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101.
102.
We generalize our results of a second order Jupiter-Saturn planetary theory to be applicable for the case of the four major planets.We use the Von Zeipel method and we neglect powers higher than the third with respect to the eccentricities and sines of the inclinations in our expansions. We consider the critical terms as the only periodic terms. 相似文献
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El Nour AH 《GeoJournal》1989,18(4):369-377
The study of urbanization has, in recent years, assumed increasing importance in developing countries not only because these countries are in the process of facing rapid urbanization, but also because the process of urbanization has been recognized as a part of a larger process of economic and social change which is affecting the rural areas. 相似文献
107.
Karstified features and surficial calcareous crust (caliche) develop on the upper most surfaces of the Middle Miocene rocks in the area between Quseir and Mersa Alam along the Red Sea coast, Egypt. Detailed studies of the caliche profile revealed various textures and fabrics denoting a cyclicity in deposition as well as diagenetic differentiation crystallization and deformation. The occurrence of these caliche deposits suggest that the Middle Miocene rocks in the study area have been subjected to alternating periods of rainfall and intense evaporation.
Zusammenfassung Karstphänomene und Kalkkrusten (Caliche) haben sich auf den Oberflächen der Gesteine des Mittelmiozäns im Gebiet zwischen Quseir und Mersa Alam entlang der Küste des Roten Meeres in Ägypten entwickelt. Eingehende Untersuchungen von Kalkkrusten Profilen lassen unterschiedliche Strukturen und Gefüge erkennen, die sowohl zyklische Bildung belegen als auch diagenetische Kristallisations-Differentiation und Deformation. Das Auftreten dieser Caliche-Bildungen legt nahe, daß die mittelmiozänen Gesteine im Untersuchungsgebiet abwechselnd regenreichen Perioden und solchen mit starker Evaporation ausgesetzt waren.
Résumé Des structures karstiques et des croûtes calcaires superficielles (caliches), se sont formées à la surface des roches du Miocène moyen dans la région comprise entre Ouseir et Mersa Alam, le long de la côte de la mer Rouge, en Egypte. L'étude détaillée de profils de la caliche révèle des structures variées qui indiquent un dépôt cyclique ainsi qu'une cristallisation différentielle et une déformation diagénétique. La présence de tels dépôts de caliche suggère que les roches du Miocène moyen de cette région ont été soumises alternativement à des périodes de pluie et d'évaporation intense.
Quseir Mersa Alam — . , , , , . , .相似文献
108.
Summary The Reitan (1963) regression equation of the form lnw =a +bT
d
has been examined and tested to estimate precipitable water vapor content from the surface dew point temperature at different locations. The results of this study indicate that the slopeb of the above equation has a constant value of 0.0681, while the intercepta changes rapidly with latitude. The use of the variable intercept technique can improve the estimated result by about 2%.With 6 Figures 相似文献
109.
Mineralogical data, coupled with whole-rock major and trace element data of mafic xenoliths from two occurrences of the Egyptian Tertiary basalts, namely Abu Zaabal (AZ) near Cairo and Gabal Mandisha (GM) in the Bahariya Oases, are presented for the first time. Chemically, AZ basalts are sodic transitional, while those of GM are alkaline. In spite of the different petrographic and geochemical features of the host rocks, mafic xenoliths from the two occurrences are broadly similar and composed essentially of clinopyroxene, plagioclase, alkali feldspar, and Fe–Ti oxides. The analytical results of host rocks, xenoliths and their minerals suggest that the xenoliths are cognate to their host magmas rather than basement material. The mafic xenoliths are olivine-free and contain alkali feldspar contrary to the phenocryst assemblage of the host rocks, confirming that they are not cumulates from the host magma. The geochemical and mineralogical characteristics show that the precursor magmas of these xenoliths are more fractionated and possibly contaminated compared to those of the host rocks. Estimated crystallization conditions are 1–3 kbar for xenoliths from both areas, and temperature of 950–1100 °C vs. 920–1050 °C for AZ and GM, respectively. These cognate xenoliths probably crystallized from early-formed, highly-fractionated anhydrous magma batches solidified in shallow crustal levels, possibly underwent some AFC during their ascent, and later ripped-up during fresh magma pulses. The xenoliths, although rare, provide an evidence for the importance of crystal fractionation at early evolution of the Egyptian Tertiary basalts. 相似文献
110.
The synoptic circulation over Saudi Arabia is complicated and frequently governed by the effect of large-scale pressure systems. In this work, we used NCEP–NCAR global data to illustrate the relationship between climatic variables and the main pressure systems that affect the weather and climate of Saudi Arabia, and also to investigate the influence of these pressure systems on surface air temperature(SAT) and rainfall over the region in the winter season. It was found that there are two primary patterns of pressure that influence the weather and climate of Saudi Arabia. The first occurs in cases of a strengthening Subtropical High(Sub H), a weakening Siberian High(Sib H), a deepening of the Icelandic Low(Ice L), or a weakening of the Sudanese Low(Sud L). During this pattern, the Sub H combines with the Sib H and an obvious increase of sea level pressure(SLP) occurs over southern European, the Mediterranean, North Africa, and the Middle East. This belt of high pressure prevents interaction between midlatitude and extratropical systems, which leads to a decrease in the SAT,relative humidity(RH) and rainfall over Saudi Arabia. The second pattern occurs in association with a weakening of the Sub H, a strengthening of the Sib H, a weakening of the Ice L, or a deepening of the Sud L. The pattern arising in this case leads to an interaction between two different air masses: the first(cold moist) air mass is associated with the Mediterranean depression travelling from west to east, while the second(warm moist) air mass is associated with the northward oscillation of the Sud L and its inverted V-shape trough. The interaction between these two air masses increases the SAT, RH and the probability of rainfall over Saudi Arabia, especially over the northwest and northeast regions. 相似文献