Melts and residua geochemistry in a low-to-mid crustal section (Central Spain)

Granulite terranes from Central Spain are Hercynian anatectic areas of mid- crustal levels (P-T conditions: 750-800 degrees C: and 4-6 kb). The granuli te xenolith suite of the same sector comes from the lower crust as deduced from their P-TF estimates (850-950 degrees C and 8-11 kb). Chemical differe nces between granulites from terranes and those from xenoliths are less mar ked in Central Spain than in other places as this xenolith suite lack mafic lithologies. Granulitic xenoliths show bl and Rb depletion. and occasional ly a subtle enrichment in Ba, Fe, Mg, Ti, (V) and HREE. Contents in Zr, Th, Y, and REE in both granulite types might be explained as a consequence of the minor role of accessory phases in controlling the geochemistry- of the residual rocks in the lower crust. Migmatitic leucosomes and other felsic a natectic melts show the same trend of Rb and K enrichment and Fe, Mg, Ti, C r, Ni, V and Th, Y, Zr, Nb, REE impoverishment (compared to protoliths) tha n granitic plutons. Although plutonic granites show higher Ca (Na), Fe and MO, contents a genetic link with anatectic melts is suggested. Isotopic dif ferences (Sr, O) between granitic plutons and anatectic melts might he a re flection of their derivation from a different crustal level in an isotopica lly stratified crust, (C) 2001 Elsevier Science Ltd. Ail rights reserved.