Iranian plateau

The Iranian plateau, sometimes called the Persian plateau, is both a geological feature and a historical region. Geologically, it sits on the Eurasian plate, squeezed between the Arabian and Indian plates. It is bounded by the Zagros Mountains to the west, the Caspian Sea and Köpet Dag to the north, the Armenian Highlands to the northwest, the Strait of Hormuz and Persian Gulf to the south, the Indian subcontinent to the southeast, and the Hindu Kush and Sulaiman Mountains to the east. Historically, this area includes the ancient regions of Parthia, Media, Persis, and parts of what was once Greater Iran. The Zagros Mountains mark its western edge, and sometimes the eastern slopes of those mountains are also considered part of the plateau. The Encyclopædia Britannica specifically excludes lowland Khuzestan and notes that Elam stretched from the Mesopotamian plain onto the Iranian plateau.

The plateau stretches about 2,000 kilometers from the Caspian Sea in the northwest to the Sulaiman Mountains in the southeast. It covers roughly 3,700,000 square kilometers, taking in most of Iran, all of Afghanistan, and those parts of Pakistan west of the Indus River. Despite its name, the terrain is far from flat and includes several mountain ranges. The highest point is Noshaq in the Hindu Kush, at 7,492 meters, while the lowest is the Lut Desert in eastern Iran, below 300 meters.

In geology, the plateau formed mainly from Gondwanan terranes that accreted between the Turan platform to the north and the Zagros fold-and-thrust belt. The suture zone where the Arabian plate moves northward into Eurasia is the plateau itself. It is well studied because of its role in continental collision and Iran’s long history of geological research, especially in economic geology.

Geographically, the plateau is defined as the area north of the folded mountain belts created by the Arabian-Eurasian collision. Under this definition, southwestern Iran is not included. The plateau runs from East Azerbaijan province in northwestern Iran through Afghanistan and into Pakistan west of the Indus. It also includes small parts of Azerbaijan, Iraqi Kurdistan, and Turkmenistan. The northwestern part, where the Pontic and Taurus Mountains meet, is rugged, with higher elevations, a harsher climate, and more rain than the Anatolian plateau. This area is called the Anti-Taurus, with peaks averaging over 3,000 meters. Mount Ararat, Turkey’s highest point at 5,137 meters, lies here, as does Lake Van at 1,567 meters. Major rivers rise in the Anti-Taurus: the Aras flows east to the Caspian, while the Euphrates and Tigris flow south into the Persian Gulf. Smaller streams feed the Black Sea or Lake Van. The Indus River begins in Tibet and flows through Pakistan, roughly tracing the plateau’s eastern edge. Southeast Anatolia, south of the Anti-Taurus, is rolling hills and a broad plateau that extends into Syria, with elevations dropping from about 800 meters in the north to 500 meters in the south. Wheat and barley are traditional crops there.

The plateau’s mountain ranges fall into five subregions. The Northwest Iranian Ranges include the Alborz, with Damavand at 5,610 meters. The Southwest Iranian Ranges are the Zagros, with Dena at 4,409 meters. The Central Iranian plateau has Kūh-e Hazār at 4,500 meters and Kuh-e Jebal Barez. The Eastern Iranian Ranges include the Kopet Dag, Kuh-e Siah Khvani at 3,314 meters, and the Eshdeger Range at 2,920 meters. Balochistan features Sikaram at 4,755 meters, Kuh-e Taftan at 3,941 meters, and Zargun at 3,578 meters. Rivers and plains include the Kavir Desert, Lut Desert, Hamun-e Jaz Murian, Halil River, Gavkhouni, Zayandeh River, Sistan Basin, Helmand River, and Farah River.

Historically, the Iranian plateau may have been a key population hub after modern humans left Africa. Around 50,000 years ago, it is thought that “Common Eurasians” diverged there into “Ancient East Eurasians” and “Ancient West Eurasians,” then spread in two waves during the Initial Upper Paleolithic (about 45,000 years ago) and Upper Paleolithic (about 38,000 years ago). Ancient and modern populations on the plateau share a genetic component with the Ancient West Eurasian lineage that remained in this hub, but also show ancestry from Basal Eurasians and Ancient East Eurasians due to contact starting in the Paleolithic. In the Bronze Age, Elam stretched across the Zagros, linking Mesopotamia and the plateau. The kingdom of Aratta, known from cuneiform texts, may have been in the central plateau. In classical times, the region was called Persia, after the Achaemenid dynasty from Fars. The Middle Persian term *Erān* (modern *Irān*) began to refer to the state, not just an ethnic group, during the Sasanian era.

Archaeological sites and cultures on the plateau include the central Iranian plateau’s “Jiroft culture,” Shahr-e Sukhteh, Konar Sandal, Tepe Yahya, and Zayandeh.