Crystallization of Hydrous Ti-Rich Basaltic Magma and Its Implication for the Origin of Fe−Ti Oxide in Layered Intrusions of the Emeishan Large Igneous Province

Abstract

A series of crystallization experiments have been carried out by using natural Emeishan Ti-rich hydrous basalts as starting materials at a pressure of 0.5 GPa and temperatures of 800–1 000 °C to constrain the origin of Fe−Ti−V oxide ore deposits. Our experimental results demonstrate that the sandwich- and trellis-type ilmenite lamellae in titanomagnetite of layered intrusions can be formed by the reaction of earlier crystallized ilmenite and the evolved parental magma. During evolution of parental basaltic magma, the Fe−Ti oxide should be composed of titanomagnetite+ilmenite in the earlier stage, but changed to titanomagnetite+titanomagnetite-ilmenite intergrowth±ilmenite at the later stage. Accordingly, the Panzhihua Fe−Ti oxide ores, which are mainly composed of titanomagnetite, should be formed earlier than the adjacent gabbro, in which titanomagnetite-ilmenite intergrowth is the major form of the Fe-Ti oxide.

Keywords

high pressure and high temperature experiment / crystallization / Fe-Ti oxide / layered intrusion / high-Ti basalt / petrology

References

Cawthorn R G, Ashwal L D. Origin of Anorthosite and Magnetitite Layers in the Bushveld Complex, Constrained by Major Element Compositions of Plagioclase. Journal of Petrology, 2009, 50(9): 1607-1637.

Charlier B, Grove T L. Experiments on Liquid Immiscibility along Tholeiitic Liquid Lines of Descent. Contributions to Mineralogy and Petrology, 2012, 164(1): 27-44.

Charlier B, Namur O, Toplis M J, . Large-Scale Silicate Liquid Immiscibility during Differentiation of Tholeiitic Basalt to Granite and the Origin of the Daly Gap. Geology, 2011, 39(10): 907-910.

Duchesne J C. Fe−Ti Deposits in Rogaland Anorthosites (South Norway): Geochemical Characteristics and Problems of Interpretation. Mineralium Deposita, 1999, 34(2): 182-198.

Ganino C, Arndt N T, Zhou M F, . Interaction of Magma with Sedimentary Wall Rock and Magnetite Ore Genesis in the Panzhihua Mafic Intrusion, SW China. Mineralium Deposita, 2008, 43(6): 677-694.

Holtz F, Johannes W, Tamic N, . Maximum and Minimum Water Contents of Granitic Melts Generated in the Crust: A Reevaluation and Implications. Lithos, 2001, 56(1): 1-14.

Hou T, Veksler I V. Experimental Confirmation of High-Temperature Silicate Liquid Immiscibility in Multicomponent Ferrobasaltic Systems. American Mineralogist, 2015, 100(5/6): 1304-1307.

Lindsley D H. Some Experiments Pertaining to the Magnetite-Ulvöspinel Miscibility Gap. American Mineralogist, 1981, 66(7/8): 759-762

Liu P P, Zhou M F, Wang C Y, . Open Magma Chamber Processes in the Formation of the Permian Baima Mafic-Ultramafic Layered Intrusion, SW China. Lithos, 2014, 184/185/186/187: 194-208.

Luan Y, Song X Y, Chen L M, . Key Factors Controlling the Accumulation of the Fe−Ti Oxides in the Hongge Layered Intrusion in the Emeishan Large Igneous Province, SW China. Ore Geology Reviews, 2014, 57: 518-538.

Mitchell A A, Eales H V, Johan Kruger F. Magma Replenishment, and the Significance of Poikilitic Texlures, in the Lower Main Zone of the Western Bushveld Complex, South Africa. Mineralogical Magazine, 1998, 62(4): 435-450.

Morse S A. Compositional Convection Trumps Silicate Liquid Immisciblity in Layered Intrusions: A Discussion of Liquid Immiscibility and the Evolution of Basaltic Magma by Veksler et al.. Journal of Petrology, 2008, 49(12): 2157-2168.

Namur O, Charlier B, Toplis M J, . Crystallization Sequence and Magma Chamber Processes in the Ferrobasaltic Sept Iles Layered Intrusion, Canada. Journal of Petrology, 2010, 51(6): 1203-1236.

Pang K N, Zhou M F, Lindsley D, . Origin of Fe−Ti Oxide Ores in Mafic Intrusions: Evidence from the Panzhihua Intrusion, SW China. Journal of Petrology, 2008, 49(2): 295-313.

Price G D. Subsolidus Phase Relations in the Titanomagnetite Solid Solution Series. American Mineralogist, 1981, 66: 751-758.

Sauerzapf U, Lattard D, Burchard M, . The Titanomagnetite-Ilmenite Equilibrium: New Experimental Data and Thermo-Oxybarometric Application to the Crystallization of Basic to Intermediate Rocks. Journal of Petrology, 2008, 49(6): 1161-1185.

Snyder D, Carmichael I S E, Wiebe R A. Experimental Study of Liquid Evolution in an Fe-Rich, Layered Mafic Intrusion: Constraints of Fe−Ti Oxide Precipitation on the T−fO₂ and T−ϱ Paths of Tholeiitic Magmas. Contributions to Mineralogy and Petrology, 1993, 113(1): 73-86.

Song X Y, Qi H W, Hu R Z, . Formation of Thick Stratiform Fe−Ti Oxide Layers in Layered Intrusion and Frequent Replenishment of Fractionated Mafic Magma: Evidence from the Panzhihua Intrusion, SW China. Geochemistry, Geophysics, Geosystems, 2013, 14(3): 712-732.

Song X Y, Zhou M F, Cao Z M, . Late Permian Rifting of the South China Craton Caused by the Emeishan Mantle Plume?. Journal of the Geological Society, 2004, 161(5): 773-781.

Tan W, Liu P, He H P, . Mineralogy and Origin of Exsolution in Ti-Rich Magnetite from Different Magmatic Fe−Ti Oxide-Bearing Intrusions. The Canadian Mineralogist, 2016, 54(3): 539-553.

Toplis M J, Carroll M R. An Experimental Study of the Influence of Oxygen Fugacity on Fe−Ti Oxide Stability, Phase Relations, and Mineral-Melt Equilibria in Ferro-Basaltic Systems. Journal of Petrology, 1995, 36(5): 1137-1170.

Van Tongeren J A, Mathez E A. Large-Scale Liquid Immiscibility at the Top of the Bushveld Complex, South Africa. Geology, 2012, 40(6): 491-494.

Veksler I V, Dorfman A M, Borisov A A, . Liquid Immiscibility and the Evolution of Basaltic Magma. Journal of Petrology, 2007, 48(11): 2187-2210.

Vincent E A, Wright J B, Chevallier R, . Heating Experiments on Some Natural Titaniferous Magnetites. Mineralogical Magazine, 1957, 31(239): 624-655.

Wang C, Jin Z M, Gao S, . Eclogite-Melt/Peridotite Reaction: Experimental Constrains on the Destruction Mechanism of the North China Craton. Science China Earth Sciences, 2010, 53(6): 797-809.

Wang C Y, Zhou M F. New Textural and Mineralogical Constraints on the Origin of the Hongge Fe−Ti−V Oxide Deposit, SW China. Mineralium Deposita, 2013, 48(6): 787-798.

Wang C Y, Zhou M F, Zhao D G. Fe−Ti−Cr Oxides from the Permian Xinjie Mafic-Ultramafic Layered Intrusion in the Emeishan Large Igneous Province, SW China: Crystallization from Fe- and Ti-Rich Basaltic Magmas. Lithos, 2008, 102(1/2): 198-217.

Xu Y G, Chung S L, Jahn B M, . Petrologic and Geochemical Constraints on the Petrogenesis of Permian-Triassic Emeishan Flood Basalts in Southwestern China. Lithos, 2001, 58(3/4): 145-168.

Zhang Z C, Mao J W, Saunders A D, . Petrogenetic Modeling of Three Mafic-Ultramafic Layered Intrusions in the Emeishan Large Igneous Province, SW China, Based on Isotopic and Bulk Chemical Constraints. Lithos, 2009, 113(3/4): 369-392.

Zhou M F, Arndt N T, Malpas J, . Two Magma Series and Associated Ore Deposit Types in the Permian Emeishan Large Igneous Province, SW China. Lithos, 2008, 103(3/4): 352-368.

Zhou M F, Chen W T, Wang C Y, . Two Stages of Immiscible Liquid Separation in the Formation of Panzhihua-Type Fe−Ti−V Oxide Deposits, SW China. Geoscience Frontiers, 2013, 4(5): 481-502.

Zhou M F, Malpas J, Song X Y, . A Temporal Link between the Emeishan Large Igneous Province (SW China) and the End-Guadalupian Mass Extinction. Earth and Planetary Science Letters, 2002, 196(3/4): 113-122.

Zhou M F, Robinson P T, Lesher C M, . Geochemistry, Petrogenesis and Metallogenesis of the Panzhihua Gabbroic Layered Intrusion and Associated Fe−Ti−V Oxide Deposits, Sichuan Province, SW China. Journal of Petrology, 2005, 46(11): 2253-2280.