Ubicación del contacto bioestratigráfico plioceno-pleistoceno al noroeste de San José - sur de la provincia de Manabí
Fecha
2015
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Facultad de Ciencias Naturales. Universidad de Guayaquil
Resumen
es conocida la ubicación del contacto bioestratigráfico Plioceno-Pleistoceno en la Cuenca Manabí. El contacto debe estar localizado en las formaciones Canoa del Plioceno o Tablazo del Pleistoceno. La presente tesis está orientada a la ubicación del contacto Plioceno-Pleistoceno en el Sur de la Cuenca Manabí, al noroeste de la localidad de San José. El objetivo es determinar las edades relativas y paleoambientes de las formaciones, y ubicar el contacto bioestratigráfico Plioceno-Pleistoceno. Para este propósito se recolectaron 18 muestras en 6 afloramientos, 5 ubicados en los acantilados de San José y 1 en la quebrada La Vainilla; para realizar análisis micropaleontológicos y descripciones litológicas. Los resultados biostratigráficos y paleoecológicos fueron: La Formación Canoa Inferior tiene una edad relativa de Plioceno Temprano (Zona N18-N19), en base principalmente a la ocurrencia de Globigeinoides obliquus obliquus, que litológicamente corresponde a una capa de arcillolita arenosa (muestra M-3). La Formación Canoa Superior tiene una edad relativa del Plioceno Tardío-Pleistoceno Temprano (Zona 1/2N21-2/3N22), por la ocurrencia de Neogloboquadrina asanoi, la extinción de Globorotalia acostaensis y Neogloboquadrina humerosa, que litológicamente corresponde a una capa de arenisca (muestra M-15). El contacto bioestratigráfico Plioceno-Pleistoceno fue asignado en el afloramiento 4, situado en el acantilado a 750 m al Sur de la desembocadura de la quebrada El Mono, el resultado obtenido de la muestra M-9 determinó una edad relativa Plioceno Tardío-Pleistoceno Temprano temprano (Zona 1/2N21-1/3N22), en base a la aparición de Neogloboquadrina asanoi y la extinción de Globigerina parabulloides, que litológicamente corresponde a una capa de arenisca arcillosa de la Formación Canoa Superior. El paleoambiente de depositación de los sedimentos del Plioceno Temprano-Pleistoceno Temprano fue Marino de aguas cálidas con profundidades de Plataforma Continental Interna a Central; en base a la abundancia de foraminíferos planctónicos de una asociación Tropical o Ecuatorial y asociaciones de foraminíferos bentónicos característicos de la Plataforma Interna a Central. La ubicación del contacto bioestratigráfico y la paleoecología del Plioceno-Pleistoceno, facilitará a la exploración hidrocarburífera e hídrica de la Cuenca Manabí.
It is not known the location of the Pliocene-Pleistocene biostratigraphic contact in Manabí Basin. The spot must be located at the Pliocene Canoe or Tablazo Pleistocene formations. This thesis is aimed to locate the contact Pliocene-Pleistocene in the south of the Manabí Basin, at the northwest point of San José town. The goal is to figure out the relative ages and palaeoenvironment of the formations and locate the contact of Pliocene-Pleistocene biostratigraphic. For this purpose 18 samples were collected in 6 outcrops, 5 located on the cliffs of San Jose and one in the ravine La Vainilla; in order to do micropaleontological analysis and lithologic descriptions. The biostratigraphic and paleoecological results were the following: Lower Canoe Formation has a relative Early Pliocene age (N18-N19 Zone), based mainly on the occurrence of Globigeinoides obliquus obliquus, which corresponds to a lithologic sandy argillite layer (sample M-3). Higher Canoe Formation has a relative age of the Late Pliocene-Early Pleistocene (Zone 1/2N21-2/3N22), by the occurrence of Neogloboquadrina asanoi, extinction of acostaensis Globorotalia and Neogloboquadrina humerosa that lithology corresponds to a layer of sandstone (sample M-15). The biostratigraphic contact Pliocene-Pleistocene was assigned in outcrop 4 located on the cliff at 750 m south of the mouth of the creek El Mono, the result of sample M-9 point to a relative age Late Pliocene-Pleistocene Early early (Zone 1/2N21-1/3N22), based on the appearance of Neogloboquadrina asanoi and extinction of Globigerina parabulloides that lithology corresponds to a layer of clayey sandstone Higher Canoe Formation. The paleoenvironment of deposition of sediments Early Pliocene-Early Pleistocene were from sea warm water with depths of central inner continental platform; based on the abundance of planktonic foraminifera from a tropical or equatorial association and associations benthic foraminifera characteristic of the central internal platform. The location of biostratigraphic contact and Pliocene-Pleistocene paleoecology, provide the hycrocarburipher and water exploration of Manabí Basin.
It is not known the location of the Pliocene-Pleistocene biostratigraphic contact in Manabí Basin. The spot must be located at the Pliocene Canoe or Tablazo Pleistocene formations. This thesis is aimed to locate the contact Pliocene-Pleistocene in the south of the Manabí Basin, at the northwest point of San José town. The goal is to figure out the relative ages and palaeoenvironment of the formations and locate the contact of Pliocene-Pleistocene biostratigraphic. For this purpose 18 samples were collected in 6 outcrops, 5 located on the cliffs of San Jose and one in the ravine La Vainilla; in order to do micropaleontological analysis and lithologic descriptions. The biostratigraphic and paleoecological results were the following: Lower Canoe Formation has a relative Early Pliocene age (N18-N19 Zone), based mainly on the occurrence of Globigeinoides obliquus obliquus, which corresponds to a lithologic sandy argillite layer (sample M-3). Higher Canoe Formation has a relative age of the Late Pliocene-Early Pleistocene (Zone 1/2N21-2/3N22), by the occurrence of Neogloboquadrina asanoi, extinction of acostaensis Globorotalia and Neogloboquadrina humerosa that lithology corresponds to a layer of sandstone (sample M-15). The biostratigraphic contact Pliocene-Pleistocene was assigned in outcrop 4 located on the cliff at 750 m south of the mouth of the creek El Mono, the result of sample M-9 point to a relative age Late Pliocene-Pleistocene Early early (Zone 1/2N21-1/3N22), based on the appearance of Neogloboquadrina asanoi and extinction of Globigerina parabulloides that lithology corresponds to a layer of clayey sandstone Higher Canoe Formation. The paleoenvironment of deposition of sediments Early Pliocene-Early Pleistocene were from sea warm water with depths of central inner continental platform; based on the abundance of planktonic foraminifera from a tropical or equatorial association and associations benthic foraminifera characteristic of the central internal platform. The location of biostratigraphic contact and Pliocene-Pleistocene paleoecology, provide the hycrocarburipher and water exploration of Manabí Basin.