Landform evolution in the arid northern United Arab Emirates: Impacts of tectonics, sea level changes and climate

• We divide the Northern Emirates into four physiographic regions and describe each.
• We review evidence for landform evolution in the Northern Emirates.
• We discuss the impact of climate and sea level change on landscape evolution.
• Alluvial processes laid down the alluvial plains in the early to mid-Quaternary.
• The plains were covered by sand dunes in the late Quaternary.

The interaction of wind and water may well be the key influence on the modern geomorphology of the arid regions of the world, and has had a strong influence on long-term landscape evolution in these areas. This is the case for the landforms of the northern United Arab Emirates, where aeolian landforms in the west lie on alluvial deposits, and are adjacent to fluvial landforms in the east. Even within the aeolian forms there is evidence of modern and past water activity. Modern river flow is rare and largely confined to the mountains. However, rivers and alluvial activity were more important during certain periods in the past. This study describes the landforms of the Northern Emirates (NE) and relates their form and evolution to alternating periods of arid and humid climates. The study was initially carried out to provide a background for the soil survey of the NE. Details of landform character and materials were explored during the survey, which involved detailed site and soil descriptions at 10,020 auger and Geoprobe sites (2 m depth), 200 backhoe pits (2 m depth), and 150 drill observations (10 m depth). The main landforms identified in the study area are the Hajar Mountains, alluvial plains (fans, plains and wadis), dunes (ridges, sand veneer, rising dunes) and coastal forms. The influence of uplift and tilting of the Hajar Mountains during the Miocene and more recently is considered. Sea level changes in the Arabian Gulf are also important. The impacts of past climate change on the evolution of landforms is discussed and related to alternating periods of arid and wet climates. The north-westerly Shamal wind is primarily responsible for the formation and continued evolution of the dune fields seen in the NE today.