Seismological observations in Northwestern South America: Evidence for two subduction segments, contrasting crustal thicknesses and upper mantle flow

Yarce, J.; Monsalve, Gaspar; Becker, T. W.; Cardona, A.; Poveda, Esteban; Alvira, Daniel; Ordóñez-Carmona, Oswaldo

doi:10.1016/j.tecto.2014.09.006

Cited by 50 publications

(38 citation statements)

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“…The tectonic assembling of the Northwestern Andes involves different processes that have occurred during more than 200 Myr, where several episodes of subduction and accretion have taken place since at least Cretaceous time [ Restrepo and Toussaint , ; Cediel et al ., ]. Different subduction segments and styles are known to exist in this part of the Andes [e.g., Pennington , ; van der Hilst and Mann , ; Gutscher et al ., ; Taboada et al ., ; Cortés and Angelier , ; Yarce et al ., ]. The existence of an east‐west striking slab tear (Caldas Tear, see Figure ), approximately 240 km long, has been proposed, which probably splits up the subduction into two distinct segments [ Vargas and Mann , ; Salazar and Vargas , ].…”

Section: Geologic and Tectonic Settingmentioning

confidence: 99%

“…In regions of high deformation and plate convergence in South America, the lithosphere might have a more complex configuration, since superposition of oceanic and continental plates might occur, and phenomena like subduction‐erosion play a role in the mass budgets [ Kay et al ., ; Keppie et al ., ; Stern , ]. In the Northern Andes, the multiple converging plates and blocks, and the presence of several subduction segments and styles [ van der Hilst and Mann , ; Vargas and Mann , ; Yarce et al ., ; Chiarabba et al ., ; Syracuse et al ., ], may add complexity to the lithospheric configuration. Masy et al .…”

Section: Introductionmentioning

confidence: 99%

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Lithospheric thickness estimation beneath Northwestern South America from an S‐wave receiver function analysis

Blanco

Vargas

Monsalve

2017

Geochem Geophys Geosyst

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We make use of the S‐to‐P receiver function technique beneath Colombia and neighboring regions to make a first‐order approximation of the depth of the Lithosphere‐Asthenosphere Boundary (LAB) and, therefore, of lithospheric thickness. A deconvolution technique was used to calculate the receiver functions, and after a moveout correction and a time‐depth conversion, LAB depths for different tectonic regions of northwestern South America were obtained. Results are typically between 65 and 110 km, consistent with previous estimates around the world and other regions in South America. Lithospheric thickness beneath an oceanic island in the Caribbean is ∼80 km, whereas for the Ecuador‐Colombia Trench it is ∼65 km, and around 100 km for the Panama Arc. The transition to the continent is associated with an increase in LAB depth, where it can reach ∼110 km, with no significant differences among terranes and/or tectonic blocks.

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Section: Geologic and Tectonic Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lithospheric thickness estimation beneath Northwestern South America from an S‐wave receiver function analysis

Blanco

Vargas

Monsalve

2017

Geochem Geophys Geosyst

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“…Correlations between elevation and crustal thicknesses below the Cocuy Sierra have been evaluated through receiver function data. These analyses indicate that the crustal thickness is between 40 and 45 km (Mora‐Páez et al, ; Poveda et al, ; Yarce et al, ). This crustal root alone is potentially insufficient to account for the observed high elevations.…”

Section: Introductionmentioning

confidence: 99%

“…This crustal root alone is potentially insufficient to account for the observed high elevations. Indeed, based on seismic data, Yarce et al () estimated substantial (>1 km) residual topography, particularly pronounced in the Cocuy Sierra.…”

Section: Introductionmentioning

confidence: 99%

Constraints on the Cenozoic Deformation of the Northern Eastern Cordillera, Colombia

et al. 2018

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The Eastern Cordillera of Colombia rose to maximum elevations of >5 km during the Cenozoic by inversion of a Mesozoic rift basin. Previous studies proposed that the exhumation of the Eastern Cordillera increased from ~6 Ma to the present due to the interplay between tectonic shortening and climate. In this study, we integrate new field observations, structural data, low‐temperature thermochronology, thermobarometry, and vitrinite reflectance along a section through the Tablazo, Cocuy, and Llanos regions to estimate the amount of shortening and the exhumation history. Our results indicate that shortening started as early as the latest Maastrichtian‐Paleocene in the Tablazo and Cocuy regions. Exhumation migrated eastward, starting in the Paleocene in the west and continuing in the Miocene in the east. The amount and rate of exhumation peaked in the Cocuy region with values of <5 km and < 0.4 km/Ma, respectively. At the highest elevations in the Cocuy Sierra, we also found evidence of a low‐pressure/high‐temperature metamorphic overprint, possibly related to shallow and local magmatic intrusions that occurred in the Late Miocene. Our cross‐section interpretation suggests a low amount of shortening (13%) that is mainly accommodated by high‐angle inverted faults and by the frontal thrust system. The presence of shallow magmatic bodies, moderate exhumation, and low shortening raises questions about the processes (isostatic versus dynamic) that drove the topographic growth of the high Cocuy Sierra.

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“…Subduction of multiple plates in northwestern South America is expressed in the offset of Andean topography in Colombia, complex seismicity indicating several slab segments, and the termination of Andean volcanism at ~5.5°N. This has been explained by a northeastern (“Bucaramanga”) and a southwestern (“Cauca”) slab segment, in the nomenclature of Pennington [], with the separation coincident with the extent of volcanism [e.g., Pennington , ; van der Hilst and Mann , ; Taboada et al ., ; Gutscher et al ., ; Ojeda and Havskov , ; Cortés and Angelier , ; Vargas and Mann , ; Yarce et al ., ]. However, the origin of the different slab segments and their respective subduction angle remains debated.…”

Section: Introductionmentioning

confidence: 99%

Seismic anisotropy and slab dynamics from SKS splitting recorded in Colombia

Porritt

Becker

Monsalve

2014

Geophysical Research Letters

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The Nazca, Caribbean, and South America plates meet in northwestern South America where the northern end of the Andean volcanic arc and Wadati-Benioff zone seismicity indicate ongoing subduction. However, the termination of Quaternary volcanism at~5.5°N and eastward offset in seismicity underneath Colombia suggest the presence of complex slab geometry. To help link geometry to dynamics, we analyze SKS splitting for 38 broadband stations of the Colombian national network. Measurements of fast polarization axes in western Colombia close to the trench show dominantly trench-perpendicular orientations. Orientations measured at stations in the back arc, farther to the east, however, abruptly change to roughly trench parallel anisotropy. This may indicate along-arc mantle flow, possibly related to the suggested "Caldas" slab tear, or a lithospheric signature, but smaller-scale variations in anisotropy remain to be explained. Our observations are atypical globally and challenge our understanding of the complexities of subduction zone seismic anisotropy.

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Seismological observations in Northwestern South America: Evidence for two subduction segments, contrasting crustal thicknesses and upper mantle flow

Cited by 50 publications

References 55 publications

Lithospheric thickness estimation beneath Northwestern South America from an S‐wave receiver function analysis

Lithospheric thickness estimation beneath Northwestern South America from an S‐wave receiver function analysis

Constraints on the Cenozoic Deformation of the Northern Eastern Cordillera, Colombia

Seismic anisotropy and slab dynamics from SKS splitting recorded in Colombia

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