Resumen de The Upper Cretaceous and Lower Paleocene of the Eastern Bogota Plateau and Llanos Thrustbelt, Colombia: Alternative Appraisal to the Nomenclature and Sequence Stratigraphy

Luis Eduardo Vergara S., Germán Rodríguez Ch.

• español

  EI registro estratigráfico de la parte oriental de la Sabana de Bogotá y el Piedemonte Llanero ha sido estudiado con base en columnas estratigráficas y pozos petroleros, lo cual ha conducido a un esquema alternativo de nomenclatura estratigráfica y de estratigrafía secuencial. La Formación Chipaque (Cenomaniense-Campaniense) está suprayacida por el Grupo Guadalupe en la Sabana de Bogotá y por el Grupo Palmichal en la zona del Piedemonte Llanero. De base a tope la correlación entre las formaciones de estos grupos se propone así: La Formación Arenisca Dura (Campaniense) del Grupo Guadalupe corresponde a la Formación Arenitas de San Antonio del Grupo Palmichal; la Formación Plaeners (Campaniense-Maastrichtiense) a la Formación Lodolitas de Aguacaliente. La Formación Arenisca de Labor, el llamado nivel de "Lutitas y areniscas finas" y la Formación Arenisca Tierna del Grupo Guadalupe corresponden a la Formación Arenitas de San Luis de Gaceno del Grupo Palmichal. Una parte de la porción inferior de la Formación Guaduas de la Sabana de Bogotá es equivalente a la Formación Guaduas del Grupo Palmichal. EI Grupo Palmichal se redefine excluyendo a la Formación Socha Inferior, principalmente por existir una discordancia en su límite inferior, y se incluyen en el las Formaciones anteriormente mencionadas. Los ambientes deposicionales varían de acuerdo a los cambios del nivel del mar, tanto de segundo como de tercer orden. La Forrnacion Chipaque en la Sabana de Bogotá representa un (super)ciclo de segundo orden que comprende por 10 menos cuatro secuencias de tercer orden. De manera similar, el Grupo Guadalupe y la Formación Guaduas son supersecuencias, en las cuales otras secuencias de mayor frecuencia se pueden delinear. Un periodo de erosión mayor, documentado aquí en el pozo Medina-Ilia causado pérdida parcial del registro del piso Maastrichtiense. La siguiente secuencia está representada en su parte inferior par un sistema de nivel bajo, dentro de la Formación Socha Inferior.

• English

  The Upper Cretaceous stratigraphic record of the Eastern Bogota Plateau and Llanos Thrustbelt of Colombia was studied in several outcrop sections and oil wells, leading to an alternative scheme of stratigraphic nomenclature and sequence stratigraphic interpretation. The Chipaque Formation (Cenomanian-Campanian) is overlain by the Guadalupe Group in the Bogota Plateau and by the Palmichal Group in the Llanos Thrustbelt. From oldest to youngest, the correlation between the subdivisions of these two groups is as follows: The Arenisca Dura Formation (Campanian) of the Guadalupe Group, corresponds to the Arenitas de San Antonio Formation of the Palmichal Group; the Plaeners Formation (Campanian-Maastrichtian) to the Lodolitas de Aguacaliente Formation; the Arenisca de Labor, the so-called "Lutitas y areniscas finas" and the Arenisca Tlerna Formations of the Guadalupe Group correspond to the Arenitas de San Luis de Gaceno Formation of the Palmichal Group. In turn, a lower part of the Guaduas Formation of the Bogota Plateau is equivalent to the Guaduas Formation of the Palmichal Group. The Palmichal Group is redefined by excluding the overlying Socha Inferior Formation from it, mainly because the Socha Inferior's lower limit is represented in some places by an unconformity. Additionally, the above mentioned formations are included now in the Palmichal Group. Major depositional environments shift according to sea level fluctuations of second and third order. The Chipaque Formation of the Bogota area is a second order (super)cycle where at least four third order sequences are circumscribed. Likewise, the Guadalupe Group and the Guaduas Formation are supersequences that bear higher frequency sequences. A major erosion period, documented here in the Medina-1 well, cannibalized part of the Maastrichtian of the Palmichal Group. The youngest sequence studied is represented in its lower portion by the lowstand deposits of the Socha Inferior Formation. The Upper Cretaceous stratigraphic record of the Eastern Bogota Plateau and Llanos Thrustbelt of Colombia was studied in several outcrop sections and oil wells, leading to an alternative scheme of stratigraphic nomenclature and sequence stratigraphic interpretation. The Chipaque Formation (Cenomanian-Campanian) is overlain by the Guadalupe Group in the Bogota Plateau and by the Palmichal Group in the Llanos Thrustbelt. From oldest to youngest, the correlation between the subdivisions of these two groups is as follows: The Arenisca Dura Formation (Campanian) of the Guadalupe Group, corresponds to the Arenitas de San Antonio Formation of the Palmichal Group; the Plaeners Formation (Campanian-Maastrichtian) to the Lodolitas de Aguacaliente Formation; the Arenisca de Labor, the so-called "Lutitas y areniscas finas" and the Arenisca Tierna Formations of the Guadalupe Group correspond to the Arenitas de San Luis de Gaceno Formation of the Palmichal Group. In turn, a lower part of the Guaduas Formation of the Bogota Plateau is equivalent to the Guaduas Formation of the Palmichal Group. The Palmichal Group is redefined by excluding the overlying Socha Inferior Formation from it, mainly because the Socha Inferior's lower limit is represented in some places by an unconformity. Additionally, the above mentioned formations are included now in the Palmichal Group. Major depositional environments shift according to sea level fluctuations of second and third order. The Chipaque Formation of the Bogota area is a second order (super)cycle where at least four third order sequences are circumscribed. Likewise, the Guadalupe Group and the Guaduas Formation are supersequences that bear higher frequency sequences. A major erosion period, documented here in the Medina-1 well, cannibalized part of the Maastrichtian of the Palmichal Group. The youngest sequence studied is represented in its lower portion by the lowstand deposits of the Socha Inferior Formation.