The main article summarized is by the authors: Ralph O. Allen, Hany Hamroush, and Daniel J. Stanley entitled the Impact of the Environment on Egyptian Civilization Before the Pharaohs. The authors provide the reader with adequate background information before going into to their research findings. Nile floods, local climatic conditions, and the paleogreography of the Nile Valley governed the paleoenvironment of Egypt during these prehistoric times. Annual floods carried fresh sediments that were deposited when the water overflowed the banks and were instrumental to agriculture as seeds were spread on water becoming trapped by the banks as the flood receded, and settled to the bottom along with fresh Nile sediment. Anticipating the onset of floods, which provided the unique opportunity for growth, became one of the key elements in the development of religious customs and practices
Most early archaeological sites such as Nekhen are inaccessible to the flood plain of the Nile bordering or under the modern cultivation zone. Currently, most of these prehistoric sites are situated beneath land where 50 million people now live. Obviously this is problematic for the archaeologists involved in this research. To get around this the archaeologists at the Smithsonian Institutue collected and analyzed sediment mineral in rocks from layers dated to before the age of the Pharaohs in rocks covering the terrains of Nile headwaters in eastern and central Africa. Observations of the heavy minerals in these core samples indicated oscillations in the total sediment load and the relative contributions from the different terrains in Africa. This poses a problem in itself because the small abundance of the minerals used, and irregularities in local transport and deposition of the suspended sediments create considerable variability.
Analysis of these sediments indicates that deposits from at least 6000-5200 B.P. were substantial and then the pattern changed. Floods stopped carrying sediments up onto areas that are presently at the edge of the cultivation zone. Local conditions resulted in the deposition of sediments derived from the wadi or the valley running perpendicular to the Nile at Nekhen. Trace element characteristics suggest that this local wadi material differed from the normal Nile sediments. About 4500 B.P., well after unification of the Two Lands of Upper and Lower Egypt, the Nile sediments were again deposited in the area far beyond its banks, but the total amount of sediment was reduced. A difference in the trace element ratios between the pre-5200 B.P. Nile sediments and those deposited after 4500 B.P. This was interpreted as a change in the relative contribution from the two Nile sources.
Also, even though there were periodic changes some changes are noteworthy as they coincide with major anthropological events in Egypt. Around 6400 B.P. there was maximum flooding and sediment load from the Ethiopian plateau. This theory is consistent with independent geological observations in Ethiopia, which mark this time frame as the beginning the predynastic period in Egypt. The other notable change occurred between 5600 B.P. and 5200 B.P., when floods and sediments from Ethiopia were at a minimum. This low sediment load from one source appears to have been exacerbated around 5200 B.P., when floods from central Africa (also decreased dramatically. The lower levels of floodwaters were apparent at Nekhen between 5200 and 4500 B.P., as suggested by the accumulation rates indicated by the Delta cores. Whereas the overall amount of sediment (floods) decreased, relative contributions from the two general sources changed.
These changes coincide with the era that marks the beginning of the dynastic period with the unification and creation of the first nation state. All of this information may indicate that the climatic changes that dramatically affected the Nile floods throughout the valley and over ex- tended periods of time may have been important to the evolution of the society along the banks of the river. This article is impressive researchers make use of cutting edge NMR, spectroscopic, and dating techniques. There is a lot research till to be done on the topic I am not completely convinced on their findings as a reader, but I commend them for the great effort.
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