Comentarios al trabajo titulado: “Distribution of bedrock channel erosion: micro and mesoforms in fluviokarstic canyons”, de Sanchis, C.; Segura, F. y Rosselló, V. M., en Cuaternario y Geomorfología (2011), 25(3-4), 59-69.

Comment on “Distribution of bedrock channel erosion: micro and mesoforms in fluviokarstic canyons”, by Sanchis, C.; Segura, F. and Rosselló, V. M., in Cuaternario y Geomorfología (2011), 25(3-4), 59-69.

Carlos de Santisteban Bové

Departament de Geologia. Universitat de València. C/ Dr. Moliner, 50, 46100 – BURJASSOT (Valencia). Carlos.santisteban@uv.es

Resumen:

La Rambla de Tambúc, es un río en roca que forma parte de la cabecera del conjunto de tributarios del río Júcar que drenan la Muela de Cortes de Pallás y Macizo del Caroig (Valencia). Se halla emplazada en el interior de un cañón relicto, formado, en varias fases, por el encajamiento de dos cauces meandriformes. En su fondo afloran calizas y dolomías del Cretácico Superior en capas con una posición sub-horizontal. La exposición del techo de los estratos hace que en el lecho del cauce rocoso de la rambla, se hallen formas originadas en distintos momentos del tiempo, siendo algunas de ellas herencia de estructuras sedimentarias cretácicas. En este trabajo se aporta nueva información sobre la naturaleza compuesta del cañón que contiene a la Rambla de Tambúc, y se discute el origen de algunas de las estructuras que se hallan presentes en su lecho.

Abstract:

The ravine of Tambúc, is part of the head of one of tributaries of the Júcar river, placed in the eastern part of the Muela de Cortes de Pallás and Macizo del Caroig (Valencia). It occupies a relic Upper Miocene – Quaternary incised valley. Alhough it has been described previously as generated by fluviokarstic processes, the forms of recent karstification they do not explain the development of the fluvial incision. The ephemeral current river of Tambúc’s Ravine occupies a compound valley, with a meandering pattern. This meandering pattern is controlled by a dense network of two systems of vertical joints. Nowadays these joints determine the liberation of fractured blocks and pebbles. The action of the gravity processes and the flow during floodings they are the mechanisms that more contribute to the transport of sedimentary particles. In their bottom they outcrop, in an horizontal manner, Upper Cretaceous limestones and dolostones. The exposure of the upper surface of the mesozoic layers, in the bedrock of the channel, produce that some morphological features have a strong inheritance of cretaceous structures. In this way relic karstification surfaces, stromatolite and thombolite domes, and icnites of dinosaurs are exposed in the top of beds that outcrop in the river bed. It is evident that they are not current forms and that do not have any relation with the current fluvial hydrodynamics Its presence only indicates that the recent erosion allows the exposure of previous forms, that already were present in the upper surface of horizontal beds. The set of forms, and of structures that generate forms that exists in the riverbed of Tambúc’s Ravine they are the consequence of processes developed in a geochronological interval of 84 My. Some of them are relic forms for what the factor of geological inheritance must be considered in the geomorphological analysis.