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The Qattara Depression ((アラビア語:منخفض القطارة) ''Munḫafaḍ al-Qaṭṭārah'') is a depression in the north west of Egypt in the Matruh Governorate and is part of the Libyan Desert. It is considered the world's largest natural sinkhole.() It lies below sea level and is covered with salt pans, sand dunes and salt marshes. The region extends between latitudes of 28°35' and 30°25' North and longitudes of 26°20' and 29°02' East.〔El Bassyony, Abdou. 1995. ''"Introduction to the geology of the Qattara Depression,"'' International Conference on the Studies and Achievements of Geosciences in Egypt, 69 (85-eoa)〕 Some twenty kilometres west of the depression lie the oasis of Siwa and Jaghbub in smaller but similar depressions. The Qattara Depression contains the second lowest point in Africa at below sea level, the lowest being Lake Assal in Djibouti. The depression covers about , a size comparable to Lake Ontario or twice as large as Lebanon. Due to its size and proximity to the Mediterranean Sea shore it has been studied for its potential to generate hydroelectricity. ==Geography== The depression has the form of a teardrop with the point of the drop facing east and the broad deep area facing the south west. The northern side of the depression is characterised by steep escarpments up to 280 meters high, marking the edge of the adjacent El Diffa plateau. To the south the depression slopes gently up to the Great Sand Sea. Within the Depression there are salt marshes, under the northwestern and northern escarpment edges, and extensive dry lakes (dry lake beds) that flood occasionally. The marshes occupy approximately , although wind blown sands are encroaching in some areas. About a quarter of the region is occupied by dry lakes composed of hard crust and sticky mud, and occasionally filled with water. The depression was formed by salt weathering and wind erosion working together. First the salts crumble the depression floor and then the wind blows away the resulting sands.〔Aref M.A.M., El-Khoriby E., Hamdan M.A. 15 June 2002. (''The role of salt weathering in the origin of the Qattara Depression, Western Desert, Egypt'' ). Geomorphology, Volume 45, Issues 3-4, Pages 181-195.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Qattara Depression」の詳細全文を読む スポンサード リンク
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