Deep carbon cycles constrained by a large-scale mantle Mg isotope anomaly in eastern China
MetadataShow full item record
Although deep carbon recycling plays an important role in the atmospheric CO2 budget and climate changes through geological time, the precise mechanisms remain poorly understood. Since recycled sedimentary carbonate through plate subduction is the main light-d26Mg reservoir within deep-Earth,Mg isotope variation in mantle-derived melts provides a novel perspective when investigating deep carbon cycling. Here, we show that the Late Cretaceous and Cenozoic continental basalts from 13 regions covering the whole of eastern China have low d26Mg isotopic compositions, while the Early Cretaceous basalts from the same area and the island arc basalts from circum-Pacific subduction zones have mantle-like or heavy Mg isotopic characteristics. Thus, a large-scalemantle low d26Mg anomaly in eastern China has been delineated, suggesting the contribution of sedimentary carbonates recycled into the upper mantle, but limited into the lower mantle. This large-scale spatial and temporal variation of Mg isotopes in the mantle places severe constraints on deep carbon recycling via oceanic subduction.
Showing items related by title, author, creator and subject.
Origin of carbonatites in the South Qinling orogen: Implications for crustal recycling and timing of collision between the South and North China BlocksXu, C.; Chakhmouradian, A.; Taylor, R.; Kynicky, J.; Li, W.; Song, W.; Fletcher, Ian (2014)Most studies of compositional heterogeneities in the mantle, related to recycling of crustal sediments or delaminated subcontinental lithosphere, come from oceanic setting basalts. In this work, we present direct ...
Identification of an ancient mantle reservoir and young recycled materials in the source region of a young mantle plume: Implications for potential linkages between plume and plate tectonicsWang, Xuan-Ce; Li, Zheng-Xiang; Li, X.; Xu, Y.; Li, X.; Li, J. (2013)Whether or not mantle plumes and plate subduction are genetically linked is a fundamental geoscience question that impinges on our understanding of how the Earth works. Late Cenozoic basalts in Southeast Asia are globally ...
Variable involvements of mantle plumes in the genesis of mid-Neoproterozoic basaltic rocks in South China: A reviewWang, Xuan-ce; Li, X.; Li, W.; Li, Zheng-Xiang (2009)Ca. 825-720 Ma global continental intraplate magmatism is generally linked to mantle plumes or a mantle superplume that caused rifting and fragmentation of the supercontinent Rodinia. Widespread Neoproterozoic igneous ...