| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4682967 | Journal of South American Earth Sciences | 2006 | 9 Pages |
The geometry of a sector in the groundwater basin of the Tulum Valley has been studied to determine the shape, thickness, and vertical and horizontal distribution of the grain size, as well as the depositional environmental conditions of the Quaternary deposits that fill the valley. The geomorphologic features of the area have been investigated on the basis of aerial photographs checked with fieldwork. Three subsurface sections were prepared for a hydrogeological analysis of the area. These cross-sections were prepared by combining information from descriptions of well samples and interpretations of geophysical logs of wells and electric resistivity surveys. Within the studied area, the floor of the groundwater basin is asymmetrically shaped; the Quaternary deposits, which lie on an impervious or poorly pervious electrically conductive hydrogeologic basement of Late Tertiary age, reach a thickness of 670 m in the west and only 215 m in the eastern extreme. The Tulum Valley Basin is divided into two subbasins by a fault system trending NNE–SSW, which plays an important role in the configuration of the basin and the distribution of the Quaternary sediments units, as well as the distribution of aquifers in the subsurface. The western subbasin has a thicker cover and coarser grain sizes than the eastern one, where the sediments have more fine-grained intercalations and hardpans. The latter are probably pedogenic in origin.
ResumenSe analiza la geomorfología y la hidrogeología de un sector ubicado en la parte central del valle de Tulum, provincia de San Juan, República Argentina, entre los paralelos de 31° 32′ y 31° 40′ de latitud sur y los meridianos de 68°19′ y 68° 27′ de longitud oeste de Greenwich. Las cinco unidades geomorfológicas mapeadas son: el cauce menor del río San Juan, la llanura de inundación, los cauces de los arroyos Agua Negra y Los Tapones, la planicie aluvial antigua y los médanos. Se construyeron tres perfiles hidrogeológicos de los que se desprende que: la forma de la cuenca del Tulum es asimétrica debido a la actividad tectónica ocurrida desde antes del Cuaternario a través del Sistema de fallamiento del Tulum. El relleno cuaternario, de oeste a este, se apoya sobre un basamento impermeable a profundidades que de oeste a este van desde los 670 a los 215 metros. La cuenca se subdivide en dos subcuencas, una al oeste de la falla de Tulum más profunda y otra al este de la falla de menor profundidad. Ambas con características hidrogeológicas diferentes para la prospección del agua subterránea.
