Catastrophic slab loss in southwestern Pangea preserved in the mantle and igneous record

GIANNI, GUIDO; CÉSAR NAVARRETE

NATURE COMMUNICATIONS

Nature

Año: 2022 vol. 13

2041-1723

The Choiyoi Magmatic Province represents a major episode of silicic magmatism in southwesternPangea in the mid-Permian-Triassic, the origin of which remains intensely debated.Here, we integrate plate-kinematic reconstructions and the lower mantle slab record beneathsouthwestern Pangea that provide clues on late Paleozoic-Mesozoic subducting slab configurations.Also, we compile geochronological information and analyze geochemical datausing tectono-magmatic discrimination diagrams. We demonstrate that this magmatic eventresulted from a large-scale slab loss. This is supported by a paleogeographic coincidencebetween a reconstructed 2,800-3,000-km-wide slab gap and the Choiyoi Magmatic Provinceand geochemical data indicating a slab break-off fingerprint in the latter. The slab break-offevent is compatible with Permian paleogeographic modifications in southwestern Pangea.These findings render the Choiyoi Magmatic Province the oldest example of a geophysicallyconstrained slab loss event and open new avenues to assess the geodynamic setting of siliciclarge igneous provinces back to the late Paleozoic.