Calabrian forearc uplift paced by slab–mantle interactions during subduction retreat

• Published in: Nature geoscience Vol. 16; no. 6; pp. 513 - 520
• Main Authors: Gallen, Sean F., Seymour, Nikki M., Glotzbach, Christoph, Stockli, Daniel F., O’Sullivan, Paul
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.06.2023; Nature Publishing Group
• Subjects: 704/2151/210; 704/2151/215; 704/2151/562; Catchment area; Catchments; Convection; Convection cells; Crustal thickness; Earth and Environmental Science; Earth science; Earth Sciences; Earth System Sciences; Fault lines; Geochemistry; Geology; Geomorphology; Geophysics/Geodesy; Mantle convection; Quaternary; Rock; Rocks; Slabs; Subduction; Subduction (geology); Tectonic geomorphology; Tectonics; Topography; Transition zone; Trends; Uplift; Upper mantle; Velocity
• ISSN: 1752-0894; 1752-0908
• DOI: 10.1038/s41561-023-01185-4

Evidence from landscape evolution may provide critical constraints for past geodynamic processes, but has been limited by the large uncertainties of topographic reconstructions. Here we present continuous 30-million-year rock uplift histories for three catchments in the Calabrian forearc of southern Italy, using a data-driven inversion of tectonic geomorphology measurements. We find that rock uplift rates were high (>1 mm yr −1 ) from about 30 to 25 million years ago (Ma) and progressively declined to <0.4 mm yr −1 by ~15 Ma, then remained low before abruptly increasing around 1.5–1.0 Ma. These uplift rates do not match the forearc’s subduction velocity record, implying that uplift was not dominated by crustal thickening due to subduction-driven sediment influx. Through comparisons with slab descent reconstructions, we instead argue that the forearc uplift history primarily reflects the progressive establishment and abrupt destruction of an upper-mantle convection cell with strong negative buoyancy. We suggest that the convection cell vigour increased as the slab-induced mantle flow field began to interact with the 660-km mantle transition zone, causing uplift rates to decline from 25 to 15 Ma. Then, once the slab encountered the transition zone, the fully established convection cell subdued uplift rates, before being disrupted by slab fragmentation in the Quaternary, driving rapid forearc uplift. Interactions between subducting slabs and the 660-km mantle transition zone can influence mantle convection and forearc uplift, according to rock uplift histories of the Calabrian forearc spanning the past 30 million years.