Paleotethys slab pull, self-lubricated weak lithospheric zones, poloidal and toroidal plate motions and Gondwana tectonics

VIZÁN, H.; PREZZI, C.; GEUNA, S. E.; JAPAS, M. S.; RENDA, E.; FRANZESE, J.; VAN ZELE, A.

GEOSPHERE

GEOLOGICAL SOC AMER, INC

Lugar: Boulder; Año: 2017 vol. 13 p. 1 - 14

1553-040X

The Gondwana megacontinent was composed of different domains separated by self-lubricated weak lithospheric zones of which two could have extended into Laurasia. Displacement vectors determined through three consecutive paleomagnetic-constrained paleogeographic reconstructions (Early Pennsylvanian - Early Guadalupian ca. 320/270 Ma; Late Guadalupian - Middle Triassic ca. 260/240 Ma; and Late Triassic - early Late Jurassic ca.230/160 Ma) show similar orientations to coeval tectonic stresses along Gondwana. Triggered by slab pull at the northern subduction margin of the Paleotethys Ocean, differential displacements between the Gondwana domains caused localized deformation along their borders, reactivating old weak lithospheric zones (e.g. Ventana Fold Belt, basins as Cuvette in central Africa and as Neuquén in the Pacific margin of Gondwana). We propose that the wide extent of these structures was possible due to the transmission of mantle toroidal flow induced by strike-slip movements along these focused self-lubricated weak lithospheric zones, along with a drift of Pangea to the north. These processes occurred simultaneously with a major mantle re-organization from a huge cold downwelling to a hot upwelling event that was determined by thermal energy storage below Pangea.