干旱区生态环境知识资源中心

Five dust storms that occurred in 2008 (15 March, 11 April, 28 April, 25, May and 26 June) in addition to the many sand dunes disseminated in the Western Desert of Iraq are sampled. The worse dust storm that occurred in Iraq in 11 April, 2008 covered 75% of the Iraq area and deposited 6.9 million tons approximately as a total weight of fallout during just 8 h, declining temperature 6A degrees C. During the episodes of dust storms, visibility decreased enormously, no more than 30 m. Many people were taken to hospitals after sustaining breathing problems. Some of them died. Clay fraction is the dominant part in the dust storms forming 70% besides a little silt (20.6%) and sand (9.4%), then classified as mature arkose of clay to sandy clay, whereas sand dunes are formed from 72.7% sand, 25.1% silt and 2.19% clay, then classified as mature arkose of silty sand. Sand dunes have much maturity. Mineralogical composition of dust storms and sand dunes are Quartz (49.2%, 67.1%), feldspar (4.9%, 20.9%), calcite (38%, 5%), gypsum (4.8%, 0.4%), dolomite (0.8%, 1%) and heavy minerals (3.2%, 6.6%), respectively. Heavy mineral suites in the dust storms are represented by zircon, pyroxene, hornblende, chlorite and magnetite; whereas the sand dunes are represented by zircon, tourmaline, garnet and pyroxene, concentrated within sand fraction. Heavy minerals according to satellite images revealed the dry land of Sahara Desert in North Africa and the Arabian Peninsula as well as Syria and Jordan were a major source of the dust storms that have occurred in Asia, including Iraq.