سنجش قابليت انواع رخساره‌هاي ژئومورفولوژي در تامين منابع گرد و غبار غرب خوزستان

Evaluating the Capability of Various Types of Geomorphological facies in supplying dust sources in the west of Khozestan province- Iran

ﭘﺪﯾﺪه ﮔﺮدوﻏﺒﺎر ﯾﮑﯽ از ﻣﺨﺎﻃﺮات در ﮐﺸﻮر اﯾﺮان و اﺳﺘﺎن ﺧﻮزﺳﺘﺎن ﻣﺤﺴﻮب ﻣﯽﮔﺮدد. در اﯾﻦ ﭘﮋوﻫﺶ ﺑﺎ اﺳﺘﻔﺎده از ﻋﻤﻠﯿﺎت ﻣﯿﺪاﻧﯽ و آزﻣﺎﯾﺸﮕﺎﻫﯽ، ﻣﻄﺎﻟﻌﻪ ﻣﻨﺎﺑﻊ ﮔﺮد و ﻏﺒﺎر و ﻗﺎﺑﻠﯿﺖ رﺧﺴﺎرهﻫﺎي ﻣﺨﺘﻠﻒ ﺑﺮاي ﺗﻮﻟﯿﺪ ﮔﺮد و ﻏﺒﺎر از ﻣﻨﺎﻃﻖ ﻏﺮب ﺧﻮزﺳﺘﺎن ﺻﻮرت ﭘﺬﯾﺮﻓﺘﻪ اﺳﺖ. ﺑﺮ اﯾﻦ اﺳﺎس ﻧﻘﺸﻪ اﻟﮕﻮي ﻓﻀﺎﯾﯽ رﺧﺴﺎرهﻫﺎ ﺗﺮﺳﯿﻢ و ﺑﺎ اﺳﺘﻔﺎده از آن 12 ﺷﺎﺧﺺ ﻓﻠﺰي ﺛﺎﺑﺖ در رﺧﺴﺎرهﻫﺎ ﮐﺎﺷﺘﻪ ﺷﺪ ﮐﻪ ﺑﻌﺪ از ﺳﻪ روز ﮔﺮد و ﻏﺒﺎر در زﻣﺴﺘﺎن 1396 و ﺑﻬﺎر 1397 )2018/1/20 و 2018/2/19 و 2018/4/23( اﺧﺘﻼف ارﺗﻔﺎع آﻧﻬﺎ اﻧﺪازهﮔﯿﺮي ﺷﺪ و ﻫﻤﭽﻨﯿﻦ ﻧﻤﻮﻧﻪﻫﺎي ﺧﺎك ﺳﻄﺤﯽ از ﻋﻤﻖ 0-3 ﺳﺎﻧﺘﯽﻣﺘﺮ ﺳﻄﺢ زﻣﯿﻦ از ﻧﻘﺎط ﻣﺨﺘﻠﻒ ﻣﻨﻄﻘﻪ ﻧﯿﺰ ﺟﻤﻊآوري ﮔﺮدﯾﺪ و آزﻣﺎﯾﺶ داﻧﻪﺳﺠﯽ ﺑﺎ اﻟﮏ ﺧﺸﮏ و ﻫﯿﺪروﻣﺘﺮي ﺑﺮروي آﻧﻬﺎ ﺻﻮرت ﭘﺬﯾﺮﻓﺖ ﮐﻪ ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد رﺳﻮﺑﺎت ﻋﻤﺪﺗﺎ رﯾﺰ داﻧﻪ ﻫﺴﺘﻨﺪ و ﺑﯿﺸﺘﺮﯾﻦ ﺗﺠﻤﻊ رﺳﻮﺑﺎت در ﺳﯿﻨﯽ زﯾﺮ اﻟﮏ دﺳﺘﮕﺎه ﺷﯿﮑﺮ )رﺳﻮﺑﺎت رد ﺷﺪه از اﻟﮏ 200( ﻣﯽﺑﺎﺷﺪ. ﻫﻤﭽﻨﯿﻦ ﻧﺘﺎﯾﺞ ﻫﯿﺪروﻣﺘﺮي آﺷﮑﺎر ﺳﺎﺧﺖ ﮐﻪ در ﻣﺤﺪوده ﻋﻤﻮﻣﯽ ﺟﻔﯿﺮ ﻣﻘﺪار ﺗﻮزﯾﻊ ذرات ﻣﺎﺳﻪ، ﺳﯿﻠﺖ و رس ﺑﻪ ﮔﻮﻧﻪاي اﺳﺖﮐﻪ ﺑﺎﻓﺖ ﺧﺎك در اﯾﻦ ﻣﺤﺪوده ﺳﯿﻠﺘﯽ رﺳﯽ ﻟﻮﻣﯽ ﻣﯽﺑﺎﺷﺪ و در ﻧﻤﻮﻧﻪﻫﺎي ﺑﺴﺘﺮ ﺧﺸﮏ ﺷﺪه ﺗﺎﻻب ﻫﻮراﻟﻌﻈﯿﻢ و ﺷﻤﺎل ﺳﻮﺳﻨﮕﺮد ﻧﯿﺰ ﻫﻤﯿﻦ ﻧﺘﺎﯾﺞ ﺻﺎدق اﺳﺖ. ﻋﻼوه ﺑﺮ اﯾﻦ در ﻣﺤﺪوده رﯾﮓ ﺧﻮزﺳﺘﺎن ﻣﯿﺰان ﻣﺎﺳﻪ ﺑﻪ ﺷﺪت اﻓﺰاﯾﺶ ﻣﯽﯾﺎﺑﺪ و در ﻣﻘﺎﺑﻞ ﻣﯿﺰان رﺳﻮﺑﺎت دﯾﮕﺮ ﮐﺎﻫﺶ ﻣﯽﯾﺎﺑﺪ و ﺑﺎﻓﺖ ﺧﺎك از ﻧﻮع ﻣﺎﺳﻪاي ﻟﻮﻣﯽ ﻣﯽﺑﺎﺷﺪ. ارزﯾﺎﺑﯽ ﺷﺎﺧﺺﻫﺎ ﻣﺸﺨﺺ ﮐﺮد ﮐﻪ در ﺗﻤﺎﻣﯽ ﺷﺎﺧﺺﻫﺎ، رﺳﻮﺑﺎت ﺑﺴﺘﺮ رﺧﺴﺎرهﻫﺎ در زﻣﺎن ﺑﺮوز ﮔﺮد و ﻏﺒﺎر ﻣﻨﺘﻘﻞ ﻣﯽﺷﻮﻧﺪ ﺑﻪﻧﺤﻮي ﮐﻪ ﺑﯿﺸﺘﺮﯾﻦ ﻣﯿﺰان ﺟﺎﺑﻪﺟﺎﯾﯽ در ﺑﺴﺘﺮ ﺷﺎﺧﺺ-ﻫﺎي S5 ،S4 و S6 ﺑﺎ ﺗﻔﺎوﺗﯽ ﺑﯿﺶ از 5 ﺳﺎﻧﺘﯽﻣﺘﺮ اﻧﺪازهﮔﯿﺮي ﮔﺮدﯾﺪ. ﺑﻨﺎﺑﺮاﯾﻦ ﺑﺮاﺳﺎس ﻣﻄﺎﻟﻌﺎت ﺻﻮرت ﭘﺬﯾﺮﻓﺘﻪ در اﯾﻦ ﭘﮋوﻫﺶ ﻓﺮﺳﺎﯾﺶ ﺳﻄﺤﯽ ﺧﺎك در ﻧﻮاﺣﯽ ﺟﻔﯿﺮ و زﻣﯿﻦﻫﺎي ﺧﺸﮑﯿﺪه ﺗﺎﻻب ﻫﻮراﻟﻌﻈﯿﻢ داراي ﻗﺎﺑﻠﯿﺖ ﮔﺮد و ﻏﺒﺎري ﻓﺮاوان ﻣﯽﺑﺎﺷﺪ ﮐﻪ ﻣﯽﺗﻮان ﻧﻘﺶ آﻧﻬﺎ را در ﺑﺮوز و ﺗﺸﺪﯾﺪ ﮔﺮد و ﻏﺒﺎر در اﺳﺘﺎن ﺧﻮزﺳﺘﺎن ﻣﻮﺛﺮ داﻧﺴﺖ.

IntroductionA‌ dust storm is a common environmental hazard in the Iran, especially in Khuzestan province. It is important to note that the temporal and spatial variations of dust cause the dust to diffuse from different facies. Accordingly, various methods have been developed to identify dust sources, most notably the use of field and laboratory work. Therefore, in this study, we study the internal dust sources and different facies capabilities for producing dust from western Khuzestan.Materials and methodsIn this study, first, a spatial map of the facies was prepared in which the Landsat 8 and Sentinel 1 satellite images were used on 21/4/2018. Then, three metal rods were planted in all faces using fieldwork. Then the height difference of the rods was measured in three consecutive time periods after the dust storms in winter and spring 2018. Also, surface samples (0-3 cm) were collected at the rod location. The samples were transferred to Ferdowsi University laboratory and grain size analysis was performed. Finally, a hydrometric test was carried out to determine soil mineral and soil texture.Results and discussionThe results showed that the sediments are predominantly fine-grained, with the highest accumulation of sediment under the sieve of the shaker. Also, Hydrometric results indicated that the Jofer area has silty clay loamy soil and in the dry bed samples of the Hoor_Al_Azim Wetland and north Susangerd, the results are similar to the Jofer area. Assessment of the rods illustrated that bed sediments were transported at the time of dust formation. The maximum displacement was measured at the location bed S4, S5, and S6 with a difference of more than 5 cm.ConclusionIn this study, the internal dust sources were studded and different facies capabilities for producing dust from western Khuzestan were measured. Results indicate the sediments due to environmental conditions are not coherent and have no solidarity. In addition, internal border sources of dust have been found to play a major role in the spread of dust in western Khuzestan.