Lagoa Santa Karst: Cradle of Brazilian Cave Studies

Abstract

The Lagoa Santa Karst is the best known karst area in Brazil and has been studied since the early 1800s. This area is developed over Precambrian limestone of the Sete Lagoas Formation, Bambuí Group, and displays scenic surface karst landforms, especially limestone cliffs, karst lakes, and karst plains, in addition to numerous solution dolines. Thick soil sequences derived from overlying phyllites cover a significant portion of the karst, but exhumation is presently taking place, exposing karst outcrops with subsoil karren features. Karst hydrology is primarily autogenic, with short groundwater flow routes. Limestone outcrops are vertically dissected, exposing ancient paragenetic caves intersecting cliff faces. More than 700 caves are known in the area, the majority of which are short (<100 m long) with abundant sedimentation. The area’s early fame derived from the remarkable Pleistocene fossil remains excavated by pioneer Danish naturalist Peter Wilhelm Lund. This material is derived primarily from cave breccia and has formed the basis of vertebrate paleontology in Brazil. U-series and radiocarbon dating yielded fossil ages between Late Holocene (~9 kyr B.P.) and mid-Pleistocene (>350 kyr). Lund was also the first to describe ancient human remains frequently found in caves and rock shelters. Lagoa Santa is now known to contain hundreds of archaeological sites dating from the Early Holocene/Late Pleistocene and has been at the center of the debate on the origin and age of human colonization in the Americas. The Lagoa Santa Karst faces severe environmental threats due to limestone mining and the expansion of the metropolis of Belo Horizonte and its surrounding towns. A number of preservation areas have now been established, improving the conservation status of this landmark Brazilian karst area.