RT Journal Article
T1 Geochemical and isotopic disequilibrium in crustal melting:An insight from the anatectic granitoids from Toledo, Spain
A1 Barbero González, Luis C.
A1 Villaseca González, Carlos
AB In the Hercynian Anatectic Complex of Toledo (ACT) the anatectic granitoids includeleucogranitic leucosomes, leucogranitic massifs, and restite-rich granites. They show a broad range ofinitial Sr and Nd isotope ratios from 0.71 I to 0.720 and 0.51164 to 0.51203, respectively, which clearlyindicate the absence of isotopic homogenization in the melts. Broadly, the ranges reflect the isotopicvariation of the metapelitic protoliths. If crusta! melting occurs under water-undersaturated conditions,as is the case of the ACT, the generated melts do not isotopically and chemically equilibrate with thegranulitic residuum. The preservation of heterogeneities could arise through a number of pmcesses. (1)duration of the process:in which the presence of melts with disequilibrium features, and the high solidcontent of several of the granites in the ACT point to a very short-lived magmatic system, (2) limiteddiffusion in which poorly segregated and volatile undersaturated granitoids have a very restrictedopportunity for isotopic and chemical homogenization, and (3) magma dynamics in which the lowmelting rates, the high restite and low water contents, and the silica-rich composition of these granites,together with the small volume and high viscosity values of the melts, seriously restrict the physicalprocesses leading to homogenization.
PB American Geophysical Union
SN 0148-0227
YR 1995
FD 1995
LK https://hdl.handle.net/20.500.14352/58644
UL https://hdl.handle.net/20.500.14352/58644
LA eng
DS Docta Complutense
RD 7 may 2024