Following the steps of CHIPA: Chilenia and Patagonia formed the same drift terrain that collided with the southwest Gondwana margin during the middle Paleozoic

TOMEZZOLI RENATA NELA; CRISTALLINI ERNESTO OSVALDO; TICKYJ, HUGO; ARZADÚN, GUADALUPE; CALVAGNO, J.M.; CHOQUE, GISELLE; FEBBO, M.B.; SAGUAS, ELIANA

Frontiers in Earth Sciences

Lausanne: Frontiers Media S.A.

Año: 2023 vol. 11 p. 1 - 22

2296-6463

Geological evidence indicates that the deformation along the southwestGondwana margin began during the Middle-to-Late Devonian (the AcadianCháñica orogenic phase in Argentina). It has been interpreted that thisdeformation occurred as a consequence of the collision of Chilenia from thewest and Patagonia from the south-southwest with Gondwana. As both Chileniaand Patagonia collided at the same time, in this study, we proposed that thesecontinental blocks conform to the same allochthonous drift terrain, named here asCHIPA. The geological evolution of this margin is still under debate. Field work,paleomagnetic studies, and anisotropy of magnetic susceptibility (AMS) studieswere integrated from different localities along this paleomargin in Argentina. InPermian rocks, all the geological indicators show a clear regional NW-SEelongation signature and NE-SW shortening direction. The middle Devonian toPermian patterns are more complex as the result of stress interference and theoverlapping of orogenic activities with different intensities and ages. Thedeformation that started as the product of the CHIPA collision with Gondwanaduring the Middle Devonian continued through the Permian (the Hercinian-SanRafael orogenic phase in Argentina) as post-collisional compressive deformation,consequence of the paleogeographic re-organization of Gondwana andLaurentia, which moved toward the Equator from the south and the north,respectively, to form the Pangea supercontinent during the Triassic.