Permian flood basalts and mafic intrusions in the Jinping (SW China)–Song Da (northern Vietnam) district: Mantle sources, crustal contamination and sulfide segregation

Wang, Christina Yan; Zhou, Mei‐Fu; Qi, Liang

doi:10.1016/j.chemgeo.2007.05.017

Cited by 222 publications

(146 citation statements)

References 61 publications

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“…The mantle is an important reservoir for H, which mainly occurs as H 2 in fluid inclusions trapped in mantle minerals [25]. Therefore, existence of H 2 in clinopyroxene, plagioclase, and apatite is consistent with the fact that the three intrusions are derived from mantle plume-derived magmas [37]. Experimental results indicate that the solubility of H 2 in silicate melt is 0.48 wt% at 1.5 GPa [38], much lower than the solubility of H 2 O [39].…”

Section: Variations Of Volatile Compositions Of Magnetite Clinopyroxmentioning

confidence: 65%

Volatile and C-H-O isotopic compositions of giant Fe-Ti-V oxide deposits in the Panxi region and their implications for the sources of volatiles and the origin of Fe-Ti oxide ores

Xing

Wang

Zhang

2012

Sci. China Earth Sci.

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The Panzhihua, Hongge, and Baima Fe-Ti-V oxide deposits in the Panzhihua-Xichang (Panxi) region are hosted in large layered mafic-ultramafic intrusions. The layered intrusions intrude either the Neoproterozoic Dengying Formation, composed mainly of limestone, or the Paleoproterozoic Hekou Formation, composed of meta-sedimentary-volcanic rocks. It remains unclear if the wall rocks have been involved during the fractionation of magmas and have affected the sequence of crystallization of Fe-Ti oxide. Volatiles and their C-H-O isotopic compositions of magnetite, apatite, clinopyroxene, and plagioclase of different types of ores from the three intrusions are analyzed using a technique of stepwise heating mass spectrometer to evaluate the role of wall rocks in the formation of Fe-Ti oxide ores. Volatiles released from magnetite are composed mainly of H 2 O and CO 2 , whereas the other minerals are composed mainly of H 2 O, CO 2 and H 2 . At 800-1200°C temperature interval, the average  13 C values of CO 2 of all the minerals from the three intrusions range from 7.7‰ to 13.5‰ and the average  18 O CO 2 values from 19.1‰ to 19.5‰, which are scattered in a mixed field with basalt and the two types of wall rocks as end-members, indicating that CO 2 from the wall rocks may have been involved in the magmas from which the three intrusions formed. At 400-800C temperature interval, both  13 C values (13.7‰ to 17.9‰ on the average) and  18 O values (16.2‰ to 19.2‰ on the average) of CO 2 of all the minerals are lower than those for 800-1200C temperature interval, and much closer to the values of the wall rocks. Abundant H 2 O released at the 400-800C temperature interval has relatively low   D values ranging from 90‰ to 115‰, also indicating the involvement of fluids from the wall rocks. The average bulk contents of volatiles released from magnetite of the Hongge, Baima, and Panzhihua intrusions are 4891, 2996, and 1568 mm 3 STP/g, respectively, much higher than those released from other minerals in total, which are 382, 600, and 379 mm 3 STP/g, respectively, indicating that magnetite crystallized from magmas with much more volatiles than other minerals. This can be interpreted as that crystallization of clinopyroxene and plagioclase in the early fractionation of magmas resulted in volatiles such as H 2 O that were eventually enriched in the residual magmas and, at the same time, fluids from the wall rocks may have been involved in the magmas and were trapped in magnetite, which crystallized later than clinopyroxene and plagioclase. Three giant Fe-Ti-V oxide deposits in the Panxi (Panzhihua-Xichang) region, SW China, are hosted in the Panzhihua, Hongge, and Baima layered mafic-ultramafic intrusions. These intrusions are unique in that large amounts of massive and semi-massive ores occur in the lower parts of the intrusions, whereas rhythmic layering composed of vari-

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Section: Variations Of Volatile Compositions Of Magnetite Clinopyroxmentioning

confidence: 65%

Volatile and C-H-O isotopic compositions of giant Fe-Ti-V oxide deposits in the Panxi region and their implications for the sources of volatiles and the origin of Fe-Ti oxide ores

Xing

Wang

Zhang

2012

Sci. China Earth Sci.

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“…High temperature ultramafic volcanic rocks are recognized within the inner zone of the ELIP (Hanski et al 2004(Hanski et al , 2010Hou et al 2006;Zhang et al 2006;Wang et al 2007;Ali et al 2010;He et al 2010;Kamenetsky et al 2012). There are also correlative units, including picrite, in the Song Da zone of northern Vietnam which was translated by ~600 km sinistral offset during the Paleogene activation of the Ailao Shan-Red River fault system (Chung et al 1997).…”

Section: Ultramafic Volcanic Rocksmentioning

confidence: 99%

“…However, there are different interpretations regarding the nature of their source. The prevailing view is that the ultramafic rocks are pristine primitive melts from the starting plume-head that were modified, in some cases, via interactions with one of, or a combination of crustal material and lithospheric mantle melts and assimilation-fractional crystallization (AFC) processes (Hanski et al 2004(Hanski et al , 2010Zhang et al 2006;Wang et al 2007;Li et al 2010;He et al 2010). Some of the picrite shows the most depleted Sr-Nd-Os isotope signatures (i.e.…”

Section: Ultramafic Volcanic Rocksmentioning

confidence: 99%

“…TiO 2 < 2.5 wt.%) are considered to be derived from either the subcontinental lithospheric mantle (SCLM) or picritic magmas that assimilated upper crust (Fig. 4) (Xiao et al 2004;Wang et al 2007;Fan et al 2008;Song et al 2008;Zhou et al 2008;Qi et al 2010). The significance of the basalt groups is that the composition is indicative of the type of mineral deposit (i.e.…”

Section: The Emeishan Flood Basaltsmentioning

confidence: 99%

“…> 20%) amount of melting from a garnet-bearing mantle source (Hanski et al 2004(Hanski et al , 2010Zhang et al 2006;Wang et al 2007;Kamenetsky et al 2012). However, there are different interpretations regarding the nature of their source.…”

Section: Ultramafic Volcanic Rocksmentioning

confidence: 99%

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Igneous Rock Associations 16. The Late Permian Emeishan Large Igneous Province

Shellnutt

2015

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The origin of volatiles in the Emeishan large igneous province, China: Constraints from chemical and C–He–Ar isotopic compositions of volatiles in picrites and basalts

Tang

Bao

et al. 2021

Geological Journal

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The Emeishan large igneous province (LIP) consists of Permian flood basalts and coeval intrusive rocks with compositions varying from mafic-ultramafic rocks to syenites and granites. The volatiles in the Emeishan LIP are dominated by H 2 O with high H 2 , indicating that the plume-derived magma was generated under a reduced condition. Picrite has minor contents of H 2 S without detectable SO 2 , and the basalt samples show no detectable H 2 S and SO 2 , indicating that the basaltic magma may have undergone sulphur-saturation during magma evolution. The δ 13 C values of CO 2 andCH 4 in picrites and basalts are between the values of mantle and crustal organic carbon. This, together with the distribution patterns among CH 4 homologue, indicates contribution of recycled sediments to the Emeishan mantle-derived magma. The 3 He/ 4 He ratios of volatiles extracted from olivine and pyroxene phenocrysts of picrites vary from 0.01 to 0.66 Ra, and those from pyroxene separates of olivine websterite samples in the Zhubu intrusion vary from 0.92 to 1.05 Ra. The low 3

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Permian flood basalts and mafic intrusions in the Jinping (SW China)–Song Da (northern Vietnam) district: Mantle sources, crustal contamination and sulfide segregation

Cited by 222 publications

References 61 publications

Volatile and C-H-O isotopic compositions of giant Fe-Ti-V oxide deposits in the Panxi region and their implications for the sources of volatiles and the origin of Fe-Ti oxide ores

Volatile and C-H-O isotopic compositions of giant Fe-Ti-V oxide deposits in the Panxi region and their implications for the sources of volatiles and the origin of Fe-Ti oxide ores

Igneous Rock Associations 16. The Late Permian Emeishan Large Igneous Province

The origin of volatiles in the Emeishan large igneous province, China: Constraints from chemical and C–He–Ar isotopic compositions of volatiles in picrites and basalts

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