engleski

Periodicities of paleoclimate variations in the first high-resolution nonorbitally tuned grain size record of the past 1 Ma from SW Hungary and regional, global correlations

This paper presents the results of grain-size analyses of an independently-dated loess/paleosol record dating back ca. 1 Ma from SW Hungary. The record follows an upward coarsening trend with a clear prevalence of coarse silts and fine sands. Variations are mainly controlled by fluctuations in sand input highlighting iterative changes in dust aerodynamics over the past 1 Ma in the source region found 50–100 km NW of our site. Based on our results regional factors influenced the intensity and nature of dust accumulation. Contrasting trends with the Chinese Loess Plateau in certain periods reflect a greater importance of the Atlantic region driving the evolution of nearby continental ice sheets. Proximity and expansion of these had significant impact on local wind field. Low topography of the surrounding mountain belts allowed for the intrusion of stronger cold winds, higher abrasion in the source region and transportation of coarser particles to the site from 700 to 450 ka. Another marked upward increase in grain-size from 400 ka can be linked to increasing continentality which along with tectonic activity resulted in a drop in the groundwater table in the source region and intensified erosion of formerly relatively stable surfaces bringing more coarse material to our site.

Past aeolian dynamics ; Cycles ; Loess grain-size ; Middle & Upper Pleistocene ;

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