An integrated analysis of an orogen-sedimentary basin pair: Latest Cretaceous-Cenozoic evolution of the linked Eastern Cordillera orogen and the Llanos foreland basin of Colombia

Abstract

The integration of restored basin geometry and internal features of syntectonic units (e.g., stratal architecture, thickness, sandstone composition) with fl exural modeling of the lithosphere constrains the evolution of a basin and its fl exural history related to orogenic growth (spatial/temporal loading confi guration). Using this approach, we determined the Maastrichtian-Cenozoic polyphase growth of the Eastern Cordillera of Colombia, an inverted Mesozoic extensional basin. The record of this growth occurs in an Andean (post-middle Miocene) thrust belt (the Eastern Cordillera) and in adjacent foreland basins, such as the Llanos Basin to the east. This approach permitted the identification of fi ve tectono-stratigraphic sequences in the foreland basin and fi ve phases of shortening for the Eastern Cordillera. Thermochronological and geochronological data support the spatial and temporal evolution of the orogen-foreland basin pair. The geometry of tectonic loads, constrained by fl exural models, reveals shortening events of greater magnitude for the uppermost two sequences than for pre-middle Eocene sequences. Tectonic loads for the late Maastrichtian-middle Eocene phases of shortening were less than 3 km high and 100 km wide. For the late Eocene-middle Miocene phase, tectonic loads changed southward from 6 km to less than 4 km, and loads were wider to the north. The strong Andean inversion formed today's Eastern Cordillera structural confi guration and had equivalent tectonic loads of 10-11 km.Integrated analysis is necessary in polyphase orogenic belts to defi ne the spatial and temporal variation of tectonic load and foreland basin confi gurations and to serve studies that seek to quantify exhumation and threedimensional analyses of thrust belts. For the Bayona et al. 1172Geological Society of America Bulletin, September/October 2008 Eastern Cordillera, thermochronological sampling must span the width of the Eastern Cordillera rather than be concentrated in a single range.

Paleocene wind-dispersed fruits and seeds from Colombia and their implications for early Neotropical rainforests

“…Three taxa from the Cerrejón Formation were collected from the middle and upper levels of a ca 700-m-thick stratigraphic sequence composed of abundant and thick coals, sandstones, and siltstones (Bayona et al 2008). The Cerrejón strata have been dated as middle-late Paleocene (ca 58-60 Ma) based on pollen zonation, correlations with stable carbon isotopic data, and marine microfossils (Jaramillo et al 2007.…”

Huesser Horizon: A Lake and a Marine Incursion in Northwestern South America During the Early Miocene

“…More than 8000 m of sandstone and mudstone siliciclastic sediments, interspersed with thin layers of marginal marine sediments, were accumulated in the Barco, Cuervos, Mirador, Carbonera, Léon, and Guayabo formations (Cooper et al, 1995;Bayona et al, 2008). The fossil record of mollusks in these formations is very rare or exhibits poor preservation throughout the whole sequence.…”

Zonas Transversales en El Dominio Axial De La Cordillera Oriental - Bloque Yacente De La Falla De Soapaga (Sátiva Sur - Sátiva Norte, Boyacá)

“…En la Cordillera Oriental, las fallas inversas que involucran basamento, se caracterizan por una segmentación longitudinal de decenas de kilómetros y son interpretadas como fallas normales reactivadas (Montes et al, 2008;Bayona et al, 2008;Horton et al, 2010). La segmentación de estas estructuras conforma el modelo de crecimiento de la falla, combinando acumulación de desplazamiento en buzamiento con expansión de fallas longitudinales (Kammer y Sánchez, 2006).…”