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

Abstract

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.

Grenvillian remnants in the Northern Andes: Rodinian and Phanerozoic paleogeographic perspectives

“…Late Paleozoic tectonic reconstructions of Pangea show a major spatial overlap between northern South America and the Paleozoic and Proterozoic terranes that formed the core of central and southern Mexico and Middle America (Rowley and Pindell, 1989;Dickinson and Lawlor, 2001). This new paleogeographic scenario (Bayona et al, 2006, submitted for publication) for the Jurassic partly resolves this problem with some of the Colombian terranes (such as Santa Marta, Santander and the Central Cordillera) located in northern Peru -Ecuador with the Mexican terranes situated on the Colombian margin.…”

“…4A, Bayona et al, 2006, submitted for publication). Most of the displacement probably occurred before the Early Cretaceous (Bayona et al, 2006, submitted for publication), probably triggered by oblique Jurassic subduction and later Pangea break-up that opened the proto-Caribbean Ocean in northern South America (Aspden et al, 1987;Pindell, 1993). The geochronological signature of the Grenvillian crustal basement in northern Peru supports a correlation with these Colombian terranes.…”

U-Pb LA-ICP-MS GEOCHRONOLOGY AND GEOCHEMISTRY OF JURASSIC VOLCANIC AND PLUTONIC ROCKS FROM THE PUTUMAYO REGION (SOUTHERN COLOMBIA): TECTONIC SETTING AND REGIONAL CORRELATIONS

“…Early-Middle Jurassic (180-200 Ma) magmatic rocks also have been found in other segments of the Colombian Andes (FIGURE 1), including the Santander and Santa Marta massifs (Altenberger and Concha, 2005;Cardona et al, 2011), and are also common along most of the Andean Chain (Mpodozis and Ramos, 2008;Vásquez et al, 2011) Although some of the Jurassic remnants in the Colombian Andes may have been displaced from southern latitudes (Bayona et al, 2006), the existence of a major Jurassic continental scale magmatic province and its apparent link with extensional basins (Mpodozis and Ramos, 2008;Sarmiento et al, 2006;Vásquez et al, 2011) reflect the plate convergence following Pangea break-up, and the subduction of an old Pacific plate that controlled the growth of a continental magmatic arc and the contemporaneous regional scale magmatic activity (Busby, 2012;Cawood and Buchan, 2007;Cawood et al, 2009).…”

“…This structural complexity reflects several episodes of Mezo-Cenozoic oceanic terrane accretion, continental arc growth and strike translation of paraautochthonous continental terranes (Bayona et al, 2006;Bayona et al, 2010;Escalona and Mann, 2010;Montes et al, 2010;Pindell et al, 1998;Pindell et al, 2005;Spikings et al, 2014;Spikings et al, 2005;Toussaint and Restrepo, 1996;Villagómez et al, 2011;Villagómez and Spikings, 2013).…”

“…Different tectonic environments have been proposed to explain this major Jurassic province in the Northern Andes: (1) continental arc magmatism associated to back-arc basin formation (Aspden et al, 1987;Bustamante et al, 2010;Pindell and Tabbutt, 1995;Sarmiento et al, 2006;Spikings et al, 2014;Van der Lelij et al, 2015); (2) rift related setting associated with the Pangea breaking and the development of Proto-Caribbean sea between North and South America (Cediel et al, 2000;Cediel et al, 2003;Jaillard et al, 1990). A major difficulty for the understanding of this tectonic scenario is the existence of late Mesozoic and early Cenozoic terrain translation along the Jurassic continental margin, which modified the latitudinal position of the Jurassic magmatic domains (Bayona, et al, 2006).…”