Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The tailing dumps of the mining district of Tlalpujahua and El Oro (DIMITO) were stacked on the active drainage system and covering a basement consisting of carbonaceous limestones and shales ± andesites, which constitute the host rock of the epithermal Au vein-type deposit. This geomorphological setting shows deep channels and gullies of erosion and it has been estimated a loss of material > 27–34% of its original volume. We present mapping of five tailing dumps that were placed ~68 year ago as well as the mineralogical and geochemical characterization of 12 profiles and 48 samples. Tailings are essentially siliceous-calcareous slime with clasts. Their pH is slightly alkaline from 7.5 to 8.5 and they show low conductivity <80 µS/cm. They are constituted by abundant quartz (≥ 53–68 %), lithics (7-20 %), calcite (≥12 %), silicates (9–11 %), Fe-Ti oxides (≥2–3 %) and sulphides and sulphosalts (≤2 %). Bulk composi- tions are characterized by SiO2 (56–92 %), Al2O3 (>15–13 %), CaO+MgO (≥5–11 %), Fetot (≤3–5 %), S (0.3–0.91 %), and C (3.4 –6.1 %). DIMITO tailings show values of Au (1.2–1.61 g/ton), Ag (28.1–46.8 g/ton), Pb (53.3–145.2 g/ton) and Zn (155.9–354.5 g/ton), suggesting that they could still have some economic recovering. In relation to the concentrations of the potentially toxic elements, the values of Sb (27.3–72.2 g/ton) signifi- cantly exceed high risk of the LMP (WHO, 2015), and a dozen samples of Pb and Zn and As (25.2–40.5 g/ton) show higher values than low-risk of the LMP. However, these values are scattered and random in each profile, so its toxic potential is discussed based on its mineralogical-geochemical correlation and its potential mobility. In order to estimate the acid-base accounting (ABA) of the DIMITO, we carried out a mathematical model based from the Gauss-reduction normalization of the geochemical data and their relationships with normative mineralogy. We found that the mineralogy represents a powerful proxy for the diagnostic of the toxic potential of the waste mines and that in general the tailings show not risk of acide mine drainage generation. However, we discuss the environment impact of the tailing dumps and the relationships with the actual land use of the DIMITO.

This paper is a contribution to the knowledge of the crustal structure of the eastern flank of the Valle Fértil - La Huerta ranges (Western Sierras Pampeanas, San Juan, Argentina) at 31°S, in the Andean foreland region, where the Nazca plate is subducting horizontally at about 100 km depth. A 1D velocity model was constrained, combining petrographic and seismological observations from analysis of 19 igneous and metaigneous plutonic rocks belonging to the Famatinian (Ordovician) magmatic arc, which make up most of the crystalline basement of these ranges. Granitoid lithologies predominate in the northern region whereas mafic lithologies are more common to the south. The seismological analysis consisted of modeling teleseismic receiver functions near three seismological stations: LUNA, MAJA and CHUC, in places where those rocks are dominant. Thus, P and S seismic-wave velocities (Vp and Vs) and Poisson´s coefficient (ν), among other elastic parameters, were obtained. The seismic velocity model indicates an overthickened crust with an average thickness between 55 and 60 km, which matches with global average values (~41km); this agrees well with the hypothesis of partial eclogitization in the lower crust. The presence of two seismic velocity discontinuities at mid-crustal levels (12 and 28 km depths), likely associated to décollements, might be related to the accretion of the Cuyania terrane to the Pampia terrane. We obtained low P seismic-wave velocities (Vp ~5.8 km/s), Vp/Vs ratio (~1.70) in upper crust levels consistent with granitoid lithologies, as well as high P seismic-wave velocities (Vp ~6.76 km/s), Vp/Vs ratio (~1.78) in lower crust levels; these figures match with mafic lithologies of a more dense (~3.00 g/cm3),  lower crust with respect to other back-arc Andean regions. Also, these values are consistent with the existence of mafic rocks composed of olivine, ortho- and clinopyroxene, which constitute the root of the Famatinian magmatic arc. These results indicate high-grade metamorphic conditions and depths corresponding to geophysical properties of middle to lower crust and correlate with the hypothesis of a dehydrated, cool and magnesium-enriched mantle located in the region between the subducted Nazca slab and the bottom of the Cuyania terrain crust.

Plutonic rocks of the Puerta del Sol area, in central Sonora, represent the extension to the south of the El Jaralito batholith, and are part of the footwall of the Sierra Mazatán metamorphic core complex, whose low-angle detachment fault bounds the outcrops of plutonic rocks to the west. Plutons in the area record the magmatic evolution of the Laramide arc and the Oligo-Miocene syn-extensional plutonism in Sonora. The basement of the area is composed by the ca. 1.68 Ga El Palofierral orthogneiss that is part of the Caborca block. The Laramide plutons include the El Gato diorite (71.29 ± 0.45 Ma, U-Pb), the El Pajarito granite (67.9 ± 0.43 Ma, U-Pb), and the Puerta del Sol granodiorite (49.1 ± 0.46 Ma, U-Pb). The younger El Oquimonis granite (41.78 ± 0.32 Ma, U-Pb) is considered part of the scarce magmatism that in Sonora records a transition to the Sierra Madre Occidental magmatic event. The syn-extensional plutons are the El Garambullo gabbro (19.83 ± 0.18 Ma, U-Pb) and the Las Mayitas granodiorite (19.2 ± 1.2 Ma, K-Ar). A migmatitic event that affected the El Palofierral orthogneiss, El Gato diorite, and El Pajarito granite between ca. 68 and 59 Ma might be related to the emplacement of the El Pajarito granite. The plutons are metaluminous to slightly peraluminous, with the exception of El Oquimonis granite, which is a peraluminous two-mica, garnet-bearing granite. They are mostly high-K calc-alkaline with nearly uniform chondrite-normalized REE and primitive-mantle normalized multielemental patterns that are characteristic of continental margin arcs and resemble patterns reported for other Laramide granites of Sonora. The Laramide and syn-extensional plutons also have Sr, Nd and Pb isotopic ratios that plot within the fields reported for Laramide granites emplaced in the Caborca terrane in northwestern and central Sonora. Nevertheless, and despite their geochemical affinity to continental magmatic arcs, the El Garambullo gabbro and Las Mayitas granodiorite are syn-extensional plutons that were emplaced at ca. 20 Ma during development of the Sierra Mazatán metamorphic core complex. The 40Ar/39Ar and K-Ar ages obtained for the El Palofierral orthogneiss, the Puerta del Sol granodiorite, the El Oquimonis granite, and the El Garambullo gabbro range from 26.3 ± 0.6 to 17.4 ± 1.0 Ma and are considered cooling ages associated with the exhumation of the metamorphic core complex.

During last decade, Colima town suffered from an increase in flooding and inundation. These episodes occurred during extreme rainfall events, such as hurricanes Jova in2011and  Manuelin2013 both with averages rainfall intensities of 200 mm per day, but also during high intensity and short duration rainfall through the rain season.Natural soils in the region are derived from the volcaniclastic deposits originated from the activity of the Volcán de Colima. Land use analyses were performed based on field work on a target area(TA) that was then used to perform a supervised classification using SPOT images taken in 2005, 2009 and 2015 in the studied area that corresponds with the hydrological basin that drains into the urban area of Colima and Villa de Ávarez. The three main land use classifications were defined: Native, Cultivated and Urban surfaces (each of them with their own subdivisions). 33 soil samples were collected and analyzed to determine their physical proprieties such as: particle size distribution, bulk and particle densities, water weight and soil porosity, organic matter content, pH and electrical conductivity. The in situ hydraulic conductivity test was done using a Drip-Infiltrometer device to obtain the Ks value.Soils correspond to Andosols with more than 88% sand, up to 8% silt and 3% clay. They came out positive in the allophane test in more than 80% of the samples. The average water contents were of 14%, 21% and 13% for natural, cultivated and urban soils respectively. Bulk density average values were below 1.30 gr/cm3 and particle average densities below 2.30 gr/cm3. Porosity varies from 29 to 55%. The organic matter vary from almost cero to 11%. pH data pointed to the existence of phosphorus, iron, copper, zinc, and manganese and the electric conductivity classified them as sodic soils. in the in situ infiltration experiments yielded Ks values of 32.16 to 0.50 mm/h for native soils, Ks of 25 mm/h for cultivated and Ks from 10 to 0.8 mm/h for urban soils.Land use time-space analysis in the TA showed that from  2005 to 2015 the urban land use growth was of 13%,cultivated lands decreased an 11%, while natural areas decreased only 1%.For the complete study zone, urban land use increased  by2% from 2005 to 2009 and remained in the same amount for 2015. From2009 to 2015 cultivated area decreases by8%and change to  native lands due to field abandoning.Based on this research results, the increase in flooding and inundation in the Colima-Villa de Álvarez area could be related to the land use change, especially the increase in urban land that largely reduce the infiltration rate as the decrease in cultivated area which resulted to be the type of soil in the area with the highest infiltration rate. These anthropic land use evolution promotes inundation not only during extreme hydrometeorological event but also during the common rainfalls events causing several damages on infrastructures and death.

It is estimated that 80–85% of the water extracted from aquifers in Mexico is used for agricultural production, and in general, there is an inadequate management that causes different damages to the environment, highlighting the depletion and contamination of groundwater, among others. The purpose of this work is to quantify the water balance and dynamics in the unsaturated zone by means of daily measurements of different meteorological parameters and the moisture profiles of a soil that was treated to conservation practices in the Independence Aquifer (Upper La Laja River Basin tributary of the Lerma-Chapala). The stratigraphy of the site was obtained through continuous records of electrical conductivity and granulometry in unaltered soil samples - to which physical properties and organic matter content were determined - in their first 2.50 m depth. The changes in moisture content at 0.15, 0.30, 0.60, 0.90 and 1.20 m were controlled by Time Domain Refractometry (TDR). The saturated permeability was quantified with the Guelph Permeameter, complemented with infiltration tests. A one-dimensional numerical model was used to develop predictive tools. The results indicate that progressive capture of carbon occurred and that a saturated hydraulic conductivity of up to Kfs = 5 m∙d-1 has been reached, in the first 0.60 m of depth, which contrasts up to two orders of magnitude with traditional soil management; allowing the gradual filtering of a total water sheet of 6,753 mm for three days, which would cover any sequence of maximum rainfall events recorded in the region. The RDT sensors showed a rapid increase in moisture content along the profile, indicating that the characteristics obtained in the soil allow the immediate input and storage of rainwater, with a minimum evaporation rate and zero runoff. The present work demonstrates that it is feasible to favor the infiltration of sufficient rainwater for the production of staple and fodder crops and to reduce the impacts of negative incidents because of climate change. This applies to irrigation crops, which would allow the progressive reduction of groundwater extraction, by more than 50%, through adequate conservation practices, a fundamental aspect in the management of the aquifer.

The fossil deposit Cañadón Las Horquetas, placed in the centre-south of the Chubut Province, includes the Bajo Barreal Formation of early Cenomanian – late Turonian age. This site presents the greater abundance and diversity of fossil vertebrates in the San Jorge Gulf Basin. The diagenetic processes reported herein represent a little addressed subject in taphonomic studies involving dinosaurs. We present for the first time information on the permineralization processes that affected the dinosaur remains preserved in overflow deposits from the Bajo Barreal Formation, as well as new sedimentological data of the studied unit.Samples from three specimens were studied by chemical analysis, polarization petrographic microscope, X-ray diffraction and scanning electron microscopy (SEM). These studies show that all the dinosaurs have had a similar diagenetic history, with the same pattern of mineral replacement. Besides, the similar chemical composition found in the fossils and in the bearing rocks suggest that the enrichment with new elements found in the studied dinosaur remains was due to the direct exchange with the sediments in which they were buried. The now reported diagenetic conditions can be preliminarily extended to the whole lower member of the Bajo Barreal Formation.

In order to determine the heavy metals content and distribution in an area cultivated with sugarcane in the Río Hondo basin, southern Quintana Roo, Mexico, 10 samples of surficial sediments were collected from the main agricultural drain and 18 samples from soils developed on a karst aquifer. The samples were obtained on february 2016, during the dry season. Concentrations of Hg, Cd, Cu, and Fe and physicochemical parameters such pH, organic matter and cation exchange capacity were measured. In order to understand the distribution of the heavy metals, we performed descriptive statistics, Pearson correlation, analysis of variance, t test, principal component analysis and hierarchical clustering analysis. The mean concentration of heavy metals in soil, in descending order were: Fe > Cu > Cd > Hg with soil values of 25,334.13 mg∙kg-1, 10.56 mg∙kg-1, 0.55 mg∙kg-1 and 0.02 mg∙kg-1, respectively; the sediment values found were 19,952.68 mg∙kg-1, 8.00 mg∙kg-1, 0.54 mg∙kg-1 and 0.06 mg∙kg-1, respectively. The physical and chemical parameters were homogeneous within the study area. The origin of Hg, Cd and Cu concentrations could be anthropogenic. Although Fe is naturally found in the study area, it is possible that the current distribution of this metal is also due to agricultural activity. The main factor in the distribution of heavy metals in the agricultural soils of the sugarcane zone is the carrying of soil particulates caused by runoff, and the greater contribution of these pollutants to the agricultural drain occurs mainly by the entrainment of particulates from gleysol type soils.

La información de bienestar animal (BA) en las unidades de producción (UP) de México es escasa, por lo que el objetivo de este estudio fue evaluar el grado de bienestar de vacas lecheras en producción, mediante la aplicación del protocolo europeo Welfare Quality® (WQ®) en cuatro municipios del estado de Hidalgo. Se evaluaron 1,187 vacas en producción, secas y vaquillas gestantes, distribuidas en 52 UP, seleccionadas por pertenecer al sistema familiar y participación voluntaria. En los formatos de WQ® se recabó la información por encuesta estructurada, medición de recursos y a partir de la observación animal, con ajustes a las condiciones del sistema de producción y respetando el orden y tiempo sugerido por el protocolo. En el análisis de la información se aplicaron los algoritmos de árbol de decisiones, suma ponderada y funciones I-Spline y la integral de Choquet. La clasificación final coloca a todas las UP como aceptables y corroborado en el simulador de WQ® en línea. La calificación en cada Principio (P) fue de 39 puntos para P1, 48 para P2, 23 en P3 y P4 con 28 puntos. Aun cuando el protocolo es una herramienta útil para la valoración del bienestar animal en el sistema de producción a pequeña escala del altiplano mexicano, la aplicabilidad no es total, por ello se hace necesario el desarrollo de protocolos propios, validados y probados científicamente que representen más fehacientemente la realidad del bienestar animal en este sistema. 

It was able to identify 23 isolates of Gallibacterium anatis through conventional culture and biochemical tests, and identification confirmed through PCR method. A disk diffusion test determined antimicrobial resistance to commonly used antibiotics in the poultry area. Isolates were more susceptible to ceftiofur (73 %) and florfenicol (68 %). All isolates showed marked resistance to penicillin, tylosin, lincomycin, ampicillin, enrofloxacin, oxytetracycline, norfloxacin and cephalexin. The presence of Gallibacterium anatis is associated with respiratory and reproductive problems in populations of commercial laying hens. Isolates showed marked resistance to different antibiotics, probably due to excessive medication in the presence of this organism.

En el presente estudio se determinó la prevalencia de endometritis subclínica y su efecto en la tasa de gestación en vacas lecheras en manejo intensivo. Entre los días 35 y 45 posparto se seleccionaron 237 vacas sin patologías uterinas (vacas con útero involucionado y sin secreciones vaginales anormales); a todas ellas se les tomó una muestra citológica de endometrio mediante la técnica de Cytobrush. Los frotis se procesaron con la tinción de Diff-Quick. Se contaron un total de 200 células y se determinó la proporción de células polimorfo nucleares (PMN). Las vacas con ≥ 6 % de PMN se consideraron con endometritis subclínica. Cuarenta y tres por ciento (103/237) de las vacas presentó endometritis subclínica. Las vacas con puerperio patológico tuvieron mayor probabilidad de padecer endometritis subclínica que las vacas con puerperio normal (60 vs 36 %, respectivamente; razón de probabilidad= 2.69). Las vacas normales tuvieron mayor tasa de gestación en el primer servicio que la vacas con endometritis subclínica (31.4 vs 20.0 %; respectivamente; razón de probabilidad= 2.02) y la proporción de vacas gestantes en el día 120 posparto fue mayor en las vacas normales que en las vacas con endometritis subclínica (51.6 vs 37.9 %, respectivamente; razón de probabilidad= 1.98). Se concluye que la prevalencia de endometritis subclínica en vacas lecheras entre los días 35 y 45 posparto es de 43 %, lo cual disminuyó en un 11.4 % la tasa de gestación en el primer servicio y en un 13.7 % la tasa de gestación acumulada en el día 120 posparto.