Petrologic and geochemical constraints on the petrogenesis of Permian–Triassic Emeishan flood basalts in southwestern China

Xu, Yi–Gang; Chung, Sun‐Lin; Jahn, Bor‐ming; Gen-yao, WU

doi:10.1016/s0024-4937(01)00055-x

Cited by 822 publications

(516 citation statements)

References 39 publications

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“…This is a proof of crust contamination (DePaolo & Wasserburg 1979). For correlation, the Emeishan basalts (Xu et al 2001;Xiao et al 2004;Zhang et al 2006;Liu & Zhu 2009 and references therein) are Permian-Triassic, they overlap the Permian carbonate formation and are covered by Triassic sedimentary sequences. Great CFB outpourings are genetically connected with "mantle plume activities".…”

Section: Discussionmentioning

confidence: 87%

“…close to our samples. Siberian continental basalts have ages of 250.3± 1.1 Ma (Reichow et al 2009;Shelnut & Jahn 2011) and the Emeishan flood basalt (~260 Ma) in southwestern China (Xu et al 2001;Hou et al 2011 Triassic period. Up to now, the origin of flood basalts, which are represented mainly by tholeiitic basalts, is highly disputable and a variety of models have been developed to explain their origin, but their genesis and sources are very complex.…”

Section: Discussionmentioning

confidence: 99%

“…Generally, the LT basalts are interpreted as a derivation from a shallower lithospheric mantle which underwent assimilation and fractional crystallization Arndt et al (1993);Sharma 1997;Xu et al 2001;Yan et al 2007 and references therein). The Hronicum basic rocks are characterized by low Nb/La ratio, ranging from 0.56 to 0.33, and a negative correlation between Nb/La and SiO 2 which indicates that the evolved lavas underwent assimilation and fraction crystallization.…”

Section: Discussionmentioning

confidence: 99%

“…%). According to Xu et al (2001), the basalts can be classified as high-Ti (HT) and low-Ti (LT) basalts in terms of TiO 2 concentration ( < 2 % TiO 2 ) and < 500 Ti/Y. In the studied samples, the TiO 2 content (1.07-1.76 wt.…”

Section: Geochemistrymentioning

confidence: 99%

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Geochemistry and Sr, Nd isotopic composition of the Hronic Upper Paleozoic basic rocks (Western Carpathians, Slovakia)

Vozár¹,

Spišiak²,

Vozárová³

et al. 2015

Geologica Carpathica

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The paper presents new major and trace element and first Sr-Nd isotope data from selected lavas among the Permian basaltic andesite and basalts of the Hronicum Unit and the dolerite dykes cutting mainly the Pennsylvanian strata. The basic rocks are characterized by small to moderate mg # numbers (30 to 54) and high SiO 2 contents (51-57 wt. %). Low values of TiO 2 (1.07-1.76 wt. %) span the low-Ti basalts. Ti/Y ratios in the dolerite dykes as well as the basaltic andesite and basalt of the 1 st eruption phase are close to the recommended boundary 500 between high-Ti and low-Ti basalts. Ti/Y value from the 2 nd eruption phase basalt is higher and inclined to the high-Ti basalts. In spite of this fact, in all studied Hronicum basic rocks Fe 2 O 3 * is lower than 12 wt. % and Nb/La ratios (0.3-0.6) are low, which is more characteristic of low-Ti basalts. The basic rocks are characterized by Nb/La ratios (0.56 to 0.33), and negative correlations between Nb/La and SiO 2 , which point to crustal assimilation and fraction crystallization. The intercept for Sr evolution lines of the 1 st intrusive phase basalt is closest to the expected extrusions age (about 290 Ma) with an initial 87 Sr/ 86 Sr ratio of about 0.7054. Small differences in calculated values I Sr document a partial Sr isotopic heterogeneity source (0.70435-0.70566), or possible contamination of the original magma by crustal material. For Nd analyses of the three samples, the calculated values εCHUR (285 Ma) are positive (from 1.75 to 3.97) for all samples with only subtle variation. Chemical and isotopic data permit us to assume that the parental magma for the Hronicum basic rocks was generated from an enriched heterogeneous source in the subcontinental lithospheric mantle.

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Section: Discussionmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Geochemistrymentioning

confidence: 99%

See 2 more Smart Citations

Geochemistry and Sr, Nd isotopic composition of the Hronic Upper Paleozoic basic rocks (Western Carpathians, Slovakia)

Vozár¹,

Spišiak²,

Vozárová³

et al. 2015

Geologica Carpathica

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“…The ELIP is composed dominantly of continental flood basalt with temporally and spatially associated mafic-ultramafic intrusions and syenitic plutons. It is believed to have formed by a mantle plume at ~260 Ma [13][14][15].…”

Section: Geological Backgroundmentioning

confidence: 99%

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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Geochemistry of river‐borne clays entering the East China Sea indicates two contrasting types of weathering and sediment transport processes

Yang

et al. 2015

Geochem Geophys Geosyst

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The East China Sea is characterized by wide continental shelf receiving a huge input of terrigenous matter from both large rivers and mountainous rivers, which makes it an ideal natural laboratory for studying sediment source‐to‐sink transport processes. This paper presents mineralogical and geochemical data of the clays and bulk sediments from the rivers entering the East China Sea, aiming to investigate the general driving mechanism of silicate weathering and sediment transport processes in East Asian continental margin. Two types of river systems, tectonically stable continental rivers and tectonically active mountainous rivers, coexist in East Asia. As the direct weathering products, clays can better reflect the silicate weathering regimes within the two river systems. Provenance rock types are not the dominant factor causing silicate weathering intensity difference existed in the East Asian rivers. The silicate weathering intensity of tectonically stable river basins is primarily driven by monsoon climate, and the sediment transfer is relatively slow because of natural trapping process and increasing damming effect. The geochemistry of these river‐borne sediments can thus indicate paleo‐weathering intensities in East Asian continent. In contrast, silicate weathering intensity in tectonically active mountainous rivers is greatly limited by strong physical erosion despite the high temperature and highest monsoon rainfall. The factors controlling silicate weathering in tectonically active catchments are complex and thus, it should be prudent to use river sediment records to decipher paleoclimate change. These two different silicate weathering regimes and sediment transport processes are manifestations of the landscape evolution and overall dominate the sedimentation in Asian continental margin.

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Petrologic and geochemical constraints on the petrogenesis of Permian–Triassic Emeishan flood basalts in southwestern China

Cited by 822 publications

References 39 publications

Geochemistry and Sr, Nd isotopic composition of the Hronic Upper Paleozoic basic rocks (Western Carpathians, Slovakia)

Geochemistry and Sr, Nd isotopic composition of the Hronic Upper Paleozoic basic rocks (Western Carpathians, Slovakia)

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

Geochemistry of river‐borne clays entering the East China Sea indicates two contrasting types of weathering and sediment transport processes

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