Basalts of the Harrats as Heritage Stone for Saudi Arabia

The basalts of western Arabia’s harrats (lava fields) constitute the largest Neogene–Quaternary monogenetic volcanic province on Earth, significantly influencing the landscape and human evolution since the Paleolithic era. Basalts are notably heavy, strong, and dark construction materials, distinguishing them from other regional building materials. The harrats represent extensive dark rock deserts that define the harsh landscape of western Arabia. Spanning nearly 3000 km and rising approximately 1000 m above sea level atop the Arabian Plate, they delineate a vast zone in western Arabia. The flat surfaces of the harrats have likely facilitated human migration since the Paleolithic era. Basalt is the predominant rock type in this expansive area, constituting a significant element of the region’s landscape and cultural heritage as heritage stones. Although not traded directly, these basalts supported early commerce in Arabia, shaping north-south trade routes for millennia. Basaltic harrats served as zones with favorable habitation conditions due to their elevated locations, lava tubes that channeled surface runoff, and broad inter-cone regions with scoria infill that promoted rapid vegetation growth and created ecological niches to sustain early humans. Historically, basalt was utilized as foundation stones or facades in building constructions. During the Early Islamic period, particularly under the Ottoman Empire, basalt became an integral construction material for mosques and other significant structures such as railway stations, fortresses, and government buildings. Basalt now serves as a significant geo-educational resource aimed at enhancing Saudi society’s resilience to volcanic hazards.