Impact of Anthropogenic Factor on Karst Landscape (Zemo Imereti Structural Plateau Case Study), Georgia, Caucasus

摘要

The Zemo Imereti (Chiatura) Structural Plateau covers the easternmost part of the western Georgia limestone belt and is the only region of the platform karst in the entire Caucasus. Zemo Imereti Plateau’s complex structural studies revealed that the karst landscape has been completely transformed due to human strong economic activities, mainly related to the manganese unplanned, predatory extraction. The ore mining process completely destroyed the soil and vegetation cover thus creating “anthropo-badlands”. Due to manganese open-cast mining, the layers located over limestones are almost totally removed and heavy rains stipulate intense washout of substances from loose rocks. Intense washout of manganese extracted from mines and high contamination of river water streams take place directly in the river beds. Karst sinkholes and wells are common in the plateau, which are often used as waste fills-storages by the local population. Contaminated underground karst waters flowing into the above mentioned landforms are directly related to the karst springs used by the population and occasionally cause their turbidity and contamination, which is also confirmed by our indicator tests. As a laboratory study of the samples showed, mineralization of underground karst waters in the study area is 1.5 - 3 times higher than similar values in neighboring karst areas, which should be explained by the widespread of manganese open pits in the feeding basins of underground karst waters. According to the materials obtained from our surveys and calculations carried out, karst (chemical) denudation (surface 64.2 - 190.6 m~(3)/km~(2)/year, underground 1.5 - 117.0 m~(3)/km~(2)/year) has been increased in the study area than in other karst regions of Georgia, which is also related to technologic factors.