The Bible (Genesis 6–9) describes a worldwide flood (the Noachian Flood) covering even the highest mountains of the earth and the construction of a huge boat (a rectangular box-like craft) that transported animals, at least two of a kind of all land animals on the earth. The Qur'an (Suras 11 and 71) has almost a duplicate story with a similar huge boat that transported animals and a worldwide flood. In addition two older stories exist in ancient Babylonian epics that describe a huge flood. One is the Epic of Gilgamesh, describing a flood on the Euphrates River (Academy of Ancient Texts nd). The other is the Epic of Atrahasis, which has a huge flood on the Tigris River (Byers nd).
In the Epic of Gilgamesh, [Utnapishtim] is warned that a god plans to destroy all humanity and is told to build a ship to save himself, his family, friends, and cattle. In the Epic of Atrahasis, a tribal chief survived with his family by floating in a boat down to the Persian Gulf. After the flood subsided, the chief got out on dry land and erected an altar and sacrificed to a water god so that such a flood would not happen again (Anonymous nd-a). Noah also built an altar when he got off the Ark and offered sacrifices (Genesis 8:20). Because these stories all describe an ancient huge flood in Mesopotamia, it is extremely likely that a huge flood could have occurred. However, the next question is: "Did the Noachian Flood cover the whole earth?"
Scientific Evidence Against a Whole-Earth Flood
The Bible says that the rains that created the Noachian Flood lasted for 40 days (Genesis 7:17), that the waters prevailed on the earth for 150 days (Genesis 7:24), and after these 150 days the waters gradually receded from the earth so that by the seventh month and the seventeenth day, Noah's Ark came to rest upon the mountains of Ararat (Genesis 8:4). A year plus two months and twenty-seven days later the earth was dry enough so that Noah,his family, and the load of animals could disembark from the Ark (Genesis 8:14).
Because this flood was intended by God to destroy all flesh on earth (Genesis 6:13) and because sedimentary rocks on all continents contain fossils that supposedly represent the "destroyed flesh of all life," it might be thought that the Bible story, describing a wholeearth flood, was true. However, interlayered with these fossil-bearing sedimentary rocks on all continents are layers of evaporite rock salt (sodium chloride), gypsum (hydrated calcium sulfate), anhydrite (calcium sulfate), and various potash and magnesium salts, which are associated with red beds (shales) containing fossilized mud cracks (Schreiber and others 2007).
Many of these mineral compounds and red beds have combined thicknesses on different continents of more than one kilometer (~3,281 feet) (Collins 2006). The red beds are red because they contain red hematite (iron oxide) which formed from magnetite grains that were oxidized while the muds were exposed to oxygen in open air. The mud cracks can form only under drying conditions that cause the mud to shrink and form polygonal cracks. The evaporite mineral compounds in the layers are deposited in the correct chemical order predicted by the solubility of each kind of ion in these compounds and whose increasing concentrations during the evaporation of water would cause them to precipitate in a predictable depositional sequence as the water volume decreased. Such evaporite deposits would be expected to occur where a marine sea was once present and to disappear when the sea became completely dry. Therefore, one could expect these evaporites to be at the top of the supposed Noachian Flood deposits when the water supposedly receded and the land dried out, but certainly not in different levels in between older and younger fossiliferous "Flood deposits".
We read in the Bible that there is only one time in which the Flood waters are said to recede and leave the earth dry. That is, no multiple worldwide climatic conditions are described in which flooding, then drying to a dry earth, more flooding, more drying to a dry earth, in repeated cycles that occur over and over again in that Flood year. On that basis, it is logical that all the kinds of evaporite deposits and red beds in many different levels in the supposed Noachian Flood deposits could form only in local climates with desert drying-conditions and could not possibly have formed all at the same time — a time when a flood covered the whole earth for more than one year (Collins 2006). On that basis, the Noachian Flood story cannot describe a whole-earth flood, but it could only represent a large regional flood.
Regional Evidence for the Noachian and Similar Floods
Two rivers, the Euphrates and Tigris flow through Mesopotamia, which is now the country of Iraq (Figure 1). 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.