Plains and drumlin fields
The landscapes of plains and drumlin fields of Central Estonia, located immediately to the south of the Pandivere Upland, form a southern extension of Watershed-Estonia. As in to the Pandivere Upland, rolling till plains also dominate the relief in this region. Unlike Pandivere, however, the basement rocks here lie under a much thicker cover of Quaternary deposits and the relief is characterised by more pronounced drumlins. The prominence of the drumlin fields is a direct result of the existence of the Pandivere Upland, which served as an ice-shed during the Ice Age. The upland obstructed free advancement of the continental glacier at the end of the Ice Age, dividing the glacier into separate ice lobes. These moved past the upland on both sides: one along the western slope, towards the southwest, in the direction of Pärnu Bay, and the other along the eastern slope, to the southeast, into the Peipsi Basin. Drumlins are the landforms which form under conditions of a dynamic balance between the exaration and accumulative activitiesof continental glaciers. Therefore, they could more distinctly develop in areas to the southwest and southeast of the Pandivere Upland.
As the glaciers advanced mainly from the northwest to the southeast, larger drumlins and the ice-ploughed depressions, were formed on the territory of the present Saadjärve Drumlin Field or Vooremaa (the Estonian for The Drumlin Field). The ice lobe that branched southwest formed a group of smaller drumlins in an area between the present Paide and Türi towns. As embranchment of ice lobes took place also in more southern areas, and as the advancement of each smaller ice lobe that formed was increasingly influenced by the relief of the subsurface, till plains with drumlins occur also in many other places, such as in the areas of Põltsamaa and Kolga-Jaani and even further south, on the slopes of the Sakala Upland.
The relief of Central Estonia is dominated by rolling till plains. These formed during the relatively steady retreat of the continental ice, when the clastic material contained in the glaciers was deposited. Part of the sedimentary material was transported here also under the ice during the invasion stage of continental glaciers. This is evident by the fact that the oblong pebble contained in the till are clearly oriented in the direction of the movement of the ice. As a rule, the till in Central Estonia is loamy sand or sandy loam containing limestone pebble and having a relatively complex mineral and chemical composition and a high content of clay minerals. The latter are formed in the course of chemical weathering of mineral particles of till, and they contain nutrients available for plants.
The main components of the mechanical structure of till — loamy sand and sandy loam — have a high water holding capacity, thanks to which the soils formed on till have a relatively favourable water regime and are rarely subjected to drought. As a result of the combined effect of these two factors, these areas formerly supported a rather species-rich vegetation, under which Cambisols and Luvisols have been formed. These thick soils with a favourable water and aeration regime, high nutrient content and medium humus content have proved the most productive agricultural soils in Estonia. Therefore, the Central Estonian plains, similarly to the Pandivere Upland, belong to the most extensively cultivated landscapes in Estonia. The fields in this area often occupy several hundreds of square kilometres and alternate with large cluster villages. Coniferous forests and grasslands can be found here in small patches mostly located on the borderlands of the plains.Details about this article
Created: 05.06.2001 16:38
Modified: 28.09.2012 17:34