Assimilation of carbonate country rock by the parent magma of the Panzhihua Fe-Ti-V deposit (SW China): Evidence from stable isotopes

• DOI: 10.1016/j.gsf.2012.12.006
• Publication Date: 2013-01-10T01:35:14Z
• Authors: Clément Ganino; Chris Harris; Nicholas T. Arndt; Stephen A. Prevec; Geoffrey H. Howarth
• Keywords: Protolith; Country rock; Large igneous province; Wall rock; Igneous differentiation; δ18O; Magma chamber

The Panzhihua intrusion in southwest China is part of the Emeishan Large Igneous Province and host a large Fe-Ti-V ore deposit. During emplacement main intrusion, multiple generations mafic dykes invaded carbonate wall rocks, producing contact aureole. We measured oxygen-isotope composition intrusions, their constituent minerals, samples country rock. Magnetite plagioclase from have δ18O values that are consistent with magmatic equilibrium, formed magmas were 1–2‰ higher than expected mantle-derived magma. unmetamorphosed rock has high values, ranging 13.2‰ (sandstone) to 24.6–28.6‰ (dolomite). skarns marbles aureole lower δ13C protolith suggesting interaction fluids exchange equilibrium adjacent especially numerous intruded This would explain alteration which significantly for Depending on exact assumed magma contaminant, amount assimilation required produce elevated value was between 8 13.7 wt.%, assuming simple mixing. mechanism contamination unclear but may involve combination bulk rock, mixing melt CO2-rich fluid derived decarbonation marls dolomites. These mechanisms, particularly latter, probably involved formation ores.