MIDDLE MIOCENE VOLCANISM IN THE SOUTH CARIBBEAN DEFORMED BELT (SINU BELT, NORTHERN COLOMBIA): PETROTECTONIC HYPOTHESIS
Time constraints from this magmatic activity overlap with major phases of basin subsidence and possible extension in northern Colombia.
We suggest that the position of this belt near the ocean-continent plate interface (resembling a fore arc position?) and the association with extensional conditions in the margins may reflect upper plate roll-back conditions and some modifications in the slab angle. This transient condition in the margin may have allow inflow of a modified astenospheric mantle.
The associated extension on the upper continental plate in northern Colombia may be also link to the final accommodation of the Panama block against the South American margin and the tectonic escape of the composite continental margin blocks.