The emerging picture of prehistoric Arabia suggests that early modern humans were able to survive periodic hyperarid oscillations by contracting into environmental refugia around the coastal margins of the peninsula. This paper reviews new paleoenvironmental, archaeological, and genetic evidence from the Arabian Peninsula and southern Iran to explore the possibility of a demographic refugium dubbed the “Gulf Oasis,” which is posited to have been a vitally significant zone for populations residing in southwest Asia during the Late Pleistocene and Early Holocene. These data are used to assess the role of this large oasis, which, before being submerged beneath the waters of the Indian Ocean, was well watered by the Tigris, Euphrates, Karun, and Wadi Batin rivers as well as subterranean aquifers flowing beneath the Arabian subcontinent. Inverse to the amount of annual precipitation falling across the interior, reduced sea levels periodically exposed large portions of the Arabo-Persian Gulf, equal at times to the size of Great Britain. Therefore, when the hinterlands were desiccated, populations could have contracted into the Gulf Oasis to exploit its freshwater springs and rivers. This dynamic relationship between environmental amelioration/desiccation and marine transgression/regression is thought to have driven demographic exchange into and out of this zone over the course of the Late Pleistocene and Early Holocene, as well as having played an important role in shaping the cultural evolution of local human populations during that interval.
Recent fieldwork conducted throughout the Arabian subcontinent indicates that human demography was far more complex than has been considered until now. Contrary to expectations of a well-trodden Stone Age highway, new data collected by archaeologists working in Yemen (Crassard 2009; Delagnes et al. 2008; Fedele 2009), Oman (Jagher 2009; Rose and Usik 2009), and the United Arab Emirates (UAE; Marks 2009; Uerpmann, Potts, and Uerpmann 2009) suggest that parts of the peninsula may have served as population refugia, enabling indigenous hunter-gatherers to survive in localized pockets during periodic climatic downturns (Rose and Petraglia 2009). Far from finding East African–derived lithic technologies spilling over into Arabia, freshly unearthed evidence points to a conspicuous lack of connection with African lithic industries following the last interglacial (Rose and Usik 2009). These industries tend to exhibit a distinct Arabian tradition, suggesting minimal demographic input from outside the peninsula. Thus, it is germane to consider the possibility that humans have continuously occupied parts of Arabia for the past 100,000 years, if not longer.
The Arabian subcontinent houses a mosaic of microenvironments, some of which provided stable, predictable sources of food and freshwater even during the most hyperarid phases of prehistory. At times when glacial conditions led to increased aridity and widespread environmental degradation, reduced sea levels exposed large portions of the continental shelf and caused the formation of “coastal oases” fed by upwelling subterranean springs (Faure, Walter, and Grant 2002). Taking into account the concentration of freshwater resources in coastal and other low-lying areas, as well as annual rates of precipitation, figure 1 depicts three proposed refugia around Arabia: (1) the Red Sea basin and ‘Asir-Yemeni highlands, (2) the southeast Arabian littoral zone, and (3) the exposed basin of the Arabo-Persian Gulf.1
There are few places on earth that have undergone such profound shifts in landscape as the Arabian Peninsula. Over the course of the Quaternary, the subcontinent has been affected almost exclusively by two climatic regimes: westerlies and the Indian Ocean monsoon system. Westerlies are storms that form over the Mediterranean and advance down the Arabo-Persian Gulf, scattering light to moderate rainfall (40–120 mm/yr) around the Gulf territories throughout the winter months. The Indian Ocean monsoon is responsible for summer khareef storms that bring cool temperatures, high humidity, and frequent rains to the Dhofar Mountains and coastal plain along the southern coastline of Arabia between late June and early September.
The Indian Ocean monsoon is particularly sensitive to fluctuations in global insolation patterns; during glacial periods, the intertropical convergence zone (ITCZ) drifts to the south, while a return to warmer conditions causes the ITCZ to shift further north and deposit seasonal rains far into the Rub’ Al Khali desert. Throughout the Pleistocene, these meteorological dynamics have caused dramatic oscillations across the interior, transforming barren sand seas into fertile grasslands and back again (e.g., Fleitmann et al. 2007; McClure 1976; Parker and Rose 2008). Variable distribution of water and food over time likely had significant demographic implications, creating a cyclical ebb and flow of population expansion and contraction from the three core refugia depicted in figure 1 into marginal zones along the periphery.
Given the extent of the exposed land within the Gulf basin, the abundance of food, water, lithic raw material, and its conscripted geographic position, this sizable inland depression is thought to have formed one of the most important oases in the ancient world. Situated along the eastern edge of the peninsula, the Arabo-Persian Gulf is among the shallowest seas in the world, with average depths of just 40 m. When global sea levels dropped below this mark at the onset of MIS 4, more than 100,000 km2 of land were continuously exposed for the ensuing 70,000 years. During that interval, the basin housed a rich mosaic of freshwater springs, river floodplains, mangrove swamps, and estuaries (Al-Hinai, Moore, and Bush 1987; Alsharhan and Kendall 2003; Butler 1969; Diester-Haass 1973; Evans 1966; Georgiev and Stoffers 1980; Gischler et al. 2005; Lambeck 1996; Saleh et al. 1999; Sarnthein 1972; Seibold and Vollbrecht 1969; Stoffers and Ross 1979; Sugden 1963; Uchupi, Swift, and Ross 1996, 1999; Williams 1999; Wilkinson and Drummond 2004). Adding to its appeal, there are high-quality chert deposits exposed in patches across the landscape. Bahrain, Qatar, and the islands just off the coast of Abu Dhabi Emirate are riddled with such outcrops (Beech, Elders, and Shepherd 2000; Cavelier 1970; Edgell1992; Kapel 1967).
The Arabo-Persian Gulf basin is the terminus of several major river systems (fig. 2); the majority of all freshwater in southwest Asia ultimately drains into this large depression via surface runoff and underground rivers (Alsharhan et al. 2001; Shiraz and Münster 1992; Sultan et al. 2008). Currently much of the subterranean freshwater upwells from beneath the central Gulf through karstic limestone lining the basin, called khawakb in local Bahraini dialect. “Coastal oases” are likely to have formed around these khawakb when reduced sea levels exposed the surrounding landscape and triggered increased pressure on the hydrostatic head of the aquifers (Faure, Walter, and Grant 2002). The island of Bahrain, meaning in Arabic “the two seas,” is thought to reference the dual saltwater sea surrounding the island and freshwater sea upwelling from the submerged floor of the Gulf.
Two rivers, the Euphrates and Tigris flow through Mesopotamia, which is now the country of Iraq. There are several layers in exposed rocks near these two rivers in southeastern Mesopotamia (Iraq) that are likely flood deposits. Most are about a foot (0.3 m) thick, but one is as much as 3 meters thick (MacDonald 1988). Flood debris from this same thick deposit along the Euphrates River near the ancient Sumerian city of Shuruppak about 200 km southeast of Baghdad has been dated by the C14 method, giving an age of 2900 BCE (Best nd). Flood deposits 2.4 meters feet thick are also reported by MacDonald (1988) as far northeast as the ancient Babylonian city of Kish (120 km south of Baghdad). At any rate, the many flood-deposit layers show that flooding in southeastern Mesopotamia was not unusual in ancient times.
The Garden of Eden (Hebrew גַּן עֵדֶן, Gan ʿEdhen) is the biblical “garden of God”, described most notably in the Book of Genesis chapters 2 and 3, and also in the Book of Ezekiel. The “garden of God”, not called Eden, is mentioned in Genesis 14, and the “trees of the garden” are mentioned in Ezekiel 31. The Book of Zechariah and the Book of Psalms also refer to trees and water in relation to the temple without explicitly mentioning Eden.
Traditionally, the favoured derivation of the name “Eden” was from the Akkadian edinnu, derived from a Sumerian word meaning “plain” or “steppe”. Eden is now believed to be more closely related to an Aramaic root word meaning “fruitful, well-watered.” The Hebrew term is translated “pleasure” in Sarah’s secret saying in Genesis 18:12.
The story of Eden echoes the Mesopotamian myth of a king, as a primordial man, who is placed in a divine garden to guard the tree of life. In theHebrew Bible, Adam and Eve are depicted as walking around the Garden of Eden naked due to their innocence. Eden and its rivers may signify the real Jerusalem, the Temple of Solomon, or the Promised Land. It may also represent the divine garden on Zion, and the mountain of God, which was also Jerusalem. The imagery of the Garden, with its serpent and cherubs, has been compared to the images of the Solomonic Temple with its copper serpent, the nehushtan, and guardian cherubs.
Juris Zarins believes that the Garden of Eden was situated at the head of the Persian Gulf, where the Tigris and Euphrates Rivers run into the sea, from his research on this area using information from many different sources, including Landsat images from space. In this theory, the Bible’s Gihon River would correspond with the Karun River in Iran, and the Pishon River would correspond to the Wadi Batin river system that once drained the now dry, but once quite fertile central part of the Arabian Peninsula.
David M. Rohl (British Egyptologist and former director of the Institute for the Study of Interdisciplinary Sciences) posits a location for the legendary Garden of Eden in Iranian Azerbaijan, in the vicinity of Tabriz upon which the Genesis tradition was based. According to Rohl, the Garden of Eden was then located in a long valley to the north of Sahand volcano, near Tabriz. He cites several geographical similarities and toponyms which he believes match the biblical description. These similarities include the nearby headwaters of the four rivers of Eden, the Tigris (Heb. Hiddekel, Akk. Idiqlat), Euphrates (Heb. Perath, Akk. Purattu), Gaihun-Aras (Heb., Gihon), and Uizun (Heb. Pishon)
Gihon is the name of the second river mentioned in the second chapter of the biblical Book of Genesis. The Gihon is mentioned as one of four rivers (along with the Tigris, Euphrates, and Pishon) issuing out of the Garden of Eden that branched from a single river within the garden. The name (Hebrew Giħôn גיחון) may be interpreted as “bursting forth, gushing”.
The Gihon is described as “encircling the entire land of Cush“, a name associated with Ethiopia elsewhere in the Bible or Kush. This is one of the reasons that Ethiopians have long identified the Gihon (Giyon) with the Abay River (Blue Nile), which encircles the former kingdom of Gojjam. From a current geographic standpoint this would seem impossible, since two of the other rivers said to issue out of Eden, the Tigris and the Euphrates, are in Mesopotamia. However, the scholar Edward Ullendorff has argued in support of this identification. The city in the Mesopotamian area which best fits the description is called Kish (derivative of Kush or Cush) located in a plain area (Sumerian ‘edin’) and resembles an area that is repeatedly flooded by the rivers Euphrates and Tigris.
Nineteenth century, modern, and Arabic scholars have sought to identify the “land of Cush” with Hindu Kush, and Gihon with Amu Darya (Jihon/Jayhon of the Islamic texts). Amu Darya was known in the medieval Islamic writers as Jayhun or Ceyhun in Turkish.This was a derivative of Jihon, or Zhihon as it is still known by the Persians.
Gihon has also been associated with the Araxes (modern Aras) river of Turkey. Another proposed idea is that the Gihon river no longer exists, or has significantly altered its course, since the topography of the area has supposedly been altered by the Noachian Flood.