Dikaka: Plants and plant-root structures associated with aeolian sand
Abstract Plant-root structures, which are normally associated with low-lying swamp-like environments, have locally been found in the dune sands of arid deserts. The Arabic word “dikaka”, meaning scrub-covered dune sand, has been chosen to designate the latter type of plant structure. Such structures are common only in Tertiary and younger dune sands and represent desert environments having at least a sporadic supply of water, for example from the sea or an occasional rain storm. Dikaka, preferentially cemented by gypsum, is found where this water has been particularly saline. An abundance of Recent dikaka can stabilise formerly mobile dune sand but, in so doing, can destroy the dune bedding so that the aeolian origin of the sand becomes difficult to recognise.