Page 260 - Changing Living Spaces
P. 260

Aleksander Panjek and Gregor Kovačič


                 The erosional relief forms on the slopes of the northern edge of the
               Karst, i.e. also in the vicinity of Štanjel, were formed in a younger geological
               period, probably in the last 2 million years, when the surface of the neigh-
               bouring flysch area north of the Karst lowered significantly (Radinja 1974,
               21–33). This lowering is the result of the lower resistance of flysch rocks
               to denudation processes, which means that the surface on flysch rocks
               lowers much faster than the surface on carbonate rocks (limestones and
               dolomites). Various measurements have shown that under current cli-
               matic conditions, the surface on the Karst plateau lowers at a rate of 20-
               100 mm per 1000 years (Cucchi, Forti and Ulcigrai 1994, 55–62; Gams
               2003), while the denudation rate on flysch rock is 400-5000 mm per 1000
               years (Zorn 2008).
                 The above-mentioned difference in the resistance of the rocks to fac-
               tors related to surface lowering has caused the valleys in the northern
               flysch area of the Karst to deepen and move to a lower position compared
               to the plateau. This caused the surface waters of the northern part of the
               Karst to change their course toward the lower flysch area; the fluvial ero-
               sion caused by the streams began to form erosion gullies on the northern
               slope of the Karst plateau. As long as the area was covered with flysch,
               smaller intermittent surface waters flowed from this edge towards the
               Branica, Raša and Vipava valleys. After the flysch was eroded in the upper
               part of the Trsteljska brda hills and on the northern slopes below, a series
               of erosional gullies emerged as inherited fluvial-denudational landforms
               on carbonate bedrock; in the case of the Vrpoljska brda hills in the south
               of the Karst, Uroš Stepišnik (2011) came to the same conclusion. The in-
               herited landforms on the northern marginal slope of the Karst prove that
               there was a major flysch thrust sheet in this area, which was eroded (den-
               udated) in the course of geological history.

               ‘Neverlake’ Near Štanjel: Physical-Geographical Aspects
               The main subject of interest is the area in the immediate vicinity of Štanjel
               called ‘Jezero’ (‘Lake’). It is a doline of a distinctly elongated shape, run-
               ning in a northwest-southeast direction, located about 1 km northwest of
               Štanjel. The longer axis of the doline measures 1,160 m, while the short-
               er axis of the widest part of the doline measures only 161 m. Thus, the
               doline’s shape resembles a valley, but it does not meet the geographical
               criteria for this relief shape, since it is a depression closed on all sides.
               The circumference of the doline at the edge of the relatively flat bottom
               with the surrounding hillslopes is about 2,600 m; its area is just under


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