Wang Zhao-Xue, Liu Sheng-Ao, Li Shuguang, Liu Di, Liu Jingao
State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China.
Natl Sci Rev. 2022 Jan 8;9(6):nwac001. doi: 10.1093/nsr/nwac001. eCollection 2022 Jun.
Outgassing of carbon dioxide from the Earth's interior regulates the surface climate through deep time. Here we examine the role of cratonic destruction in mantle CO outgassing via collating and presenting new data for Paleozoic kimberlites, Mesozoic basaltic rocks and their mantle xenoliths from the eastern North China Craton (NCC), which underwent extensive destruction in the early Cretaceous. High Ca/Al and low Ti/Eu and Mg are widely observed in lamprophyres and mantle xenoliths, which demonstrates that the cratonic lithospheric mantle (CLM) was pervasively metasomatized by recycled carbonates. Raman analysis of bubble-bearing melt inclusions shows that redox melting of the C-rich CLM produced carbonated silicate melts with high CO content. The enormous quantities of CO in these magmas, together with substantial CO degassing from the carbonated melt-CLM reaction and crustal heating, indicate that destruction of the eastern NCC resulted in rapid and extensive mantle CO emission, which partly contributed to the early Cretaceous greenhouse climate episode.
地球内部二氧化碳的脱气作用在漫长的地质时期内调节着地表气候。在此，我们通过整理和展示来自华北克拉通东部（NCC）的古生代金伯利岩、中生代玄武岩及其地幔捕虏体的新数据，研究克拉通破坏在地幔二氧化碳脱气过程中的作用。华北克拉通东部在早白垩世经历了广泛的破坏。在煌斑岩和地幔捕虏体中广泛观察到高Ca/Al、低Ti/Eu和Mg，这表明克拉通岩石圈地幔（CLM）普遍受到再循环碳酸盐的交代作用。对含气泡熔体包裹体的拉曼分析表明，富含碳的CLM的氧化还原熔融产生了CO含量高的碳酸化硅酸盐熔体。这些岩浆中大量的CO，以及碳酸化熔体与CLM反应产生的大量CO脱气和地壳加热，表明华北克拉通东部的破坏导致了地幔CO的快速和广泛排放，这在一定程度上促成了早白垩世的温室气候事件。
