Agua Caliente Research Articles

Rainbow Serpents and Boiling Springs: Indigenous Sovereignty and the Fight for Groundwater in the United States and Australia

Around the world, Indigenous people are preparing for futures of climate uncertainty and resource shortages. Indigenous communities are looking to the past and seeking guidance from their traditions – diverse systems of knowledge that change over time – so that they and future generations might nurture connections to the “deep time” of geological and human histories. In this essay we examine how the Wangan and Jagalingou Family Council in Australia and the Agua Caliente Band of Cahuilla Indians in the United States have taken long-term views on ecological sustainability and sovereignty. We focus on these two Indigenous communities on opposite sides of the Pacific Ocean because they are among the highest-profile battles over ancient groundwater in the past decade. Set against a backdrop of global settler state interference and exploitative economic practices, both cases reveal how the concept of kinscapes – or a shared sense of relatedness to interconnected ecosystems, histories, and places (or nodes) of belonging – can sharpen our understanding of environmental stewardship and its importance to Indigenous sovereignty. Whereas mining corporations and settler governments continue to make decisions with short- to medium-term objectives in mind, Wangan and Jagalingou and Agua Caliente leaders have used legal battles over groundwater to underscore their spiritual and physical connectedness with local environments. Like Indigenous communities around the world, the Wangan and Jagalingou Family Council and the Agua Caliente Band of Cahuilla Indians are making ontological choices by asserting their sovereignty through environmental stewardship.

Origin of the internal basement massif of the Guatemala Suture Zone: evidence from U-Pb geochronology and Sm-Nd and Lu-Hf isotope systematics

Abstract The origin of eclogite-bearing granitoid gneisses and metapelites of the Chuacús Complex is investigated. This complex represents the internal basement massif of the Guatemala Suture Zone, a part of the western North America–Caribbean plate boundary. LA-ICP-MS U-Pb and trace element zircon data are combined with whole-rock Sm-Nd and Lu-Hf isotopes to re-evaluate granitoid petrogenesis and inquire into the sedimentary record. New granitoid ages of ca. 1030–1010 Ma are reported, adding to those already known of ca. 1100, 990 and 225 Ma. Stenian A-type granitoids within the bimodal Cubulco unit formed by mixing of magmas derived from late Palaeoproterozoic crust and mantle-derived melts produced in an extensional setting during Rodinia assembly. During the Tonian, an extended (or later) period of extensional tectonics produced peraluminous granitoids (Pachajob gneiss) by anatexis of rejuvenated late Mesoproterozoic crust. After a hiatus encompassing most of the Neoproterozoic, marine sedimentation occurred between the Ediacaran and the early Palaeozoic as recorded by the Palibatz schist, a sequence formed by detritus sourced from peri-Gondwanan continental areas. No evidence of middle to late Palaeozoic magmatism or sedimentation was found in the studied area. Late Triassic granitoids (Agua Caliente unit) were produced by mixing melts from late Mesoproterozoic crust with enriched mantle magmas in response to post-collisional thinning during the western Pangea breakup. This extensional stage led to considerable thinning of the Chuacús crust and its evolution into a passive margin that would be prone to subduct during the Cretaceous.

Towards an Architectural Theory of Jurisdictional Technics: Midcentury Modernism on Native American Land

How should we do the history of US midcentury modernist architecture—a period marked by intense campaigns of Native American dispossession in the face of organised Indigenous resistance? The spatial development of the Agua Caliente Band of Cahuilla Indians’ ancestral lands in Palm Springs, California, offers an illustrative case study for these intersections; a history of colonial settlement both enabled and constrained as much by canonical architects like Albert Frey and Richard Neutra as by the Agua Caliente’s own highly influential political activism. This history challenges the perfect model of nested state jurisdiction—seamlessly connecting territory and expertise—to show a tangle of jurisdictional relations of various degrees and kinds of opacity, marked and mediated by architecture. This article explores these entanglements as the effects of “jurisdictional technics,” or how architecture organised relations of authority among and between competing regimes of order.

Wood lots and horticultural intensification in Prehistoric Tucson, B.C. 2,100-A.D. 500

This study presents the results of a long-term, large-data set paleoethnobotanical study of wood use along the Santa Cruz River floodplain, near Tucson, Arizona. Over the interval from 2,100BCE to A.D.50, local villagers depleted regional saltbush stocks by overharvesting them for fuel. At the same time, they became increasingly reliant on mesquite. We explore the implications of the reduction of saltbush, and the dependence on mesquite. We combine information from ancient wood charcoal assemblages, an ancient pollen assemblage, estimates of likely per capita fuelwood consumption rates, and estimates of mesquite and saltbush productivity. We show that vast amounts of land had to be set aside for sustainable mesquite harvesting. We suggest that the need for mesquite management for fuel emerged coevally with agricultural intensification prior to A.D. 50. Thereafter, additional demands for fuel during the Agua Caliente phase further escalated the need for managing wood lots. This study is germane for scholars of the prehistoric American Southwest, and also for people studying pre-pottery early agricultural societies or prehistoric community resource ownership worldwide.

A Mesoproterozoic to Jurassic history of continental eclogites from the Guatemala Suture Zone–implications for a peri-Amazonian ancestry

Cretaceous continental eclogites of the Chuacús Complex (Guatemala Suture Zone) contain an extensive record spanning more than 1.1 Ga. In this study, we combine U-Pb zircon geochronology, Sm-Nd and Lu-Hf isotope systematics, and geochemistry with field observations to determine the origin of eclogite protoliths. Mafic precursors are multiple comprising Ectasian to Middle Jurassic rocks originated in convergent, within-plate, and continental rift settings. Eclogites with estimated ca. 1.3 Ga protolith ages display chemical and isotopic features suggesting that mafic precursors formed in an extensional arc setting. These rocks are part of a complexly folded gneiss sequence (El Chol unit) that underwent pervasive perturbation of the zircon U-Pb system during a polymetamorphic evolution. One generation of OIB-like protoliths yield crystallization ages of 1.1–1.0 Ga, were derived from an enriched mantle source, and belong to a bimodal igneous assemblage (Cubulco unit) related to intraplate magmatism. An additional eclogite with OIB characteristics is part of a considerably younger bimodal suite (Agua Caliente unit) emplaced at ca. 228 Ma during a renewed pulse of within-plate activity. The youngest eclogite protoliths crystallized at ca. 168–162 Ma and represent E-MORB-type metabasites derived from a depleted mantle source and contaminated with variable amounts of crustal material. Hence, the geological record of the Chuacús eclogites includes evidence for: (1) extensional magmatism in a pre-Rodinian continental arc setting, (2) Stenian intraplate magmatism compatible with global large igneous province activity around Rodinia, (3) the initial breakup of western equatorial Pangea during the Late Triassic, and (4) the consequent Middle Jurassic rifting of Middle America terranes from the northwestern Gondwana margin. These data imply that the internal continental massif of the Guatemala Suture Zone may have evolved from a peri-Amazonian crust in the same way as other basement inliers of Mexico and the Northern Andes formerly adjoined within Pangea.

Whiteness on the Green

Between the early 1950s and 1970s, Palm Springs, California, a leisure and resort community in the Coachella Valley, entered into a dramatic era of growth driven by an unlikely factor: golf. Exclusive and elite country clubs employed new forms of environmental and social engineering as they transformed the arid landscape into lush, emerald fairways. The rapid rate of growth meant that courses were built without concern for significant social and ecological side effects. In particular, golf’s arrival brought new power dynamics to the valley that displaced and disenfranchised local communities of color, including the Agua Caliente band of Cahuilla Indians and a neighborhood of low-income African Americans and Mexican Americans who lived in the path of development. This expansion-oriented program of development is an example of what we might call the “leisure-industrial complex,” in which private enterprise, public policy, and cultural norms combined to create an economic machinery that soon commanded the Coachella Valley. As such, the history of Coachella golf is not just the history of a sport, but the history of how leisure came to dominate the landscape, the environment, and the people of the California desert.

Exploring the use of Moringa oleifera as a vegetable in Agua Caliente Nueva, Jalisco, Mexico: A qualitative study

AbstractPeople in Mexico speak of the medicinal properties of Moringa oleifera (“moringa”), but they know less about its nutritive properties. A qualitative, participatory approach was utilized to explore the use of moringa as a vegetable in Agua Caliente Nueva, Jalisco, by enrolling 14 female participants (mothers over 18) who were nutritional gatekeepers of the family and were responsible for preparing family meals using moringa leaves. Participants prepared meals with moringa and participated in semi‐structured interviews to record their perceptions of foods, shopping habits, and knowledge and experience using moringa. The study objectives were to assess the regional acceptability and feasibility of introducing a readily available and nutritious plant into diets, and to examine whether moringa could potentially serve as part of a solution to the double burden of malnutrition in Mexico. Findings suggest that given its ability to thrive in this dry tropical region, moringa has the potential to be recognized as a viable component in the traditional diet in this small “ejido” communal farming community.

New chronological constraints on intense Holocene eruptions and landslide activity at Tacaná volcanic complex (Mexico)

Usual methods are unfortunately unsuitable to accurately date many Holocene deposits and landforms from active Mexican volcanoes. This is notably the case for the Tacaná Volcanic Complex (TVC), located in the State of Chiapas in southern Mexico, and the San Marcos Department in Guatemala. The complex consists of the Chichuj, Tacaná, and San Antonio volcanoes and the Ardillas dome. Tacaná volcano, the main summit of the TVC, collapsed 15 ± 5 ka ago ( 40 Ar/ 39 Ar), producing the Agua Caliente Debris Avalanche. The result was the formation of a horseshoe-shaped crater 600 m wide open to the northwest. Afterward, several undated effusive and explosive eruptions occurred. All these eruptions are likely Late Pleistocene to Holocene in age because the landforms derived from that activity overlap the horseshoe-shaped crater. To corroborate this hypothesis, we used surface exposure dating with in situ- produced cosmogenic 36 Cl combined with lichenometry and dendrochronology in the summit domes, the Ardillas dome, the horseshoe-shaped crater's cliff, and an andesitic lava. The 36 Cl exposure ages (9.3 ± 1.9 ka; 8.9 ± 0.9 ka; 8.6 ± 1.7 ka) of the summit domes are statistically indistinguishable within the associated uncertainties and suggest that the domes formed during Early Holocene. Instead, the southern part of the Late Pleistocene collapsed crater yielded significantly younger ages ranging from 5.3 ± 0.6 to 7.0 ± 0.8 ka. These ages are assumed to be minimum and might indicate later rockfall activity and instability, affecting the horseshoe-shaped crater. The 36 Cl exposure age of an andesitic lava (0.4 ± 0.1 ka), emplaced to the SW of Tacaná, is in good agreement with lichenometry (>347 yr). These ages could represent a gravitational collapse event associated with phreatic explosions vented close to a scar collapse. The 36 Cl exposure ages derived from the Ardillas lava dome (0.3 ± 0.1 ka) do not correspond to its emplacement age. The dome must be older than pyroclastic deposits dated at 760 ± 30 yr BP ( 14 C) that cover its surface. Strikingly, the 36 Cl, lichenometrical and dendrochronological data of the “Andesitic” lava and the Ardillas dome are associated with NE-SW landslide scars, explosion craters, phreatic vents, fumarolic activity, and tensional fractures. All these features are perpendicular to the NW-SE minimum stress regime (σ3), affecting the TVC and generating gravitational activity. Nowadays, gravitational collapses represent a real threat to the surrounding populations that can be triggered not only by volcanic activity but also by seismicity and extraordinary rains.

Geology and geochronology of the Jurassic magmatic arc in the Magdalena quadrangle, north-central Sonora, Mexico

This work reports on the geology and U–Pb LA-ICPMS zircon geochronology of a crustal section that is part of the Jurassic magmatic arc in the Magdalena quadrangle of north-central Sonora, Mexico. This rock succession is variably metamorphosed and strained as it was affected by Late Cretaceous shortening, intruded by early Tertiary granitoids, and further exhumed in the lower plate of the early Miocene Magdalena metamorphic core complex. The older and more extensively exposed Jurassic unit is the >3.5 km thick Sierra Guacomea rhyolite that is composed of massive to poorly bedded rhyolite, bedded quartz-phyric rhyolitic ignimbrite and interbedded ash-fall tuffs and quartz-rich sandstone beds. Three rhyolite samples collected at different localities of its outcrops yielded concordia ages of 175.2 ± 0.9, 171.7 ± 0.6, and 171.4 ± 0.7 Ma. The quartz-phyric Rancho La Víbora, Los Vallecitos, and the Agua Caliente rhyolitic domes that are associated with the Sierra Guacomea rhyolite yield concordia ages of 176 ± 0.8, 174.4 ± 0.9 and 173.1 ± 0.8 Ma, respectively. The Rancho Los Pozos unit composed of interbedded rhyolitic ash-fall tuff and flows, sandstone, siltstone and subordinate limestone beds has an estimated thickness of 600 m and yielded a crystallization concordia age of 170.7 ± 0.6 Ma from a rhyolite bed. The porphyritic El Rincón granite that intrudes into the Sierra Guacomea rhyolite yields crystallization ages of 167.43 ± 0.42 and 164.4 ± 0.7 in samples from different localities. The La Jojoba metasandstone that consists of foliated, quartz-rich to arkosic strata of fluvial origin is at least 900 m thick; detrital zircon grains dated from three sandstone samples yielded dominantly Jurassic ages with peaks at 172, 170, and 163.7 Ma, and a combined maximum depositional age of ca. 163 Ma.The younger plutons are the porphyritic El Nopalito granite that has an interpreted crystallization age of 160.8 ± 0.6 Ma, and the leucocratic, two-mica, garnet-bearing La Cebolla granite that yielded a concordia age of 158.1 ± 1 Ma. These granitic intrusions record the waning magmatic pulses of the arc, in the study quadrangle, but their volcanic equivalents were not identified. Inherited zircon grains in the reported volcanic and plutonic units are only of Jurassic age, except by two Proterozoic zircon grains yielded by the El Nopalito granite. The El Salto granite augen gneiss is a xenolith dated at 1071.9 ± 5 Ma that indicates the presence of Grenvillian basement in the study area.Major- and trace-element geochemical data indicate that the volcanic and plutonic units are silica-rich, mostly high K calc-alkaline to shoshonitic rocks associated with a continental margin arc setting. The plutons are mostly peraluminous, and in conjunction with trace element geochemistry data, they suggest crustal assimilation of magmas emplaced in a probably thickened continental crust. Chondrite-normalized REE patterns and primitive mantle-normalized trace element diagrams also suggest partial melting and fractional crystallization processes.The ages obtained indicate that the arc in the study area developed from ca. 176 to 158 Ma, encompassing a 17 m.y. interval of magmatism and associated sedimentation. Regional correlation and geochronologic published data indicate that the arc crustal section of the Magdalena quadrangle is part of the Jurassic magmatic arc that regionally lasted from ca. 190 to 158 Ma.

Supply and Demand Analysis of Water Resources. Case Study: Irrigation Water Demand in a Semi-Arid Zone in Mexico

To sustainably use water resources, it is important to quantify water availability in a certain region. Due to climate change, population increase, and economic development, water demand increases continuously. Consequently, the difference between supply and demand of water becomes a significant issue, especially in arid and semi-arid regions. In this research, the Soil and Water Assessment Tool (SWAT) model has been applied to the Guadalupe river basin, to assess supply and demand analysis of water resources in this area, specifically for the irrigation of agricultural crops and municipal uses. From the land use, soil type, and terrain slope maps, 763 Hydrostatic Release Units (HRU) were estimated, distributed in the diverse relief types making up the basin, featured by mountains, hills, plateaus, plains, and valleys. For the crop area, 159 HRU were found with the three slope classification types, where 57 HRU represent 91% of the cultivated area on slopes, from 0 to 15%, located in the Ojos Negros and Guadalupe Valleys. The Soil Conservation Service method (SCS) was used to estimate the average monthly runoff and soil moisture content. As a result, water resource parameters related to the supply were determined with this, e.g., runoff, aquifer recharge, flow, infiltration, and others. Crop coefficient values (Kc) were used to determine crop evapotranspiration (ETc), to estimate the water demand of these for each month, using the multi-year monthly average reference evapotranspiration (ETo) calculated with the SWAT model. Overall good performance was obtained considering average monthly discharges data from the Agua Caliente gauging station. The model was calibrated, modifying the parameters chosen according to sensitivity analysis: SCS curve number, base-flow factor, ground-flow delay, and the threshold for return-flow occurrence. The Soil and Water Assessment Tool–Calibration and Uncertainty Programs SWAT-CUP has different goodness-of-fit indicators for the model e.g., determination coefficient (R2), standard deviation of the measured data (RSR), Nash–Sutcliffe coefficient of efficiency (NSE), and others. Multiple iterations were performed, resulting in a ratio between the root mean square error and the standard deviation of the measured data (RSR) of 0.61, a coefficient of determination (R2) of 0.70, and a Nash–Sutcliffe efficiency coefficient (NSE) of 0.63. A supply–demand analysis of the volume generated by the runoff from the basin was performed using the method of estimating useful volume for a reservoir. It is observed in these results that only positive deviations were obtained, implying that runoff in this basin is not enough to meet monthly demand. Finally, the need to establish actions to ensure water management efficiency is highlighted, both for irrigation of agricultural crops and for supply to the region population.

Stenamoeba dejonckheerei sp. nov., a Free-Living Amoeba Isolated from a Thermal Spring.

Two amoeboid organisms were obtained from water samples taken from a thermal spring, "Agua Caliente", in Northwestern Mexico. The isolates were obtained when samples were cultivated at 37 °C on non-nutrient agar coated with Escherichia coli. The initial identification of the isolates was performed morphologically using light microscopy. The samples were found to have trophozoite morphology consistent with members of the genus Stenamoeba, a genus derived in 2007 from within the abolished polyphyletic genus Platyamoeba. Further analysis was performed by sequencing PCR products obtained using universal eukaryotic primers for the small subunit ribosomal ribonucleic acid (SSU rRNA) gene. Sequencing primers were designed to allow the comparison of the 18S rRNA gene sequences of the new isolates with previous sequences reported for Stenamoeba. Phylogenetic relationships among sequences from Stenamoeba were determined using Maximum Likelihood analysis. The results showed the two "Agua Caliente" sequences to be closely related, while clearly separating them from those of other Stenamoeba taxa. The degrees of sequence differentiation from other taxa were considered sufficient to allow us to propose that the Mexican isolates represent a new species.

Determinación del grado de bioalfabetización en estudiantes provenientes de escuelas cercanas a la zona de influencia de la Universidad Técnica Nacional

En el presente estudio se determinó el grado de bioalfabetización en estudiantes provenientes de escuelas cercanas a la zona de influencia de la Universidad Técnica Nacional, donde participaron diez centros educativos procedentes de cuatro cantones en la provincia de Guanacaste, a saber: Cañas, Tilarán, Bagaces y Abangares. Un total de 141 estudiantes de tercero y cuarto año fueron abordados, el 50,35 % correspondió al género femenino y 49,65 % al masculino. El grupo etario se mantuvo entre los 10 y 11 años de edad. Con la investigación se determinaron los principales factores que influyen sobre las comunidades en cuanto a temas ambientales. El mayor índice de bioalfabetización general lo presentó la escuela San Antonio de Javilla en Cañas (0,96) y el menor índice lo presentó la escuela Celestino Álvarez Ruíz de la comunidad de Montano de Bagaces. Únicamente dos escuelas (San Antonio de Javilla en Cañas y Agua Caliente de Bagaces) presentaron grados altos de bioalfabetización con valores de iguales a 0,96 y 0,80 respectivamente.

Multivariate analysis of CO2, H2S and CH4 diffuse degassing and correlation with fault systems in Agua Caliente - Tzitzio, Michoacán, México

The quantitative relationships between soil gas flux anomalies and faults systems in Agua Caliente-Tzitzio geothermal system were analyzed statistically. The main degassing features are related with thermal springs. The data used in the multivariate analysis are geothermal gas fluxes and spatial structural data (i.e., local fault strike). Exploratory Data Analysis (EDA) and Multivariate Analysis of Variance (MANOVA) were implemented, for the first time, to statistically describe the relation between the location of degassing features and the presence of some local fault systems, discriminating the direction of the main discharge channels and pointing to higher permeability faults. The results show that there is a statistically significant correlation between diffuse degassing of CO2 and CH4 and the N-S and E-W fault systems. Conversely, H2S degassing does not show any correlation with the fault systems, which may be related with the higher H2S reactivity compared with that of CO2 and CH4. It is highly recommended to use EDA and MANOVA techniques in order to establish the main degassing directions in geothermal and volcanic areas.

When the Well Runs Dry: Groundwater Policy and Sustainability Post–Agua Caliente

Author(s): Tyra, Alec D. | Abstract: In the height of a seven-year drought in California, The Agua Caliente Band of Cahuilla Indians (the Tribe) sued the Coachella Valley Water District and Desert Water Agency (Together as “Water Districts”) to secure their right to groundwater stored in the Coachella Valley Aquifer (Aquifer). The Aquifer, like most groundwater resources in California, was severely taxed during the drought. This forced California to respond by passing the Sustainable Groundwater Management Act (SGMA), the first groundwater regulation in the State’s history. SGMA requires “sustainable groundwater management” for all basins by creating Groundwater Sustainability Plans (GSPs). These plans are, in effect, stakeholder negotiations on basin management. Basin adjudications will likely occur if these negotiations break down. In Agua Caliente Band of Cahuilla Indians v. Coachella Water District, the Ninth Circuit became the first federal court to expand the definition of Winters rights to include groundwater. Winters rights are federally reserved rights to water to help sustain the primary purpose of a federal reservation. The expanded definition of Winters rights increases the bargaining power of tribes, as stakeholders, in the GSPs and any possible basin adjudication. This decision greatly impacts California and other states in the Ninth Circuit. It would also have major implications for Arizona if Arizona had not been managing groundwater in much of the state since the 1980s. Additionally, Arizona recognized a tribal right to groundwater in Gila III in 1999. Agua Caliente affects the future of water supplies by broadening the definition of federally reserved rights to include tribes’ right to groundwater. This Comment recommends that private and public stakeholders across the West follow Arizona’s lead with respect to water planning in the Ninth Circuit’s jurisdiction by using settlement agreements with tribes to secure contested supplies of groundwater.

Determinación de As(III) y As(V) en los pozos de las plantas de remoción de arsénico de Costa Rica

Se realizó la separación y cuantificación del arsénico soluble, particulado, As(III) y As(V) en los pozos de las seis plantas de remoción de arsénico operadas por AyA en Guanacaste y Alajuela: Bebedero de Cañas, Montenegro y Agua Caliente, Falconiana y Quintas Don Miguel en el cantón de Bagaces y Santa Cecilia de El Amparo y Cristo Rey en Los Chiles. Se empleó la espectrometría de masas con plasma de acoplamiento inductivo (ICP-MS) así como cromatografía de intercambio aniónico (CIA) con resina Dowex 1-X8 de 50 a 100 mallas. Se validó la metodología obteniendo las siguientes figuras de mérito: límite de detección 0,1 μg/L, límite de cuantificación 0,2 μg/L, veracidad de diferentes fracciones y mezclas entre (97-104) %, con coeficientes de variación entre (0,9-12,8) % con coeficientes de variación entre (0,9- 12,8) %, así como una repetibilidad de 0,2% y una repetibilidad intermedia de 0,3% (n=7). Se efectuaron ocho muestreos mensuales y en los seis pozos prevalece el arsénico soluble sobre el particulado. En todos los pozos guanacastecos y en Cristo Rey de Los Chiles predomina As(V) sobre As(III), siendo el As(III) no detectable, detectable o en concentraciones ligeramente superiores al límite de cuantificación. En el caso de Santa Cecilia de El Amparo, hay mezcla de As(III) y As(V) en razones de concentraciones muy similares y predominando uno sobre otro dependiendo del muestreo. Además este pozo es el que posee menor concentración de oxígeno disuelto (1,5 mg/L), mientras que los restantes pozos tienen concentraciones superiores.

FUTURES OF GAMING: HOW CASINOS AND GAMBLING MIGHT EVOLVE IN THE NEAR FUTURE

FUTURES OF GAMING: HOW CASINOS AND GAMBLING MIGHT EVOLVE IN THE NEAR FUTURE

The Pucallpa Nest and its constraints on the geometry of the Peruvian Flat Slab

Seismic nests (or clusters) are typically defined as regions of high seismic activity at intermediate depths that do not move over time and are not associated with volcanic activity at the surface (e.g. Zarifi and Havskov, 2003; Zarifi et al., 2007; Prieto et al., 2012). In this study, we focus on a seismic nest located in central Peru beneath the Amazon basin city of Pucallpa. The location of this nest is just beyond the eastern-most extent of the Peruvian flat slab, similar to the settings of two other South American clusters, the Bucaramanga and Pipanaco nests. While the Pucallpa nest is visible in the figures of many earlier papers on intermediate depth South American seismicity, it has not to our knowledge been described as a seismic nest before. We present the first detailed description of the Pucallpa nest, compare it to other established nests, and discuss its implications for our understanding of the Peruvian flat slab. Our results indicate that the Pucallpa nest demarcates the northern margin of a sag in the horizontally subducting Nazca plate in central Peru. The position of the nest along the projected location of the downgoing Mendaña fracture zone is consistent with local variations in b-values and could help to explain both the nest's genesis and the co-located change in slab geometry. The nest is also spatially well correlated with the northern margin of the thick-skinned Shira Mountains and with the high heat flow associated with the Agua Caliente dome (Hermoza et al., 2006; Navarro Comet, 2018). Further study is needed to understand the effects of the complex Peruvian slab geometry on the formation of thick skinned deformation and heat flow anomalies on the overriding South American continent.

Potentially pathogenic genera of free-living amoebae coexisting in a thermal spring

Little is known about the prevalence of Balamuthia mandrillaris within the environment due to its difficult isolation, but once an axenic culture is established, it is relatively easy to maintain. As most of the time researchers are interested mainly in isolating B. mandrillaris from environmental samples, the flora that accompanies it becomes second in importance. Therefore, this study aimed to determine which potentially pathogenic free-living amoebae, in addition to B. mandrillaris, could be found co-inhabiting a source of natural thermal water called “Agua Caliente” (Mexico), where this amoeba has previously been detected twice by molecular methods. A third sampling from this same source was carried out to try to isolate B. mandrillaris and other free-living amoebae using 37 and 45 °C as isolation temperatures. For PCR techniques, specific primers were used for B. mandrillaris, Naegleria fowleri, and Acanthamoeba species, plus a universal primer set for the eukaryotic 18S SSU rRNA gene for other isolated amoebae. PCR products were sequenced for final identification. 42 strains of the primary isolate were obtained, but only 34 could be kept in culture. Of them, 23 strains were identified as Naegleria lovaniensis, eight strains as Acanthamoeba jacobsi, two strains as Stenamoeba sp. and only one was identified as Vermamoeba vermiformis. The isolation of B. mandrillaris was once again not successful, but the presence of potentially pathogenic and nonpathogenic free-living amoebae is reported for the first time in this type of water in Mexico thanks to molecular methodology.

Indoor Air Quality in Housing and Health in Women of Agua Caliente, Poncitlán, Jalisco, México (2018)

Background / aim: In rural areas, solid fuels such as wood are usually used to cook food. In Agua Caliente, Mexico 94% of households depend on this fuel to meet their energy needs for cooking, activity that suppose the influence on indoor air quality and the health of people. The aim of this study was to characterize the levels of particulate matter in the air of the kitchens and at the same time to know the thermal comfort index to which cooks are exposed in the home and the symptoms they perceive.Methods: It was measured in the indoor air of the kitchens the number of particles/ft3 of the particles with diameter 0.3 µm, 0.5 µm, 1 µm, 2.5 µm, 5 µm y 10 µm issued by 30 stoves that use wood as fuel (14 traditional stoves and 16 ecological stoves), at the same time values of ambient temperature and relative humidity were taken and the home cooks were interviewed to know the symptoms that they manifest. Descriptive and statistical determinations were made to analyze emissions, thermal comfort index and symptoms.Results: The amount of particulate material/ft3 for all particle sizes measured at the precautionary and danger levels for humans were found in more than 60% of the houses, the emissions of MP0.3, MP0.5, MP2.5 from ecological stoves and traditional stoves at these levels were found in more than 80% of homes, the thermal comfort index considered in caution, extreme caution and danger showed a tendency to occur in a greater percentage in homes with traditional stoves > 64% compared to 31% of homes with ecological stove at the precaution level. 93% of the women reported not having any symptoms associated with the use of the wood stove.Conclusions: The study showed that both ecological stoves and traditional stoves generate emissions of particles that are injurious to health, a situation that is not reflected in the symptoms perceived by women; the thermal comfort index showed improvement when using ecological wood stoves.

Biological and geological characterization of modern biofilms and microbial mats and comparison with similar lithified structures in Colombian Cretaceous formations

Microorganisms may play an important role in the aggregation of sediments and the formation of sedimentary structures. Biofilms are microbial aggregates that, in a mature stage, can develop into microbial mats, fibrillar networks that irreversibly bind filaments of cyanobacteria and sediments, inside which it has been identified a stratification with functional groups of microorganisms that coexist, generate symbiotic relationships and potentially modify the characteristics of sediments and sedimentary rocks, particularly in extreme environments. In this work, filamentous cyanobacteria from biofilms of a lacustrine environment with intervals of flooding/desiccation and a saline environment, and a microbial mat from the Agua Caliente Thermal, El Rosal, Cundinamarca, are identified. In the biofilms, most cyanobacteria were found to belong to the Orden Oscillatoriales, while in the microbial mat cyanobacteria of the order Orden Nostocales were also recognized. Two rock samples isolated from the thermal which genesis was possibly influenced by the activity of cyanobacteria are described and classified. One of them, named R-1, is a calcareous rock inside which it was possible to differentiate biolaminations and an apparent dominance of biomineralization processes. This sample was both classified as a travertine and a microbial framestone with stromatolitic and thrombolytic texture. The second one, called R-2, is a siliciclastic rock classified as a mudstone and a microbial boundstone. Finally, a comparison between the sedimentary structures identified in those rocks with similar structures in the formations La Luna, Paja and Tetuán and the microbially-induced sedimentary structures (MISS) described in the literature is performed. Based on morphological resemblance, fibrillar networks identified locally in those formations are interpreted as possible biolaminations originated from the activity of cyanobacteria.