...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of African Earth Sciences >Petrological and geochemical study of Birimian ultramafic rocks within the West African Craton: Insights from Mako (Senegal) and Loraboue (Burkina Faso) lherzolite/harzburgite/wehrlite associations
【24h】

Petrological and geochemical study of Birimian ultramafic rocks within the West African Craton: Insights from Mako (Senegal) and Loraboue (Burkina Faso) lherzolite/harzburgite/wehrlite associations

机译：西非克拉通内双峰岩超镁铁质岩石的岩石学和地球化学研究：来自马可（塞内加尔）和洛拉布维（布基纳法索）的锂铁矿/哈兹伯格岩/辉石岩协会的见解

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In Archean and Paleoproterozoic greenstone belts, ultramafic (UM) rock occurrences are commonly found in close association within basic and differentiated magmatic series. In the Kedougou-Kenieba Inlier (West African Craton), UM rocks are interbedded within the Birimian (2.1 Ga) Mako tholeiitic series (basalts, gabbros). UMs are typically lherzolite, harzburgite and wehrlite, characterized by their cumulative textures and relative pro-portions of chromite, olivine, clinopyroxene, amphibole +/- orthopyroxene. Geochemical study (Major, REE and trace elements in whole rocks and mineral (mainly clinopyroxene and amphibole) and Sr/Nd isotopic records suggest the existence of different types of complexes. The first one consists of lherzolite + harzburgite assemblages whereas the second one consists of isolated wehrlite massifs. Both complexes highlight two different geodynamic environments, the first association being significantly more juvenile or mantle-related than isolated wehrlites which show more evolved geochemical signatures.UM rocks (dunite + wehrlite) of Loraboue (greenstone belt of Boromo, Burkina Faso) associated with calcalkaline series display the same mineralogical composition as the Mako UM rocks but exhibit a different whole rock composition characteristic of mature island-arc magmas and showing U-shaped REE pattern for both clinopyroxene and host rock, and a clear negative Nb anomaly.The Mako UMs suggest that this portion of the Birimian crust was built in an oceanic context evolving from a MORB-like domain to an increasingly mature volcanic arc domain.
机译：在太古宙和古元古代绿岩带中，通常在基本岩浆和微岩浆系列中发现超镁铁质（UM）岩石事件紧密相关。在Kedougou-Kenieba Inlier（西非克拉通）中，UM岩石夹在Birimian（2.1 Ga）Mako韧性系列（玄武岩，辉长岩）内。 UMs通常为锂铁矿，钙镁矿和辉绿岩，其特征在于它们的累积质地和亚铬铁矿，橄榄石，斜辉石，斜闪石+/-正火石的相对比例。地球化学研究（整个岩石和矿物中的主要，稀土元素和痕量元素（主要是斜辉石和斜闪石）和Sr / Nd同位素记录表明存在不同类型的复合物，第一个由锂铁矿+钙锰矿组合组成，而第二个由锂铁矿+辉石组成。这两个复合体都突出了两个不同的地球动力学环境，第一个关联比显示出更多演化地球化学特征的孤立白垩岩与幼年或地幔相关性要强得多。Loraboue（布基纳法索，博罗莫的绿岩带）的UM岩石（白云母+辉绿岩）与钙长石系列相关的）表现出与Mako UM岩石相同的矿物组成，但展现出成熟的岛弧岩浆的整体岩石组成特征，并且对斜辉石和主体岩石均表现出U形REE模式，并且Nb异常明显。 Mako UMs认为Birimian地壳的这一部分是在海洋环境下建立的。从类似MORB的区域过渡到逐渐成熟的火山弧区域。

著录项

相似文献

  • 外文文献
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号