A RE-APPRAISAL OF THE USE OF TRACE ELEMENTS TO CLASSIFY AND DISCRIMINATE BETWEEN MAGMA SERIES ERUPTED IN DIFFERENT TECTONIC SETTINGS
A RE-APPRAISAL OF THE USE OF TRACE ELEMENTS TO CLASSIFY AND DISCRIMINATE BETWEEN MAGMA SERIES ERUPTED IN DIFFERENT TECTONIC SETTINGS
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DOI：
10.1016/0012-821x(79)90133-x
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发表时间：
1979-11
影响因子：
5.3
通讯作者：
David A. Wood;J. Joron;M. Treuil
中科院分区：
文献类型：
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作者：
David A. Wood;J. Joron;M. Treuil
将几种构造环境中基性熔岩的亲湿岩浆元素组成与原始地幔的估计组成进行了比较。观测到的变化被用来细分为两个主要类型的洋中脊玄武岩（MORB）根据脊段的构造特征，他们从爆发。脊段与积极的剩余重力，深度和热流异常爆发E型MORB主要是在更多的hymmagmatophile元素富集，但也包括岩浆类型，其中大部分这些元素都耗尽。富集型和亏损型E型MORB的La/Ta比值（E型MORB La/Ta> 10，N型MORB La/Ta> 15）和Hf/Ta比值（E型MORB Hf/Ta> 7，N型MORB Hf/Ta> 7）可与正常脊段（N型MORB）的玄武岩区分开来。E型MORB以其较高的Hf/Ta比值（>2）与洋岛玄武岩区别开来。Th-Hf-Ta三角图用于区分不同的海底玄武岩以及在破坏性板块边缘喷发的玄武岩，这些玄武岩在Ta和Nb中亏损。该图还可以区分来自不同构造环境的熔岩，以及识别已被大陆地壳污染的熔岩。
The hygromagmatophile element composition of basic lavas from several tectonic environments are compared with the estimated composition of the primordial mantle. The observed variations are used to subdivide mid-ocean ridge basalts (MORB) into two main types according to the tectonic character of the ridge segment from which they were erupted. Ridge segments with positive residual gravity, depth and heat flow anomalies erupt E-type MORB which are predominantly enriched in the more hygromagmatophile elements, but also include magma types which are depleted in most of these elements. Both enriched and depleted E-type MORB can be distinguished from the basalts erupted at normal ridge segments (N-type MORB) by their La/Ta ratios (in E-type MORB La/Ta ∼10, in N-type MORB La/Ta is ∼15) and by Hf/Ta ratios (in E-type MORB Hf/Ta> 7, in N-type MORB Hf/Ta> 7). E-type MORB can be distinguished from the basalts erupted at ocean islands by their higher Hf/Ta ratios (>2). A Th-Hf-Ta triangular diagram is used to discriminate between the different ocean floor basalts as well as those erupted at destructive plate margins, which are depleted in Ta and Nb. This diagram can also distinguish between silicic lavas from the different tectonic environments as well as identifying lavas that have been contaminated with continental crust.