Reinitiation of modern-style plate tectonics in the Early Neoproterozoic: evidence from a ∼930 Ma blueschist-facies terrane in South China

Journal article

When and how plate tectonics operated throughout Earth's history remain a matter of debate. The absence of low-temperature/high-pressure metamorphic rocks during Earth's middle age (∼1.8–0.8 Ga) leads to some arguing for a temporary shutdown or change of modern-style plate tectonics throughout the Mesoproterozoic and Early Neoproterozoic. Here we report the first discovery of ∼930 Ma blueschist-facies metamorphic rocks (Tianli Schist) from the Jiangnan Orogen, South China. Peak pressure–temperature conditions of ∼425–475 ℃ and ∼0.8–1.1 GPa recorded by these units represent an average geothermal gradient of ∼14 ℃/km, characteristic of cold subduction zones. Available geologic and geochronologic constraints indicate that the Tianli Schist protolith was deposited in the southeast margin of the Yangtze Block and subsequently experienced blueschist-facies metamorphism during ocean closure at ∼930 Ma. Combined with the global metamorphic record, our results suggest that modern-style plate tectonics did not operate continuously since initiation in the Early Paleoproterozoic, but was inhibited in the Mesoproterozoic and restarted again at the end of Earth's middle age.

Authors: Wu, L-G; Chen, Y; Palin, RM; Li, Q-L; Zhao, L

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Precambrian Research
• Volume: 401
• Article number: 107276
• Publication date: 2023-12-28
• Acceptance date: 2023-12-20
• DOI: 10.1016/j.precamres.2023.107276
• EISSN: 1872-7433
• ISSN: 0301-9268
• Language: English
• Keywords: cold subduction; plate tectonics; Neoproterozoic; blueschist; Tianli Schist