CHARACTERIZATION OF SPINEL PERIDOTITES BY OLIVINE SPINEL COMPOSITIONAL RELATIONSHIPS - REVIEW AND INTERPRETATION

被引:841
作者
ARAI, S
机构
[1] Department of Earth Sciences, Kanazawa University, Kanazawa, Ishikawa
关键词
D O I
10.1016/0009-2541(94)90066-3
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
A comprehensive review on igneous petrological characteristics of mantle-derived spinel peridotites was made on the basis of their olivine-spinel compositional relationships. The spinel peridotites (harzburgites and lherzolites), of both massif and xenolithic derivations, plot in a narrow band, the olivine-spinel mantle array, in terms of Fo of olivine and C# (Cr/(Cr + Al) atomic ratio) of chromian spinel. The Cr# of spinel grows rapidly within the olivine-spinel mantle array with a slight increase of Fo. Their Cpx/(Opx + Cpx) volume ratio decreases towards the high-Fo, high-Cr# end; it is 0.1 for Cr# = 0.5-0.6. Peridotite suites from each tectonic setting lie in a particular part of the olivine-spinel mantle array. The olivine-spinel mantle array possibly consists of integrated Fo-Cr# residual trends formed at various conditions (P(total) and P(H2O)). Cr# of residual spinel coexisting with olivine of a particular Fo increases with a decrease of P(total) and/or with an increase of P(H2O) on partial melting. Origins of peridotite suites can be constrained to some extent in terms of the Fo-Cr# residual trends, for example, some of the Japan-arc mantle peridotites and fore-arc peridotites are low-pressure and/or hydrous restites, and subcontinental and oceanic hot-spot peridotites are high-pressure and/or anhydrous restites. Fertile alpine-type lherzolites with Cr# almost-equal-to 0.1 are of subcontinental origin. Other alpine lherzolites are most frequently of sub-arc origin, sometimes of sub-ocean floor origin, and rarely of sub-continental origin. Most of the alpine-type harzburgites are of fore-arc origin.
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页码:191 / 204
页数:14
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