HYDROLOGY OF A LARGE, HIGH RELIEF, SUBTROPICAL CAVE SYSTEM: SISTEMA PURIFICACION, TAMAULIPAS, MEXICO

Sistema Purificacion, a 82 km long and 955 m deep cave system in the northern Sierra Madre Oriental of Mexico, is developed on the western flank of the Huizachal-Peregrina anticlinorium in the middle Cretaceous Tamabra and underlying Tamaulipas Formations. Impervious beds above and below the cave cause groundwater to flow to the surface, resulting in many small springs. Larger springs emerge from karst conduits in the lower Tamaulipas Formation, particularly during and after intense rains. Streams in the upper portion of the system mostly follow the dip of bedding near the Tamabra-Tamaulipas contact until trapped in the trough of a third-order syncline. Vadose flow in the middle part of the cave system follows axial plane fractures. The trough of the north-trending Infiernillo syncline, and the impervious underlying La Joya beds act as a local hydrologic barrier perching water in the lower carbonates and filling chambers in the lowest parts of Sistema Purificacion.