The Panama Isthmus is located on the SW boundary of the Caribbean plate, at the junction of the South American, Nazca and Cocos plates. The isthmus is composed of two island arcs forming Central America. It formed by a complex history of plate subductions. The major tectonic event in this region is attributed to the accretion of Central America with South America between 12 and 25 Ma. The aim of this thesis is to document the deformation before, during and after the accretionary continental process. The main purpose is to better understand how a volcanic arc collides against a continental margin in order to reconstruct the tectonic history of this region since 70 Ma until today. This thesis combines: - a sedimentological and paleontological studies, - a structural study from spatial, geophysical and field work data, - a thermochronological study (AFT), - and an interpretative seismic study. I propose the initiation of progressive and oblique arc-continent collision during 40-37 Ma. The Caribbean plate, trapped between the arc and the continent, progressively disappeared beneath the South American continent. Around 15 Ma, the Colombian part of Central America was accreted and the convergence of Panama toward the continent progressed and produced a new subduction zone whereby the Caribbean plate subducted beneath the Panama Isthmus. Compressive deformations, caused by the collision, still actively control the migration of sedimentary masses, allowing the progressive emergence of the isthmus and forming the inter-American land bridge.
Nature and structure of the inter-american isthmus, Panama : implication for the reconstruction and the geodynamic evolution of the Caribbean plate