Evidence for the Aeolian Origin of Loess in the Danubian Plain

Pages: 
pp. 31-39
Geological Institute of the Bulgarian Academy of Sciences, 1113 Sofia, Acad. G. Bonchev St., 24
Abstract: 

The present work considers the evidences for the Aeolian origin of loess in the Danubian plain, put forward by previous authors, which have been amended with results from new investigations.
   One of the main proofs consists in the grain-size composition changes of the loess complex from north to south, from east to west and with depth. Other evidences are the well expressed directions of loess winnowing in the Danubian plain: from west-northwest and north-northeast. The next evidence for the Aeolian origin of loess is the sequence in the loess accumulation process. It was started before 2.59 Ma BP along the coast of the Dacian basin and after its regression loess winnowing was also spread on the occupied by the basin territories (0.82 Ma BP). The loess complex becomes younger towards the Danubian terraces.
   The deflation of the loess fine earth material occurred from the flooded areas of the Paleodanube River and its tributaries, from the Black sea shelf and the clayey alluvium of the Dacian basin. The orientation of the deflation area with respect to the transporting Aeolian corridor was one of the reasons for the differences in the lithostratigraphy and the thickness of the loess complex. Five loess regions were differentiated in the Danubian plain: Northeast, “Yantra-Vit”, “Vit-Ogosta”, “Ogosta-Lom” and the Black Sea region.

Й. Эвлогиев. Данные об эолическом происхождении лесса Дунайской равнины. В работе приведены данные об эолическом происхождении лесса Дунайской равнины. Уже известные из литературы доказательства дополнены результатами новых исследований.
Одним из главных доказательств являются изменения в гранулометрическом составе лесса с севера на юг, с востока на запад и сверху вниз по разрезам. Второе доказательство — это хорошо выраженные направления, которые контролировали накопление лесса на территории Дунайской равнины: с запад-северозапада и с север-северовостока. Доказательством является также последовательность в его накоплении. Накопление лесса началась вдоль берегов Дакийского бассейна еще до 2.59 Mа ВР. После регрессии бассейна оно расширилось и охватило его территорию (0.82 Ма ВР). Возраст лессовых комплексов омолаживается по направлению к Дунайским террасам.
Тонкий терригенный материал лесса поступал с затопленных участков Палеодуная и его притоков, с черноморского шельфа и с глинистого аллювия Дакийского бассейна. Ориентировка питающей суши по отношению к коридору эолического транспорта является одной из причин различий в литостратиграфии и мощности лессовых комплексов Дунайской равнины. Выделено пять лессовых регионов: северо-восточный, Янтра-Витский, Вит-Огостенский, Огоста-Ломский и Черноморский.

Keywords: 

loess, Aeolian origin, lithology, stratigraphy, Pleistocene

VOLUME 36 (3-4)/December 2007

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria, G. Bonchev Str., Block 24
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria, G. Bonchev Str., Block 24
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria, G. Bonchev Str., Block 24
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria, G. Bonchev Str., Block 24
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria, G. Bonchev Str., Block 24
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria, G. Bonchev Str., Block 24
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria, G. Bonchev Str., Block 24
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria, G. Bonchev Str., Block 24

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev str., bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev str., bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Bulgaria, 1113 Sofia, Acad. G. Bonchev Str., Bl. 24

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Acad. G. Bonchev St., Bl. 24
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Acad. G. Bonchev St., Bl. 24

Geological Institute of the Bulgarian Academy of Sciences, 1113 Sofia, Acad. G. Bonchev St., 24

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
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Instituto Andaluz de Ciencias de la Tierra, CSIC, Granada, Spain
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University of Granada, Granada, Spain
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
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University of Granada, Granada, Spain
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences, 24 Acad G. Bonchev Str., 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Geological Institute, Bulgarian academy of Scienses, 1113 Sofia, 24 G. Bonchev Str.
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Geological Institute, Bulgarian academy of Scienses, 1113 Sofia, 24 G. Bonchev Str.

Sofia University “St. Kliment Ohridsky”, 1000 Sofia, 15 Tsar Osvoboditel Blvd.
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Geological Institute Bulgarian Academy of Sciences, 1113 Sofia, 24 G. Bonchev Str.
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Geological Institute Bulgarian Academy of Sciences, 1113 Sofia, 24 G. Bonchev Str.
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Ministry of Environment and Water, 1000 Sofia, 22 Maria Louisa Blvd.

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria

Bulgarian Academy of Sciences, Geological Institute, Acad. G. Bonchev St. Bl. 24, 1113 Sofia, Bulgaria
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Middle East Technical University, Department of Geological Engineering, 06531 Ankara, Turkey
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General Directorate of Mineral Research and Exploration, Department of Geological Research, 06520 Ankara, Turkey
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General Directorate of Mineral Research and Exploration, Department of Geological Research, 06520 Ankara, Turkey

Geophysical Institute, Bulgarian Academy of Sciences, 1113 Sofia
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences
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Geological Institute, Bulgarian Academy of Sciences
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Geological Institute, Bulgarian Academy of Sciences