Al-Hammad

Al-Hammad Desert
A satellite image of the Levant region showing the Hammad Badia as a barren desert stretching from northern Saudi Arabia through Jordan's Mafraq governorate into Syria and Iraq.
Highest point
Peak	815 km2 (315 sq mi)
Dimensions
Area	166,000 km2 (64,000 sq mi)
Geography
Location	Iraq, Syria, Jordan, Saudi Arabia

Al-Hammad Desert is a region distinguished by its flat terrain, which extends from northern Saudi Arabia through eastern Jordan to the southeastern region of Syria and western Iraq.

Al-Hammad Desert is considered a region of desertification, traditionally inhabited by the Bedouins, known as the nomadic people of the desert. Some of these Bedouins have left the desert and settled in cities, yet they continue to hold onto their rich Bedouin customs and traditions.

Etymology

The term "Al-Hammad" is used in geomorphology to describe landforms where over 50% of the surface is covered by stones. The size of these stones ranges from the size of a human hand to the size of a human head, making the terrain difficult to traverse. The region is classified into three types based on the types of rocks that cover it: basalt, limestone, and flint.

Geography

Plateau constitutes a portion of the Arabian Shield, with 12% of its surface area comprising rock outcrops originating from the Paleozoic and Mesozoic eras. These rock formations are particularly prevalent in the eastern section, with notable examples observed in the Al-Qa'arah region of Iraq. The remainder of the surface is comprised of formations from the Cenozoic era, which include marine, continental, and volcanic basaltic deposits. Basalt formations typically manifest as bands extending from north to south in the eastern part and from north-northwest to southeast in the western part. Sedimentary layers slope gently from the northeastern and southwestern edges towards the center, creating a flat or slightly undulating surface. The depressions in these areas provide ample space for windblown and alluvial Quaternary deposits.

Plateau sections

The plateau is topographically divided from southwest to northeast as follows:Wadi Al-Sirhan Depression, 330-kilometer-long trough of relaxation, situated between the Haifa oil pumping station in the north of Jordan and Ghwaita Jarad in the south of Saudi Arabia. The depression is bounded by the basaltic plateau to the east and is marked by the Hadhdho Salt Flat and several smaller salt flats and mud flats along its length, situated in the middle of the basin. The depression's elevation is 550 meters above sea level, with predominant Quaternary and Miocene (Neogene) formations, except its far northern tip. The central portion of the region is distinguished by arid soil with clay layers, whereas the north of area is typified by dry limestone soil, and the southern region exhibits a transition to desert and sandy desert soil.

Western valleys of Wadi Al-Sirhan

Exhibits a southwesterly slope, reaching the edge of the Hamad Basin and elevations between 1,050 and 1,010 meters. These valleys typically flow in an eastward direction towards the Wadi Al-Sirhan Depression. The southern portion of the region encompasses Quaternary alluvial deposits, some of which are windborne, while the northern region is characterized by Paleogene formations, and the central areas are predominantly Cretaceous. The soil composition is predominantly dry gypsum or limestone, with desert alluvial soil observed in the valleys.

Basaltic plateau

It is situated between Diera Al-Talool and Salkhad in the extreme west and northwest of Syria, and Al-Mufrijiyah or the edges of Harrat Al-Harra in the south of Saudi Arabia. The elevation of the plateau exceeds 1,400 meters in Jabal Al-Arab, situated to the south of Salkhad. This elevation marks the eastern and northern water divides of the Wadi Al-Sirhan Basin. The plateau is composed of a multitude of volcanic flows spanning a range of ages, from the early Neogene to the late Quaternary. The plateau's rugged terrain is marked by dozens of volcanic cones, some of which exhibit characteristics such as broken craters or craters that resemble lakes. An example of this is Jabal Sees. A multitude of closed basins, comprising clayey mudflats or salty sabkhas, are present in the region. These basins experience desiccation during the summer months, with notable examples including the Manqar and Ghub Sabkhas in Syria and the Mataita and Fifth Station Sabkhas in Jordan, as well as Dukra and other salt lakes in Saudi Arabia. The surface is predominantly basaltic rock, with interspersed dry limestone or gypsum soils, as well as desert soils in some areas. These include sandy desert soils in the center and alluvial desert soils to the south.

Central Hamad Plateau

Which extends from the northernmost point of the western basin to its southeastern border. The eastern and northern margins of the plateau delineate the hydrological boundary between the Euphrates valleys and the Palmyra Basin, on one side, and the salt flats and valleys with autonomous internal drainage on the other. The mountain rises to an elevation of approximately 1,000 meters above sea level. Its northern and eastern borders feature jagged edges due to vertical erosion by cutting valleys. The ridges of the Hamad Plateau rise to elevations between 30 and 60 meters above the surrounding terrain. The plateau also contains volcanic flows and cones, including Jabal Al-Tanaf and Al-Ghrab, which traverse the region. On the Syrian side of the plateau, there are several sabkhas, including Al-Zuqf, Al-Tanaf, and Al-Shaheemi. The soil composition is primarily dry limestone or gypsum, followed by desert soil and alluvial desert soil.

Euphrates Basin and Palmyra Basin area

Exhibits similarities to the preceding regions with respect to soil composition and is situated in the northeastern portion of the Hamad Basin. The region differs structurally, being part of the western side of the Rutba Uplift. Paleozoic layers are exposed in the Al-Qa'rah region, while Mesozoic layers are present in most of the remaining areas of the Iraqi side of the Hamad Basin and in some parts of the Saudi side in the extreme east. The lowest points of the Hamad Basin are located in the valleys, with the lowest point reaching 450 meters. Notable valleys in Syria include Al-Murabba', Al-Miyah, and Suwab, while in Iraq, the Horan valley is of particular significance. In Saudi Arabia, the Al-Abyad valley is also of interest.