An Asthenospheric Upwelling Beneath Central Mongolia — Implications for Intraplate Surface Uplift and Volcanism

Comeau, Matthew J.; Becken, Michael; Kuvshinov, Alexey; Grayver, Alexander; Käufl, Johannes; Batmagnai, Erdenechimeg; Tserendug, Shoovdor; Дэмбэрэл, С.

doi:10.1111/1755-6724.14836

Cited by 3 publications

(1 citation statement)

References 18 publications

(21 reference statements)

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“…7) is detected near the village of Erdenestsogt, which stretches downwards through the resistive upper crust. This is believed to be related to the young (< 1 million years ago) intraplate volcanism found at this location (Ancuta et al 2018), which was one of several volcanic environments imaged by Comeau et al (2018b). South of this anomaly, a highly resistive feature (> 1000 Ωm; R1) is…”

Section: Line 2000mentioning

confidence: 79%

Crustal architecture of a metallogenic belt and ophiolite belt: implications for mineral genesis and emplacement from 3-D electrical resistivity models (Bayankhongor area, Mongolia)

Comeau

Becken

Kuvshinov

et al. 2021

Earth Planets Space

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Crustal architecture strongly influences the development and emplacement of mineral zones. In this study, we image the crustal structure beneath a metallogenic belt and its surroundings in the Bayankhongor area of central Mongolia. In this region, an ophiolite belt marks the location of an ancient suture zone, which is presently associated with a reactivated fault system. Nearby, metamorphic and volcanic belts host important mineralization zones and constitute a significant metallogenic belt that includes sources of copper and gold. However, the crustal structure of these features, and their relationships, are poorly studied. We analyze magnetotelluric data acquired across this region and generate three-dimensional electrical resistivity models of the crustal structure, which is found to be locally highly heterogeneous. Because the upper crust (< 25 km) is found to be generally highly resistive (> 1000 Ωm), low-resistivity (< 50 Ωm) features are conspicuous. Anomalous low-resistivity zones are congruent with the suture zone, and ophiolite belt, which is revealed to be a major crustal-scale feature. Furthermore, broadening low-resistivity zones located down-dip from the suture zone suggest that the narrow deformation zone observed at the surface transforms to a wide area in the deeper crust. Other low-resistivity anomalies are spatially associated with the surface expressions of known mineralization zones; thus, their links to deeper crustal structures are imaged. Considering the available evidence, we determine that, in both cases, the low resistivity can be explained by hydrothermal alteration along fossil fluid pathways. This illustrates the pivotal role that crustal fluids play in diverse geological processes, and highlights their inherent link in a unified system, which has implications for models of mineral genesis and emplacement. The results demonstrate that the crustal architecture—including the major crustal boundary—acts as a first‐order control on the location of the metallogenic belt.

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Section: Line 2000mentioning

confidence: 79%

Crustal architecture of a metallogenic belt and ophiolite belt: implications for mineral genesis and emplacement from 3-D electrical resistivity models (Bayankhongor area, Mongolia)

Comeau

Becken

Kuvshinov

et al. 2021

Earth Planets Space

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Morphodynamic development of the Terkhiin Tsagaan Lake Depression, Central Mongolia: Implications for the relationships of Faulting, Volcanic Activity, and Lake Depression Formation

Enkhbold

Khukhuudei²,

Kusky³

et al. 2022

J. Mt. Sci.

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Melt Pockets in Garnet Megacrysts from Cenozoic Alkali Basalts of the Shavaryn Tsaram Vicinity, Mongolia

Aseeva

Avchenko

Карабцов

et al. 2022

Acta Geologica Sinica (Eng)

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Garnet megacryst with a multiphase inclusion from intraplate alkali basalts of the Shavaryn Tsaram (Tariat, Mongolia) was the object of the study. This unusual aggregate consists of porous glass, Ti-rich biotite, orthopyroxene, spinel, clinopyroxene, olivine, and ilmenite. WinTWQ 2.32 thermodynamic simulation of this system revealed a few intervals of equilibrium. Pressure and temperature adjustment reflected in the paragenetic minerals of the melt pocket. The capture of already crystallised garnet megacryst was at P = 0.8-1 GPa and T = 1120-1160°C. Mineral crystallisation inside the melt pocket, accompanied by external inputs, occurred at P = 0.75-0.95 GPa; T = 790-1120°C. Symplectite assemblage formed in the garnet megacryst due to decomposition at (P = 0.55-0.7 GPa; T = 850-930°C). The study of the oxygen isotope content in primary garnet and biotite of the melt pocket showed that the δ 18 O VSMOW values are the same and correspond to that of typical mantle xenoliths. However, the chemical and microcomponent composition of the melt pocket minerals reveals a material that differs from basalts and peridotites. Thus, it has been revealed that the multiphase inclusion in the garnet megacryst formed not only on account of the garnet's substance, but also due to the entrapped material of the Earth's interior.

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An Asthenospheric Upwelling Beneath Central Mongolia — Implications for Intraplate Surface Uplift and Volcanism

Cited by 3 publications

References 18 publications

Crustal architecture of a metallogenic belt and ophiolite belt: implications for mineral genesis and emplacement from 3-D electrical resistivity models (Bayankhongor area, Mongolia)

Crustal architecture of a metallogenic belt and ophiolite belt: implications for mineral genesis and emplacement from 3-D electrical resistivity models (Bayankhongor area, Mongolia)

Morphodynamic development of the Terkhiin Tsagaan Lake Depression, Central Mongolia: Implications for the relationships of Faulting, Volcanic Activity, and Lake Depression Formation

Melt Pockets in Garnet Megacrysts from Cenozoic Alkali Basalts of the Shavaryn Tsaram Vicinity, Mongolia

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