| 岚皋金云角闪辉石岩类捕虏体特征 |
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| 引用本文： | 徐学义,黄月华,夏林圻,夏祖春.岚皋金云角闪辉石岩类捕虏体特征[J].岩石矿物学杂志,1996,15(3):193-202. |
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| 作者姓名： | 徐学义 黄月华 夏林圻 夏祖春 |
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| 作者单位： | 中国地质大学，西北大学地质系，地质矿产部西安地质矿产研究所 |
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| 摘 要： | 陕西岚皋地区碱质基性超基性潜火山杂岩中的金云角闪辉石岩类捕虏体，主要由透辉石、富钛韭闪石、高Ｔｉ金云母、磷灰石及钛铁矿组成。捕虏体发育三联晶、碎裂边、扭折变形等固相线下变形变质结构，与正常地幔尖晶石二辉橄榄岩成分相比，捕虏体富ＴｉＯ２、Ｆｅ２Ｏ３、ＣａＯ、Ｎａ２Ｏ、Ｋ２Ｏ，贫ＭｇＯ；其稀土元素具富集特征，尤其富集ＬＲＥＥ；微量元素配分型式显示富亲石不相容元素的特征。岩相学、矿物学及岩石化学特征表明，该类捕虏体为交代地幔捕虏体，它代表了北大巴山早古生代裂谷作用时期的异常地幔。交代营力可能源于地幔热柱的上升，在地幔深处可能以熔体交代作用为主，往上逐渐以流体交代作用为主
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| 关 键 词： | 金云角闪辉石岩 交代 地幔捕虏体 地幔交代作用 地幔热柱 |
Characteristics of Phlogopite-Amphibole Pyroxenite Xenoliths from Langao County, Shanxi Province |
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| Abstract: | Phlogopite-amphibole pyroxenite xenoliths within alkaline basic-ultrabasic aubvolcanic complex are composed of diopside, titanium-rich pargasite, high-titanium phlogopite, apatite and ilmenite, exhibiting threeling, cataclastic and kink-banded textures. Compared with original spinel lherzolite from eastern China, the xenoliths are enriched in TiO2, Fe2O3, CaO,Na2O, K2O, with an apparent depletion in MgO. Chondrite-normalized REE patterns and primordial mantle normalized trace elements data show that they are enriched in REE (especially
LREE) and incompatible trace elements. Petrographic, mineralogical and chemical characteristics indicate that the xenoliths are metasomatized mantle xenoliths, which represent the anomalous mantle of early Palaeozoic rift in northern Daba Mountain. Mantle plume was the most probable agent for producing the xenoliths. with the ascending of the mantle plume, major metasomatic agents changed from melts to fluids. |
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| Keywords: | phlogopite-amphibole pyroxenite metasomatized mantle xenoliths mantle metasomatism mantle plume |
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