+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Evolution of the Archean and Paleoproterozoic lower crust beneath the Trans-North China Orogen and the Western Block of the North China Craton

Gondwana Research 22(1): 73-85

Evolution of the Archean and Paleoproterozoic lower crust beneath the Trans-North China Orogen and the Western Block of the North China Craton

We report U-Pb ages and Hf isotopes of zircons in granulites from two continental suture zones in the North China Craton (NCC) from granulite xenoliths entrained in the Cenozoic Hannuoba basalts within the Trans-North China Orogen (TNCO) that amalgamates the Western and Eastern Blocks, and from a mafic granulite associated with ultrahigh-temperature (UHT) granulites within the Inner Mongolia Suture Zone (IMSZ) that welds the Yinshan and Ordos Blocks. The zircons in these rocks, together with the inherited zircons from Mesozoic subalkalic intrusives of these regions, show several distinct U-Pb age populations and provide constraints on the evolution of the lower crust beneath the NCC. Parts of the older zircons from the TNCO yield discordant data that project to ages of about 2.5 to 2.7 Ga. These old zircons show Hf TDMmodel ages of 2.6-2.9 Ga suggesting the existence of Archean lower crust beneath the TNCO, which is coupled with the Neoarchean metamorphic basement and greenstone belt. A major zircon population grew at 1.75 ~ 2. Ga, consistent with the timing of the Paleoproterozoic collision between the various crustal blocks within the NCC, suggesting that this event had a significant effect on the Archean lower crust. The older inherited zircons from the Western Block also yield discordant data that project to younger ages of about 1.8 to 1.9 Ga. This age is consistent with the timing of intrusion of the mafic magmatic protoliths of the granulites associated with the UHT rocks in the khondalite belt within the IMSZ. These older zircons yield Hf TDMmodel ages of 2.-2.5 Ga suggesting that the lower crust beneath the Western Block in the NCC to be dominantly Paleoproterozoic, and decoupled with the Archean metamorphic basement of the region. Yet another population of zircons from the Hannuoba banded granulite xenoliths, garnet-bearing pyroxenite cumulate and dark pyroxenite xenoliths yield a large spread of Phanerozoic concordant ages ranging from 47 Ma to 4 Ma with peaks at 315 Ma, 22 23 Ma, 12 Ma and 46 Ma. The Late Paleozoic zircons predominantly occur in the garnet-bearing pyroxenite xenoliths and yield variable ?Hf(t) values of ? 24 to + 18. Triassic ~ Cretaceous zircons mainly occur in the banded granulite xenoliths and yield highly variable ?Hf(t) values, ranging from ? 48 to + 16. The Tertiary zircons occur only in the dark pyroxenite xenoliths and show a restricted ?Hf(t) with a dominant range from to + 18. These data suggest episodic magmatic underplating in the ancient lower crust of the NCC, lasting continuously throughout Phanerozoic, producing zircons from the underplated magmas or providing the heat source for the recrystallization of zircons from the ancient crust. Our data clearly demonstrate the important events of Phanerozoic magmatic underplating beneath the Neoarchean - Paleoproterozoic crust of the NCC.Different generations of zircons found in granulite and pyroxenite xenoliths. Lower crust beneath the TNCO formed in the Archean. Paleoproterozoic tectonic event had a significant imprint in the crustal evolution. Episodic underplating modified isotopic composition of the ancient lower crust.

Accession: 036203783

DOI: 10.1016/

Related references

Liu, J.; Rudnick, R.L.; Walker, R.J.; Gao, S.; Wu, F.Y.; Xu, W.L.; Xu, Y.G., 2010: Os isotope evidence for diachronous formation of lithospheric mantle beneath the Trans-North China Orogen, North China Craton. Geochimica et Cosmochimica Acta 74.12, Suppl. 1: A613

H.Y.nhong; Zhao Guochun; Sun Min, 2007: Paleoproterozoic post-orogenic evolution of the North China Craton; geochemical and isotopic constraints from the Xiyanghe Group along the southern margin of the North China Craton. Geochimica et Cosmochimica Acta 71(15S): A388

Zhao Guochun; Sun Min; Wilde Simon A.; L.S.nzhong, 2005: Late Archean to Paleoproterozoic evolution of the North China Craton; key issues revisited. A recently proposed model for the evolution of the North China Craton envisages discrete Eastern and Western Blocks that developed independently during the Archean and collided along the Trans-North China Orogen during a Paleoproterozoic orogenic...

Jianping Zheng; W.L.G.iffin; Suzanne Y.O.Reilly; Fengxiang Lu; Chunmei Yu; Ming Zhang; Huimin Li, 2004: U-Pb and Hf-isotope analysis of zircons in mafic xenoliths from Fuxian kimberlites; evolution of the lower crust beneath the North China Craton. Mafic xenoliths from the Paleozoic Fuxian kimberlites in the North China craton include garnet granulite, and minor pyroxene amphibolite, metagabbro, anorthosite and pyroxenite. The formation conditions of the amphibolites are estimated at 745–8...

Kusky, T.M.; Windley, B.F.; Zhai, M.-G., 2007: Tectonic evolution of the North China Block; from orogen to craton to orogen. Geological Society, London, Special Publications 280(1): 1-34

Yin Changqing; Zhao Guochun; Sun Min; Leung Winghang; Zhang Jian, 2007: Metamorphic evolution and tectonic implications of the Qianlishan-Zhuozishan Complex, westernmost part of the Paleoproterozoic khondalite belt in the western block of the North China Craton. Geochimica et Cosmochimica Acta 71(15S): A1146

Zhao Guochun, 1999: High-pressure metamorphism of mafic granulites from the Trans-North China Orogen; implications for Palaeoproterozoic amalgamation of the North China Craton. Abstracts - Geological Society of Australia 56: 56-59

Han.B.O-Fu.X., Zhao.R.N.R.Ng.L., Lin-Lin.Y.Ng.J.N-Hui.Y.Ng.Y.E-Heng, 2012: 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. 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...

Trap P.; Faure M.; Lin W.; Monie P., 2007: Late Paleoproterozoic (1900-1800 Ma) nappe stacking and polyphase deformation in the Hengshan-Wutaishan area; implications for the understanding of the Trans-North China Belt, North China Craton. The Hengshan-Wutaishan area forms part of the Trans-North-China Belt developed in response to the final amalgamation of the North China Craton. The Hengshan-Wutaishan Domain and the adjacent Fuping Massif constitute the largest and the most repres...

Pierre Trap; Michel Faure; Wei Lin; Nicole L.B.eton; Patrick Monié, 2012: Paleoproterozoic tectonic evolution of the Trans-North China Orogen toward a comprehensive model. In this contribution we present a reconstruction of the overall lithotectonic architecture, from inner zones to external ones, of the Paleoproterozoic Trans North China Orogen, within the North China Craton. Moreover, forward thermobarometrical mo...