Lithospheric Structure of Northwestern Venezuela: Implications for the Understanding of Continental Margins Evolution
F. Mazuera, A. Escalona and M. Schmitz
Event name: 80th EAGE Conference and Exhibition 2018
Session: Poster: Sedimentology - Case Studies
Publication date: 11 June 2018
Info: Extended abstract, PDF ( 1.71Mb )
Price: € 20
Western Venezuela is located in a complex deformation zone due to the Caribbean-South American plates interactions. Several models regarding the shallow and deep structure have been proposed, nevertheless, most of these studies are based on basin-scale observations. As a part of the GIAME project, new onland refraction profiles have been acquired across the Guyana Shield, the main orogenic belts, and the Caribbean allochtonous terranes, with a total length of ~2500 km of 2D seismic data. In this work, an analysis of a 560 km long profile is presented. The Northern Andes profile consists of 545 short-deployment seismometers, which recorded 13 land shots. The seismic data was used to generate a two-dimensional P-wave model showing velocities between 3.2-5.7 km/s for sedimentary covers; 6.1-6.5 km/s for upper crust, and 6.7 to 7.2, and 7.8 to 8.4 km/s for lower crust and upper mantle, respectively. The most prominent features imaged were a crustal thinning beneath the Falcón basin due to a previous history as a back-arc basin. In addition, lateral variability suggests collisional process related to suture zones between both Proterozoic and Paleozoic, and Paleozoic and Mesozoic-Cenozoic provinces. Finally, the Caribbean slab was observed in a low-angle subduction context beneath NW South America.