The cookies is used to store the user consent for the cookies in the category "Necessary". This cookie is set by GDPR Cookie Consent plugin. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". The cookie is used to store the user consent for the cookies in the category "Analytics". These cookies ensure basic functionalities and security features of the website, anonymously. Necessary cookies are absolutely essential for the website to function properly. In form and function, a pediment is similar to an alluvial fan, the difference being that a pediment is an erosional landform and a fan is constructional’ (A. Gilbert (1882) for the surfaces of the alluvial fans that encircle mountains in deserts.Īccording to Kirk Bryan (1922) ‘pediments are slopes of transportation cut on bedrock, usually covered with a veneer of alluvium in transit from high to lower levels. The term (pediment) was first used by G.K. Pediments situated between mountain front and bajada in intermontane basin are broad, extensive, and gently sloping areas of rockcut surfaces which spread as aprons around the bases of mountains. The slope in its upper part ranges between 8° and 10° but it becomes 1° tozero in its lowermost portion touching the playa (fig. Thus, bajada is a wholly depositional feature.
Bajada is formed due to coalescence of several alluvial fans. Gently sloping depositional plain between pediments and playa is called bajada. Such salt-covered playa beds are called salinas. Evaporation of playa lake water results in the formation of encrustation of alkaline materials (sodium bicarbonate or sodium carbonate), salt deposits such as borax. Playa lakes may last for days, weeks or even longer before they are completely dried up by evaporation. These are called ‘khabari’ and ‘mamlaha’ in Arabian deserts while they are known as ‘shafts’ in Sahara. The playas range in areal extent from a few square metres to tens of square kilometres. Some water collects in the centre of is a playa in the centre of the Tarim Basin. Numerous ephemeral streams after originating from the surrounding mountain fronts drain into the bolsons.
Such basins are characterized by 3 unique landforms which from the mountain front downward are pediments, bajadas and playas (fig. The intermontane basins in arid or semiarid areas are generally called bolsons. Such type of landscape is called badland topography. Thus, the ground surface becomes so uneven and corrugated due to numerous gullies and ravines that it becomes entirely difficult to walk on it. The linear fluvial erosion results in the formation of ravines and gullies which are divided by numerous undulating narrow ridges. The regions of weak sedimentary formations are extensively eroded by numerous rills and channels which are occasionally developed due to occasional rainstorms. Badland, pediments, bajadas and playas are special types of landforms of arid and semi-arid regions caused by mechanical disintegration of rocks and water action.