Petrological and geochronological discrimination of two white-mica generations in a granite cored from the Larderello-Travale geothermal field (Italy)

被引：6

作者：

Villa, IM ^{[1
]}

Ruggieri, G ^{[1
]}

Puxeddu, M ^{[1
]}

机构：

[1] CNR, IST INT RIC GEOTERMICHE, I-56126 PISA, ITALY

来源：

EUROPEAN JOURNAL OF MINERALOGY | 1997年 / 9卷 / 03期

关键词：

muscovite; Larderello-Travale; granite; Ar-39/Ar-40; dating; geothermal fields; FLUID; SPECTRA; SYSTEM; BELT;

D O I：

暂无

中图分类号：

P57 [矿物学];

学科分类号：

070901 ;

摘要：

A magmatic muscovite in a granitic dyke cored at 4.1 km depth in the Larderello-Travale geothermal field is overgrown by hydrothermal muscovite. Electron-microprobe data on the white-mica separate confirms very small-scale intergrowths. The staircase-shaped Ar-39/Ar-40 age spectrum of the white-mica mixture anticorrelates with the Cl/K ratio and is best explained by the differential breakdown of the two-phase mixture during in-vacuo heating. This allows to infer an age for the hydrothermal mica, < 2.0 Ma, well resolved from that of the magmatic muscovite, greater than or equal to 2.5 Ma; the granite which initiated the thermal anomaly in Travale is thus at least 2.5 Ma old.

引用

页码：563 / 568

页数：6

共 18 条

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[2]

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[3]

BATINI F, 1985, GEOTHERM RES COUNC T, V9, P253

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