en
Scientific article
English

A genetic link between albitic magmas and IOCG mineralization in the Ossa Morena Zone (SW Iberia)

Publication date2021
Abstract

A detailed geological and isotopic study of the Colmenar deposit (Ossa Morena Zone, SW Iberia) shows that the magnetite- rich mineralization formed by complex magmatic-hydrothermal processes related to the crystallization of water-rich albite- magnetite igneous rocks derived from the crystallization of unusual melts formed during anatexis in a high temperature-low pressure metamorphic regime. The most likely protolith includes a sequence of iron-rich chemical sediments, amphibolite and possible meta-evaporites of early Cambrian age. The albite-magnetite rock occurs as up to 20cm-thick dyke and breccia bodies and show complex immiscibility relationships with an albite-K-feldspar-quartz leucogranite. Iron-rich fluids exsolved during the crystallization of these melts are responsible of the formation of hydrothermal breccias and the widespread replacement of the hosting calc-silicate hornfels by a magnetite-ferroactinolite-albite assemblage along syn-mineralization shear zones. Geochronological data obtained for mineralization and related hydrothermal alteration points to a Variscan age (ca. 340Ma), interpreted also as the age of the high-grade metamorphism driving anatexis at the Valuengo Metamorphic Complex. Despite the low Cu and Au contents, this mineralization shares features with the IOCG systems, which in other districts show a spatial relationship with albite-rich rocks, evaporites and pre-existing iron mineralization. The observations presented from Colmenar support an alternative genetic model with prospective implications for the Ossa Morena Zone that can be extrapolated to other IOCG belts worldwide.

Keywords
  • IOCG
  • Magnetite
  • Geochronology
  • Radiogenic isotope geochemistry
  • Albitite
Citation (ISO format)
CARRIEDO, Jorge et al. A genetic link between albitic magmas and IOCG mineralization in the Ossa Morena Zone (SW Iberia). In: Journal of Iberian Geology, 2021. doi: 10.1007/s41513-021-00162-3
Main files (1)
Article (Published version)
accessLevelRestricted
Identifiers
ISSN of the journal1886-7995
293views
0downloads

Technical informations

Creation02/22/2021 11:23:00 AM
First validation02/22/2021 11:23:00 AM
Update time03/16/2023 12:07:08 AM
Status update03/16/2023 12:07:07 AM
Last indexation05/06/2024 6:42:54 AM
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack