La carta della unità geomorfologiche della regione di Medenine (Tunisia meridionale)
MELIS M. T.
Writing – Original Draft Preparation
;
2008-01-01
Abstract
This map is a methodological purpose of remote sensing application for a new definition of a system of landform interpretation. In this paper a satellite study is proposed on an area that covers the south western side of Medenine (southern Tunisia), where a research project involves the Italian TeleGIS Lab of University of Cagliari, Tunisian IRA Centre on desertification and degradation problem and the University of Tunis. The Saharan platform in southern Tunisia is divided into different geomorphologic units connected to recent structural neotectonic evidence and climate evolution. The remote sensing over a DTM model approach has been applied to study geomorphologic analysis and morpho- dynamic evolution by photo interpretation, field work and digital processes on Landsat TM data. This interpretation confirms the interaction between the most recent tectonics of the Atlas orogeny and the rapid drying of the climate. The main morphological feature is represented by monoclinal structures which constitute a cuesta system controlled by the Gafsa-Medenine distensive fault trend. This monocline system is a morpho-structural and morpho- climatic limit between the plain of Medenine and the Mesozoic carbonate landform with differences of altitude of 500 metres. The plain of Medenine constitutes the evolution of the parallel retreat of slopes with intense phenomena of sheet and gully erosion and locally a slope replacement; the piedmont zone and the knick along the scarp is undulated because of coalescing of adjacent alluvial fans. The glacis area mainly is covered by gypsum and calcareous crust; the aeolian dynamics and the lack of soil limit the agricultural use and the vegetation growth. These processes are causing prohibitive conditions for agricultural use and grazing is the principal economical resource. The Morpho-unit of Mesozoic carbonate is constituted by a series of structural surfaces of the monoclinal system that disappears beneath the dunes of the Grand Erg Oriental. The aeolian dynamics is actually active and visible on satellite image like crescent shaped sand-dunes (barchans) with direction of prevailing wind from south-west. The tectonic control is well exposed along the rivers as meandering valleys and terraces with different degree of deepness developed in different climatic regime and correlated to other base level. Interesting information was been carried out from the integration with DTM model in terms of landform classification.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.