Beneath Iran's bone-dry Great Salt Desert lies a massive, ancient, buried ocean

Countries & Cities · Published 30 September 2026 Swipe more like this →

In short: To the casual observer, Dasht-e Kavir appears as a desolate, sun-scorched expanse that has remained unchanged since the dawn of time. Yet, geologists see a different story written in the landscape: a complex, shifting history defined by the evaporation of a vast, prehistoric ocean that once covered central Iran.

Located roughly 300 kilometers east-southeast of Tehran, the Dasht-e Kavir, or Great Salt Desert, is a geological palimpsest. Tens of millions of years ago, this region was submerged beneath a salt-rich ocean that surrounded a central Iranian microcontinent. As this ancient sea eventually evaporated, it deposited a staggering layer of salt reaching depths of 6 to 7 kilometers.

Because salt has a relatively low density, it behaves uniquely when buried under layers of younger, softer rock. Over time, the salt layer can slowly push upward, piercing through the overlying strata to form geological structures known as salt domes or diapirs. Geologists have identified approximately 50 of these large diapirs across the desert landscape. These domes are not static; they are subject to constant erosion from wind and rain, which gradually strips away the surface rock and exposes the internal salt structures in cross-section.

The desert's complexity is further heightened by ongoing tectonic forces. Beyond the salt domes, the landscape features north-south-trending structures, including raised and lowered fault zones that align with the region’s mountain ranges. Geologist Callan Bentley notes that these deformations indicate plate tectonic activity occurring after the initial formation of the salt domes. This interplay between ancient deposition, salt diapirism, and modern tectonic folding creates a unique, rugged terrain that serves as a physical record of millions of years of environmental change.

Understanding these mechanisms is vital for interpreting the desert's evolution. The salt domes act as a chronological marker, helping researchers constrain the timing of diapirism to a period preceding the regional folding. By studying these exposed cross-sections, scientists can reconstruct the environmental shifts that transformed a once-wetter, ocean-covered basin into the arid, salt-crusted expanse observed today.

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