Journal ArticleDOI
P–T–t paths and tectonic history of an early Precambrian granulite facies terrane, Jining district, south‐east Inner Mongolia, China
Lu Liangzhao,Jin Shiqin +1 more
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TLDR
The widespread khondalite series of south-east Inner Mongolia consists largely of biotite, hornblende, sodic plagioclase and quartz in garnet or orthopyroxene.Abstract:
The widespread khondalite series of south-east Inner Mongolia consists largely of biotite–sillimanite–garnet gneiss and quartzo-feldspathic gneiss with some marble and mafic granulite layers. It has experienced two metamorphic events at c. 2500 and 1900–2000 Ma.
A pre-peak stage of the first metamorphism at T= 600–700°C and P > 6–7 kbar is recognized by the relict amphibolite facies assemblage Ky–Grt–Bt–Pl–Qtz and ‘protected’inclusions of biotite, hornblende, sodic plagioclase and quartz in garnet or orthopyroxene. The peak stage, with T=c. 800 ± 50°C and P 8–10 kbar, is characterized by the widespread granulite facies assemblages Sil–Grt–Bt–Kfs–Pl–Qtz in gneiss and Opx–Cpx–Pl ± Hbl ± Grt in granulite. The P–T–t path suggests that the supracrustal sequence was buried in the lower crust by tectonic thickening during D1–D2.
The beginning of the second metamorphism is characterized by further temperature rise to 700°C or more at lower pressure. This stage is manifested by the appearance of cordierite after garnet, fibrolite (Sil2) after biotite in gneiss and transformation of Hbl1 into Opx2 and Cpx2 in granulite. Coronas of symplectitic Opx2 + Pl2 surrounding Grt1 and Cpx1 in mafic granulite are interpreted as products of near-isothermal decompression. The P–T–t path may be related tectonically to waning extension of the crust by the end of the early Proterozoic.read more
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Late Archean to Paleoproterozoic evolution of the North China Craton: key issues revisited
TL;DR: In this paper, the authors proposed a model for the evolution of the North China Craton that envisages discrete Eastern and Western Blocks that developed independently during the Archean and collided along the Trans-North China Orogen during a Paleoproterozoic orogenic event.
Journal ArticleDOI
Archean blocks and their boundaries in the North China Craton: lithological, geochemical, structural and P–T path constraints and tectonic evolution
TL;DR: In this paper, a mantle plume model is proposed for the formation and evolution of Late Archean basement rocks in the Eastern and Western Blocks based on a combination of extensive exposure of TTG gneisses, affinities of mafic rocks to continental tholeiitic basalts, presence of voluminous komatiitic rocks, dominant diaprism-related domiform structures, anticlockwise P-T paths, and a short time span from the primary emplacement of the TTG and ultramafic-to-maf
Journal ArticleDOI
Precambrian geology of China
Guochun Zhao,Peter A. Cawood +1 more
TL;DR: In this article, the authors proposed a model for the origin of the 2.55-2.50-Ga metamorphic pulse in the North China Craton (NCC), which is interpreted as a major phase of juvenile crustal growth in the craton.
Journal ArticleDOI
Lithotectonic elements of Precambrian basement in the North China Craton: Review and tectonic implications
Guochun Zhao,Mingguo Zhai +1 more
TL;DR: In this article, the authors show that the 2.6-2.5 Ga basement rocks in the eastern and western parts of the NCC formed under different tectonic settings from those in the central part, consistent with subduction and continent-continent collisional belts.
Journal ArticleDOI
Amalgamation of the North China Craton: Key issues and discussion
Guochun Zhao,Peter A. Cawood,Sanzhong Li,Simon A. Wilde,Min Sun,Jian Zhang,Yanhong He,Changqing Yin +7 more
TL;DR: In this article, a model for assembly and stabilization of the various Archean blocks of the NCC in the Paleoproterozoic has been proposed, based on the analysis of available stratigraphic, structural, geochemical, metamorphic and geochronologic data.
References
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Journal ArticleDOI
Nomenclature of amphiboles
TL;DR: The Na-Ca-Mg-Fe-Mn-Li amphibole group was proposed in this article, which is defined by 0.50 apfu (atoms per formula unit), with members whittakerite and ottoliniite.
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Experimental calibration of the partitioning of Fe and Mg between biotite and garnet
John M. Ferry,Frank S. Spear +1 more
TL;DR: In this article, the cation exchange reaction Fe3Al2Si3O12 + KMg3AlSi3AlO10(OH) + KFe3-alSi3 O10(O10)2 has been investigated by determining the partitioning of Fe and Mg between synthetic garnet and biotite.
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An experimental study of the effect of Ca upon garnet-clinopyroxene Fe-Mg exchange equilibria
D. J. Ellis,David H. Green +1 more
TL;DR: In this paper, a series of basaltic compositions and compositions within the simple system CaO-MgO-FeO-Al2O3-SiO2 have been crystallized to garnet-clinopyroxene bearing mineral assemblages in the range 24-30 kb pressure, 750°-1,300° C temperature.
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Pyroxene thermometry in simple and complex systems
TL;DR: In this article, a semi-empirical equation of state for the diopside enstatite miscibility gap has been proposed for ortho-and clinopyroxene solid solutions.
Journal ArticleDOI
Stability of andalusite and the aluminum silicate phase diagram
TL;DR: In this article, the effects of Si-Al disorder, fibrolite and sample preparation, comparison with previous data, geothermal gradient implications, and comparison of previous data were discussed.