Global warming and an increasingly drier climate in various parts of the world result in more dust storms. To understand how these storms are caused, researchers are gazing into the past to comprehend where the dust came from, for how long, and over what distances it was carried. An international research team directed by Dr. Aditi K. Dave and Professor Kathryn Fitzsimmons from the Department of Geosciences at the University of Tübingen, along with collaborators from Romania, Brazil, Kazakhstan, and Tajikistan, have presently developed a new technique of doing this. They glance at irregular sites, known as “defect centers,” in the crystal configuration of the mineral quartz, which often appears in sediments. Their research has been published in Geophysical Research Letters.
To trace the origin of quartz in dust, the research team analyzed two defect centers, namely the “E1′” and the “peroxy” center, in the mineral’s crystal structure. These centers are created when an oxygen atom in the silica crystal lattice leaves its usual place and moves to an open position. “The concentration of E1′ and peroxy defect centers increases with the age of the quartz-bearing rock,” says Aditi Dave. Nonetheless, once the quartz is eroded from the rock and creates sediments, the defect centers suffer no further changes. The wind carries the deposits as dust over long distances and sediments it as Loess.
The research team assessed their method on loess samples from the Ili Basin in Kazakhstan and the Tajik Depression in Tajikistan, which is realized to have several dust sources and also derive from rocks of several ages. “Our method was able to clearly distinguish sediments from these two basins in Central Asia, thus reaffirming the basis of our approach,” explains Aditi Dave. Sediments are deemed archives of past environmental change. “This method offers an important addition to the study of tracking sediment transport and consequently to past climate studies, which is essential to understanding the present-day landscape response to changing climate,” Kathryn Fitzsimmons adds.