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| Format: | Artículo científico |
| Language: | en |
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Universitat de Barcelona
2007
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| Online Access: | https://www.redalyc.org/articulo.oa?id=50550407 |
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Table of Contents:
- Coastal geomorphology and evolution of Tierra del Fuego (Southern Argentina) G. G. Bujalesky Ciencias de la Tierra Sea level Holocene Gravel beaches Tierra del Fuego The northeastern Atlantic coast and the Beagle Channel are significant geomorphological areas of Tierra delFuego (Southern Argentina). The northeastern Atlantic coast is located at the extra Andean lowlands (South-American Plate Domain). This coast line undergoes a macrotidal regime and is exposed to high energy wavesand intense westerly winds. Extensive and wide beaches and littoral forms are composed of gravel and coarsesand. This zone was a free-ice area since 1,8 Ma B.P. Glacigenic deposits were re-worked by litoral processesthat formed gravel beaches during sea level highstands of the. During the Holocene (i.e. approximately 5,000years B.P.) gravel barriers plugged the inner estuaries of the palaeoembayments These barriers suggest a relativesea level fall of 0.214 m each 1,000 years, but a portion of this gradient could be due to wave dynamics sincegreater set-up of the storm waves enters the embayments. The growth of the northern gravel beach ridge plainsand spits at the seaward flank of the embayments took place under limited sediment supply. The elongation ofthese littoral forms was triggered by erosion and sediment recycling at the seaward side (cannibalism), resultingin a significant landward retreat. Southward the gravel beach ridge plains underwent a regressive trend duringthe Holocene. They do not reveal either erosion, or sediment recycling, or significant landward retreat. The BeagleChannel connects the Pacific and Atlantic oceans. It is a 300 m depth basin separated from the AtlanticOcean by a 30 m depth shallow sill. The Beagle Channel is located at the active seismotectonic setting of theFuegian Andes (Scotia Plate Domain). It is a 5 km wide tectonic valley that was completely covered by ice duringthe Last Glaciation. After this period, glaciofluvial and glaciolacustrine environments developed in the basin.The Beagle valley was rapidly flooded by the sea immediately after the Younger Dryas, 11,000 year B.P. Itundergoes a micro tidal range regime and shows a rugged, rocky shoreline where pocket gravel beaches developin the embayments. Holocene raised beaches can be recognized in many places along the channel and their elevationsvary considerably, reaching maximum elevations of 10 m above the present counterpart at ages of 6,000years B.P. The estimated average tectonic uplift for this period is 1.5 to 2.0 mm/year 2007 artículo científico 1695-6133 https://www.redalyc.org/articulo.oa?id=50550407 en http://www.redalyc.org/revista.oa?id=505 Geologica Acta: an international earth science journal application/pdf Universitat de Barcelona Geologica Acta: an international earth science journal (España) Num.4 Vol.5