HAL: hal-00076871, version 1

DOI: 10.1016/S0895-9811(02)00063-9

IRD Horizon id: PAR00002996

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Journal of South American Earth Sciences 15 (2002) (4) 391-407

Andean deformation and rift inversion, eastern edge of Cordillera Oriental (Guateque-Medina area), Colombia.

Yannick Branquet 1, A. Cheilletz 2, P. R. Cobbold 3, P. Baby 4, B. Laumonier 5, G. Giuliani 2

(2002)

In the Guateque–Medina area, Paleozoic basement and Mesozoic rift basins have been uplifted and exhumed during the Andean orogeny (12 Ma to present). Surface exposures and subsurface data constrain the deformation style and the rift geometry. We have mapped a regional transect and restored a cross section. We have also reconciled existing stratigraphic data, from cordillera, foothills and foreland basin, and have added new data of our own. In Early Cretaceous shales, there is evidence for fault-controlled sedimentation. A brecciated evaporitic layer, which is locally emerald bearing, has acted as a regional detachment. The underlying basement, composed of Paleozoic sediments, crops out as the Quetame Massif. It was uplifted during the Andean orogeny on a series of high-angle reverse faults. The main SE-verging Tesalia fault has resulted from Andean reactivation of an Early Cretaceous normal fault, which bounded a half-rift. A series of NW-verging back-thrusts may have resulted from Andean reactivation of Paleozoic faults. Between the back-thrusts and the Tesalia fault is a basement pop-up. It may be part of a flower structure, because components of right-lateral slip have been identified. These are attributed to eastward subduction of the Nazca plate beneath South America. In general, the style and timing of Andean deformation in the Guateque–Medina area are compatible with the plate tectonic setting of the northern Andes.

1:	Institut des Sciences de la Terre d'Orléans (ISTO)
	CNRS : UMR6113 – INSU – Université d'Orléans
2:	Centre de recherches petrographiques et géochimiques (CRPG)
	CNRS : UPR2300 – INSU
3:	Géosciences Rennes (GR)
	CNRS : UMR6118 – INSU – Centre Armoricain de Recherches en Environnement – Université de Rennes 1
4:	Laboratoire des Mécanismes et Transfert en Géologie (LMTG)
	CNRS : UMR5563 – Observatoire Midi-Pyrénées – Université Paul Sabatier [UPS] - Toulouse III – Institut de recherche pour le développement [IRD] : UMR154
5:	École nationale supérieure des Mines de Nancy
	Université de Lorraine

subject

:

Sciences of the Universe/Earth Sciences/Tectonics

keyword(s): Andean deformation – Rift inversion – Colombia – Cordillera Oriental – Guateque–Medina are

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From: Nathalie Pothier <>

Submitted on: Thursday, 16 November 2006 13:25:02

Updated on: Thursday, 16 November 2006 14:11:29