Accretion of Central America Volcanic Arc and Consequences on the Migration of Cenozoic Sediments from South America

Barat, Flore¹; Maurin, Thomas; Mercier de Lepinay, Bernard; Sosson, Marc; and Auxietre, Jean-Luc
¹[email protected]

The accretion age of Central America volcanic arc with the South America Plate and its processes are both still controversial. We focused this study in eastern Panama in order to reconstruct the tectonic evolution of this area since the Paleocene. The knowledge of tectonic processes allows us to better constrain the formation of petroleum basins and their sedimentary environments. Moreover, the age and the origin of sediments involved in the North Panama Deformed Belt (NPDB) remain an enigma. Our effective approach incorporates field work data, remote sensing analyses (ERS2 SAR images), detailed biostratigraphic data (nannoflora and foraminifera) and seismic line interpretations.

From our onshore and offshore results and other recent studies, we propose the following tectonic reconstruction: The collision between the Central America volcanic arc on the Caribbean plate and the South America Plate started in Middle Eocene. Since that time, until today, the relative eastward motion of the Caribbean Plate with respect to the South America Plate led the suture between the two plates to progress northwards (like a progressively closed zip). Therefore, the Uraba basin was formed and shortened during Oligo-Miocene. The initiation of the NPDB coincides with the last compressive episode. The immediate proximity of the South America Plate during the Middle Eocene provides a high input of sediments into the Atrato-Chucunaque-Tuira basin under development and probably a high contribution of organic matter due to the oil leak at the Garachiné- 2 well in the onshore Sambu basin and oil shows in the wells of Chucunaque-Tuira basin. The paleo Atrato River, deviated during the Middle Miocene as a consequence of the ongoing accretion, has fed the Uraba basin and a large part of NPDB. Then, the progressive accretion of this volcanic arc produced the migration of sedimentary deposits from the west to the east of this arc, with sediments coming from the erosion of South America.

AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013