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Caracterización de los minerales del dique gabroideo de Messejana - Plasencia en su sector nor-oriental

Andonaegui Moreno, Pilar and Villaseca González, Carlos and López García, José Ángel (2005) Caracterización de los minerales del dique gabroideo de Messejana - Plasencia en su sector nor-oriental. Geogaceta, 38 . pp. 219-222. ISSN 0213-683X

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Abstract

In the gabbroic Messejana–Plasencia dyke we have distinguished three types of pyroxenes: enstatite,
pigeonite and augite. Enstatite and augite have been the first minerals that have crystallized at high T
(1100ºC – 1150ºC). Pigeonites (@1000ºC) are later and finally appear symplectic two-pyroxene intergrowths
around the orthopyroxene. Plagioclase have a continuous zonation with cores of An75 towards rims of
An18. Occasionally, there is a micrographic intergrowth of orthoclase–quartz or albite-quartz interstitially
to the plagioclase and pyroxene framework. Three types of amphibole have been distinguished: ferroedenite,
magnesiohornblende and ferroactinolite. The estimated temperature range of amphibole crystallization is
low suggesting that most amphiboles are subsolidus. Finally, biotite are FeO and TiO2 rich, its crystallization
being late when residual liquids were enriched in those elements.


Item Type:Article
Uncontrolled Keywords:Messejana–Plasencia dyke, Tholelitic gabbro, Mineral chemistry, P-T conditions
Subjects:Sciences > Geology > Geochemistry
ID Code:12399
Deposited On:10 Mar 2011 12:49
Last Modified:06 Feb 2014 09:23

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