The Mesopotamian Delta Region: A Reconsideration of Lees and Falcon

Lees and Falcon's study of 1952 challenged traditional concepts of paleogeography in the Mesopotamian plain. In particular, an earlier theory that considered the head of the Persian Gulf to have been in the vicinity of Baghdad and Samarra in the late pre-historic period (5000-4000 B.C.) was negated by evidence that world-wide sea levels were lower than present at that time. A related early theory claimed simple delta advance to have filled the northern portion of the Gulf, at the same time translating the shoreline seaward. This theory was also rejected by Lees and Falcon who claimed, on the basis of stratigraphic evidence and recent tectonic activity, that the head of the Gulf had not been significantly northwest of its present position since the Pliocene. Recent research in the region suggests the latter claim to have been premature. Continuity of submerged post-Pleistocene marine terraces between Abu Dhabi and Kuwait point to little historic tectonic movement in the western portion of the delta. Marine clays and silts below the delta that had been used to indicate major subsidence imore reasonably show a marine or estuarine embayment perhaps extending as far inland as Amara and caused by the attainment of a near present sea level between 4000 and 3000 n.c. Alluvial sediments overlying these clays indicate overall progradation of the delta region for a distance of 150 to 180 km during the historic period. Textual sources that consistently relate the city sites of Ur and Eridu with a seacoast may have more validity than was previously considered.