Sublithospheric diamond ages and the supercontinent cycle.

Timmerman, Suzette; Stachel, Thomas; Koornneef, Janne M; Smit, Karen V; Harlou, Rikke; Nowell, Geoff M; Thomson, Andrew R; Kohn, Simon C; Davies, Joshua H F L; Davies, Gareth R; Krebs, Mandy Y; Zhang, Qiwei; Milne, Sarah E M; Harris, Jeffrey W; Kaminsky, Felix; Zedgenizov, Dmitry; Bulanova, Galina; Smith, Chris B; Cabral Neto, Izaac; Silveira, Francisco V; Burnham, Antony D; Nestola, Fabrizio; Shirey, Steven B; Walter, Michael J; Steele, Andrew; Pearson, D Graham

Abstract

Subduction related to the ancient supercontinent cycle is poorly constrained by mantle samples. Sublithospheric diamond crystallization records the release of melts from subducting oceanic lithosphere at 300-700 km depths and is especially suited to tracking the timing and effects of deep mantle processes on supercontinents. Here we show that four isotope systems (Rb-Sr, Sm-Nd, U-Pb and Re-Os) applied to Fe-sulfide and CaSiO inclusions within 13 sublithospheric diamonds from Juína (Brazil) and Kankan (Guinea) give broadly overlapping crystallization ages from around 450 to 650 million years ago. The intracratonic location of the diamond deposits on Gondwana and the ages, initial isotopic ratios, and trace element content of the inclusions indicate formation from a peri-Gondwanan subduction system. Preservation of these Neoproterozoic-Palaeozoic sublithospheric diamonds beneath Gondwana until its Cretaceous breakup, coupled with majorite geobarometry , suggests that they accreted to and were retained in the lithospheric keel for more than 300 Myr during supercontinent migration. We propose that this process of lithosphere growth-with diamonds attached to the supercontinent keel by the diapiric uprise of depleted buoyant material and pieces of slab crust-could have enhanced supercontinent stability. [Abstract copyright: © 2023. The Author(s).]

Citation

Timmerman, S., Stachel, T., Koornneef, J. M., Smit, K. V., Harlou, R., Nowell, G. M., …Pearson, D. G. (2023). Sublithospheric diamond ages and the supercontinent cycle. Nature, 623, 752-756. https://doi.org/10.1038/s41586-023-06662-9

• Journal Article Type: Article
• Acceptance Date: Sep 20, 2023
• Online Publication Date: Oct 18, 2023
• Publication Date: Nov 23, 2023
• Deposit Date: Dec 12, 2023
• Publicly Available Date: Dec 12, 2023
• Journal: Nature
• Print ISSN: 0028-0836
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 623
• Pages: 752-756
• DOI: https://doi.org/10.1038/s41586-023-06662-9
• Public URL: https://durham-repository.worktribe.com/output/1883718