Karstbase Bibliography Database
Karstbase Bibliography Database
The Bodoquena plateau, developed over the Corumbá Group (Neoproterozoic III – Paraguai Fold Belt), is a carbonate rock highland relative to the non carbonate lowlands of the Mato Grosso do Sul State, mid-western Brazil.
Based on 1:60.000 scale morphological analysis of the karst topography, three main compartments were defined. The first one is a mixed recharge karst system (mainly autogenic), dominated by labyrinth and polygonal karst landforms, developed over limestone of the Bodoquena plateau. The second unit is characterized by essentially autogenic recharge, residual hills and karstic plains with dolines, developed mainly over dolomites of the Miranda river depression (lowlands). The third one, characterizes an interestratal karst system in proterozoic limestones overlain by sandstones of the Aquidauana Formation of the phanerozoic Paraná basin. This geomorphological unit is localized at the southern extremity of the Bodoquena plateau, exhibiting flat topography, with frequent dolines in sandstone, of up to 700 m in diameter.
Although the Bodoquena karst system is well developed, as can be inferred based on the presence of several vauclusian springs, blind valleys in the northwest border, dolines and a deep conduit aquifer evidenced through productive water wells, the cave incidence is low as are their dimensions, considering the large carbonate rock exposure. Four cave patterns were recognized, which are related to the above geomorhological units: 1) large irregular breakdown halls in plan view and dipping planes in longitudinal section (following bedding and joint surfaces), which frequently reach up to 90 m beneath the water table, sometimes with large lakes, as for example, the Lago Azul cave (Bonito municipality). This pattern is the most frequent cave type of the second unit, occurring at the dolomitic residual hills with karst plains; 2) network caves with anastomotic pattern in plan view and circular to elliptical conduits with lateral anastomosis in cross section. They occur mostly associated with the labyrinth and polygonal karst topography of the first morphological unit and rarely with the unit of residual hills and plains; 3) caves with meandering conduits in plan view, sometimes with active or inactive allogenic stream sinks, associated with the polygonal and labyrinth karst topography; 4) Steep dipping phreatic conduits, characterizing vauclusian springs, occurring at the limestone plain along the base of the eastern escarpment of the Bodoquena plateau.
The recent tectonic activity along the Bodoquena plateau area was detected by the following features: vadose speleothems submerged at least 16 m beneath the lowest seasonal water level stage; limestone highland with escarpment beside dolomitic lowlands; northern part of the carbonate plateau with deep entrenched river valleys in contrast with the southern sector of open valleys and less entrenchment; linear structure observed in 1:250.000 scale which marks the border of the Pantanal basin and crosses the Bodoquena plateau.