Palaeozoic - Early Mesozoic geological history of the Antarctic Peninsula and correlations with Patagonia: Kinematic reconstructions of the proto-Pacific margin of Gondwana

The Antarctic Peninsula preserves geological evidence of a long-lived continental margin with intrusive, volcaniclastic and accretionary complexes indicating a convergent margin setting from at least the Cambrian to the Cenozoic. We examine the poorly understood units and successions from the Palaeozoic to the Early Mesozoic and develop detailed kinematic reconstructions for this section of the margin. We use existing geochronology, along with newly presented U-Pb detrital zircon geochronology, combined with detailed field evidence to develop correlations between geological units and tectonic events across Patagonia and the proto-Antarctic Peninsula. The continental margin of Gondwana/Pangea was a convergent margin setting punctuated by crustal block translation, deformation, magmatic pulses (flare-ups) and development of thick accretionary complexes. These events are strongly linked to subducting slab dynamics and a para-autochthonous model is proposed for the long-lived margin. Major magmatic pulses are evident during the Ordovician (Famatinian) and Permian, and the magmatic record is reflected in the detrital zircon age profiles of metasedimentary successions of the northern Antarctic Peninsula and Tierra del Fuego. Major tectonic events during the Carboniferous - Permian (Gondwanide Orogeny) and Triassic (Chonide Event - Peninsula Orogeny) are recognised across the Antarctic Peninsula - Patagonia and are correlated to potential terrane suturing and flat slab dynamics. Our kinematic reconstructions developed in GPlates, combined with geological field relationships have allowed us to model the locus of magmatism relative to the active margin and also the likely source for thick sedimentary successions.

Automated summary

The Antarctic Peninsula has preserved evidence of a long-lived continental margin with various geological units, suggesting a convergent margin setting from the Cambrian to the Cenozoic. Through the use of geochronology and field evidence, along with detailed kinematic reconstructions, the relationships between geological units and tectonic events in Patagonia and the proto-Antarctic Peninsula have been established. The Gondwana/Pangea continental margin experienced crustal block translation, deformation, magmatic pulses, and development of thick accretionary complexes, which were influenced by subducting slab dynamics.