Dades sobre paleocarst i espeleocronologia de les illes Balears
[eng] The litho-stratigraphic record of the Balearic Islands, basically composed by carbonate rocks, include noticeable paleokarstic phenomena particularly owing to the complex tectonic structuration experienced by the Western Mediterranean basin all along its geological history. T...
| Autores: | , , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2011 |
| País: | España |
| Institución: | Universidad de las Islas Baleares |
| Repositorio: | Biblioteca Digital de les Illes Balears |
| OAI Identifier: | endins:Endins_2011v35p213 |
| Acceso en línea: | http://ibdigital.uib.es/greenstone/sites/oai-site/collect/endins/index/assoc/Endins_2/011v35p2.dir/Endins_2011v35p213.pdf http://ibdigital.uib.es/greenstone/library/collection/endins/document/Endins_2011v35p213 |
| Access Level: | acceso abierto |
| Palabra clave: | Speleology Spain Balearic Islands Geomorphology Spain Balearic Islands |
| Sumario: | [eng] The litho-stratigraphic record of the Balearic Islands, basically composed by carbonate rocks, include noticeable paleokarstic phenomena particularly owing to the complex tectonic structuration experienced by the Western Mediterranean basin all along its geological history. The most outstanding paleokarst features and associated breccia deposits are observed in the Jurassic limestones and, especially, in the postorogenic Upper Miocene carbonate rocks, where abundant funnel-shaped collapse structures (Messinian in age) have tightly conditioned the geomorphological evolution of the eastern coast of Mallorca. Regarding the karstification occurred in Pliocene and Quaternary times, the islands arise as exceptional scenarios in order to obtain valuable speleochronological data from quite different sources. The base level variations –controlled in turn by oscillations of the sea level–, as well as the evolutionary trends of endemic vertebrates that lived in the Balearic Islands, provide a solid chronological frame to undertake the geomorphologic study of Balearic caves and its sediments. Particularly, the glacio-eustatic oscillations experienced by the Mediterranean Sea remain accurately recorded by means of horizontal paleolevels of phreatic speleothems, mostly corresponding to Upper Pleistocene and Holocene sea-stands. The isotopic investigations (U-Th, 14C) carried out on these carbonate precipitates, as well as on speleothems in general, have supplied abundant absolute dating which strongly contribute to the chronological assessment of the endokarst evolution undergone in our islands. All the evidences gathered till now seem to place in the Pliocene, and in some cases even before, the main speleogenetic phases occurred in the archipelago. During the Middle and Upper Pleistocene, the caves in the Balearic Islands had only experienced minor morpho-sedimentary modifications embracing –in a significant number of cave sites– the deposition of abundant speleothems together with the emplacement of paleontological deposits that include endemic vertebrate fauna. |
|---|