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Metaluminous pyroxene-bearing granulite xenoliths from the lower continental crust in central Spain: their role in the genesis of Hercynian I-type granites

Villaseca González, Carlos and Orejana García, David and Paterson, Bruce A. and Billstrom, Kjell and Pérez-Soba Aguilar, Cecilia (2007) Metaluminous pyroxene-bearing granulite xenoliths from the lower continental crust in central Spain: their role in the genesis of Hercynian I-type granites. European journal of mineralogy, 19 . pp. 463-477. ISSN 0935-1221

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Abstract

Basic and intermediate meta-igneous xenoliths are very scarce within the granulite population transported by the Permian
alkaline lamprophyric dyke swarmof the Spanish Central System(SCS). These xenoliths aremetaluminous pyroxene-bearing
charnockites (sensu lato). They show LREE-poor plagioclase and orthopyroxene-clinopyroxene. Crystallization conditions were
estimated at about 850 to 1000 ◦C and 9 to 11 kbar, a slightly higher range than that estimated for the associated peraluminous
granulites, but indicating derivation from the lowermost crust.
Whole-rock geochemistry suggests that the charnockite samples are not a cogenetic suite. The more basic varieties have affinities
with cumulates from previous calc-alkaline underplated protoliths, whereas intermediate charnockites have a restitic origin. The
similarity in Sr-Nd-Pb isotopic signatures between these restitic charnockites and some SCS I-type granites suggests a genetic
relationship. This study, including Pb isotopic data from the whole granulite xenolith suite, reinforces the lower-crustal derivation
of the SCS Hercynian granitic batholith.


Item Type:Article
Uncontrolled Keywords:Granulite xenoliths, Pyroxene mineral chemistry, Hercynian granites, Igneous petrology, Lower crust, Central Spain
Subjects:Sciences > Geology > Petrology
ID Code:12409
Deposited On:11 Mar 2011 10:42
Last Modified:26 Nov 2012 09:10

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