La evolución isotópica de los fluidos ligados a los Sistemas Hidrotermales tardi y postvariscos del Sistema Central Español.
- F. Tornos 1
- A. Delgado 2
- C. Casquet 3
- C. Galindo 3
- E.Reyes 2
- 1 ITGE. e/Ríos Rosas, 23. 28003 Madrid
- 2 Estación Experimental del Zaidín (CSIC). Prof.Albareda, 1. 18008 Granada
- 3 Dpto.Petrología. Fac.Geología. Universidad Complutense Madrid. 28040 Madrid
ISSN: 0213-683X
Año de publicación: 1996
Número: 20
Páginas: 1501-1503
Tipo: Artículo
Otras publicaciones en: Geogaceta
Resumen
The late to postvariscan hydrothermal activity of the Spanish Central System extends almost from ca. 300 Ma to the present. lt consists of several independent stages that can be grouped in two different hydrothermal regimes. There is a first hydrothermal event (295 ± 15 Ma) spatially related with minar intrusions of Late Variscan peraluminous granitoids. Here, highly confinated hydrothermal celIs dominated by lithostatic pressure involve local fluids of complex composition and likely metamorphic origin; modified low-saline meteoric waters occur in the more distal manifestations only. Three recorded younger hydrothermal pulses (ca.274±6, 150±5 and 100 Ma) involving low-saline waters were channelized along regional structures. Here, waters of meteoric origin that infiltrate to a great depth into the basement, leading to a 818O-shift of the fluids and a leaching of sulphur and metals from the host rocks. During upwelling, hydrothermal rocks are generated by fluid-rock interaction and boiling. In the shallow section of the system, the mixing with surficial complex brines led to the formation of fluoritebarite (Zn-Pb-Ag) veins, but no ó18O- 8D variation could be detected.