Precambrian Research
Guozheng Sun a,b,*, Shuwen Liu c,*, Sanzhong Li a,b,*, Timothy M. Kusky d, Fangyang Hu e,
Han Bao c, Lei Gao f, Yalu Hu g, Shengyao Yu a,b, Liming Dai a,b, Lintao Wang a,b, Xi Wang a,b
a Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Lab of Submarine Geosciences and Prospecting Techniques, MOE and College of Marine
Geosciences, Ocean University of China, Qingdao 266100, China
b Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
c Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, Peking University, Beijing 100871, China
d State Key Lab for Geological Processes and Mineral Resources, Center for Global Tectonics, School of Earth Sciences, China University of Geosciences, Wuhan 430074,
China
e Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
f School of Earth Sciences and Resources, China University of Geosciences Beijing, Beijing 100083, China
g Development Research Center, China Geological Survey, Beijing 100037, China
Identification and detailed studies of ancient orogens are one of the most important scientific problems for understanding the formation and evolution of early continental crust. However, it is tough to identify the original architecture of ancient orogenic belts due to the strong disturbances of late tectonothermal events, which makes it hard to reconstruct the formation mechanism and evolution process of early microplates. Here we used the spatial–temporal evolution of Neoarchean tectono-magmatism to trace orogenic processes of the Neoarchean continental crust of the North China Craton. Regional investigations in lithological assemblages, structural geology, chronology, geochemistry, and isotopic characteristics suggest that the Archean crystalline basement of the Eastern Liaoning Range in the northeastern North China Craton may be divided into three tectonic zones, each with its independent tectono-thermal evolution. We suggest therefore that these are independent terranes, namely microplates. Anshan-Benxi microplate in the southwest is a ~ 3.8 to ~ 2.9 Ga ancient continental nucleus with abundant Neoarchean (2.54–2.49 Ga) crust-derived K2O-rich granitoids. Waitoushan-Weiziyu-Jiubing microplate in the center is mainly composed of ~ 2.7 Ga tonalite-trondhjemite-granodiorite suite and 2.6–2.5 Ga diversified granitoids with some remnants of ancient oceanic lithosphere. Liaobei microplate in the northeast contains mainly late Neoarchean (2.57–2.52 Ga) magmatic rocks with minor Mesoarchean (~3.1 Ga) crustal materials. We summarize the formation mechanism, essential features, and identification marks of the Archean orogenic belt, and conclude that the Eastern Liaoning Range experienced the following four stages of Neoarchean geodynamic evolution. (1) In the early Neoarchean (2.71–2.68 Ga), intra-oceanic subduction generated the ~ 2.7 Ga island arc belt (proto-Waitoushan-Weiziyu-Jiubing microplate); (2) The 2.60–2.56 Ga warm subduction of oceanic slabs reformed proto-Liaobei microplate, and re-deformed the residual ~ 2.7 Ga island arc belt; (3) During 2.56–2.54 Ga, the Waitoushan-Weiziyu-Jiubing microplate and Liaobei microplate were amalgamated by an ‘arc-arc’ collision; (4) At the end of Archean (2.54–2.50 Ga), the Waitoushan-Weiziyu-Jiubing microplate + Liaobei microplate and proto-Anshan-Benxi microplate were finally aggregated through the ‘arc-proto-continental’collision, forming a unified crystalline basement of the Eastern Liaoning Range. Our work suggests that the short-term, small-scale subduction-collision orogenic cycles within pristine plate tectonic regimes played a crucial role in the Neoarchean crustal growth and evolution of the North China Craton.
