Articles | Volume 8, issue 2
Research article
28 Jun 2017
Research article |  | 28 Jun 2017

Intensity of geodynamic processes in the Lithuanian part of the Curonian Spit

Algimantas Česnulevičius, Regina Morkūnaitė, Artūras Bautrėnas, Linas Bevainis, and Donatas Ovodas

Abstract. The paper considers conditions and intensity of aeolian and dune slope transformation processes occurring in the wind-blown sand strips of the dunes of the Curonian Spit. An assessment of the intensity of aeolian processes was made based on the analysis of climatic factors and in situ observations. Transformations in aeolian relief forms were investigated based on the comparison of geodetic measurements and measurements of aerial photographs. Changes in micro-terraces of dune slopes were investigated through comparison of the results of repeated levelling and measurements of aerial photographs. The periods of weak, medium, and strong winds were distinguished, and sand moisture fluctuations affecting the beginning of aeolian processes were investigated. The wind-blown sand movements were found to start when sand moisture decreased by 2 % in the surface sand layer and by up to 5 % at a depth of 10 cm. In 2004–2016, the wind-blown sand movements affected the size of reference deflation relief forms: scarp length by 8 %, scarp width by 35 %, pothole length by 80 %, pothole width by 80 %, roll length by 17 %, roll width by 18 %, hollow length by 17 %, and hollow width by 39 %. The elementary relief forms in the leeward eastern slopes of the dunes experienced the strongest transformations. During a period of 5 months, the height of micro-terraces of the eastern slope of the Parnidis Dune changed from 0.05 to 0.64 cm. The change was related to fluctuations in precipitation intensity: in July–August 2016 the amount of precipitation increased 1.6-fold compared with the multiannual average, thus causing the change in the position of terrace ledges by 21 %.

Short summary
The article analysed the problems of aeolian relief changes. The changes are determined by climate, neo-tectonics, and human impact. The most important climate factors are wind speed and wind direction. Strong permanent winds induced fast sand drying and activated deflation processes, which were further accelerated by a constant stream of visitors to the dunes. The neo-tectonic movements formed micro-terraces on the eastern dune slope, which changes on wet sand pressure.
Final-revised paper