Crustal growth and intracrustal recycling in the middle segment of the Trans-North China Orogen, North China Craton: a case study of the Fuping Complex

Abstract

The most important crustal growth on Earth occurred at ~2.7 Ga, but the North China Craton (NCC) is characterized by prevalent development of ~2.5 Ga juvenile crust, with relatively rare records of ~2.7 Ga crustal growth. The Fuping Complex in the middle segment of the Trans-North China Orogen (TNCO) between the Eastern and Western blocks of the NCC is composed mainly of ~2.5 Ga Fuping tonalitic–trondhjemitic–granodioritic (TTG) gneisses and Longquanguan augen gneisses, ~2.1 Ga Nanying granitic gneisses and the Wanzi supracrustal rocks. Previous studies have suggested one major phase of crustal growth at ~2.5 Ga, possible intracrustal recycling at ~2.1 Ga and the presence of older rocks in the Fuping Complex, but there has been no record of ~2.7 Ga crustal growth. The Fuping TTG gneisses are dominated by stromatic migmatite, and new U–Pb dating of magmatic zircons from two stromatic migmatite samples yielded three different ages: (1) 2.75 Ga, which is the oldest age obtained from the Fuping TTG gneisses, (2) 2.54 Ga, which just falls in the published zircon U–Pb age range of 2.53 to 2.47 Ga for the Fuping TTG gneisses, and (3) 2.11 Ga, which is almost the same as the age of the Nanying granitic gneisses. Therefore, there are two generations of TTG gneisses in the Fuping Complex. Importantly, both of the 2.75 and 2.54 Ga zircons have the highest εHf(t) values, almost equal to the contemporaneous depleted mantle. This indicates high contributions of juvenile material to the two generations of TTG gneisses. In contrast, the 2.11 Ga zircons have apparently low εHf(t) values of −0.47 to +2.04, just falling in between 2.55 and 2.75 Ga continental crust values. This strongly suggests the reworking of the two generations of TTG gneisses at 2.1 Ga. Zircon U–Pb and Hf isotopes convincingly reveal two major phases of crustal growth in the Fuping Complex at ~2.7 and ~2.5 Ga, the same as in the northern and southern segments of the TNCO, and also confirm one major phase of intracrustal recycling at ~2.1 Ga, which may be responsible for the Nanying granitic gneisses.

Metamorphic evolution and SIMS U–Pb geochronology of orthopyroxene‐bearing high‐Psemipelitic granulite in the Fuping area, middle Trans‐North China Orogen

“…2.73 Ga to c . 2.48 Ga, which is similar to the ages of Fuping TTG gneiss (2.75–2.48 Ga; Guan et al., 2002; Han et al., 2012; Liu et al., 2002; Lu, et al., 2014b; Meng et al., 2017; Tang et al., 2016; Zhao et al., 2002). This probably suggests a sedimentary provenance from TTG rocks and deposition after c .…”

“…Mafic granulite and amphibolite occur as enclaves or lenses preserved in the highly deformed TTG gneiss. The protolith of the TTG gneiss was formed at 2.75–2.48 Ga and experienced metamorphism during 1.88–1.80 Ga (Guan, Sun, Wilde, Zhou, & Zhai, 2002; Han et al., 2012; Liu, Pan, Li, Li, & Zhang, 2002; Lu, et al., 2014b; Meng et al., 2017; Tang, Santosh, Tsunogae, & Teng, 2016; Zhao, Wilde, Cawood, & Sun, 2002), which is consistent with the metamorphic age at 1.92–1.83 Ga of the mafic granulite and amphibolite enclaves (Liu et al., 2019; Meng et al., 2017; Qian et al., 2018; Tang et al., 2017), indicating a regional amphibolite–granulite facies metamorphism. (b) The Wanzi supracrustal association is located in the middle and south parts of the Fuping area, which is represented by a set of amphibolite facies gneiss, pelitic schist, calc‐silicate, marble and amphibolite.…”

Paleoproterozoic/Mesoproterozoic tectonism in the northern fringe of the Western Dharwar Craton (India): Its relevance to Gondwanaland and Columbia supercontinent reconstructions

“…The overwhelming number of existing metamorphic ages (U‐Pb and Pb‐Pb zircon ages and Th‐U‐total Pb monazite ages; Figure b) in the CITZ is populated in the ranges, 1.5–1.7 Ga and 1.1–0.9 Ga [ Bhowmik et al ., , ; Reddy et al ., ], with Paleoproterozoic ages [ Roy and Hanuma Prasad , ; Mahato et al ., ; Rekha et al ., ] in the CITZ restricted to granulite facies enclaves in the northern fringe of the CITZ (Figure b). By contrast, most ages in TNCO are populated in the range 1.8–1.9 Ga and 2.0–2.1 Ga [ Guan et al ., ; Zhao et al ., , , ; Yang et al ., ; Kröner et al ., ; Liu et al ., ; Xia et al ., , ; Trap et al ., ; Han et al ., ], and Meso/Neoproterozoic metamorphic ages are virtually unknown (Figure a). In view of the above, we suggest the CITZ‐TNCO correlation within the broader framework of the Paleoproterozoic Columbia supercontinent assembly [ Zhao et al ., ] needs to be reexamined, in spite of the better geometric fit between the two orogens.…”

“…The CITZ bound by SNNF and CISZ (thick broken lines) shown by the large box in Figure 1a is enlarged in Figure 1b [Trap et al, 2011] showing age distribution in the orogen. a, Kröner et al [2005a]; b, Zhao et al [2005]; c, Xia et al [2006]; d, Xia et al [2008]; e, Guan et al [2002]; f, Zhao et al [2002]; g, Trap et al [2008]; h, Liu et al [2005]; i, Zhao et al [2007]; j, Yang et al [2004]; and k, Han et al [2012]. The dotted line is the TNCO boundary by Zhao et al [2000a].…”

Archean crustal evolution in the southeastern North China Craton: New data from the Huoqiu Complex

“…In particular, ∼2.5 Ga tonalite-trondhjemite-granodiorites (TTGs) and calc-alkaline granitoids were considered to constitute about 80% of the exposure of the NCC (Zhao et al, 2001;Zhao, 2014). However, in recently years voluminous zircon U-Pb ages show that >2.6 Ga rocks and zircons occur widely in the NCC as well (Diwu et al, 2010a,b;Dong et al, 2012;Du et al, 2010;Faure et al, 2007;Geng et al, 2012;Han et al, 2012;Jahn et al, 2008;Jiang et al, 2010;Kröner et al, 2005a,b;Liu et al, 2013;Lu et al, 2008a;Ma et al, 2013;Wan et al, 2010aWan et al, , 2011aWan et al, , 2012aWang et al, 2007Wang et al, , 2011a; Wang and Liu, 2012;Wu et al, 2008a;Yang et al, 2013;Zheng et al, 2004Zheng et al, , 2009Zhu et al, 2013), indicating that the distribution of >2.6 Ga continental crust in the NCC is probably greater than previously thought (Jiang et al, 2010;Wan et al, 2011a;Zhao and Guo, 2012). On the other hand, whether these >2.6 Ga rocks and zircons reflect crustal growth or reworking remains an open debate.…”