Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: AGU Advances
Cratons are widespread features within the continental lithosphere that are often viewed as highly stable due to their great age. An assumed outcome of this stability is that both the cover rocks cratons support and the cratons themselves represent important records of Earth’s evolution in deep time. However, what causes stability and how real it actually is remain important questions about continental evolution, preservation of the rock record attributable to vertical motions, and ultimate craton breakup.
By combining seismic, petrologic, and other data from North America, Liu et al. [2023] produced a model that can explain a globally common seismic discontinuity seen within cratonic mantle lithosphere. They attribute this to a fluid alteration front and partial melting, likely related to deeper mantle metasomatism that in turn could be related to dynamics such as volatile release from subducted slabs. Such a model seems a good candidate to explain the mid-lithosphere discontinuities seen globally.
The authors go on to note that next steps in validating this model include improved coverage of seismic stations in cratonic regions, and integration of both different types of seismic measurements as well as joint inversions with magntotelluric data.
Citation: Liu, T., Chin, E. J., & Shearer, P. (2023). Strong physical contrasts across two mid-lithosphere discontinuities beneath the northwestern United States: Evidence for cratonic mantle metasomatism. AGU Advances, 4, e2023AV001014. https://doi.org/10.1029/2023AV001014
—Peter Zeitler, Editor, AGU Advances