Origin of Fe-Ti Oxide Ores in Mafic Intrusions: Evidence from the Panzhihua Intrusion, SW China

2007/12/12 by Kwan‐Nang Pang, K.-N. Pang, Mei‐Fu Zhou +7 · 231 citations
Chemistry · Earth and Planetary Sciences · #Chemistry #Fractionation #Geochemistry #Geological and Geochemical Analysis #Geology #High-pressure geophysics and materials #Intrusion #Large igneous province #Layered intrusion #Mafic #Magma #Magma chamber #Magmatism #Materials science #Metallurgy #Mineral #Mineralogy #Oxide #Volcano #earthquake and tectonic studies

paper · pdf · doi:10.1093/petrology/egm082

published in Journal of Petrology 49(2), 295-313 (Oxford University Press)

openalex publication_date 2007/12/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/26

Abstract

Economic concentrations of Fe^Ti oxides occur as massive, conform-able lenses or layers in the lower part of the Panzhihua intrusion, Emeishan Large Igneous Province, SW China. Mineral chemistry, textures and QUILF equilibria indicate that oxides in rocks of the intrusion were subjected to extensive subsolidus re-equilibration and exsolution. The primary oxide, reconstructed from compositions of titanomagnetite in the ores and associated intergrowths, is an alumi-nous titanomagnetite (Usp40) with 40 wt % FeO, 34 wt % Fe2O3, 165 wt % TiO2, 53 wt % Al2O3, 35 wt %MgO and 05 wt % MnO. This composition is similar to the bulk composition of the oxide ore, as inferred from whole-rock data.This similarity strongly suggests that the ores formed from accumulation of titanomagnetite crystals, not from immiscible oxide melt as proposed in earlier studies. The occurrence of oxide ores in the lower parts of the Panzhihua intrusion is best explained by settling and sorting of dense titanomag-netite in the ferrogabbroic parental magma.This magma must have crystallized Fe^Ti oxides relatively early and abundantly, and is likely to have been enriched in Fe and Ti but poor in SiO2. These features are consistent with fractionation of mantle-derived melts under relatively high pressures (10 kbar), followed by emplacement of the residual magma at 5 kbar. This study provides definitive field and geochemical evidence that Fe^Ti oxide ores can form by accumulation in ferrogabbro. We suggest that many other massive Fe^Ti oxide deposits may have formed in a similar fashion and that high concentrations of phosphorus or carbon, or periodic fluctua-tion of fO2 in the magma, are of secondary importance in ore formation. KEY WORDS: ELIP; Fe^Ti oxide ore; layered intrusion; Panzhihua; QUILF

Citations

• Distinct mantle sources of low-Ti and high-Ti basalts from the western Emeishan large igneous province, SW China: implications for plume–lithosphere interaction
• A temporal link between the Emeishan large igneous province (SW China) and the end-Guadalupian mass extinction
• Geochemistry, Petrogenesis and Metallogenesis of the Panzhihua Gabbroic Layered Intrusion and Associated Fe–Ti–V Oxide Deposits, Sichuan Province, SW China

Cited by

• Composition of the Chilled Marginal Rocks of the Panzhihua Layered Intrusion, Emeishan Large Igneous Province, SW China: Implications for Parental Magma Compositions, Sulfide Saturation History and Fe–Ti Oxide Mineralization
• Integrated O–Sr–Nd isotope constraints on the evolution of four important Fe–Ti oxide ore-bearing mafic–ultramafic intrusions in the Emeishan large igneous province, SW China
• Mineral compositional constraints on petrogenesis and oxide ore genesis of the late Permian Panzhihua layered gabbroic intrusion, SW China
• Timing of Ti-magnetite crystallisation and silicate disequilibrium in the Panzhihua mafic layered intrusion: Implications for ore-forming processes
• Open magma chamber processes in the formation of the Permian Baima mafic–ultramafic layered intrusion, SW China
• Trace element compositions of apatite from the middle zone of the Panzhihua layered intrusion, SW China: Insights into the differentiation of a P- and Si-rich melt
• Provenance discrimination of upper Yangtze River basin sediments: New insights from heavy mineral signatures and detrital magnetite geochemistry
• Petrogenetic implications of mineral chemical data for the Permian Baima igneous complex, SW China
• Non-silicate needles and metals in peridotites from Himalayan ophiolite, Western Ladakh, India: evidence of deep Earth origin
• Origin and thermal evolution of Cr-V-Ti magnetites (lodestones) from Coorg massif, southern India
• Integrating mineralogy, geochemistry and aeromagnetic data for detecting Fe-Ti ore deposits bearing layered mafic intrusion, Akab El-Negum, Eastern Desert, Egypt. [europepmc]
• Occurrence and lithogeochemical composition of iron ore in Ngororero District, Rwanda. [europepmc]

Related

• Geochemistry, Petrogenesis and Metallogenesis of the Panzhihua Gabbroic Layered Intrusion and Associated Fe–Ti–V Oxide Deposits, Sichuan Province, SW China
• Composition of the Chilled Marginal Rocks of the Panzhihua Layered Intrusion, Emeishan Large Igneous Province, SW China: Implications for Parental Magma Compositions, Sulfide Saturation History and Fe–Ti Oxide Mineralization
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