Gravel bars in low-sinuosity streams (Permian and Triassic, central Spain)
The Buntsandstein sequence of the central area of ranges from a variety of fluvial facies, low in the succession, to tidal mudstones and carbonates in the youngest and most eastem areas. This paper is restricted to the conglomerates in the lowest part of the fluvial sequence. These were deposited in...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 1983 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/25830 |
| Acceso en línea: | http://hdl.handle.net/10261/25830 |
| Access Level: | acceso abierto |
| Palabra clave: | Buntsandstein facies Spain conglomerates Braided streams Channel systems Sheets of gravels |
| Sumario: | The Buntsandstein sequence of the central area of ranges from a variety of fluvial facies, low in the succession, to tidal mudstones and carbonates in the youngest and most eastem areas. This paper is restricted to the conglomerates in the lowest part of the fluvial sequence. These were deposited in bar and channel systems dominated by gravelly, low-sinuosity braided streams. Their distribution reflects both the pre-existing topography and synsedimentary tectonic movements. Six main facies have been distinguished (in order of decreasing abundance): sheets of massive conglomerates, channel-fill conglomera tes, coarse-medium sandstones, lateral accretion conglomera tes. tabular cross-stratified conglomerates, fine-grained sediments. Sheets of gravels, formed as longitudinal bars, were by far the major feature ofsediment accumulation. Units of lateral accretion, if not ver y frequent, are quite important as they probably represent modifications of bars during waning stage. Two big cycles may be seen in these conglomera tes. They correspond to different physiographic models. The lower cycle was mainly formed by smaller channels and bars than was the upper cycle. The lower cycle is mainly formed by channel deposits, whilst in contrast, the upper cycle is mainly made up of longitudinal bars. The change in sedimentation may be due to tectonic movements that occurred in the basin during Buntsandstein deposition. |
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