Geomorphology of the lower Mesopotamian plain at Tell Zurghul archaeological site

Figures & data

Figure 1. Satellite imagery (ESRI TerraColor NextGen) of the study area (red rectangle) and the location of satellite imageries in Figure 2 (black squares).

The satellite image from the TerraColor NextGen dataset where the red rectangle defines the study area. The latter is in the southern Mesopotamian Plain (as shown by the map in the left corner), along the Shatt al-Gharraf River, northward from Nasiriyah. The study area encloses the archaeological site of Girsu (the northernmost site), Lagash, Tell Zurghul, and Guabba (the southernmost site), which belong to the ancient State of Lagash.

Figure 2. Satellite imageries (ESRI TerraColor NextGen) of inactive fluvial channels (A, B), active canals (C), and the active fluvial channels with the perpendicular herringbone pattern of the crops (D). In Figure 2A, the black arrows point out the yellowish-brownish features of the inactive fluvial channels, while the red rectangles highlight the herringbone pattern of inactive canals. In Figure 2B, the black lines point out the ridge-and-swale texture of the scroll bars.

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Four different optical TerraColor NextGen images (namely, A, B, C, and D) representing the main optical characteristics of the inactive and active fluvial channels. Fig 2A represents the tone of inactive fluvial channels, essentially brownish and yellowish, with a sinuous meandering pattern and where occasionally the traces of inactive irrigation canals with a herringbone pattern occur. Fig 2B represents the scroll bars frequently linked with a channel belt, delimited by two black lines. The scroll bars are characterized by a ridge-and-swale profile that we can appreciate thanks to the alternation between darker and lighter pixels. Fig 2C shows the regular spatial distribution of the irrigation canals with a rectangular pattern, as well as Fig 2D, where the green pixels highlight the perpendicular direction of crops along the active fluvial channels.

Figure 3. The multispectral indices NDVI and CR; the highest values of both indices are in the westernmost sector over the active Shatt al-Gharraf floodplain.

The study area is coloured according to the maximum values of the Normalized Difference of Vegetation Index (NDVI) and the Clay Ratio (CR). Their maximum distribution is in the western sector where active fluvial landforms occur, while the eastern sector shows the lowest values, pointing out the absence of vegetation and the prevalence of sandiest deposits.

Figure 4. Satellite view (A) and AW3D30 DSM (B) where the altimetric profile has been constructed along an inactive crevasse splays on the right bank of the Shatt al-Gharraf. The modified crevasse channels (MCC) are higher than the inactive crevasse channels (ICC).

The colour-coded classified AW3D30, where on the left bank of the Shatt al-Gharraf River an inactive crevasse splay has been recognized. Its boundary has been mapped with a light green line, while several channels, recognized both as modified crevasse channels and inactive crevasse channels, are mapped with dark and light green lines, respectively. In the lower-left corner, the altimetric profile of the crevasse apex sector shows the higher elevation of the modified crevasse channels, while the inactive crevasse channels are considerably lower.

Figure 5. The irrigation canals mapped with red lines partially overlap the inactive fluvial channels traced by black dotted lines.

The TerraColor NextGen image where red lines mapped the system of irrigation canals. Some irrigation canals followed the same direction of inactive fluvial channels, partially deleting their traces, but the black arrows point out where the texture and the meandering pattern allow the recognition of an inactive fluvial channel.

Figure 6. The UAV orthophoto of Tell Zurghul archaeological site acquired on 2017 (MAIN^© Missione Archeologica Italiana a Nigin).

The UAV natural-color orthophoto of Tell Zurghul archaeological site.

Figure 7. Natural-color images acquired by MODIS instruments carried by Terra and Aqua Satellites. Severe dust storms over Iraqi territory dated on 16 May 2022 (A) and 31 October 2017 (B). Images available online at NASA Earth Observatory (n.a.) website (https://earthobservatory.nasa.gov/images)

Two natural-color imageries acquired by MODIS Satellite where two dust storms dated on 16 May 2022 and 31 October 2017 are detectable. Indeed, where the Mesopotamian Plain is completely hidden by yellowish pixels corresponds to the areas with the highest concentrated dust.

Figure 8. The AW3D30 reclassification where the four main TDCs of the study area are recognized and mapped.

The reclassification of AW3D30 DSM where the pixels below the value of 6 m a.s.l. are coloured blue. In this manner, the northern and western sectors of the study area result above sea level during the maximum marine ingression, as well as the archaeological sites of Lagash, Tell Zurghul and Guabba. Moreover, four main terminal distributary channels result above sea level and prograde southward, allowing their mapping.

NASA Earth Observatory. (n.a.). Retrieved June 4, 2022, from https://earthobservatory.nasa.gov/images/related/39006/dust-storm-in-the-middle-east

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Data availability statement

The data that support the findings of this study are available from the corresponding author, Iacobucci G., upon reasonable request.