Since the time of the rainy Holocene, there have been periods of consecutive rain and drought on Egypt. Study of carbon 14 in the long-lived coniferous tree rings could see activity in the sun （spots and solar flares...Since the time of the rainy Holocene, there have been periods of consecutive rain and drought on Egypt. Study of carbon 14 in the long-lived coniferous tree rings could see activity in the sun （spots and solar flares） during eleven years cycle, as well as knowledge of possible flooding of the Nile and the periods of increase and decrease of the extent necessary to meet the soil around Lake Qarun in Fayoum-Egypt. From historical records in ancient Egypt and Muslim countries, the possible link between periods of the disappearance of sunspots on the solar disc for several years and is known to inch lower level and role of the minimum level of Mandour creeping ice on Southern Europe to the Mediterranean Sea, and the offset of the drought in North Africa and the Sahel region of Africa during the last thousand years. Analyzed pollen fossils of the overlapped layers of soil in two areas of the Delta were Avaris in Sharkiya Province and Mendes in Dakahliya Province. The study pointed out that there are differences due to environmental conditions, demonstrated by the analysis of soil pH, increased electrical connectivity also, the evidence of sulfates and chlorides indicate high salinity of Mendes and Avaris. Also the analysis of fossil pollen of successive layers of soil for both regions resulted in findings of fossil pollen of the species Chenopodiaceae by 51.2%, in Mendes, while, 7% in the Avaris. This is strong evidence of the existence conditions of salt in Mendes than Avaris archaeological sites.展开更多
In the Cameroonian sudano-sahelian and sahelian zone, karal soils i.e., vertisoils and soils with vertic similarities largely spread on tropical black clay in depressions and fiat sectors. Those black cotton soils are...In the Cameroonian sudano-sahelian and sahelian zone, karal soils i.e., vertisoils and soils with vertic similarities largely spread on tropical black clay in depressions and fiat sectors. Those black cotton soils are out of season＇s sorghum loft, locally called as muskwari. As the staple diet in the Cameroonian dry areas, this crop becomes more and more an alternative to drying or better to climate changes. Till now, those soils are considered to be lacustrine or they are resulting just from weathering, according to pedologic researchs. The purpose of this communication, therefore, is to show the effects of Harmattan on the basis of our field＇s observations, investigations and superficial deposits＇ analysis： granulometry and diffractometry in the laboratory. Harmattan is a dry and stable air mass which originates from the saharian anticyclone. Its participation in edaphics process is very relevant. Indeed, dust storms take place throughout the dry season and vertisoil spreads out on various topographic locations bringing about homogeneity of texture and similarity of mineralogic spectrum. Their high kaolinite content, thin granulometric component （fine sand, silt and clay） are indicative of Aeolian loessial dust deposits. It could not be something else in this area of the most southern saharian blow of the great Saharo-Sahelian GWAS （global wind action system） in sub-equatorial latitudes, in line with the venturi formed by Ennedi and Tibesti mountains.展开更多
文摘Since the time of the rainy Holocene, there have been periods of consecutive rain and drought on Egypt. Study of carbon 14 in the long-lived coniferous tree rings could see activity in the sun （spots and solar flares） during eleven years cycle, as well as knowledge of possible flooding of the Nile and the periods of increase and decrease of the extent necessary to meet the soil around Lake Qarun in Fayoum-Egypt. From historical records in ancient Egypt and Muslim countries, the possible link between periods of the disappearance of sunspots on the solar disc for several years and is known to inch lower level and role of the minimum level of Mandour creeping ice on Southern Europe to the Mediterranean Sea, and the offset of the drought in North Africa and the Sahel region of Africa during the last thousand years. Analyzed pollen fossils of the overlapped layers of soil in two areas of the Delta were Avaris in Sharkiya Province and Mendes in Dakahliya Province. The study pointed out that there are differences due to environmental conditions, demonstrated by the analysis of soil pH, increased electrical connectivity also, the evidence of sulfates and chlorides indicate high salinity of Mendes and Avaris. Also the analysis of fossil pollen of successive layers of soil for both regions resulted in findings of fossil pollen of the species Chenopodiaceae by 51.2%, in Mendes, while, 7% in the Avaris. This is strong evidence of the existence conditions of salt in Mendes than Avaris archaeological sites.
文摘In the Cameroonian sudano-sahelian and sahelian zone, karal soils i.e., vertisoils and soils with vertic similarities largely spread on tropical black clay in depressions and fiat sectors. Those black cotton soils are out of season＇s sorghum loft, locally called as muskwari. As the staple diet in the Cameroonian dry areas, this crop becomes more and more an alternative to drying or better to climate changes. Till now, those soils are considered to be lacustrine or they are resulting just from weathering, according to pedologic researchs. The purpose of this communication, therefore, is to show the effects of Harmattan on the basis of our field＇s observations, investigations and superficial deposits＇ analysis： granulometry and diffractometry in the laboratory. Harmattan is a dry and stable air mass which originates from the saharian anticyclone. Its participation in edaphics process is very relevant. Indeed, dust storms take place throughout the dry season and vertisoil spreads out on various topographic locations bringing about homogeneity of texture and similarity of mineralogic spectrum. Their high kaolinite content, thin granulometric component （fine sand, silt and clay） are indicative of Aeolian loessial dust deposits. It could not be something else in this area of the most southern saharian blow of the great Saharo-Sahelian GWAS （global wind action system） in sub-equatorial latitudes, in line with the venturi formed by Ennedi and Tibesti mountains.
