2.7-Ga-old mafic dike in the Trans-North China Orogen of the North China Craton and its tectonic significance

• 作者: OA Haiyan Liu Chong Peng .College of Geographical Sciences Shanxi Normal University .Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources Institute of Geology Chinese Academy of Geological Sciences .School of Geo Sciences University of Edinburgh
• 来源期刊: 地球化学学报(英文）
• 学科: 地球科学
• 年，卷（期）: 2025,（6）
• 页码范围: 164-169
• 页数: 6页
• 语种: 中文

摘要

We studied an Archean mafic dike in the TransNorth China Orogen of the North China Craton, which has a magmatic age of 2701 ± 83 Ma and is currently the oldest mafic dike in the North China Craton. Such an old dike is extremely rare in the world. The presence of mafic dikes indicates that the North China Craton was in a tensional tectonic environment at 2.7 Ga. Geochemical characteristics reveal that this mafic dike belongs to continental tholeiitic basalt. Results from Hf isotope analysis reveal that the mafic dike originates from a depleted mantle. The plate assembly in the North China landmass was realized during the Archean era(2.7 Ga), and a thick and stable continental crust was formed. Therefore, the first cratonization of the North China Craton was completed before 2.7 Ga. The intrusion of the 2.7-Ga-old mafic dike from the deep lithospheric mantle of the continent indicates that the North China Craton has undergone a period of extensional tectonic activity. This event marks a significant extensional event that occurred after the cratonization of the North China Craton.