KAFR HASSAN DAWOOD
|THE HISTORY OF THE SITE AND SITE FORMATION PROCESSES|
The complementary studies carried out at Kafr Hassan Dawood by the UU-UCL-SCA Egyptian team, primarily by Dr. M. Abdel-Rahman Hamden, Prof. P. Sinclair (University of Uppsala) and Prof. F. A. Hassan have resulted in the formulation of a model of site formation processes. This model integrates different perspectives obtained from the topographic mapping, microstratigraphical investigation and geophysical prospection and is presented here in summary form. The model covers the period from the Middle Pleistocene to the present.
The late Quaternary and Holocene sediments from the site of Kafr Hassan Dawood are represented by a complex sequence of both local and Nilotic deposits. The stratigraphy comprises five sedimentary units, which are overlain by aeolian sand. Each of these is made up of several types of deposits reflecting the variability of the environment of deposition at the various epochs. These units show great thickness variability and facies changes throughout the drilled cores. These sediments can be classified into the following lithostratigraphic units, from older to younger:
(5) Alluvial-Colluvial Unit.
(4) Upper Nile Mud Unit.
(3) Upper Sand Unit.
(2) Lower Nile Mud Unit.
(1) Basal Sand Unit.
In the Middle Pleistocene (500,000-150,000 BP) the area of Kafr Hassan Dawood was part of a huge fluvial channel, a meandering river of African origin, which filled the whole Wadi Tumilat and deposited the Basal Sand Unit. The heavy mineral assemblage of these deposits may indicate that they were derived with a higher contribution from Equatorial East Central Africa than at present. In the late Upper Pleistocene (30,000-12,000 BP) the area was subjected to vigorous fluvial activity. During the last glacial maximum (25,000 and 18,000 BP), the sea level was over 100 m lower than at present. As a result of this drop, deep erosion prevailed over the whole Nile Delta. The incision and lateral degradation eroded the subaerially exposed older Pleistocene deposits. It seems that the Wadi Tumilat was excavated during this period, which eroded most of the Middle Pleistocene channels leaving remnants of the Pleistocene sands, the Basal Sand Unit, as a low wide terrace on both banks of the Wadi Tumilat, including the area where Kafr Hassan Dawood is situated. The southern part of the site can be considered as one of these terraces. At the end of the Pleistocene (14,000-12,000 BP) the area was subjected to high Nile floods, which can be correlated with the Sahaba Formation of the Nile Valley and, which led to the deposition of the Lower Mud Unit over the Wadi Tumilat and Kafr Hassan Dawood.
The upper boundary of the Lower Mud Unit is sharp undulated erosive surface. The existence of a thin layer of lag gravel of black and white cortex may be interpreted as a horizon eroded by wind and/or rainwater. During the Holocene, from 8,000 to 6,000 BP, a drop in sea level accelerated the degradation of the floodplain of the Wadi Tumilat. In the area of Kafr Hassan Dawood, small wadis drained parts of the Pleistocene terraces. The wadi channels and runnels reworked older Pleistocene sand, over the Lower Mud Unit forming the Upper Sand Unit. The mineralogy of both the Basal Sand Unit and the Upper Sand Unit are similar to each other. The presence of reddish colour paleosol as a well dissected caliche layer at the top of the Upper Sand Unit indicates relatively drier conditions and warmer summers. Subsequently, fluvial aggradation resumed during the Middle and Late Holocene in response to a series of Nile floods of various magnitudes. The deposits from this episode, the Upper Mud Unit, consist of two meters of Nile silt with intercalations of local detritus.
Shortly before the excavation of the graves at the cemetery or coeval with the early settlements in Kafr Hassan Dawood, where the main cluster of large graves were dug (the southwestern part of the KHD cemetery) was deposited the Alluvial-Colluvial Unit. This unit comprises both alluvial and colluvial sediments and runs in a longitudinal South- North direction. This unit includes gravel, sand and silt complex filling a small channel or ditch, while the latter layer consists of a white ash layer and rubble lag gravel layer rich in phytoliths covering the graves. The microstratigraphy and the lithology of this unit were recovered through the archaeological excavation. This channel is 10 m wide and 1.50 m thick and runs for more than 100 m in lateral extended sections. Lateral and vertical extensions of this unit throughout the whole area were followed through a series of test pits and hand auger holes.
Around 3,500-2,900 BC the first definite human occupation at Kafr Hassan Dawood is evidenced by the Protodynastic to Early Dynastic cemetery. The paleotopography of Kafr Hassan Dawood during this period was more or less similar to the present topography. At the southern part of the area the middle Pleistocene sand formed a high terrace while the channel sand represents a lower terrace. To the North the whole area represents a wide floodplain basin, with the main Nile branch in the Wadi Tumilat flowing far to the North of the site. This indicates that the northern part of the site was subjected to two different environmental conditions. During high floods the area was covered by water forming marshes and swampy lands in the depression along the margin of the floodplain. while during periods of low flooding the area became dry land and perhaps subject to colluvial activity or wadi runoff. The early settlers at the site selected the southern sandy terrace to locate their cemetery and judging from the occurrence of pottery in the cores the flood basin as a site for their settlement. Apparently the occupants of the site found it necessary to transport silts from the northern part of the site in order to create suitable soil conditions for burial. The geoarchaeological investigation showed close lithological similarities between silts derived from the graves and those from the cores.
During the Early Dynastic Period the cemetery area was abandoned and the settlement was covered by about 4m of silt. During the late Early Dynastic to Old Kingdom periods the area was perhaps used for other purposes e.g. cultivation. Evidence for this includes calcified root casts, manganese and ochre staining and many hearths rich in burned fruits and seeds, which occur in the soil covering the graves. Dry conditions at the end of the Old Kingdom are evidenced from thick caliche layers covering part of the southern terrace and these conditions were interrupted by short interludes of flash wadi activity, which transported local materials in addition to pottery to the flood basin.
Although there were high Nile Floods during the Middle Kingdom, these subsided during the New Kingdom and ended with low Nile Floods during Dynasty XX; the site does not appear to have been occupied during any of these periods. However, from 600 BC, during the Late Period, the area was re-occupied with strong evidence for high Nile floods forcing the occupants to select the high eastern area for settlement. The area continued to be occupied, with the settlement being expanded, during Ptolemaic times, but was shortly thereafter abandoned and subjected to wind erosion, which led to deflation of the fine material and produced a thin layer of lag gravels which forms a hard crust directly overlying the graves. The occurrence of tiny fragments of pottery at ca 4.5m and 2m in the cores in advance of more detailed investigation is preliminarily interpreted here as deriving from the Predynastic and Late Period to Ptolemaic occupations respectively. This correlates well with the standard figure of 10 mm/century for the rate of sedimentation of Nile silts.
By Hassan, Sinclair, Hamden & Tassie