Nature of the Mantle Plume under the Emeishan Large Igneous Province: Constraints from Olivine‐hosted Melt Inclusions of the Lijiang Picrites

2021 ◽  
Author(s):  
Lei Zhang ◽  
Zhong‐Yuan Ren ◽  
Le Zhang ◽  
Ya‐Dong Wu ◽  
Sheng‐Ping Qian ◽  
...  
Keyword(s):  
Mantle Plume ◽  
Melt Inclusions ◽  
Large Igneous Province ◽  
Emeishan Large Igneous Province ◽  
Igneous Province

scholarly journals Genesis of high-Ni olivine phenocrysts of the Dali picrites in the Central Emeishan large igneous province

2020 ◽  
pp. 1-10
Author(s):  
Wen-Chang Cai ◽  
Zhao-Chong Zhang ◽  
Jiang Zhu ◽  
M. Santosh ◽  
Rong-Hao Pan
Keyword(s):  
High Temperatures ◽  
Mantle Plume ◽  
Potential Temperature ◽  
Large Igneous Province ◽  
Thermal Plume ◽  
Emeishan Large Igneous Province ◽  
Igneous Province ◽  
High Concentrations ◽  
Mantle Potential Temperature

Abstract The Emeishan large igneous province (ELIP) in SW China is considered to be a typical mantle-plume-derived LIP. The picrites formed at relatively high temperatures in the ELIP, providing one of the important lines of argument for the role of mantle plume. Here we report trace-element data on olivine phenocrysts in the Dali picrites from the ELIP. The olivines are Ni-rich, and characterized by high (>1.4) 100×Mn/Fe value and low (<13) 10 000×Zn/Fe value, indicating a peridotite-dominated source. Since the olivine–melt Ni partition coefficient (KDNiol/melt) will decrease at high temperatures and pressures, the picrites derived from peridotite melting at high pressure, and that crystallized olivines at lower pressure, can generate high concentrations of Ni in olivine phenocrysts, excluding the necessity of a metasomatic pyroxenite contribution. Based on the Al-in-olivine thermometer, olivine crystallization temperature and mantle potential temperature (TP) were calculated at c. 1491°C and c. 1559°C, respectively. Our results are c. 200°C higher than that of the normal asthenospheric mantle, and are consistent with the role of a mantle thermal plume for the ELIP.

What triggered the early-stage eruption of the Emeishan large igneous province?

2019 ◽  
Vol 131 (11-12) ◽  
pp. 1837-1856 ◽  
Author(s):  
Bei Zhu ◽  
Zhaojie Guo ◽  
Shaonan Zhang ◽  
Ingrid Ukstins ◽  
Wei Du ◽  
...  
Keyword(s):  
Mantle Plume ◽  
Plate Tectonics ◽  
Early Stage ◽  
Volcanic Rocks ◽  
Large Igneous Province ◽  
Background Information ◽  
Gradual Transition ◽  
Emeishan Large Igneous Province ◽  
Igneous Province ◽  
Back Arc

Abstract The formation of the Emeishan large igneous province is widely regarded as being related to a mantle plume, but plate tectonics may also have played an important role. We analyzed the regional facies architecture of the early-stage subaqueous volcanic rocks of the central Emeishan large igneous province. The results suggest that these rocks were emplaced in a N-S–striking subaqueous rift, which existed immediately before the onset of volcanism and was persistently maintained during the early eruption stage. By linking this conclusion with the background information indicating that (1) the basaltic geochemistry in this section is indicative of a subcontinental lithospheric mantle source rather than a mantle plume source, and (2) the western Yangtze plate, where the Emeishan large igneous province was developed, was located in the back-arc region of the Permian Paleo-Tethys subduction system, we propose a new view that the early-stage eruptions of the Emeishan large igneous province were triggered by back-arc extension. The dominant functioning of the mantle plume occurred shortly after this process and inherited it, as evidenced by the following: (1) The subaqueous volcanic architecture showing back-arc geochemical affinity is laterally restricted in the presumed rift, but the overlying subaerial lavas showing plume-related geochemical features overwhelmingly flooded the whole province; (2) vertically, the source of the basaltic component in these intrarift sequences underwent a gradual transition from lithospheric origin to mantle plume origin along the stratigraphic order, as evidenced by an intercalated basaltic succession showing mixed geochemical features from the two contextual origins.

Giant radiating mafic dyke swarm of the Emeishan Large Igneous Province: Identifying the mantle plume centre

Terra Nova ◽  
2015 ◽  
Vol 27 (4) ◽  
pp. 247-257 ◽  
Author(s):  
Hongbo Li ◽  
Zhaochong Zhang ◽  
Richard Ernst ◽  
Linsu Lü ◽  
M. Santosh ◽  
...  
Keyword(s):  
Mantle Plume ◽  
Large Igneous Province ◽  
Dyke Swarm ◽  
Mafic Dyke ◽  
Emeishan Large Igneous Province ◽  
Igneous Province ◽  
Mafic Dyke Swarm
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