Composition and Sources of Sand in the Wahiba Sand Sea, Sultanate of Oman
The Wahiba Sand Sea can be divided into two physiographic units, the northern and southern regions. The Northern Wahibai region is principally a huge megaridge arrangement, while the Southern Wahiba chiefly consists of linear dunes, sand sheets, and nabkha fields. Although the Wahiba Sand Sea can be divided into two separate regions, scholars have argued that they are linked by a common source, namely coastal sands.
However, through scientific means, the data suggests that the Wahiba Sand Sea actually has two different sources, especially since the northern and southern regions are of different ages.
The Wahiba Sand Sea is located on the eastern coast of Oman and borders the Hajar Mountains to the north, the Arabian Sea to the southeast and the fan/wadi complex and localized sabkha to the west. The Northern region is far older than the southern; the megaridges in the dune developed sometime in the late Pleistocene. One scholar dates it to 8.9 ka, using1 4C dates of gastropods.
The Southern region is considerably younger; in previous studies, scholars believed the sands here were deposited sometime in the early Holocene, a time when “relatively moist climatic conditions that roughly relate to the development of the pluvial deposits in the Northern Wahib”.
The northern regions “have a high composition of mafic minerals and came primarily from local wadis that drain the adjacent Hajar Mountains. One of the prominent wadi sources is presently buried under sands of the Southern Wahiba, eliminating it as a current source of the Northern Wahiba”.
The Southern region is made up of more mineralogically mature, quartz-rich composition. Scholars believe that it is made up from two different sources itself, probably from nearby sabkha plains or the Oman Coast.
It was previously thought that the coast was the key source of sands, but through the use of “geochemical evidence suggests that the carbonate grains in the sand sea originated from the two contrasting sources along with the other grains. Carbonate grains in the Northern Wahiba are derived from wadis that drain limestones in the Hajar Mountains whereas carbonate grains in the Southern Wahiba are probably reworked from underlying aeolianites and coastal sands”.
Bibliography:
Pease, Patrick P., & Tchakerian, Vatche P. (2002) Composition and Sources of Sand in the Wahiba Sand Sea, Sultanate of Oman, Annals of the Association of American Geographers, Taylor & Francis, Ltd. on behalf of the Association of American Geographers.
