Journal
PRECAMBRIAN RESEARCH
Volume 357, Issue -, Pages -Publisher
ELSEVIER
DOI: 10.1016/j.precamres.2021.106155
Keywords
Cuoke complex; Zircon U-Pb-Hf isotopes; Archean to Paleoproterozoic; Crustal growth and reworking; Yangtze Block
Categories
Funding
- National Natural Science Foundation of China [41872120, 41772115, 41672112]
- China Geological Survey [DD20190054, DD20190370, DD20190375]
- Research Start-up Project for Introduced Talent of Yunnan University [20190043]
- Science & Technology Department of Sichuan Province [2019YJ0270]
Ask authors/readers for more resources
The newly identified Cuoke Complex in South China contains voluminous early Precambrian granitoids, providing key information for the early evolution of the Yangtze Block. The complex consists of granitoids with different crystallization ages and magmatic activities, likely derived from reworking of ancient crustal materials or remelting of juvenile continental crust.
The newly identified Cuoke Complex preserves voluminous early Precambrian granitoids, bearing key information for the early evolution of the Yangtze Block, South China. Here, we report new field observations, petrology, zircon U-Pb-Hf isotopes and trace elements for eight granitoids from this complex. The analyzed zircon domains are of magmatic origin, as evidenced by their oscillatory zoning, high Th/U ratios and magmatic rare earth element patterns. Three trondhjemitic gneisses yield crystallization ages of 3.11-3.06 Ga, documenting the oldest known rocks in the southern Yangtze Block. Their epsilon(Hf)(t) values vary from -3.2 to + 2.6 with depleted mantle two-stage (T-DM2) model ages of 3.6-3.3 Ga, indicating reworking of Paleoarchean crustal materials. Three gneissic granitoids crystallized at 2.86-2.85 Ga and reveal a significant episode of granitoid magmatism in the late Mesoarchean. They possess positive epsilon(Hf)(t) values (+0.2 to +5.0) and slightly older T-DM2 model ages (3.3-3.0 Ga), suggesting that these granitoids were most likely derived from remelting of juvenile continental crust. Two monzogranites with crystallization ages of 1.94 and 1.89 Ga display negative e epsilon(Hf)(t) values (-13.0 to -8.1) and older T-DM2 model ages (3.3-3.1 Ga), indicating substantial involvement of ancient crustal materials. Available zircon U-Pb-Hf isotopic data from the Cuoke Complex have revealed that the earliest crustal growth probably occurred in the early Paleoarchean, with significant crustal growth and reworking during the early Mesoarchean, followed by multistage crustal reworking during the late Mesoarchean to Paleoproterozoic. Integrating the results of this study with records from other Archean basement complexes in the Yangtze Block (i.e., Kongling, Zhongxiang, Douling, Yudongzi and Phan Si Pan), we propose that these complexes have diverse formation histories and generally experienced tectonothermal events at ca. 2.0-1.9 Ga, probably responding to the global-scale assembly of the Nuna supercontinent.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available