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Subantarctic macrotidal flats, cheniers and beaches in San Sebastian Bay, Tierra Del Fuego, Argentina |
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| Authors: | Federico Vilas Alfredo Arche Marcelo Ferrero and Federico Isla |
| Institution: | a Universidad de Vigo, Facultad de Ciencias, Dpto. de Geociencias Marinas y Ordenación del Territorio, Aptdo. 874, 36.200 Vigo, Spain b Instituto de Geología Económica, C.S.I.C.-U.C.M., Facultad de Geología, 28040 Madrid, Spain c Secretaría de Minería. Avda. de Santa Fé 1542, 1060 Buenos Aires, Argentina d CONICET, Centro de Geología de Costas y del Cuaternario, CC-722, 7600 Mar de Plata, Argentina |
| Abstract: | San Sebastian Bay is a large, semicircular coastal embayment situated on the Atlantic coast of Tierra del Fuego, Argentina. It is a high-energy, subantarctic environment with a tidal range of 10.4 m, influenced by large waves of Atlantic and local origin and swept by constant, strong westerly winds. A 17 km long gravel spit protects the Northern part of the Bay giving rise to a gradient in sedimentary processes. From south to north, are seven distinct sedimentary environments. Coastal sedimentation started at least 5200 years before present (BP) and a rapid progradation related to a relative sea-level drop has infilled about 6 kilometres of the Bay with a sedimentary sequence 10–11 m thick. 14-C dating of unabraded shells in the Chenier ridges of the relict part of the complex allows for a precise reconstruction of the stages of the progradation, that has slowed from 2.35 m/year at 5000 years BP to 0.6 m/year at present. The possible causes of the sea-level drop are discussed. |
| Keywords: | Tierra del Fuego macrotidal sedimentation subantarctic climate sea-level glacio-isostatic rebound chenier formation |
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