Early Permian high-K calc-alkaline volcanic rocks from NW Inner Mongolia, North China: geochemistry, origin and tectonic implications

Knowledge of the characteristics of the extensive late Palaeozoic volcanic rocks across the northernChina–Mongolia tract is essential for understanding the tectonic evolution and continental crustal growth in the Central Asian Orogenic Belt. This geochronological and geochemical study documents the...

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Main Authors: Zhang, Xiao-hui, Wilde, Simon, Zhang, H., Zhai, M.
Format: Journal Article
Published: Geological Society Publishing House 2011
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/49087
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author Zhang, Xiao-hui
Wilde, Simon
Zhang, H.
Zhai, M.
author_facet Zhang, Xiao-hui
Wilde, Simon
Zhang, H.
Zhai, M.
author_sort Zhang, Xiao-hui
building Curtin Institutional Repository
collection Online Access
description Knowledge of the characteristics of the extensive late Palaeozoic volcanic rocks across the northernChina–Mongolia tract is essential for understanding the tectonic evolution and continental crustal growth in the Central Asian Orogenic Belt. This geochronological and geochemical study documents the Early Permian mafic and felsic volcanic rocks from northwestern Inner Mongolia. The mafic rocks form two magma series with distinctive geochemical characteristics; one showing large ion lithophile element (LILE) enrichment relative to high field strength elements (HFSE) and an asthenosphere-like Sr–Nd–Pb isotopic signature, and the other featuring an elevated Nb and lithospheric isotopic signature. This result indicates that two mantle source components are involved in the magma generation: the subduction-related metasomatized asthenosphere and lithospheric mantle. The felsic rocks show strong enrichment of LILE and light REE, depletion in HFSE, and indistinguishable isotopic compositions from mafic ones. Such features are consistent with partial melts of mixed sources composed of predominant juvenile basaltic underplates and minor ancient crustal materials. These mafic and felsic rocks constitute a post-subduction high-potassium calc-alkaline magmatic suite possibly under a geodynamic regime of Palaeo-Asian Ocean slab breakoff. This regime not only provides a feasible trigger for the flipping of subduction polarity in the Solonker suture zone, but also presents a favourable venue for vertical continental crustal growth.
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publishDate 2011
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spelling curtin-20.500.11937-490872017-03-15T22:55:53Z Early Permian high-K calc-alkaline volcanic rocks from NW Inner Mongolia, North China: geochemistry, origin and tectonic implications Zhang, Xiao-hui Wilde, Simon Zhang, H. Zhai, M. asthenosphere Sr–Nd–Pb isotope felsic Palaeo-Asian Ocean slab breakoff lithospheric mantle Solonker suture zone vertical continental crustal growth mafic Central Asian Orogenic Belt Knowledge of the characteristics of the extensive late Palaeozoic volcanic rocks across the northernChina–Mongolia tract is essential for understanding the tectonic evolution and continental crustal growth in the Central Asian Orogenic Belt. This geochronological and geochemical study documents the Early Permian mafic and felsic volcanic rocks from northwestern Inner Mongolia. The mafic rocks form two magma series with distinctive geochemical characteristics; one showing large ion lithophile element (LILE) enrichment relative to high field strength elements (HFSE) and an asthenosphere-like Sr–Nd–Pb isotopic signature, and the other featuring an elevated Nb and lithospheric isotopic signature. This result indicates that two mantle source components are involved in the magma generation: the subduction-related metasomatized asthenosphere and lithospheric mantle. The felsic rocks show strong enrichment of LILE and light REE, depletion in HFSE, and indistinguishable isotopic compositions from mafic ones. Such features are consistent with partial melts of mixed sources composed of predominant juvenile basaltic underplates and minor ancient crustal materials. These mafic and felsic rocks constitute a post-subduction high-potassium calc-alkaline magmatic suite possibly under a geodynamic regime of Palaeo-Asian Ocean slab breakoff. This regime not only provides a feasible trigger for the flipping of subduction polarity in the Solonker suture zone, but also presents a favourable venue for vertical continental crustal growth. 2011 Journal Article http://hdl.handle.net/20.500.11937/49087 Geological Society Publishing House restricted
spellingShingle asthenosphere
Sr–Nd–Pb isotope
felsic
Palaeo-Asian Ocean slab breakoff
lithospheric mantle
Solonker suture zone
vertical continental crustal growth
mafic
Central Asian Orogenic Belt
Zhang, Xiao-hui
Wilde, Simon
Zhang, H.
Zhai, M.
Early Permian high-K calc-alkaline volcanic rocks from NW Inner Mongolia, North China: geochemistry, origin and tectonic implications
title Early Permian high-K calc-alkaline volcanic rocks from NW Inner Mongolia, North China: geochemistry, origin and tectonic implications
title_full Early Permian high-K calc-alkaline volcanic rocks from NW Inner Mongolia, North China: geochemistry, origin and tectonic implications
title_fullStr Early Permian high-K calc-alkaline volcanic rocks from NW Inner Mongolia, North China: geochemistry, origin and tectonic implications
title_full_unstemmed Early Permian high-K calc-alkaline volcanic rocks from NW Inner Mongolia, North China: geochemistry, origin and tectonic implications
title_short Early Permian high-K calc-alkaline volcanic rocks from NW Inner Mongolia, North China: geochemistry, origin and tectonic implications
title_sort early permian high-k calc-alkaline volcanic rocks from nw inner mongolia, north china: geochemistry, origin and tectonic implications
topic asthenosphere
Sr–Nd–Pb isotope
felsic
Palaeo-Asian Ocean slab breakoff
lithospheric mantle
Solonker suture zone
vertical continental crustal growth
mafic
Central Asian Orogenic Belt
url http://hdl.handle.net/20.500.11937/49087