Aspects of the Hydrogeology of southern Campeche and Quintana Roo, Mexico

Aspectos de la hidrogeología del sur de Campeche y Quintana Roo, México

Eugene C. Perry ROSA MARIA LEAL BAUTISTA Guadalupe Velázquez Oliman JOAN ALBERTO SANCHEZ SANCHEZ Nikklas Wagner (2021)

This paper explores strong indirect evidence for existence of a previously unrecognized deep groundwater aquifer in southern Quintana Roo, adjacent parts of Campeche, and (probably) northern Belize. The region contains rocks of Cretaceous-to-Holocene age, including: 1) an up-thrust block of the late Cretaceous carbonate known in Belize as the Barton Creek Formation, which is the oldest formation exposed in the Mexican Yucatán Peninsula, 2) the Cretaceous/ Paleogene Albion Formation consisting of weakly consolidated Chicxulub impact air-fall deposits, 3) the Paleocene-Eocene Icaiche Formation, containing a massive 25-35 m thick gypsum member that crops out over an estimated area of more than 10,000 km2 in the elevated interior region of the northern lowlands, and 4) younger rocks of relatively low permeability that flank the region on the east. Hydrogeology is dominated by ground-water and surface flow in and adjacent to the Rio Hondo Fault Zone (RHFZ) and by recharge in the elevated interior region. Groundwater in the elevated region has a high sulfate concentration and is approximately saturated with gypsum dissolved from the Icaiche Formation. High-sulfate ground-water and river water with a slightly lower gypsum saturation index than in the elevated region also occurs in the RHFZ, but no water of comparably high sulfate content is present elsewhere in the study area. This suggests that the elevated region is a recharge zone for high-sulfate groundwater carried eastward beneath a 50 km gap by a deep, previously unrecognized aquifer and then discharged into the RHFZ. Based on chemistry of chloride, sulfate and other ions it is proposed here that a deep aquifer comprising the strongly weathered upper surface of the Barton Creek Formation plus the overlying weakly consolidated Albion Formation connects the elevated recharge area with the RHFZ discharge area. If this composite permeable zone does extend westward beneath the elevated recharge zone, it is probably an excellent aquifer.

Article

HYDROGEOLOGY ICAICHE FORMATION SULFATES DEEP AQUIFER YUCATAN PENINSULA CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO HIDROLOGÍA HIDROBIOLOGÍA HIDROBIOLOGÍA

Exploración hidrogeológica en las inmediaciones del lago de Cuitzeo, Michoacán

Hydrogeological exploration in the mediations of Lake Cuitzeo, Michoacán

Ivonne Janette Cruz Aquino (2022)

La zona de Araró forma parte del acuífero Morelia-Queréndaro y se ha reportado un déficit de agua en dicho acuífero. Debido a ello, es de gran importancia el estudio de las condiciones actuales del acuífero de Araró para proveer de este vital recurso a la población. Además, se ha reportado la presencia de manifestaciones y alteraciones hidrotermales en el área que resultan de interés, debido al potencial geotérmico existente en la zona. En este sentido, los métodos electromagnéticos son herramientas muy utilizadas en la exploración de recursos hídricos subterráneos debido a que son sensibles a los cambios de conductividad eléctrica de las rocas, propiedad que se puede asociar a la presencia de fluidos. Y, dada la importancia de conocer las condiciones de los acuíferos en áreas geotérmicas y la escasa información de las condiciones hidrogeológicas actuales del acuífero somero situado en las inmediaciones de Araró, se realizó un estudio geofísico utilizando el método Transitorio Electromagnético (TEM) para así caracterizar la geometría del acuífero. Para ello, se realizaron 30 sondeos TEM distribuidos por toda la zona de estudio y se realizaron inversiones 1D empleando las técnicas de Marquardt y Occam. Los modelos geoléctricos se interpretaron correlacionando cuatros unidades hidrogeológicas: la primera unidad corresponde a la zona no saturada, con resistividades de 6 a 25 Ωm; la segunda unidad, con resistividades de 25 a 95 Ωm se asocia al acuífero; la tercera unidad con resistividades < 6 Ωm es la asociada a la capa arcillosa, producto de la alteración hidrotermal que puede estar actuando como un acuitardo, y la cuarta unidad se asocia al basamento del acuífero, cuyas resistividades son > 100 Ωm. Para conocer las características del agua, se midieron parámetros físico-químicos de muestras de agua extraídas de pozos y norias del área de estudio. Con lo anterior, se encontró una relación entre la resistividad y algunos parámetros como sólidos disueltos totales, conductividad eléctrica y temperatura, indicando que altos valores de estos parámetros se sitúan en las zonas de baja resistividad.

The Araro area is part of the Morelia-Querendaro aquifer and a water deficit has been reported in that aquifer. Due to this, it is of great importance to study the current conditions of the Araró aquifer to provide this vital resource to the population. In addition, the presence of hydrothermal manifestations and alterations has been reported in the area that are of interest, due to the existing geothermal potential in the area. In this sense, electromagnetic methods are widely used tools in the exploration of underground water resources because they are sensitive to changes in the electrical conductivity of rocks, a property that can be associated with the presence of fluids. Given the importance of knowing the conditions of the aquifers in geothermal areas and the scarce information on the current hydrogeological conditions of the aquifer located in the vicinity of Araro, a geophysical study was carried out using the Transient Electromagnetic Method (TEM) in order to characterize the geometry of the shallow aquifer. For this, 30 TEM surveys spatially distributed throughout the study area were carried out and 1D inversions were performed using the Marquardt and Occam techniques. The geoelectric models are interpreted by correlating four hydrogeological units: the first unit corresponds to the unsaturated zone, with resistivities from 6 to 25 Ωm; the second unit, with resistivities from 25 to 95 Ωm, is associated with the aquifer; the third unit with resistivities < 6 Ωm, is associated with the clay layer, a product of hydrothermal alteration that may be acting as an aquitard, and the fourth unit is associated with the basement of the aquifer, whose resistivities are > 100 Ωm. Also, physical-chemical parameters of water samples extracted from wells and waterwheels located in the study area were measured, to know the characteristics of the water. A relationship was found between resistivity and some parameters such as Total Dissolved Solids, Electrical Conductivity and Temperature, with high values of all these parameters located in low resistivity areas.

Master thesis

Acuífero, TEM, alteraciones hidrotermales, resistividad, conductividad eléctrica, temperatura Aquifer, TEM, hydrothermal alterations, resistivity, electric conductivity, temperature CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO GEOFÍSICA OTRAS OTRAS