Open Access

Paleomagnetism in Mesozoic rocks of the Northern Andes and its Implications in Mesozoic Tectonics of Northwestern South America

Earth, Planets and Space200658:BF03352621

Received: 13 December 2005

Accepted: 28 April 2006

Published: 8 November 2006


New paleomagnetic data isolated in Upper Triassic to Aptian rocks exposed in the Colombian Andes and west of the Guyana craton, in conjunction with paleomagnetic data from the Andes of Venezuela and the South American craton, permit the interpretation of along-margin northward translations of Andean Colombian terranes during the Early-Middle Jurassic. Field tests and comparison with reference paleopoles for South America indicate that characteristic components uncovered in red-siliciclastic and igneous rocks are primary, or near-depositional, and they are carried dominantly by hematite, magnetite and Ti-magnetite. Difference in declination values of characteristic components isolated in fault-bounded blocks document counter-clockwise rotations previous to syn-extensional deposition. The Jurassic tectonic scheme proposed here for the northwestern corner of South America shows an Early Jurassic, linear subduction-related magmatic arc evolving to Late Jurassic rift-related setting associated to the opening of the Proto-Caribbean Ocean and westward retreat of the subduction zone. A similar tectonic evolution for the Jurassic has been proposed for southwestern USA and the Nazas arc in Mexico.

Key words

PaleomagnetismJurassicNorthern AndesTectonics