Earthquake, Tomographic, Seismic Reflection, and Gravity Evidence for a Shallowly Dipping Subduction Zone beneath the Caribbean Margin of Northwestern Colombia

Transient slab flattening beneath Colombia

“…While there are uncertainties about the precise age of this accretion, both earlier estimates based on biostratigraphy placing the accretion age at~13-12 Ma [Duque-Caro, 1990a, 1990b and more recent work based on detrital zircons that estimate the closure of the Central American Seaway at between 15 and 13 Ma [Montes et al, 2015] are broadly consistent with these results. This indicates that the plate subducting north of this offset today is the same plate that is subducting south of this offset, in contradiction to earlier studies suggesting that the offset represents the boundary between two separate plates [e.g., van der Hilst and Mann, 1994;Taboada et al, 2000;Corredor, 2003;Cortés and Angelier, 2005;Vargas and Mann, 2013;Sanchez-Rojas and Palma, 2014;Bernal-Olaya et al, 2015a;Idárraga-García et al, 2016]. This is consistent with the Panama-Choco block being very near in its modern position by 12 Ma and that the subduction responsible for this arc is the subduction of the Nazca Plate and not the subduction between the Panama-Choco block and NW South America.…”

“…There is considerable debate on the geometries of the downgoing Nazca and Caribbean Plates [e.g., van der Hilst and Mann, 1994;Taboada et al, 2000;Corredor, 2003;Cortés and Angelier, 2005;Zarifi et al, 2007;Vargas and Mann, 2013;Bernal-Olaya et al, 2015a, 2015b, 2015cSyracuse et al, 2016;Chiarabba et al, 2016]. There is considerable debate on the geometries of the downgoing Nazca and Caribbean Plates [e.g., van der Hilst and Mann, 1994;Taboada et al, 2000;Corredor, 2003;Cortés and Angelier, 2005;Zarifi et al, 2007;Vargas and Mann, 2013;Bernal-Olaya et al, 2015a, 2015b, 2015cSyracuse et al, 2016;Chiarabba et al, 2016].…”

“…There is considerable debate on the geometries of the downgoing Nazca and Caribbean Plates [e.g., van der Hilst and Mann, 1994;Taboada et al, 2000;Corredor, 2003;Cortés and Angelier, 2005;Zarifi et al, 2007;Vargas and Mann, 2013;Bernal-Olaya et al, 2015a, 2015b, 2015cSyracuse et al, 2016;Chiarabba et al, 2016]. The northern WBZ, located >300 km from the trench, extends from 11°N to 5.5°N and includes the region of increased seismic activity known as the Bucaramanga Seismic Nest (Figure 1) [e.g., Schneider et al, 1987;Frohlich et al, 1995;Zarifi et al, 2007;Prieto et al, 2012;Bernal-Olaya et al, 2015a] at~7°N. The location of the WBZ offset (defined by Vargas and Mann [2013] as the "Caldas tear") coincides with the location of the subducting inactive Sandra Ridge spreading center [Lonsdale, 2005;Vargas and Mann, 2013].…”

“…The location of the WBZ offset (defined by Vargas and Mann [2013] as the "Caldas tear") coincides with the location of the subducting inactive Sandra Ridge spreading center [Lonsdale, 2005;Vargas and Mann, 2013]. Although different interpretations have been proposed, tomographic images and seismicity patterns are not conclusive to definitively link the northern WBZ seismicity to either trench, raising questions about whether this WBZ is due to the Caribbean slab, the Nazca slab, or both [van der Hilst and Mann, 1994;Taboada et al, 2000;Cortés and Angelier, 2005;Vargas and Mann, 2013;Bernal-Olaya et al, 2015a;Chiarabba et al, 2016;Syracuse et al, 2016]. The southern WBZ dips at a relatively constant angle of~45°a nd directly underlies the modern active Andean arc (Figure 1).…”

Linking Late Cretaceous to Eocene Tectonostratigraphy of the San Jacinto Fold Belt of NW Colombia With Caribbean Plateau Collision and Flat Subduction

“…However, convergence in the study area does not involve the Nazca Plate, but instead, it involves the Caribbean Plate, which is separated from the Cocos and Nazca Plates by the Panama‐Chocó block (inset in Figure ). It has been proposed that this area is characterized by the slow and flat slab subduction of the Caribbean oceanic plate beneath South America, forming the Bucaramanga and Caribbean flat slabs imaged and described by several researchers (Bernal‐Olaya, Mann, & Vargas, ; Chiarabba et al, ; Pennington, ; Syracuse et al, ; Taboada et al, ; Van der Hilst & Mann, ). Slow and flat slab subduction would be the cause of the low seismicity and of the lack of a magmatic arc in northwestern Colombia (inset in Figure ).…”