José Ramón Torres-Hernández

• Autonomous University of San Luis Potosí

Several reliable and extensively applied traditional geochemical, mineralogical, and petrography methods exist for identifying hydrothermal alteration of rocks. However, many of these methods require tedious and laborious sample preparation and analysis procedures. Therefore, there is a need for faster methods and reliable in their application. Bin...

The San Luis Potosí valley is an endorheic basin that contains three aquifers: a shallow unconfined aquifer of alluvial material and two deep aquifers, free and confined. The groundwater contamination documented for the shallow aquifer generates contamination of the deep unconfined type aquifer, from which part of the population’s drinking water ne...

The valley of San Luis Potosí is an endorheic basin formed by three aquifers: shallow hanging, alluvial material on a hardened horizon known as "tepetate", two deep, free and confined type. Population growth has led to gradual contamination of the surface aquifer. Recent studies documented anthropogenic, biogenic and heavy metal contamination. A re...

The Guadalcazar is located in the Mesa Central (MC) province, which is mainly composed of granitic rocks and is known for its metallogenetic. The granitic rocks contain complex Sn-Hg-Ag-F mineralization and were emplaced during Eocene to Oligocene. However, the source, origin, and evolution of magma and the tectonic setting of this magmatic area ha...

On the western part of the Valles–San Luis Potosí Platform located in Cerro Quemado near Temazcal, municipality of Armadillo de Los Infante, two sequences crop out. The lower one is the shallow-water El Abra Formation of the mid–upper Cenomanian, unconformably covered by a deep-water deposit of the upper Maastrichtian informally called here the “Te...

The Upper Cretaceous stratigraphic succession in the western part of the Valles-San Luis Potosi Platform (central to eastern Mexico) reflect the interaction between various paleo-oceanographic factors including sea-level change, tectonic factors, and the type and supply of sediments. The El Abra Formation is a shallow-water carbonate deposit that i...

The Compostela area is located in the western Trans-Mexican Volcanic Belt, which consists of volcanic rocks that produced during the Pliocene to Recent volcanism. In this paper, we present petrography, whole-rock major-and trace-element concentrations , Ar-Ar ages, and Sr-Nd isotopic data of volcanic rocks from the Compostela area in the south of t...

The aim of this study is to determine the feeding habits and home range of fossil horses (Equus conversidens and E. mexicanus) from La Presita Blanca, San Luis Potosí, central México. For this purpose, we used carbon, oxygen, and strontium isotope ratios. We compared ⁸⁷Sr/⁸⁶Sr from horses with strontium ratios of La Presita Blanca plants and soils...

The Mesa Virgen Calerilla (MVC) is located in the state of Zacatecas, Mexico. The most intense volcanism, which occurred during the Eocene, formed extensive ignimbrite deposits exposed in some parts as lava spills of rhyolitic (felsic) composition. This felsic volcanism may represent much of the MVC. This study describes whole‐rock geochemistry and...

Strontium isotopic ratios from dental enamel of fossil camels, Camelops hesternus (n=5), horses, Equus sp. (n = 5), and mammoths, Mammuthus columbi (4) from Laguna de las Cruces, San Luis Potosí, central Mexico, have been used to study their migration behavior. Four camels, all horses, and one mammoth display ⁸⁷Sr/⁸⁶Sr similar to local plants and s...

The southern part of the Mesa Central (MC) province, Mexico, is formed of several Cenozoic volcanic complexes. The Sierra de San Miguelito Complex (SSMC) is in the south-eastern part of the MC. The SSMC consists of: (1) mafic volcanic rocks of porphyritic texture and trachybasalt/basalt compositions; (2) intermediate volcanic rocks of porphyritic t...

The Pinos Volcanic Complex (PVC) is located in the San Luis Potosi Volcanic Field (SLPV) and southern region of the Mesa Central that includes Oligocene rhyolites and trachydacites. These felsic volcanic rocks are characterized by porphyritic textures with a main mineralogical arrangement of phenocrystals of quartz, potassium feldspar (sanidine), p...

The hydrogeochemical characterization and water-rock interaction processes in the subbasins of Santa Catarina and Ocampo-Paraíso in the Zona Media of San Luis Potosí have allowed identifying the types of groundwater. The results of the chemical analysis and the regional geological study show the possible rock-water interaction mechanisms. These res...

Geochemical data from Early Cretaceous volcanic rocks (ultra-basic, basic, intermediate) from the Fresnillo area (Chilitos Formation), Zacatecas, are presented in this study. These rocks are characterized by variable SiO2 = 38.1–61.7 wt %, Al2O3 = 17.5–27.2 wt %, and MgO = 0.21–6.4 wt % with the Mg# = 20.6–78.9. They are influenced by variable degr...

Paleogene−Neogene volcanic complexes are commonly found in the southern part of the Mesa Central province (MC), Mexico. The Sierra de San Miguelito Complex (SSMC) is located in the southeastern part of the MC and consists of two main phases of Oligocene and Miocene units as follows: (1) basaltic group of porphyritic texture of basalt/trachybasalt c...

En la región central de México existen zonas con extensos afloramientos de rocas calcáreas plegadas formando sistemas montañosos con intenso desarrollo cárstico. El abastecimiento de agua en esta región se logra en una parte importante de acuíferos controlados por el sistema cárstico. Aquí se analiza el flujo subterráneo entre la localidad Joya de...

Dental enamel strontium isotopic values were determined for an American lion specimen from Cedral, San Luis Potosí, Mexico. The result was similar to the ⁸⁷ Sr/ ⁸⁶ Sr values of plants and soils from the same locality, which could indicate that this animal was native to the site where it hunted prey that approached the springs found in Cedral in the...

The Yolomécatl area, northwestern Oaxaca, Sierra Madre del Sur Morphotectonic Province, Mexico, lies between 17°25′N and 17°30′N latitude, 97°29′W and 97°36′W longitude, at 2200–2500 m above sea level, and includes ∼90 km² of rugged territory, where lithostratigraphic units of Late Jurassic to Quaternary age crop out. The Tertiary succession, which...

The discrimination/characterization of depositional systems recorded in formal lithostratigraphic, Cenozoic, continental, epiclastic units of Mexico, is largely a pending task, notwithstanding its great academic and economic importance. Contributing to fill this gap, we present a first approach to discriminate and characterize the depositional syst...

Nuevo registro de los caballos del Pleistoceno Equus conversidens y E. mexicanus en San Luis Potosí 81 Resumen Usando diversos elementos óseos, se reporta la presencia de dos especies de caballo del Pleistoceno en la Presita Blanca, San Luis Potosí. Un molar inferior M-2 fue asignado a Equus mexicanus, mientras que una 1ª falange del dedo central o...

The Joya Honda maar (JHm) is located in central Mexico, 35 km NNE of the city of San Luis Potosí. It lies in the Plio-Quaternary alkaline Ventura-Espíritu Santo Volcanic Field located in the eastern part of Mesa Central province. The JHm eruption occurred at 311±19 ka (⁴⁰Ar/³⁹Ar) along a fissure that formed an elliptical crater (c. 1.3×0.9 km wide...

The Yolomécatl-Tlaxiaco Area, lies in the rugged Sierra Madre del Sur (SMS) of northwestern Oaxaca (YOTLA), southeastern Mexico. Within the area Cenozoic units unconformably overlie metamorphic, clastic and carbonate rock units of Late Paleozoic to Cretaceous ages as well as the Mixteco/Oaxaca Terrane boundary. The Cenozoic sequence, emphasized her...

In spite of ~130 years of geologic research in Mexico, much remains pending e.g. only 1/3 of this country's territory is mapped in detail [i.e., scale 1:50000], the formal stratigraphic differentiation of the continental sedimentary Cenozoic is barely started, discriminating the depositional systems that make up basic units is even less pursued. To...

The discrimination and characterization of the depositional systems registered in the formal lithostratigraphic units of our country, is practically a pending task of Mexican Geology, notwithstanding their academical and applied importance in the investigation of placer mineral deposits and of aquifers. As a contribution to fill this gap, the depos...

New geological mapping and U-Pb dating of detrital zircons and volcanic rocks permit stratigraphie revision and interpretation of pre-Late Permian deformation in the Sierra Plomosa area, located 95 km east of the city of Chihuahua and at comparable distance to the southwest of the border town Ojinaga. The Plomosas area forms the central part of a n...

RESUMEN Nueva cartografía geológica y dataciones U-Pb en circones detrí-ticos y de rocas volcánicas han permitido la revisión estratigráfica y la interpretación de deformación pre-pérmica tardía en la Sierra Plomosa, situada aproximadamente 95 km al este de la ciudad de Chihuahua y a igual distancia al suroeste de la ciudad fronteriza de Ojinaga. L...

This work deals with calcareous algae and microencrusters (incertae sedis) from the upper part of the El Abra Formation, which crops out at the W Valles–San Luis Potosí Platform. Two assemblages of calcareous algae are recognized: one composed of rivulariacean-type cyanobacteria such as Cayeuxia kurdistanensis Elliott and Garwoodia sp. as well as t...

By using strontium isotopic ratios of dental enamel from molars, we were able to reconstruct the migration context for three individuals of a Columbian mammoth population ( Mammuthus columbi ) around Laguna de las Cruces, San Luis Potosí, central México. A three-step leaching procedure was applied to eliminate secondary Sr contributions in the mola...

Alluvial fans and terraces develop in diverse regions responding to different tectonic and climatic conditions. The Motozintla basin is located in the State of Chiapas, southern Mexico and has an E–W orientation following the trace of the left-lateral Polochic Fault. The evolution of the Motozintla basin and the alluvial plain is related to several...

Mexico's Late Neogene mammal faunas are largely known from localities in the Trans-Mexican Volcanic Belt; those from other morphotectonic provinces are few and far apart. Thus, the discovery of Late Miocene vertebrates in western Sierra Madre Oriental at San Luis Potosí, the Paso del Águila local fauna, significantly adds to this meager record. The...

A calcisphere (Pithonellid) acme is recorded from Cerritos, western Valles-San Luis Potosí platform, Mexico. The abundance of these microfossils appears to constitute a global event in the Cenomanian-Turonian boundary. Their large quantity is interpreted as an indicator of changes in primary productivity during transgressive episodes. The pithonell...

The San Luis Potosí volcanic field includes two annular-shaped tectonic structures. Rhyolitic domes with topaz and cassiterite vapor phase mineralization were erupted along the smaller one. The lavas are characterized by high SiO2 (>75 wt. %), Al2O3 (11-14 wt. %), Na2O + K2O (7.5-9 wt. %) and low CaO (< 1 wt. %), MgO and TiO2 (< 0.15 wt. %). Furthe...

A calcisphere (Pithonellid) acme is recorded from Cerritos, western Valles–San Luis Potosí platform, Mexico. The abundance of these microfossils appears to constitute a global event in the Cenomanian-Turonian boundary. Their large quantity is interpreted as an indicator of changes in primary productivity during transgressive episodes. The pithonell...

The Zacatecas mining district was considered one of the most important silver deposits from colonial times until the end of the XIX century; mining operations are currently attractive, as they have found new sites with profitable economic mineralization. The study area is located north of the city of Zacatecas, where marine Triassic sequences, volc...

During the early Maastrichtian an assemblage rich in large foraminifera, mostly composed of orbitoidal foraminifera, developed in the shallow-water deposits of the Cárdenas Formation (Valles-San Luis Potosí Platform, Mexico). Among them, the most abundant is Lepidorbitoides minima, some of which display a morphologically abnormal test consisting of...

We report paleomagnetic results of thermoremanent magnetization of the lithic clasts and matrix of the Lower Panalillo ignimbrite in the San Luis Potosi Volcanic Field (CVSLP), that provide quantitative estimation of emplacement temperature range of the lithic-rich proximal facies in the Arroyo El Juachín, from which we sampled 78 specimens of lith...

The recently discovered Upper Cretaceous locality El Gorrión (SI48, San Luis Potosí, central Mexico) yielded three specimens of chaetetids. All specimens can be attributed to the genus Blastochaetetes Dietrich due to the discontinuities in the calicle walls. In addition, one of them could be classified as Blastochaetetes flabellum (Michelin) based...

The recently discovered Upper Cretaceous locality El Gorrión (SI48, San Luis Potosí, central Mexico) yielded three specimens of chaetetids. All specimens can be attributed to the genus Blastochaetetes Dietrich due to the discontinuities in the calicle walls. In addition, one of them could be classified as Blastochaetetes flabellum (Michelin) based...

We report paleomagnetic results of thermoremanent magnetization of the lithic clasts and matrix of the Lower Panalillo ignimbrite in the San Luis Potosi Volcanic Field (CVSLP), that provide quantitative estimation of emplacement temperature range of the lithic-rich proximal facies in the Arroyo El Juachín, from which we sampled 78 specimens of lith...

Prediction of prone areas for mass movement processes (MMP) is one of the major challenges in mountainous areas. This is the case of the Motozintla basin that is located along the Motagua–Polochic fault system in the Chiapas State southeastern Mexico. The area is dominated by Permian to Tertiary rocks extremely affected by faults, weathering and in...

During the early Maastrichtian an assemblage rich in large foraminifera, mostly composed of orbitoidal foraminifera, developed in the shallow-water deposits of the Cárdenas Formation (Valles-San Luis Potosí Platform, Mexico). Among them, the most abundant is Lepidorbitoides minima, some of which display a morphologically abnormal test consisting of...

Lithologic and foraminiferal analysis from the western part of the Valles-San Luis Potosí platform reflect a sea-level rise suggesting that the platform was drowned at the Cenomanian-Turonian boundary interval. Benthic and planktic foraminiferal content of the succession was identified to establish the transition from the shallow-water carbonate se...

The Zacatecas mining district was considered one of the most important silver deposits from colonial times until the end of the XIX century; mining operations are currently attractive, as they have found new sites with profitable economic mineralization. The study area is located north of the city of Zacatecas, where marine Triassic sequences, volc...

During the early Maastrichtian an assemblage rich in large foraminifera, mostly composed of orbitoidal foraminifera, developed in the shallow-water deposits of the Cárdenas Formation (Valles–San Luis Potosí Platform, Mexico). Among them, the most abundant is Lepidorbitoides minima, some of which display a morphologically abnormal test consisting of...

The San Luis Potosí volcanic field, is located in the southeastern of the Mesa Central, mainly formed by a sequence of lavas and pyroclastic fows with ages between the Middle Eocene until the Quaternary. Generally in the San Luis Potosi Volcanic Field there are fve mainly volcanic stages; the first one restringed to the middle Eocene with the emiss...

El Campo Volcánico de San Luis Potosí, se localiza en la porción sur-oriental de la Mesa Central y está formado principalmente por una secuencia de lavas y flujos piroclásticos con edades que van desde el Eoceno medio hasta el Cuaternario. En general, el Campo Volcánico de San Luis Potosí tuvo cinco etapas principales de vulcanismo. La primera etap...

At central-eastern Mexico, in the Mesa Central province, there are several ranges that were formed after the K/T Laramide compression but before the Basin and Range peak extensional episodes at middle–late Oligocene. Two important volcano-tectonic events happened during this time interval, 1) uplift of crustal blocks exhuming the Triassic–Jurassic...

Anisotropy of magnetic susceptibility (AMS) was selected as the key technique to find the source of the widespread Cantera Ignimbrite and to seek its possible relationship with the San Luis Potosí Caldera. Eighteen sites (372 specimens from 155 cores) from the Oligocene Cantera Ignimbrite were sampled. AMS was measured on a KLY2 Kappabridge. AMS da...

Anisotropy of Magnetic Susceptibility (AMS) results from a group of 17 - 18 sites (286 - 312 specimens) from the Cantera Ignimbrite - of Oligocene age and part of the San Luis Potosí Volcanic Filed (SLPVF), México - are presented and analysed in order to help to determine the source and flow directions. In each site a flow direction is inferred bas...

Pyroclastic dikes emplaced along regional NW-SE faults in the Tertiary San Luis Potosí Volcanic Field consist of vitric pumice shards, rhyolite lithics, and broken crystals of quartz, sanidine, and biotite. These clasts display a parallel orientation inside the dikes and have developed devitrification structures after emplacement. The presence of t...

Una serie de diques piroclásticos en el Campo Volcánico de San Luis Potosí está asociada a fallas regionales que cortan y basculan a la secuencia volcánica terciaria (32-27 Ma). Estos diques muestran sus raíces en las formaciones riolita San Miguelito e ignimbrita Cantera y están expuestos en los arroyos El Juachín y Las Cabras. Los diques tienen u...

Along the west-central limit between the Central Mexico Mesozoic Basin and the Valles-San Luis Potosí carbonate platform exist marked variations in style and intensity of Laramide folding (Late Cretaceous-Early Tertiary). These variations are attributed to: 1) prominent inter- and intra-formational changes in lithology and bedding thickness, and 2)...

Along the west-central limit between the Central Mexico Mesozoic Basin and the Valles-San Luis Potosí carbonate platform exist marked variations in style and intensity of Laramide folding (Late Cretaceous-Early Tertiary). These variations are attributed to: 1) prominent inter- and intra-formational changes in lithology and bedding thickness, and 2)...

There are five widely recognized stratigraphic units underlying the transgressive Oxfordian deposits in central to northeastern Mexico: (1) the submarine-fan deposits of the Zacatecas Formation, (2) the volcanogenic products of the Nazas Formation, (3) the continental deposits of the Huizachal Formation in northeastern Mexico (which contains severa...

En el noreste de México se han reportado algunos afloramientos de rocas volcánicas Triásicas y Jurásicas, cuyas características petrológicas y geoquímicas demuestran una afinidad de arco que permite relacionarlas a una margen continental activa. Más elementos que apoyan este ambiente tectónico se localizan en los estados de Durango, Zacatecas, San...