Contribución paleoclimática en la resolución de un enigma paleomagnético: la compleja evolución y formación de Pangea

GALLO, L.C.; TOMEZZOLI R.N.; ALEJANDRA DALENZ FARJAT; ROBERTO M. HERNÁNDEZ

S.M. de Tucumán

Congreso; XX Congreso Geológico Argentino; 2017

Asociación Geológica Argentina

The Wegener?s classic Pangea, also known as A-type Pangea, is the conventional plate reconstruction before its breakup in the Early Jurassic prior to the opening of the North Atlantic. The earlier history of Pangea in the Late Paleozoic is less well constrained and solely relies on paleomagnetism as the only quantitative method for determining paleolatitude prior to the Cretaceous. Nevertheless, the paleoclimatic information preserved in climate sensitive facies independently provides the paleolatitudes interpreted from paleomagnetic data. These interpretations work particularly well during the Carboniferous and Permian, where Pangea experiences movements towards the Equator. The whole evidence reached in this contribution makes it necessary to slide Laurentia to the West in relation to Gondwana in a B-type Pangea during the Upper Carboniferous, later evolving, during the Early Permian, to reach the final A-type Pangea configuration of the Upper Permian. The transition from a Pangea B to Pangea A configuration involves a large-scale continental dextral megashear zone. However, there is much scepticism surrounding this proposal and therefore Pangea B remains as a strongly debated issue. Previous interpretations for the final assembly of Pangea call upon a single-stage collision between Gondwana and Laurussia in Carboniferous times. However, recent data suggest a more complex and longer history for the early stages in the assembly of the supercontinent developed in a setting of dextral convergence between Gondwana and Laurussia.