Abstract:

This work aims at presenting the geographical characterization of the Cordisburgo karst region, in the State of Minas Gerais by applying the consolidated concepts of the “classical karst” adapted to the reality of the intertropical karst. The characterization of the karst from the Onça´s Creek basin, Velhas River basin led to an exploratory mapping of the main karst features, which was made possible by confronting data collected through LANDSAT 7 imaging, GoogleEarth images, topographic maps interpretation (1:100.000), aerial photography (1:60.000) and field control. The final product, which is presented as a map, used the methodology proposed by the Commission of Karst Phenomena of the National Geography Committee (Paris, 1965) and adapted by Kohler (1989). The choice to use this methodology was made on the grounds that the existence of many Dinaric and Intertropical Karst maps is a facilitator to a comparative analysis. As a result of this study, and for the first time in this region, a map summarized the distribution of the karst features, providing relevant information for the geoenvironmental compartmentation of the Cordisburgo area and important subsides for the sustainable management of this region. Due to its geological, geomorphologic, hydrological and biogeographical characteristics, the karst of this region is an expressive example of the Brazilian intertropical one, whose superficial and subterraneous evolution must be understood as a complex phenomenon. There is little research on the Lagoa do Jacare Formation especially regarding the amount of CaCO3 in comparison to the phyllites, quartz veins, etc. So, it is premature to state that the karst in Cordisburgo shows a low karstification rate in its entire carbonatic pack as a whole. It is possible that pure limestone sites associated to non-carbonatic layers can be found. Studies about the magnitude and the direction of underground water are still insufficient, however. All evidences leads to the fact that the endokarstic flow in the region studied is commanded towards the base level of the Velhas River basin by the Onça’s Creek. In the north of this region, the subterraneous flow seems to be also associated to the Velhas River basin, even though at lower levels, where most of the identified forms is that of an evolved karst (plains and lakes).