–– Physical geography ––Figure 1.1(a) The Mesopotamian Zone geosyncline (white hachure) forms where the Arabian
plate is forced below the Zagros Mountains. Image: NASA 2001 b MODIS. (b) Mesopotamian
Zone tectonic subunits. Arrows, hachure indicate tilt direction. (c) Mesopotamian alluvial
topology, showing sharp drop to the unstable shelf, and southeast trend tilted toward the Zagros
from L. Tharthar to the Gulf. The Wadi al-Khar’s alluvial fan tends to push Euphrates water
eastward. Fresh water ponds behind, and tidal flushing extends inland to the Zubair sill (black
bar). Manually retouched mosaic of NIMA DTED 01 ° quadrangles, with ENVITM 3. 5 linear
stretch ( 16 : 243 ) applied. (d) Boundary uplands. (e) The Shatt al-Arab deltaic system. After
Verhoeven 1998 , Sanlaville 2003. (f ) Contemporary ( 1 ) Levees, ( 2 ) Crevasse splays,
( 3 ) Alluvial soils, ( 4 ) Bird’s foot delta. Box: see Figure 1. 2 a.