Characterization of magma from inclusions in zircon: Apatite and biotite work well, feldspar less so
Characterization of magma from inclusions in zircon: Apatite and biotite work well, feldspar less so
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DOI：
10.1130/g32037.1
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发表时间：
2011-09
期刊：
影响因子：
5.8
通讯作者：
E. Jennings;H. Marschall;C. Hawkesworth;C. Storey
中科院分区：
文献类型：
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作者：
E. Jennings;H. Marschall;C. Hawkesworth;C. Storey
碎屑锆石颗粒被用来解释沉积物源和地壳演化，它们提供了独特的证据Hadean壳幔分异过程。我们证明，锆石中的矿物包裹体提供了有价值的信息下，锆石结晶的条件。从南极洲德龙宁毛德地精选的深成岩石中的锆石颗粒含有磷灰石、黑云母、角闪石和辉石的内含物，这些内含物准确地反映了主岩基质中等效相的化学成分以及整个岩石的成分。锆石中磷灰石包裹体中高浓度的Y和低浓度的Sr是演化的长英质花岗岩类寄主岩石的特征。与此相反，斜长石和碱性长石夹杂物的相对丰度和成分的锆石是去耦的整个岩石的组成，它们通常是指示花岗岩熔体，而不管散装岩石。这是最好的解释，相对于大部分的锆石结晶的后期。锆石中的磷灰石和镁铁质包裹体对碎屑锆石的潜在源岩起着制约作用，而长石包裹体对碎屑锆石的潜在源岩起着制约作用。
Detrital zircon grains are employed to decipher sediment provenances and crustal evolution, and they provide unique evidence of Hadean crust-mantle differentiation processes. We demonstrate that mineral inclusions in zircon provide valuable information on the conditions under which zircon crystallized. Zircon grains from selected plutonic rocks from Dronning Maud Land, Antarctica, contain inclusions of apatite, biotite, amphibole, and pyroxenes that accurately reflect the chemical compositions of the equivalent phases in the host-rock matrix, and the compositions of the whole rocks. High concentrations of Y and low concentrations of Sr in apatite inclusions in zircon are diagnostic of evolved, felsic granitoid host rocks. In contrast, the relative abundances and compositions of plagioclase and alkali feldspar inclusions in zircon are decoupled from the composition of the whole rock, and they are generally indicative of granitic melts regardless of the bulk rock. This is best explained by the late crystallization of zircon relative to the bulk of the feldspars. We conclude that inclusions of apatite and mafic phases in zircon constrain the potential source rocks of detrital zircon, whereas feldspar inclusions do not.