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Evolution of Northwestern South America: An interpretation Under the Concepts of Plate Tectonics, Stratigraphic Terranes, Compression, Transpression – New Exploration Frontiers

Ardila, Luis E.1 and Diaz, Lenardo
1[email protected]

Geologic models proposed in the past for the Colombian Caribbean region have been greatly influenced by existing paradigms. Most commonly proposed models are associated with subduction of the Caribbean Plate under the South American Plate. This model has been maintained by some authors up to the point that the characteristics of a subduction zone have often been ignored. The northwestern corner of South America lacks all characteristics typical of a subduction zone, such as the presence of a fore-arc, a back-arc, a volcanic arc and the occurrence of a focus of earthquakes. Therefore, a geologic model based on subduction is difficult to justify. Moreover, previous subduction models infer a Caribbean Plate moving southeastwards, which existing evidences do not support.

This paper presents a different concept about the origin of the Colombian Caribbean region. Instead, it proposes that it is the result of a series of micro and macro terranes obliquely accreted to the South America Plate, along a margin dominated by transpressive conditions. Terranes are frequently bound by dextral wrench faults.

Therefore, we are before a continental margin resulting from transforming conditions rather than convergence, with much higher expectations for the presence of structural and stratigraphic traps. Under these conditions, formation of pull-apart basins and deposition are concomitant. There, structural traps of different styles, including basement blocks and positive flower structures resulting from the transpressive conditions affecting the continental margin do occur. Prospectivity under this environment is significantly higher than in areas under subduction.

 

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