German Bayona | ARES - Academia.edu (original) (raw)
Papers by German Bayona
AGU Fall Meeting Abstracts, Dec 1, 2019
Journal of Structural Geology, Apr 1, 2002
Tectonophysics, Feb 1, 2002
Journal of Structural Geology, Dec 1, 2002
Boletín de la Sociedad Geológica Mexicana, Apr 1, 2021
11th Simposio Bolivariano - Exploracion Petrolera en las Cuencas Subandinas, Jul 29, 2012
Secciones estructurales seriadas del flanco oriental de la Cordillera Oriental de Colombia permit... more Secciones estructurales seriadas del flanco oriental de la Cordillera Oriental de Colombia permitieron cuantificar sistematicamente el acortamiento y sugerir que el frente de deformacion se comporta como una zona de transferencia de una cadena de plegamiento y fallamiento. En este esquema estructural los acortamientos sugieren que la fallas frontales principales se relevan y compensan a lo largo del frente de cabalgamiento y el acortamiento tiende a aumentar hacia el norte. Se pudieron definir tres sectores estructurales para el piedemonte, uno sur, uno central y uno norte. Entre el sur y el central el acortamiento del piedemonte disminuye drasticamente, probablemente por la presencia de una falla transversal de direccion aproximada E-W que permitio la acumulacion de una secuencia mas espesa de Cretaceo Inferior. En el sector norte del piedemonte el acortamiento aumenta drasticamente, los niveles de despague lateralmente cambian de la seccion Oligocena de la Fm. Carbonera Inferior, a los niveles de la Fm. Leon del Mioceno. Lo anterior permite que la parte centro-norte del Piedemonte presente repeticiones multiples de escamas imbricadas de la seccion Cretaceo Superior-Eoceno en zonas triangulares. En contraste a lo anterior, el acortamiento al sur tiene rampas de bajo angulo que involucran a la seccion completa del Cretaceo permitiendo estructuras amplias que involucran basamento.
Sedimentary Geology, Sep 1, 2006
AGUSM, May 1, 2007
ABSTRACT In the last 50 years few paleomagnetic studies have been carried out in the Colombian An... more ABSTRACT In the last 50 years few paleomagnetic studies have been carried out in the Colombian Andes. The first attempts were in Triassic and Jurassic igneous rocks and red beds (1960-1980), which results yielded: (1) an idea of complex vertical-axis rotations in blocks near to strike-slip faults, and (2) the difficulty of identifying Jurassic and younger magnetization components due to the same paleolatitudinal position of the South America plate since Jurassic. Paleomagnetism in Cretaceous volcanic and volcaniclastic rocks and Cenozoic intrusives to the west of the Romeral paleosuture have allowed to constrain paleolatitudinal translations of oceanic terranes and rotations associated to the complex array of strike-slip faults in the Romeral fault system. These works have been carried out by William MacDonald and co-workers in Colombia. In the last decade, paleomagnetic studies moved eastward of the Romeral paleosuture. The integration of paleomagnetic, magmatic, and stratigraphic constrains data have allowed (1) the proposition of along-margin northward translations of continental-affinity terranes along the northern margin of the South America plate during the Jurassic and (2) constrain rotation of fault-bounded blocks related to syn-extensional tectonism. These interpretations are supported by components of magnetization uncovered in Jurassic and Cretaceous rocks that passes several field tests to verify the near post-depositional age of magnetization. These rocks should be used for further paleomagnetic analyses. Magnetostratigraphy studies of sedimentary Paleogene rocks have been more challenging than in older rocks. Even though several of the sites collected have red beds or Fe-rich nodules and cementation, magnetization intensity is very low, the direction of uncovered component is parallel to the present magnetic field (with negative field tests), or new mineralization occur during heating of the sample. However, other demagnetizations techniques and rock magnetic studies should be applied in these rocks. Magnetostratigraphic studies need to be carried out in basins with volcaniclastic strata of Miocene or younger age to better constrain the uplift the Andes.
AGUFM, Dec 1, 2008
ABSTRACT In order to determine rotations and paleolatitudinal movements of several tectonic terra... more ABSTRACT In order to determine rotations and paleolatitudinal movements of several tectonic terrains in Panama, a total of 23 paleomagnetic sites of Upper Cretaceous to Pleistocene tuffs, lavas and limestones were sampled in five areas of the Panama Isthmus. In the Colon area, the left-lateral Rio Gatun fault places Upper Cretaceous and Miocene rocks to the north and Eocene-Oligocene strata to the south. Mean directions of two sites in the northern block, after tilt correction, are westerly (Upper Cretaceous, D=275.4 I=-20.8 k=20.46 a95=10.9; Miocene, D=264.6 I=5.3 k=292.35 a95=3.5), whereas the mean direction of a site in the southern block is pointing North (Oligocene, D=346.3 I=14.3 k=18.43 a95=14.4). Comparison between Oligocene and Miocene directions documents a counterclockwise rotation of the northern block of the Rio Gatun fault (81.7º ± 13.3º) with respect to the southern block. Cretaceous and Cenozoic sites record the northward path of the trailing edge of the Caribbean plate, from 10.8ºS for Late Cretaceous to 6.6ºN for Oligocene. Components isolated in the El Valle volcano and Canal areas for Middle Miocene to Pleistocene rocks, indicate normal and reverse directions similar to the present direction of the magnetic field, therefore indicating no major latitudinal displacement of the Panama Isthmus since Oligocene.
Revista de la Academia Colombiana de ciencias exactas, físicas y naturales, Dec 26, 2018
AGU Fall Meeting Abstracts, Dec 1, 2002
In peripheral foreland basins, coeval drowning and exposure of different parts of the former plat... more In peripheral foreland basins, coeval drowning and exposure of different parts of the former platform and variations in stratal architecture have been attributed mainly to tectonic and depositional loading along the collisional margin. Here, we document how pre-existing structures in the continental margin and interior affect foreland-plate relief, as well as deposition, diagenesis, and composition of distal and proximal foreland strata. Stratigraphic correlations, using a bentonite-graptolite-conodont time framework and a palinspastic map, document an early episode of basement-fault inversion in the distal foreland, and heterogeneous subsidence and provenance patterns in the middle and proximal foreland. Abrupt variations in depth of erosion of passive-margin strata and in thickness of distal foreland deposits coincide with the boundaries of the intraplate Birmingham graben. Inversion of the former graben (1) increased the magnitude of erosion on new upthrown blocks; (2) increased tectonic subsidence in adjacent blocks; (3) supplied chert and quartz detritus to shallow-marine carbonate depocenters; and (4) facilitated influx of meteoric water to aquifers in shallow-marine carbonate deposits. Tectonic subsidence of middle foreland deposits reflects local irregularities in the foredeep associated probably with reactivation of transverse basement faults (TBF). Middle foreland synorogenic clastic deposits are thicker in the Tennessee embayment of the Laurentian margin than in the Alabama promontory. Differential subsidence between embayments and promontories may cause reactivation of TBF, and relief produced by reactivation of TBF may provide sources for local conglomerates interbedded with deep-water shales. Along-strike differences in orogenic-belt deformation are reflected in sandstone composition of the proximal clastic wedge. Provenance of sand-size detritus suggests deeper erosion of the orogenic belt in areas adjacent to the promontory than in areas adjacent to the embayment. Results of this study reveal the importance of considering the effects of pre-existing structures in the interpretation of along- and across-strike variations of foreland strata, and the need to include pre-existing structures in the analysis and geodynamic modelling of foreland basins and associated orogenic belts.
Tectonophysics, Jul 1, 2022
AGU Fall Meeting Abstracts, Dec 1, 2019
Journal of Structural Geology, Apr 1, 2002
Tectonophysics, Feb 1, 2002
Journal of Structural Geology, Dec 1, 2002
Boletín de la Sociedad Geológica Mexicana, Apr 1, 2021
11th Simposio Bolivariano - Exploracion Petrolera en las Cuencas Subandinas, Jul 29, 2012
Secciones estructurales seriadas del flanco oriental de la Cordillera Oriental de Colombia permit... more Secciones estructurales seriadas del flanco oriental de la Cordillera Oriental de Colombia permitieron cuantificar sistematicamente el acortamiento y sugerir que el frente de deformacion se comporta como una zona de transferencia de una cadena de plegamiento y fallamiento. En este esquema estructural los acortamientos sugieren que la fallas frontales principales se relevan y compensan a lo largo del frente de cabalgamiento y el acortamiento tiende a aumentar hacia el norte. Se pudieron definir tres sectores estructurales para el piedemonte, uno sur, uno central y uno norte. Entre el sur y el central el acortamiento del piedemonte disminuye drasticamente, probablemente por la presencia de una falla transversal de direccion aproximada E-W que permitio la acumulacion de una secuencia mas espesa de Cretaceo Inferior. En el sector norte del piedemonte el acortamiento aumenta drasticamente, los niveles de despague lateralmente cambian de la seccion Oligocena de la Fm. Carbonera Inferior, a los niveles de la Fm. Leon del Mioceno. Lo anterior permite que la parte centro-norte del Piedemonte presente repeticiones multiples de escamas imbricadas de la seccion Cretaceo Superior-Eoceno en zonas triangulares. En contraste a lo anterior, el acortamiento al sur tiene rampas de bajo angulo que involucran a la seccion completa del Cretaceo permitiendo estructuras amplias que involucran basamento.
Sedimentary Geology, Sep 1, 2006
AGUSM, May 1, 2007
ABSTRACT In the last 50 years few paleomagnetic studies have been carried out in the Colombian An... more ABSTRACT In the last 50 years few paleomagnetic studies have been carried out in the Colombian Andes. The first attempts were in Triassic and Jurassic igneous rocks and red beds (1960-1980), which results yielded: (1) an idea of complex vertical-axis rotations in blocks near to strike-slip faults, and (2) the difficulty of identifying Jurassic and younger magnetization components due to the same paleolatitudinal position of the South America plate since Jurassic. Paleomagnetism in Cretaceous volcanic and volcaniclastic rocks and Cenozoic intrusives to the west of the Romeral paleosuture have allowed to constrain paleolatitudinal translations of oceanic terranes and rotations associated to the complex array of strike-slip faults in the Romeral fault system. These works have been carried out by William MacDonald and co-workers in Colombia. In the last decade, paleomagnetic studies moved eastward of the Romeral paleosuture. The integration of paleomagnetic, magmatic, and stratigraphic constrains data have allowed (1) the proposition of along-margin northward translations of continental-affinity terranes along the northern margin of the South America plate during the Jurassic and (2) constrain rotation of fault-bounded blocks related to syn-extensional tectonism. These interpretations are supported by components of magnetization uncovered in Jurassic and Cretaceous rocks that passes several field tests to verify the near post-depositional age of magnetization. These rocks should be used for further paleomagnetic analyses. Magnetostratigraphy studies of sedimentary Paleogene rocks have been more challenging than in older rocks. Even though several of the sites collected have red beds or Fe-rich nodules and cementation, magnetization intensity is very low, the direction of uncovered component is parallel to the present magnetic field (with negative field tests), or new mineralization occur during heating of the sample. However, other demagnetizations techniques and rock magnetic studies should be applied in these rocks. Magnetostratigraphic studies need to be carried out in basins with volcaniclastic strata of Miocene or younger age to better constrain the uplift the Andes.
AGUFM, Dec 1, 2008
ABSTRACT In order to determine rotations and paleolatitudinal movements of several tectonic terra... more ABSTRACT In order to determine rotations and paleolatitudinal movements of several tectonic terrains in Panama, a total of 23 paleomagnetic sites of Upper Cretaceous to Pleistocene tuffs, lavas and limestones were sampled in five areas of the Panama Isthmus. In the Colon area, the left-lateral Rio Gatun fault places Upper Cretaceous and Miocene rocks to the north and Eocene-Oligocene strata to the south. Mean directions of two sites in the northern block, after tilt correction, are westerly (Upper Cretaceous, D=275.4 I=-20.8 k=20.46 a95=10.9; Miocene, D=264.6 I=5.3 k=292.35 a95=3.5), whereas the mean direction of a site in the southern block is pointing North (Oligocene, D=346.3 I=14.3 k=18.43 a95=14.4). Comparison between Oligocene and Miocene directions documents a counterclockwise rotation of the northern block of the Rio Gatun fault (81.7º ± 13.3º) with respect to the southern block. Cretaceous and Cenozoic sites record the northward path of the trailing edge of the Caribbean plate, from 10.8ºS for Late Cretaceous to 6.6ºN for Oligocene. Components isolated in the El Valle volcano and Canal areas for Middle Miocene to Pleistocene rocks, indicate normal and reverse directions similar to the present direction of the magnetic field, therefore indicating no major latitudinal displacement of the Panama Isthmus since Oligocene.
Revista de la Academia Colombiana de ciencias exactas, físicas y naturales, Dec 26, 2018
AGU Fall Meeting Abstracts, Dec 1, 2002
In peripheral foreland basins, coeval drowning and exposure of different parts of the former plat... more In peripheral foreland basins, coeval drowning and exposure of different parts of the former platform and variations in stratal architecture have been attributed mainly to tectonic and depositional loading along the collisional margin. Here, we document how pre-existing structures in the continental margin and interior affect foreland-plate relief, as well as deposition, diagenesis, and composition of distal and proximal foreland strata. Stratigraphic correlations, using a bentonite-graptolite-conodont time framework and a palinspastic map, document an early episode of basement-fault inversion in the distal foreland, and heterogeneous subsidence and provenance patterns in the middle and proximal foreland. Abrupt variations in depth of erosion of passive-margin strata and in thickness of distal foreland deposits coincide with the boundaries of the intraplate Birmingham graben. Inversion of the former graben (1) increased the magnitude of erosion on new upthrown blocks; (2) increased tectonic subsidence in adjacent blocks; (3) supplied chert and quartz detritus to shallow-marine carbonate depocenters; and (4) facilitated influx of meteoric water to aquifers in shallow-marine carbonate deposits. Tectonic subsidence of middle foreland deposits reflects local irregularities in the foredeep associated probably with reactivation of transverse basement faults (TBF). Middle foreland synorogenic clastic deposits are thicker in the Tennessee embayment of the Laurentian margin than in the Alabama promontory. Differential subsidence between embayments and promontories may cause reactivation of TBF, and relief produced by reactivation of TBF may provide sources for local conglomerates interbedded with deep-water shales. Along-strike differences in orogenic-belt deformation are reflected in sandstone composition of the proximal clastic wedge. Provenance of sand-size detritus suggests deeper erosion of the orogenic belt in areas adjacent to the promontory than in areas adjacent to the embayment. Results of this study reveal the importance of considering the effects of pre-existing structures in the interpretation of along- and across-strike variations of foreland strata, and the need to include pre-existing structures in the analysis and geodynamic modelling of foreland basins and associated orogenic belts.
Tectonophysics, Jul 1, 2022