5000 BC Post-Glacial Sea Transgression

The Tigris and Euphrates delta is formed in the Persian Gulf. Many maps of the earliest periods of history show the shoreline as far north as Ur. That means the delta has filled in at least 150 miles during recorded times. substantial sea-level oscillations were experienced globally during the last deglacial hemicycle. Initial emergence commenced at 13 ka, coincident with local deglaciation, and until 10.5 ka was characterized by a relative slow rate of emergence (1.5 to 5 m/ka) interrupted by minor stillstands or transgressions associated with possible glacier re-advances. A period of accelerated emergence (15 to 30 m/ka) between 10.5 and 9 ka is correlative with rapid deglaciation of fiords. The middle and late Holocene is characterized by two brief transgressions: one between 6.5 and 5.0 ka that did not exceed 7 m asl and a present, probable slow rise in sea level that commenced 2 to 1 ka.

Post-last glacial maximum (post-LGM) sea-level transgression was punctuated by six relatively short flooding events that collectively accounted for more than 90 m of the 120-m rise. Annual sea-level rise during the two major flooding events (MWP-1A and 1B, 14.3-14.1 and 11.6-11.4 calendar ka BP, respectively) averaged ~60-80 mm/yr, compared to 2-3 mm/y during periods of slow transgression. During MWP-1A (14.3-14.1 ka BP), for example, sea level on the epicontinental East China and Yellow seas transgressed horizontally more than 2000 m/yr, compared to < 25 m/yr before and after.

The evolution of the earliest complex state-level societies and cities, from small sedentary communities, took place in southern Mesopotamia between 7.5 and 5 ka during the 'Ubaid and Uruk Periods. Recent attempts to explain this transition discount the role of environmental change and evaluate the available archaeological evidence for the development of cultural complexity in this region within a static environmental context and/or under conditions similar to those of the modern environment. However, new paleoenvironmental records clearly indicate that modern conditions differ considerably from those of the early to middle Holocene, a time of major environmental and cultural change in this key region.

James P. KENNETT and Douglas J. KENNETT hypothesize that the development of complex societies in southern Mesopotamia resulted, in part, from human responses to resource change caused by a critical confluence of eustatic and climatic changes unique to this circumscribed region. Although it is inherently difficult to link past cultural and environmental developments with mythology, based on the environmental and cultural history of the region, the Sumerian flood myth (as recorded in the Gilgamesh Epic) and the succeeding biblical flood narrative, may have their origins in the glacio-eustatic latest Quaternary transgression in the Arabo-Persian Gulf; the largest, shallowest inland sea contiguous with the ocean. Flood myths, often orally transmitted through to modern times, appear widespread among maritime societies and can be attributed to late Quaternary deglaciation and sea-level rise. The Kennetts argue that earliest written flood myth narrative (Gilgamesh) likely reflects environmental changes in Southern Mesopotamia that contributed to the emergence of cultural complexity, and hence its documentation through the development of the first writing systems.

The wetland (Ahwar) area have been formed since the deluge time of the main post global glacial melt 10,000 years ago that raised oceanic water level to 70 m (the last and the more active successive rise during the ice melting 18,000 to 10,000 years ago) and hence oceanic water from the Arabian sea were pushed in transgression to the greater Mesopotamian valley and formed the Arabian Gulf since the early Holocene. This scenario was proven in the global context based on coral reef changes in the Great Barrier Reef of the East Australian shelf and on the basis of pollen records in the Eastern Mediterranean for the glacial-interglacial transitions.

Retreat of this transgressed oceanic water 6,000 years ago formed the theme for the water fill in the depressions of Southern Iraq while continued water supply from the Tigris and Euphrates rivers formed this continued ecosystem of the wetland in Southern Iraq. This wetland ecosystem could be represented as part of the cyclic successive stages of geographic development in Mesopotamia as a response to transgressions and regressions of the latest glacial epoch on earth. Accumulated sediments in this wetland area are fluvial clay and sand during the Pleistocene while the Holocene sediments are of fluvial sand, marsh organic sediment, marine sand and silt, peat and fluvial clay and silt.

Climatic change and vegetation collapse and shortage of food were equivalent to short ice age in the northern hemisphere and volcanic activity in the Jordanian Desert, while an event of increased rainfall precipitation with increased poaceae and cultivated plants was during the Sumerian and Babylonian cultures. On the other hand, many sea level oscillations have caused many floods such as floods of Ur (5,400 years B.P.) and Kish (4,850 years B.P.) evident by flood plain deposits and the archeological records reported from Sumerian mud plate scripts. During that flood time, the Atonabishtem legend has been written. It said that he is the immortal who voyaged through the flood and floated with his group in a ship that saved them from the flood.

In 1882 and 1883 Sir Henry Howorth published a series of papers in The Geological Magazine of great interest and value, entitled Traces of a Great Post-Glacial Flood, in which he endeavoured to prove that the superficial deposits of the Pleistocene Period, such as the loess, the brick-earths, the angular gravels, the marine drifts, &c, were not deposited by fluviatile or glacial action, but were formed rapidly by a sudden and overwhelming deluge. In 1887 he published an elaborate and fascinating book called The Mammoth and the Flood, which still further developed the argument of the before-named papers, and was, as he himself declares, an attempt to confront the theory of " Uniformity " with the facts of recent geology. In this book Sir H. Howorth described the occurrence of the bones and carcases of the mammoth in Siberia, and in the islands in the Arctic Sea, and he further showed, from a review of the geological facts in Northern Europe, and in North and South America, that the great Pleistocene mammalia were swept away by a great flood.

Continuing his argument, he next demonstrated that man was present when this deluge took place, and was overwhelmed by it, for this flood closed what geologists call the Palaeolithic Age, in which man used only rude stone weapons, while in the later or Neolithic Age he was armed with weapons of polished stone. There is a great gap between these two periods. They are quite distinct as to their animals, climate, and physical geography, and the gulf between these two ages was occasioned- according to our author-by the great flood, which took place in comparatively recent times, so far as geology is concerned. Sir H. Howorth next referred to the well-known fact that there are traditions of a deluge preserved amongst most races, rude and civilized, and he concluded his argument by declaring that the flood, which geology showed closed the Pleistocene Period, was the same as these traditions refer to, and was, in fact, the deluge of Noah described in the Book of Genesis. ['The Glacial Nightmare and the Flood. By Sir Henry Howorth, K.C.I.E., M.P., F.G.S. Two vols. London : Sampson Low, Marston ft Co. 1893.]

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