Continental Basaltic Rocks
Continental Basaltic Rocks
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DOI：
10.1016/b978-0-08-095975-7.00303-x
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发表时间：
2014
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影响因子：
--
通讯作者：
G. L. Farmer
中科院分区：
文献类型：
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作者：
G. L. Farmer
在过去的几十年里，大陆玄武岩及其岩石学类群的地球化学研究已成为大陆岩石圈研究的支柱。这些火成岩之所以起到如此重要的作用，很大程度上是因为大陆玄武岩及其地幔的化学和同位素组成(见第2.05章)和地壳捕捉体(见第3.01章)为地球科学家提供了大陆深部岩石圈和下地幔化学和物理演化的最佳替代记录，否则无法直接研究这些区域。考虑到这一点，本章的主要目标是说明如何利用地球化学数据来评估这些岩石的来源和研究大陆岩石圈的演化。这里不会尝试对大陆玄武岩进行完整的概述，因为大陆玄武岩的成分范围太广，而且世界各地可获得的此类岩石的地球化学数据非常多。本章的范围仅限于讨论一组精选的超镁铁质到镁铁质成分的“板内”大陆火成岩，主要由金伯利岩、钾质和苏打质碱性玄武岩以及大陆溢流玄武岩组成。在活动大陆边缘形成的火成岩，如会聚或转换板块边缘，是大陆岩浆作用的重要例子，但这里不直接讨论(会聚边缘岩浆将在第2.11、3.11和3.18章中讨论)。第2.04章和第3.16章介绍了大洋盆地板内火成岩的地球化学。尽管玄武岩岩浆作用在地球历史上一直存在，但由于更完整地保存了较年轻的大陆镁铁质火成岩，这里提供的大多数例子都来自中、新生代火山岩田。
During the past few decades, geochemical studies of continental basaltic rocks and their petrologic kin have become mainstays of studies of the continental lithosphere. These igneous rocks have taken on such an important role largely because the chemical and isotopic composition of continental basaltic rocks and their mantle (see Chapter 2.05) and crustal xenoliths (see Chapter 3.01) provide the best proxy record available to earth scientists for the chemical and physical evolution of the deep continental lithosphere and underlying mantle, areas that are otherwise resistant to direct study. Keeping this in mind, the primary goal of this chapter is to illustrate how geochemical data can be used both to assess the origin of these rocks and to study the evolution of the continental lithosphere. A complete overview of continental basaltic rocks will not be attempted here, because continental" basalts" come in too wide a range of compositions, and because of the sheer volume of geochemical data available for such rocks worldwide. The scope of the chapter is limited to a discussion of a select group of ultramafic to mafic composition" intraplate" continental igneous rocks consisting primarily of kimberlites, potassic and sodic alkali basalts, and continental flood basalts. Igneous rocks forming at active continental margins, such as convergent or transform plate margins, are important examples of continental magmatism but are not directly discussed here (convergent margin magmas are discussed in Chapters 2.11, 3.11, and 3.18). The geochemistry of intraplate igneous rocks of the ocean basins are covered in Chapters 2.04 and 3.16. Although basaltic magmatism has occurred throughout the Earth's history, the majority of the examples presented here are from Mesozoic and Cenozoic volcanic fields due to the more complete preservation of younger continental mafic igneous rocks.