Palaeoenvironmental and climatic significance of the Puesto Almada Member (Upper Jurassic, Cañadón Asfalto Formation), at the Fossati sub-basin, Patagonia Argentina
Six facies associations are described for the Puesto Almada Member at the Cerro Bandera locality (Fossati subbasin). They correspond to lacustrine, palustrine, and pedogenic deposits (limestones); and subordinated alluvial fan, fluvial, aeolian, and pyroclastic deposits. The lacustrine?palustrine de...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2013 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/2418 |
| Acceso en línea: | http://hdl.handle.net/11336/2418 |
| Access Level: | acceso abierto |
| Palabra clave: | CAÑADÓN ASFALTO FORMATION FACIES PALAEOCLIMATOLOGY PALAEONTOLOGY PATAGONIA UPPER JURASSIC https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 |
| Sumario: | Six facies associations are described for the Puesto Almada Member at the Cerro Bandera locality (Fossati subbasin). They correspond to lacustrine, palustrine, and pedogenic deposits (limestones); and subordinated alluvial fan, fluvial, aeolian, and pyroclastic deposits. The lacustrine?palustrine depositional setting consisted of carbonate alkaline shallow lakes surrounded by flooded areas in a low-lying topography. The facies associations constitute four shallowing upward successions defined by local exposure surfaces: 1) a Lacustrine?Palustrinepedogenic facies association with a ?conchostracan??ostracod association; 2) a Palustrine facies association representing a wetland subenvironment, and yielding ?conchostracans?, body remains of insects, fish scales, ichnofossils, and palynomorphs (cheirolepidiacean species and ferns growing around water bodies, and other gymnosperms in more elevated areas); 3) an Alluvial fan facies association indicating the source of sediment supply; and 4) a Lacustrine facies association representing a second wetland episode, and yielding ?conchostracans?, insect ichnofossils, and a palynoflora mainly consisting of planktonic green algae associated with hygrophile elements. The invertebrate fossil assemblage found contains the first record of fossil insect bodies (Insecta-Hemiptera and Coleoptera) for the Cañadón Asfalto Formation. The succession reflects a mainly climatic control over sedimentation. The sedimentary features of the Puesto Almada Member are in accordance with an arid climatic scenario across the Upper Jurassic, and they reflect a strong seasonality with periods of higher humidity represented by wetlands and lacustrine sediments. |
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