RT Journal Article
T1 Crustal origin of Hercynian peraluminous granitic batholiths ofCentral Spain: petrological, geochemical and isotopic (Sr, Nd) constraints
A1 Villaseca González, Carlos
A1 Barbero González, Luis C.
AB In Central Spain, it is possible to distinguish two main types of peraluminous late-Hercynian granites: the PI types andthe PS types. The distinction between both types is made on the basis of differences in peraluminosity (PS types are moreperaluminous than PI types) and also on the appearance of some characteristic mafic minerals; PS types have biotite,cordierite and monazite as the most typical accessory phase, whereas PI types have biotite, amphibole (in the less evolvedfacies) and allanite as the accessory mineral. Both granite types have similar trace element ratios and initial Sr, Nd and Pbisotopic signatures. Initial 87Sr/86Sr ratios of both types exhibit a large range from 0.7073 to 0.7193, whereas initial εNdvaries in a restricted range from -5.4 to -6.6. The scarce associated basic rocks do not play a significant role in thechemical variability of these peraluminous granites which follow low pressure crystal fractionation trends from granodiorite/monzograniteparental magmas. Mixing and AFC modelling of Sr and Nd isotopic data reveal an unrealistically highmantle contribution. Based on major and trace element and isotopic data, an orthogneissic protolith for both granitic series isproposed. Nevertheless, none of the metamorphic country rocks of Central Spain has the appropriate Sr isotopic compositionto satisfy the origin of these granitic rocks, and so, it is argued that progressive isotopic re-equilibration of crustal materialduring the granulization of the lower Hercynian crust, together with the possibility of isotopic disequilibrium during meltingas has been demonstrated in migmatitic terranes in nearby areas. may explain the isotopic differences between the granitesand the high level metamorphic country rocks
PB Elsevier Science B.V., Amsterdam
SN 0024-4937
YR 1998
FD 1998
LK https://hdl.handle.net/20.500.14352/57019
UL https://hdl.handle.net/20.500.14352/57019
LA eng
DS Docta Complutense
RD 5 abr 2025