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The depositional conditions of longitudinal dunes based on investigations in the western part of the Lublin Upland, SE Poland

Zieliński P.

Landform Analysis

2003

Vol. 4

65--73

The development of longitudinal dunes depends on three overlapping factors: the strength and direction of winds, the amount of supplied sand, and the occurrence of vegetation which can fix the rising forms. It is assumed that longitudinal dunes in Polish territory were mainly formed from the arms of parabolic dunes, as a result of the deflation of the central parts of these dunes. However, it is possible that some longitudinal dunes in Poland could also have developed as primary forms. The detailed studies of longitudinal dunes in the western part of the Lublin Upland have revealed an important structural differentiation resulting from various development conditions of each particular form. Three models of development of longitudinal dunes are derived from these investigations: 1) They are formed by undirectional winds deflating the central parts of parabolic dunes, when sand supply is small, and vegetation fixes the rising forms. 2) They develop after a change of wind direction by 90°, in consequence of transformation of a single transversal dune or a set of parabolic dunes formed in front of or on an obstruction. 3) They are primary forms originating at obstructions, when eolian material is transported by bidirectional winds from a narrow (up to 90°) sector.