The Fangmayu Alaskan-type ultramafic intrusion: Implications for Paleoproterozoic assembly of the North China Craton

Han, Yue-Sheng; Santosh, M.; Samuel, Vinod O.

doi:10.1016/j.precamres.2018.07.027

Cited by 13 publications

(7 citation statements)

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“…Although amphibolite facies rocks are more common in this region, including in the ophiolite suite, the highest grade of metamorphism reached up to granulite facies, and information on the P – T conditions of these rocks are crucial in understanding the metamorphic history and tectonic setting. Previous studies reported peridotite, pyroxenite, and amphibolite from the surrounding areas (Han, Santosh, & Samuel, 2018). The ultramafic rocks are serpentinized.…”

Section: Geology Of the Study Area And Samplingmentioning

confidence: 89%

“…We show in Figure 19 a compilation of the previously reported age data from the Miyun area and adjacent regions of the Qianhuai microblock, where the magmatic emplacement ages range from 2512 to 2398 Ma, associated with subduction‐related magmatism (Fang et al, 2017; Han et al, 2018; Liu et al, 2018; Shi et al, 2012; Shi & Zhao, 2017; Tang & Santosh, 2018a, 2018b; Yang, Santosh, & Kim, 2017; Zhai & Santosh, 2011). A compilation of the ε Hf ( t ) values (Figure 20) from these occurrences shows mostly positive ε Hf ( t ) values suggesting that the magmas were derived from depleted mantle (juvenile) sources.…”

Section: Discussionmentioning

confidence: 99%

“…Minor anorthosites were reported from Xindi to the north of Huairou town. The results from previous studies indicate that Miyun Complex has experienced a major Palaeoproterozoic metamorphic event at 1.8 Ga and that the protolith ages are around 2.5 Ga (Fang, Sun, Liu, Wu, & Wei, 2017; Han et al, 2018; Liu, Santosh, & Samuel, 2018; Shi et al, 2012).…”

Section: Geology Of the Study Area And Samplingmentioning

confidence: 97%

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Neoarchean magmatism and Palaeoproterozoic metamorphism along the margin of the Qianhuai microblock in the North China Craton

2020

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The tectonic framework of the North China Craton (NCC) involved the building of microblocks and their incorporation into larger crustal blocks during the Late Archean followed by final cratonization through collisional assembly of the crustal blocks during the Late Palaeoproterozoic. Here we investigate a newly identified gabbro-diorite-anorthosite suite, metamorphosed under granulite facies, along the margin of the Qianhuai microblock based on field, petrological, geochemical and zircon U-Pb and Lu-Hf studies, with a view to understand the petrogenetic and metamorphic history. Mineral phase equilibria modelling of metagabbros from the suite reveals relatively high temperatures and pressures of 800-820 C and 13-14 kbar, with a typical isobaric cooling pressure-temperature path characterized by initial heating followed by moderate to high-pressure metamorphism and cooling, consistent with a thickened arc setting. The gabbro-diorite-anorthosite association is considered to represent the fractionated sequence from a common mafic magma. Magmatic zircon grains from the metagabbro yield upper intercept ages of 2522 and 2540 Ma, corresponding to the timing of formation of the mafic protolith. The lower intercept ages of 1785 and 1833 Ma mark the timing of metamorphism associated with the collisional event between the Western and Eastern blocks of the NCC. Zircon ε Hf (t) values are mostly positive for the magmatic domains suggesting that the melts were derived from depleted mantle sources. The Hf model ages indicate that the magma source involved Neoarchean-Mesoarchean juvenile components and the continental crust was reworked during metamorphism in the Late Palaeoproterozoic. The lithological association and geochemical as well as isotopic features are consistent with a convergent margin setting along a continental arc, where basaltic melts were underplated beneath the overriding arc, accompanied by lower crustal melting. Our study confirms subduction-related crust building events during the late Neoarchean followed by Late Palaeoproterozoic high-grade metamorphism associated with the final cratonization of the NCC.

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Section: Geology Of the Study Area And Samplingmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Geology Of the Study Area And Samplingmentioning

confidence: 97%

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Neoarchean magmatism and Palaeoproterozoic metamorphism along the margin of the Qianhuai microblock in the North China Craton

2020

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“…However, Proterozoic Alaskan‐type complexes were rarely reported except in Arabian–Nubian Shield, such as the Genina Gharbia complex, Egypt and Abu Hamamid complex, and South Eastern Desert, Egypt (Helmy et al, ; Helmy, Yoshikawa, Shibata, Arai, & Kagamie, ). Rare Palaeoproterozoic Alaskan‐type intrusions occur in the North China Craton (Han, Santosh, & Samuel, ).…”

Section: Introductionmentioning

confidence: 99%

The mafic–ultramafic complex of Salem, southern India: An analogue for Neoproterozoic Alaskan‐type complex

2019

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The Salem Mafic–Ultramafic Complex occurs within the northern part of Cauvery Suture Zone (CSZ), Southern Granulite Terrane (SGT), India. The complex occurs as semicircular to elongated linear body with a thick mantle section and comparatively well‐developed crustal section comprising different lithological units, also referred to as the Chalk Hills of Salem. The major rock types in the complex comprise ultramafic cumulates of dunite, peridotite, wherlite, pyroxenite, and hornblendite, mafic and felsic intrusions of gabbros and amphibolites, and quartzo–feldspathic alkaline rocks together with several ultrapotassic dykes. Geochemical studies of amphibolites from this complex indicate tholeiitic parent magma with enrichment of LIL elements (Rb, Ba, Th, and Sr) and are relatively more enriched than N‐MORB as compared with arc‐related rocks. The enrichment of LIL elements over the HFS elements and with distinct Nb, Ta, and Ti depletion relative to other HFS elements suggest the involvement of subduction‐related components in the depleted mantle source and that the magmatism occurred in an oceanic convergent realm. The mineral chemistry of dunite and peridotite shows high content of forsterite (86.9–92.2) in olivine and high Cr# value (80.85–98.73) for spinel. The tectonic discrimination plots of spinel and olivine mineral chemistry together with clinopyroxene chemistry of amphibolites reveal arc signature typical of Alaskan type of complex. The U–Pb zircon analysis of quartz monzonite intrusion within the hornblendite from the complex yielded a weighted mean age of 819 ± 2.4 Ma, suggesting that the complex formed during the Neoproterozoic and can be correlated to the Alaskan‐type complexes described from the Arabian–Nubian Shield.

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“…Archean ultramafic–mafic rocks are emplaced in diverse tectonic regimes such as part of lower oceanic crust and upper mantle sections of ocean floor spreading centre, in oceanic and continental arc roots, in crust–mantle transition zones, in intracontinental layered intrusions, and as part of intracrustal magma chambers (Eyuboglu et al, ; Han, Santosh, & Samuel, ). Based on their tectonic setting of emplacement, ultramafic–mafic intrusions are classified as orogenic and nonorogenic types.…”

Section: Introductionmentioning

confidence: 99%

Evolution of a Mesoarchean suprasubduction zone mantle wedge in the Dharwar Craton, southern India: Evidence from petrology, geochemistry, zircon U–Pb geochronology, and Lu–Hf isotopes

et al. 2019

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Petrological, geochemical, and zircon U–Pb geochronological features of Archean ultramafic–mafic complexes formed in subduction‐related settings provide significant insights into mantle source and geodynamic processes associated with subduction–accretion‐collision events in the early Earth. Here, we investigate a suite of serpentinized dunite, dunite, pyroxenite, and clinopyroxenite from an ultramafic complex along the collisional suture between the Western Dharwar Craton (WDC) and the Central Dharwar Craton (CDC) in southern India. We present petrology, mineral chemistry, zircon U–Pb geochronology, rare earth element (REE), Lu–Hf isotopes, and whole‐rock geochemistry including major, trace element, and platinum‐group element (PGE) data with a view to investigate the magmatic and metasomatic processes in the subduction zone. Mineral chemistry data from chromite associated with the serpentinised ultramafic rocks show distinct characteristics of arc‐related melt. Zircon U–Pb data from the ultramafic suite define different age populations, with the oldest ages at 2.9 Ga, and the dominant age population showing a range of 2.8–2.6 Ga. The early Paleoproterozoic (ca. 2.4 Ga) metamorphic age is considered to mark the timing of collision of the two WDC and CDC. Zircon REE patterns suggest the involvement continental crust components in the magma source. Zircon Lu–Hf analysis yields both positive and negative εHf(t) values from −3.9 to 1.5 with Hf‐depleted model ages (TDM) of 3,041–3,366 Ma for serpentinised dunite and −0.2–2.0 and 2,833–2,995 Ma for pyroxenite, suggesting that the magma was sourced from depleted mantle and was contaminated with the ancient continental crust. Geochemical data show low MgO/SiO2 values and elevated Al2O3/TiO2 ratios, implying subduction‐related setting. The serpentinized dunites and dunites show mild LREE enrichment over HREE, with relatively higher abundance of LILE (Ba, Sr) and depletion in HFSE (Nb, Zr), suggesting fluid–rock interaction, melt impregnation, and refertilization processes. The PGE data suggest olivine, chromite, and sulphide fractionations associated with subduction processes. Our study on the Mesoarchean to Neoarchean ultramafic complex provides important insights to reconstruct the history of the crust–mantle interaction in an Archean suprasubduction zone mantle wedge.

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The Fangmayu Alaskan-type ultramafic intrusion: Implications for Paleoproterozoic assembly of the North China Craton

Cited by 13 publications

References 70 publications

Neoarchean magmatism and Palaeoproterozoic metamorphism along the margin of the Qianhuai microblock in the North China Craton

Neoarchean magmatism and Palaeoproterozoic metamorphism along the margin of the Qianhuai microblock in the North China Craton

The mafic–ultramafic complex of Salem, southern India: An analogue for Neoproterozoic Alaskan‐type complex

Evolution of a Mesoarchean suprasubduction zone mantle wedge in the Dharwar Craton, southern India: Evidence from petrology, geochemistry, zircon U–Pb geochronology, and Lu–Hf isotopes

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