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6919814 
Journal Article 
Qingyuan high-grade granite–greenstone terrain in the Eastern North China Craton: Root of a Neoarchaean arc 
Peng, P; Wang, C; Wang, X; Yang, S; , 
2015 
1 
Tectonophysics
ISSN: 0040-1951 
ELSEVIER SCIENCE BV 
AMSTERDAM 
662 
7-21 
English 
WOS:000366227400002 
The Qingyuan high-grade granite-greenstone terrain is one of the first recognized granite-greenstone terrains in the Eastern North China Craton. Similar to other Archaean terrains, its tectonic environment is debated: was it an intra-continental rift or a modem analogy of arc? Occurrence and petrogenesis of major igneous series, the ultramafic-mafic and felsic volcanic rocks (>2510 Ma) and the plutons of the quartz diorite (2570-2510 Ma), TTG (2570-2510 Ma) and quartz monzodiorite (2510-2490 Ma) series in Xinbin area are investigated. The mafic intrusives and volcanic rocks have high MgO content (5.4-7.5 wt.%) and Mg-number (48-61). They show slightly depleted to flat trace element patterns. The ultramafic rocks (serpentinite) could be genetically related to the mafic rocks. The meta-dacite-rhyolite is adakitic with enriched light and middle REEs and LILEs, but significantly depleted HFSEs. The quartz diorite has high Mg-number (60-64), moderately enriched light and middle REEs and LILEs. The TIC shows distinct light but moderate middle REE-enrichment, prominent Nb-Ta-depletion but Zr-Hf-enrichment (Zr/Sm > 100). The quartz monzodiorite has moderate light and middle REE-enrichment, significant Nb-Ta-depletion, and negative Eu-/Sr-anomalies. The TTG has more depleted Sr-Nd isotopes (epsilon Nd-t = +2-+6: Sr-87/Sr-86(t) = similar to 0.700) than all the others (epsilon Nd-t = 0-+ 2; Sr-87/Sr-86(t) = 0.701-703). Their petrogenesis can be explained by an Archaean-style subduction defined as a mantle wedge-absent flat-'hot'-subduction with significant vertical tectonism in the overriding slab: the ultramafic-mafic rocks were originated from primitive mantle; the meta-dacite-rhyolite was originated from the eclogite fades overriding crust; the quartz diorite was a mixture of melts from mantle and the overriding crust; the TTG was from the subducting slab under amphibolite to amphibole-bearing eclogite fades; and the quartz monzodiorite was from the subducting slab after the derivation of the TTG. The Qingyuan terrain represents remnants of the root of a Neoarchaean arc: its anticlockwise P-T-path recorded the initiation of the arc to its cession and exhumation/cratonization at similar to 2480 Ma. (C) 2015 Elsevier B.V. All rights reserved. 
The Eastern North China Craton; Granite-greenstone terrain; Neoarchaean; TTG; Archaean-style subduction; Arc