Print this pageAn Integrated Tectonic Model for the Western Gondwana Late Paleozoic Deformation
The integration of subsurface seismic data, well information of Neuquén basin basement together with outcrop data, allowed first identifying of the orogenic segmentation of the late Paleozoic Gondwánide fold and thrust belt (FTB). A 300 km width antithetic FTB has developed along the convergent margin between the Phanthalasa oceanic plate and the Gondwana supercontinent. Its wedge-top and inner FTB sectors developed in the northern part of the basin and extended further north along to 2000 km westwards of the Paganzo and Arizaro foreland basins. A 60° clockwise rotation of the axis of the FTB, which widens to 800 km, took place along the southern margin of the basin, where a metamorphic and plutonic axial zone was developed as a result of the collision of the Patagonia and Gondwana plates in early Permian times. The prowedge segment comprised both synthetic and antithetic FTB that extended along the basement of the Neuquén embayment and Colorado basin and the Carapacha - Ventania- Cape Town belt, south of the Claromecó-Karoo foreland basin. The retrowedge antithetic FTB was developed south of the North Patagonian massif axial zone in the basement of the Austral and north Malvinas-Falkland basins and Malvinas plateau. Seismic data illuminated preserved early Permian anticlines and thrusts as well as collapsed thrust sheets that were extensionally inverted. The different segments of this FTB strongly controlled the early Mesozoic rift stages of the Neuquén and Malvinas basins, and the development of a Mesozoic intraplate deformation belt along the Patagonian suture in the southern margin of the Neuquén basin. At a large scale, the associated gondwanide intraplate deformation extended 4000 km from the orogenic front, as demonstrated by the growth of the Kiri anticline in Zaire, the uplift of different basement structures along the western and southern borders of the Chaco-paranaense basin, and the development of Las Breñas intraplate deformation belt. The late Paleozoic intraplate deformation shows similar scales to the ones documented in the Tien Shan and the Ancestral Rockies, while these paleographic reconstructions give a regional scale to the gondwánide deformation consistent with magnitude of the collision of the Patagonia microplate and associated blocks during the early Permian.
AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil