Detrital Record of the Middle to Late Paleozoic Transition from Subduction to Collision in the Northern Andes: Implications in the Paleogeographic Reconstructions of Pangea

Abstract:

Discriminating between these type of orogens and understanding the transition between subduction and collision in the Northern Andes remains elusive and controversial due to the apparent yuxtaposition of Central and South American terranes within Pangea reconstruction.

New U-Pb detrital zircon geochronology from Late Paleozoic sedimentary and meta-sedimentary rocks from the Eastern Cordillera of the Colombian Andes (Santander and Flortesta Massif) were obtained and used to discriminate changes in the relative intensity of magmatic activity and refine the timing of sedimentary accumulation and metamorphism and their relation with tectonic models. The U-Pb LA-ICP-MS results suggest that Early Devonian magmatism is significantly more limited than the former Ordovician to Silurian record and that sedimentation and metamorphism in the Eastern Cordillera of the Colombian Andes is of Late Paleozoic age.

We related the major changes in the magmatic input to the Late Paleozoic sedimentary basin as a tracer of the major changes in convergence between Laurentia and Gondwana, that formed an extremely oblique convergent margin between the Devonian and the Carboniferous until the Late Carboniferous metamorphism that end with Pangea agglutination.