Neoarchean (2.5–2.8Ga) crustal growth of the North China Craton revealed by zircon Hf isotope: A synthesis

Abstract

The crustal growth of the North China Craton (NCC) during the Neoarchean time (2.5e2.8 Ga) is a hotly controversial topic, with some proposing that the main crustal growth occurred in the late Neoarchean (2.5e2.6 Ga), in agreement with the time of the magmatism, whereas others suggest that the main crustal accretion took place during early Neoarchean time (2.7e2.8 Ga), consistent with the time of crustalformation of other cratons in the world. Zircon U-Pb ages and Hf isotope compositions can provide rigorous constraints on the time of crustal growth and the evolution and tectonic division of the NCC. In this contribution, we make a comprehensive review of zircon Hf isotope data in combination with zircon U-Pb geochronology and some geochemistry data from various divisions of the NCC with an aim to constrain the Neoarchean crustal growth of the NCC. The results suggest that both 2.7e2.8 Ga and 2.5e2.6 Ga crustal growth are distributed over the NCC and the former is much wider than previously suggested. The Eastern block is characterized by the main 2.7e2.8 Ga crustal growth with local new crustal-formation at 2.5e2.6 Ga, and the Yinshan block is characterized by w2.7 Ga crustal accretion as revealed by Hf-isotope data of detrital zircons from the Zhaertai Group. Detrital zircon data of the Khondalite Belt indicate that the main crustal growth period of the Western block is Paleoproterozoic involving some w2.6 Ga and minor Early-to Middle-Archean crustal components, and the crustal accretion in the Trans-North China Orogen (TNCO) has a wide age range from 2.5 Ga to 2.9 Ga with a notable regional discrepancy. Zircon Hf isotope compositions, coupled with zircon ages and other geochemical data suggest that the southern margin may not be an extension of the TNCO, and the evolution and tectonic division of the NCC is more complex GEOSCIENCE FRONTIERS journal homepage: www.elsevier.com/locate/gsf GEOSCIENCE FRONTIERS 3(2) (2012) 147e173 than previously proposed, probably involving multi-stage crustal growth and subduction processes. However, there is no doubt that 2.7e2.8 Ga magmatism and crustal-formation are more widely distributed than previously considered, which is further supported by the data of zircons from Precambrian lower crustal rocks, overlying sedimentary cover, modern river sediments and Late Neoarchean syenogranites. ª 2011, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. All rights reserved.

Crustal reworking in the North China Craton at ~2.5 Ga: evidence from zircon U–Pb age, Hf isotope and whole rock geochemistry of the felsic volcano‐sedimentary rocks from the western Shandong Province

“…The NCC, covering an area of over 300 000 km 2 , preserves an intensive record of~2.5 Ga tectonothermal events (Kröner et al, 1998;Zhao et al, 1998Zhao et al, , 2001Zhao et al, , 2005Shen et al, 2005;Wan et al, 2005Wan et al, , 2010Wilde et al, 2005;Nutman et al, 2011;Zhai and Santosh, 2011;Geng et al, 2012;Wang and Liu, 2012;Zheng et al, 2012). Some workers suggested that the amalgamation of micro-blocks and cratonization of the NCC took place at the end of the Neoarchaean (Wu et al, 1998;Kusky and Li, 2003;Polat et al, 2005;Zhai et al, 2005).…”

Archean-Paleoproterozoic crustal evolution of the Ordos Block in the North China Craton: Constraints from zircon U–Pb geochronology and Hf isotopes for gneissic granitoids of the basement

“…A large number of Neoarchean TTG gneisses, greenstones and metamorphic supracrustal rocks were formed at ∼2.7 Ga and ∼2.5 Ga and Paleoproterozoic igneous rocks are also present (Jahn et al, 1987;Kröner et al, 2005;Wan et al, 2011Wan et al, , 2012bDiwu et al, 2011;Zhao et al, 2012;Zhao and Zhai, 2013;Wang and Liu, 2012;Zhai and Santosh, 2011;Zhai, 2014 and references cited therein). It is widely agreed that the basement of the NCC formed through amalgamation of two or more micro-continental blocks.…”

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.…”