Age of the epigenetic karst from the central region of Sierra de los Órganos, Pinar del Río, Cuba

Abstract

The epigenetic karst age in the central region of Sierra de los Órganos, is defined from the moment the carbonated sequences are uncovered and denudation processes begin at the end of the Oligocene and early Miocene (approximately 25 Ma). Although the karstic forms in this region originated at different times, they all coexist in today’s landscape. While the area was rising up slowly and sea level changes were taking place, the regional erosion base level descended giving rise to leveling surfaces desiccated by numerous sinkholes. At this time, surface currents disappear to become underground streams, which have carved out an extensive network of galleries. Satellite images and aerial photos interpretation, geological survey, measurements of morphostructures and multivariate statistical analysis, were the methods used to establish the epigenetic karst evolution model for the region. The model includes nine surfaces of erosion base levels, in a range that goes from the 410 m a.s.l., coinciding with the older erosion base levels conserved in the area (23 Ma before the present), until the 50 m a.s.l., corresponding to the surface of current erosion.