错误。ZHANG Qi＇s comments argued that the Raobazhai ultramafic body is a mande metasomatic peridotite rather than an ophiolitie peridotite. Our answer is that metasomatic mantle is not a criterion for discriminating the nuture of mantle rock, because mantle metasomatism may occur both in continental mande and oceanic mantle. The Raobazhai ultramafic body consists of strongly depleted harzburgite and lherzolite, and some podiform and nodular chromitite ore body. The podiform chromite shows affinities of ophiolitie mantle other than that of continental mantle. The ophiolitic mantle has experienced amphibolite-granulite phase metamorphism.

关 键 词：大别山 铙钹寨岩体 高压变质作用 大洋岩石圈地幔 大陆岩石圈地幔 蛇绿岩 豆荚状铬铁矿 

分 类 号：P588.125[天文地球—岩石学]