Figure 1. Tectonic framework of Colombia showing the main physiographic elements. 1: Guajira Basin; 2: Sierra Nevada de Sta. Marta; 3: Cesar-Ranchería Basin; 4: Sierra de Perijá; 5: Maracaibo Basin; 6: Mérida Andes; 7: Lower Magdalena Valley Basin; 8: Middle Magdalena Valley Basin; 9: Eastern Cordillera; 10: Central Cordillera; 11: Western Cordillera; 12: Upper Magdalena Valley; 13: Cauca Valley. SCDB: Southern Caribbean deformed belt; OPF: Oca-El Pilar Fault System; SMBF: Sta. Marta-Bucaramanga Fault System. Location of Figure 2 is shown.