Magma mixing and unmixing related mineralization in the Karacaali Magmatic Complex, central Anatolia, Turkey
Okan Delibaş, Yurdal Genç, Cristina P. De Campos, 2011. "Magma mixing and unmixing related mineralization in the Karacaali Magmatic Complex, central Anatolia, Turkey", Granite-Related Ore Deposits, A. N. Sial, J. S. Bettencourt, C. P. De Campos, V. P. Ferreira
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The calc-alkaline Karacaali Magmatic Complex (KMC), in the Central Anatolian Crystalline Complex, is an example of an Upper Cretaceous post-collisional I-type, plutonic–volcanic association. Volcanic rocks grade from basalt to rhyolite, whilst coeval plutonic rocks range from gabbro to leucogranite. In this paper we document evidence for the occurrence of both mixing and unmixing during the evolution of this igneous complex.
Mixing of mafic and felsic magmas was observed in petrographic properties at microscopic to macroscopic scales and is further supported by mineral chemistry data.
The occurrence of unmixing is evidenced in the Fe and Cu–Mo mineralization hosted in the KMC. The iron mineralization in basaltic-andesitic rocks consists mostly of magnetite. Magnetite has been grouped into four settings: (1) matrix type; (2) vein-filling type; (3) breccia matrix type; and (4) vesicle-filling type. In contrast, Cu–Mo mineralization is related to vertical north–south trending quartz-, quartz-calcite-, and quartz-tourmaline veins crosscutting monzonitic and granitic rocks.
We propose that the intrusion of an oxidized, Fe- and Cu-rich basic magma into a partially crystallized acid magma resulted in partial mixing and may have triggered the abrupt separation of an iron-oxide-rich melt.
Our results highlight the importance of magma mixing and metal unmixing, possibly associated with stress relaxation during post-collisional evolution.
Electron microprobe analyses of plagioclase in monzonitic rocks, MMEs and electron microprobe analyses of K-feldspar in monzonitic rocks are available at http://www.geolsoc.org.uk/SUP18434.
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Granite-Related Ore Deposits
This volume brings together a collection of papers that summarize current ideas and recent progress in the study of granite-related mineralization systems. They provide a combination of field, experimental and theoretical studies. Papers are grouped according to the main granite-related ore systems: granite-pegmatite, skarn and greisen-veins, porphyry, orogenic gold, intrusion-related, epithermal and porphyry-related gold and base metal, iron oxide–copper–gold (IOCG), and special case studies. The studies provide a broad spread in terms of both space and time, highlighting granite-related ore deposits from Europe (Russia, Sweden, Croatia and Turkey), the Middle East (Iran), Asia (Japan and China) and South America (Brazil and Argentina) and spanning rocks from Palaeoproterozoic to Miocene in age.