Comparative studies on two phases of Archaean TTG magmas from different blocks of the North China Craton: petrogenesis and constraints on crustal evolution

2020 ◽  
pp. 1-16
Author(s):  
Houxiang Shan ◽  
Mingguo Zhai ◽  
RN Mitchell ◽  
Fu Liu ◽  
Jinghui Guo
Keyword(s):  
North China Craton ◽  
Lower Crust ◽  
North China ◽  
Tectonic Setting ◽  
Source Material ◽  
Crustal Growth ◽  
Garnet Amphibolite ◽  
The North ◽  
Western Block ◽  
Subducting Slab

Abstract Whole-rock major and trace elements and Hf isotopes of magmatic zircons of tonalite–trondhjemite–granodiorite (TTG) rocks with different ages (2.9, 2.7 and 2.5 Ga) from the three blocks (the Eastern Block, Western Block and Trans-North China Orogen) of the North China Craton were compiled to investigate their respective petrogenesis, tectonic setting and implications for crustal growth and evolution. Geochemical features of the 2.5 Ga TTGs of the Eastern Block require melting of predominant rutile-bearing eclogite and subordinate garnet-amphibolite at higher pressure, while the source material of the 2.7 Ga TTGs is garnet-amphibolite or granulite at lower pressure. The 2.5 Ga TTGs have high Mg#, Cr and Ni, negative Nb–Ta anomalies and a juvenile basaltic crustal source, indicating derivation from the melting of a subducting slab. In contrast, features of the 2.7 Ga TTGs suggest generation from melting of thickened lower crust. The 2.5 and 2.7 Ga TTGs in the Trans-North China Orogen were formed at garnet-amphibolite to eclogite facies, and the source material of the 2.5 Ga TTGs in the Western Block is most likely garnet-amphibolite or eclogite. The 2.5 Ga TTGs in the Trans-North China Orogen and Western Block were generated by the melting of a subducting slab, whereas the 2.7 Ga TTGs in the Trans-North China Orogen derived from melting of thickened lower crust. The Hf isotopic data suggest both the 2.5 and 2.7 Ga TTG magmas were involved with contemporary crustal growth and reworking. The two-stage model age (TDM2) histograms show major crustal growth between 2.9 and 2.7 Ga for the whole North China Craton.

scholarly journals Fluid Inclusions and C-H-O-S-Pb Isotope Systematics of the Changfagou Deposit, Jilin Province, Northeast China

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-21 ◽  
Author(s):  
Bo Peng ◽  
Bile Li ◽  
Jun Chen
Keyword(s):  
Partial Melting ◽  
North China Craton ◽  
Lower Crust ◽  
North China ◽  
Tectonic Setting ◽  
Ore Deposits ◽  
Jilin Province ◽  
Magmatic Fluid ◽  
Northern Margin ◽  
The North

The Changfagou Cu deposit in Jilin province, China, is located in the eastern segment of the northern margin of the North China Craton and lies at the southern end of the Lesser Xing’an Mountains-Zhanggangcailing Mountains. According to the mineral paragenetic association and its various relationships, the hydrothermal mineralization can be divided into 4 metallogenic stages from early to late: stage I is K-feldspar-quartz-magnetite, stage II is quartz-molybdenite, stage III is quartz-chalcopyrite (polymetallic sulfide), and stage IV is carbonate. Stages II and III are the main metallogenic stages. Overall, the metallogenic fluid associated with the Changfagou deposit is characterized as a F-rich CO2-H2O-NaCl hydrothermal system. The hydrogen and oxygen isotopic characteristics suggest the initial ore-forming fluids of the Changfagou deposit evolved from a primitive magmatic fluid and mixed with meteoric water. The sulfur and lead isotopic characteristics show that the metallogenic material was derived from partial melting of the lower crust. Phase separation or immiscibility is the important mechanism in the precipitation of molybdenum, whereas a decrease in temperature is the important mechanism in the precipitation of copper polymetallic sulfides. The above characteristics are similar to those of the porphyry deposits related to continental environments. Compared with the deposits in the Xilamulun metallogenic belt, both have similar metallogenic ages and tectonic positions. In conclusion, the Changfagou deposit formed in an intracontinental extensional environment due to lithospheric thinning. The mineralization was related to magmatism associated with partial melting of the lower crust. The intersection of the Dunhua-Mishan fracture and Kangbao-Chifeng fracture along the northern margin of the North China Craton is a promising location for porphyry ore deposits related to a continental tectonic setting.

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

2012 ◽  
Vol 22 (1) ◽  
pp. 73-85 ◽  
Author(s):  
Hong-Fu Zhang ◽  
Yue-Heng Yang ◽  
M. Santosh ◽  
Xin-Miao Zhao ◽  
Ji-Feng Ying ◽  
...  
Keyword(s):  
North China Craton ◽  
Lower Crust ◽  
North China ◽  
The North ◽  
Western Block

U–Pb and Hf-isotope analysis of zircons in mafic xenoliths from Fuxian kimberlites: evolution of the lower crust beneath the North China craton

2004 ◽  
Vol 148 (1) ◽  
pp. 79-103 ◽  
Author(s):  
Jianping Zheng ◽  
W. L. Griffin ◽  
Suzanne Y. O’Reilly ◽  
Fengxiang Lu ◽  
Chunmei Yu ◽  
...  
Keyword(s):  
North China Craton ◽  
Lower Crust ◽  
North China ◽  
Isotope Analysis ◽  
Hf Isotope ◽  
The North

scholarly journals Paleoproterozoic Multiple Tectonothermal Events in the Longshoushan Area, Western North China Craton and Their Geological Implication: Evidence from Geochemistry, Zircon U–Pb Geochronology and Hf Isotopes

Minerals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 361 ◽  
Author(s):  
Renyu Zeng ◽  
Jianqing Lai ◽  
Xiancheng Mao ◽  
Bin Li ◽  
Jiandong Zhang ◽  
...  
Keyword(s):  
North China Craton ◽  
Tectonic Evolution ◽  
North China ◽  
Regional Metamorphism ◽  
Hf Isotope ◽  
Crustal Growth ◽  
Quartz Syenite ◽  
Isotope Data ◽  
The North ◽  
Rock Types

The Alxa block is located in the southwestern margin of the North China Craton. The Paleoproterozoic tectonic evolution, crustal growth and tectonic affinity of the block remain unknown or controversial. The Longshoushan (LS) area is one of the few areas that outcrop Paleoproterozoic to crystalline basement rocks in the Alxa Block. In this study, we preset whole-rock geochemistry, zircon U–Pb geochronology and Lu–Hf isotope data from metagabbro, metadiorite, quartz syenite, granitic leucosome and pegmatoid leucosome in the LS area. These rocks all are enriched in LREE and LILE, and depleted in HREE and HFSE. Eight new LA-ICP-MS zircon U–Pb ages yielded three magmatic ages of 2044 Ma, 2029 Ma and 1940 Ma, and three metamorphic ages of 1891 Ma, 1848 Ma and 1812 Ma. Lu–Hf analyses reveal that the magmatic zircons and anatectic/metamorphic zircons from all the rock types are characterized by positive εHf(t) (−0.16 to 10.89) and variable εHf(t) (−11.21 to 6.24), respectively. Based on the previous studies and our new data, we conclude that the LS area experienced three magmatic events (2.5–2.45 Ga, ~2.1–2.0 Ga and ~1.95–1.91 Ga) and three regional metamorphism/anataxis events (~1.93–1.89 Ga, ~1.86–1.84 Ga and ~1.81 Ga) in Paleoproterozoic. The age–Hf isotope data establishes two main crustal growth events at ~2.9–2.5 Ga and ~2.2–2.0 Ga in the LS area. These data indicate that the LS area experienced intraplate extensional setting in the middle Paleoproterozoic, and continental subduction, collision and exhumation in the late Paleoproterozoic. Combining the geochronological framework and tectonic evolution, we suggest that the Alxa Block is part of the Khondalite Belt.

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