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Summary Resource histories determine how particular parts of the environment come to be defined as valuable. As elsewhere, protected areas in Latin America link the governance of people, territory, and resources by reinterpreting and reclassifying practices and environments. Set in highland Peru, the article focuses on how such revisions imply contestation of both history and future. It explores particular modes of claiming space through an archeology of the claims to knowledge and legitimacy put forward by a national park and a campesino community, respectively. Claims to space entwine with social struggles about local development where territorial claims are based on different notions of history and interpretations of the esthetic and productive values of the landscape. While the park officials navigate interests of conservation, tourism, and extraction, the campesino community mobilizes a different set of values and interests based on their historical occupation of the territories. These processes of contestation over authority and legitimacy highlight different views on the role of landscapes in the history and progress of local communities. Conservation may not only dispossess people of their land and natural resources, but also of labor and territorial sovereignty. This case shows how an Andean campesino community counters such movements by a wide repertoire of legal and social actions that works simultaneously in legal and extra-legal domains. Paper works mediate claims to territorial sovereignty, people, and resources. These claims involve contestations over interpretations of history which, besides their oral forms, materialize in paperwork such as official communications, community records, and cadastral maps, as well as in visual representations, internal statutes, and deliberate history writing. [ABSTRACT FROM AUTHOR]

The International Symposium on Andean Geodynamics (ISAG) is an international conference that was held, on average, every 3–4 years in different European cities between 1990 (Grenoble) and 2008 (Nice). These symposia usually offer an opportunity for researchers from Latin American countries and Europe as well as other countries to review the state of knowledge in geosciences on the Andes. After a long period without an edition, the 8th ISAG was organized for the first time in a Latin American country, Ecuador, from 24th to 26th September 2019. The organizing committee led by Pablo Samaniego relied heavily on the Instituto Geofísico of the Escuela Politécnica Nacional (IG-EPN) and the Institut de Recherche pour le Développement (IRD), in particular through its office in Quito, and through the Laboratoire Mixte International in France and Ecuador: "Seismes et Volcans dans les Andes du Nord" (LMI-SVAN); and the French Embassy in Ecuador. Field trips in tectonics, seismotectonics and volcanology at emblematic sites in Ecuador were organized by researchers from the IRD (Isterre and LMV), the Institut de Radio Protection Nucléaire (IRSN), IG-EPN and the University of Geneva. Four invited speakers gave presentations: Peter Molnar (University of Boulder) on the mechanisms of the Andes uplift, Suzanne Kay (Cornell University) on its magmatism, Victor Ramos (University of Buenos Aires) on the scientific approaches developed through time for the Andean orogeny and Eric Calais (Ecole Normale Supérieure de Paris) on the difficulty of dialog between seismic risk specialists and the authorities in Haiti. The symposium also provided an opportunity for more than 250 participants to meet, with more than 80 oral presentations and over 150 posters. As a result of this conference, the Editor of the Journal of South American Earth Sciences proposed to the organizing committee to publish a special issue on the contours of these presentations. Following the peer review process, 19 papers are published in this special issue. These manuscripts reflect the various disciplinary fields, geophysics and deep imaging, tectonics, volcanism, geomorphology and seismic hazard, from the local scale to the Andes as a whole. Not surprisingly, a higher density of works is found in Ecuador and the northern Andes (Figure 1). As this collection of articles reflects the outlines of a symposium and not a specific scientific question, our aim here is not to develop a synthesis of current knowledge on the Andes. We therefore present these articles in sequence, by discipline, although this categorization may appear subjective since some articles are multidisciplinary. [ABSTRACT FROM AUTHOR]

High mountains are harsh environments in which colder temperatures and higher levels of UV-B radiation are common. These abiotic conditions strongly affect animals' biology, often constraining their survival and reproduction. As a result, adaptations to live in such habitats are expected to evolve. Body color is thought to be adaptive to the environment that animals experience. Tegument melanization improves heat gain and provides photoprotection. Therefore, at high elevation, ectotherms are expected to be darker (well-melanized). We test this prediction in the paper wasp Agelaia pallipes (Hymenoptera: Vespidae), a species distributed across an elevational gradient in the Colombian Andes. We used Malaise traps and sampled a total of 146 wasps along nine elevations, ranging from 2,600–3,380 m above sea level. Standard digital photography was used to measure the body luminance and colour patterning in different body parts of dry-preserved specimens. There was striking variation in body luminance (darker and lighter), color patterning (patched, smoothed, homogeneous) and surface texture (shiny and matte), but the kind and degree of variation depended on the body part examined. Wasps from higher elevations had darker thoraces, confirming our prediction. Besides, at high elevation, the frequency of wasps with a matte rather than a shiny face strongly increased. Overall, our findings support the thermal melanism hypothesis and suggest that intraspecific color variation might be an adaptation to the environment of paper wasps. Image 1 • High mountains exhibit harsh abiotic conditions, like low temperatures and higher levels of UV-B radiation. • Tegument melanization (darkening) improves heat gain and provides photoprotection. • Females of Agelaia pallipes are darker at high elevations. • Intraspecific colour variation might be an adaptation to the environment where of paper wasps live. [ABSTRACT FROM AUTHOR]

There is a long history in the use of osseous materials from some of the earliest contexts of the Andes, yet most technology studies have focused on durable materials of ceramic, metal, and stone. In this paper, we present evidence for the continual use of osseous raw materials before and during Wari state expansion in the 1st millennium CE in the Cusco region of Peru. Results indicate that, at the site of Ak'awillay, communities were exploiting osseous raw material to produce artifacts used in textile manufacture, food processing, and ceremonial activities. We argue that wide-scale access to bone and antler raw material fostered social interactions that mediated emergent power dynamics in private and public spaces. This key line of evidence reveals that communal practices in public spaces at Ak'awillay involved food processing activities, while private settings were reserved for sharing of familial knowledge around textile production. We emphasize the greater need in the Andes for a close look at osseous technology to detect these subtle, yet integral patterns to understand social and power relations in the past. [ABSTRACT FROM AUTHOR]

The aim of this study is to assess the variability of the stable carbon and nitrogen isotope composition of herbivores -guanaco and huemul-in southern Patagonia. The study area extends from the eastern slopes of the Andes to the Atlantic Coast between 47° and 49° S. The ultimate aim of the research was to generate an isotopic ecology with an adequate spatial resolution that allows the incorporation and development of stable isotope studies in discussions of the population dynamics of hunter-gatherers in continental Patagonia. This paper presents the δ13C and δ15N values of 159 guanaco and huemul specimens, both modern and archaeological. This space was divided into three areas: Western area, Central Plateau and Eastern Area. Isotopic variability within groups was analyzed using the SIBER, from which the isotopic niches of the different groups are compared. The results show a spatial pattern of isotopic variability in herbivores, i.e. lower δ13C and δ15N values associated with forest environments in the western end of the transect and higher values, especially δ15N, towards the east, with maximum values observed near the Atlantic coast. Our results support the stated expectations on herbivore stable isotope composition variability and its association with environmental variables in a longitudinal transect across the southern Argentinean Patagonia. [ABSTRACT FROM AUTHOR]

[Display omitted] • Soils under anthropic uses showed more remarkable changes in soil properties with rainfall seasonality than soils under natural páramo. • Land-use change from natural vegetation to potato and onion crops followed by fallow reduces soil organic matter and water content and increases bulk density. • Land-use change could impair the ability of páramo catchments for streamflow buffering and this could increase surface runoff and reduce base flow. High-Andean páramos deliver essential ecosystem hydrological services from a combination of soil, vegetation, and climate characteristics, particularly in their natural state. However, agricultural activities considerably affect the páramo's ability to store, regulate, and supply water. Although there is information on the effect of potato crops (Solanum tuberosum) on páramo soils' properties, the effect of spring onion (Allium fistulosum) crops has been studied less. In addition, dry páramos are underrepresented in existent páramoś research. This study assessed the effect of rainfall seasonality (RS) and land-use change (transformation from páramo vegetation to crops) on soil hydrophysical properties associated with hydrological services (streamflow buffering) in a dry páramo in the Eastern range in Colombia. Six dominant land uses were studied: natural páramo vegetation (low slope, steep slope, and dense shrublands) and anthropic use (onion crops, potato crops, and fallow). An in-depth random stratified discrete design (0–5, 10–15, and 20–25 cm) was used to collect samples for analysis of soil organic matter (SOM), bulk density (BD), pH, and electrical conductivity (EC). Hydrophysical properties were measured at the soil surface: water retention capacity (WRC), structural stability (SS), and infiltration capacity (IC). Soils under anthropic uses showed more remarkable changes in soil properties with RS than soils under natural páramo. On the other hand, land-use change from natural vegetation to potato and onion crops followed by fallow leads to a reduction in SOM (9.8 %) and an increase in BD (0.19 gcm−3), especially at the surface level. In addition, this leads to a loss of WRC (20 % at field capacity), an increase in unstable aggregates (13 %), water erosion, and a loss of IC (44 mmh−1). This paper demonstrates the impact of land use on soil hydrophysical properties that compromise the maintenance of hydrological services and contributes to a better understanding of the complexity of Andean páramos. [ABSTRACT FROM AUTHOR]

Understanding the spatio-temporal variability of the solar resource is crucial to effectively support solar power utilization. Unfortunately, long-term and high-resolved measurements of solar irradiance are generally scarce, challenging the characterization for larger areas. In this paper, we propose a methodology to characterize the spatio-temporal variability of global horizontal irradiance (GHI) at a regional scale using long-term satellite-derived data. Spatial functional data analysis (sFDA) is used to identify areas with similar intra-annual variability patterns. The methodology is applied to a 21-year period data on Ecuador retrieved from the National Solar Radiation Database. Being the first time that sFDA is used for this purpose, the results indicate that it provides an appropriate basis for the interannual variability and complementarity analyses. In Ecuador's mainland, twenty-two subregions with four seasonal patterns are identified. The highest GHI potential (5.4 kWhm−2d−1) with the lowest variability (3.4%) is found in the Inter-Andean valleys. Further, seasonal complementarities between the coast and western Andes are identified. In Galapagos, high values are found over all islands (≥4.8 kWhm−2d−1), characterized by three subregions with one seasonal pattern. Our findings provide the first comprehensive spatio-temporal characterization of GHI in Ecuador, which aims at supporting a sustainable energy transition in the country. •A new approach to analyze the spatio-temporal variability of GHI is demonstrated. •The GHI variabilities due to microclimate effects in complex terrain are captured. •The findings provide the first comprehensive characterization of GHI in Ecuador. •High solar potential with low variability is found in the Inter-Andean valleys. •Strong seasonal complementarity between the coast and western Andes is identified. [ABSTRACT FROM AUTHOR]

The Salares Norte (SN) Au–Ag belt is here defined as an Upper Miocene-Pliocene metallogenic area, extending for nearly 200 km, located NE of the northern end of the Upper Oligocene-Lower Miocene Maricunga Belt in the central Andes of northern Chile. The belt is located just east of the main reverse NS fault systems which are part of the Sierra Castillo, Potrerillos Mine and Claudio Gay Cordillera faults, limited to the north and south by the NW-striking oblique to the arc Imilac and Wheelwright-Incahuasi regional faults systems. The epithermal deposits within the SN belt are intimately associated with the occurrence of Middle Miocene volcaniclastic basins and Middle to Upper Miocene phreatomagmatic vents and their related high-sulfidation hydrothermal systems. The volcanostratigraphy of the SN epithermal belt comprises volcaniclastic sequences, subvolcanic and volcanic rocks ranging between the Lower Miocene and the Pliocene. High-angle NS reverse faults involving Paleozoic and lower Cenozoic units form the western-southwestern limit of the belt. Folded and faulted Middle Miocene volcaniclastic and volcanic sequences form the main host rock of at least 4 phreatomagmatic events that generated maar-diatreme fields and discrete maar vents, with their related subvolcanic facies, within the widespread Upper Cenozoic volcanic arc, ranging in age between ca. 15 and ca. 4 Ma. These four phreatomagmatic events are spatially and temporarily associated to 4 main high-sulfidation hydrothermal events which have altered both the phreatomagmatic rocks and the Cenozoic country rock of the explosive activity. These hydrothermal systems have formed dozens of discrete hydrothermally altered areas where argillic, advance argillic, silicification and steam-heated alteration are common. Most of the maar fields and the hydrothermal alteration systems are emplaced within a strike-slip tectonic regime with NE-trending shortening which is accommodated in the NW-striking sinistral-normal faults and NE-striking extension structures. These fault systems crosscutting interaction favor the hydrothermal fluid circulation and migration, as well as mineral precipitation on structural and/or primary lithological traps and on NE-striking tension cracks. In summary, the SN epithermal belt is an almost 200 km long and 60 km wide area, mainly NNE-oriented, where epithermal deposits have formed during the Upper Miocene and Pliocene (ca. 13-4 Ma), emplaced within Middle to Upper Miocene volcanic and volcaniclastic sequences associated to small volcanotectonic basins oriented in NS, NE-SW and NW-SE directions, in which most of the high-sulfidation systems are associated to discrete or repetitive structurally-controlled Upper Miocene-Pliocene phreatomagmatic vents and maar fields. • This paper defines a new Au–Ag epithermal belt in the Central Andes of northern Chile. • Novel results in terms of age, volcanic stratigraphyand hydrothermal alteration. • The relationships between Upper Cenozoic HS epithermal areas, local tectonics and phreatomagmatic volcanism are discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The prevalence and diversity were higher for Haemoproteus than Plasmodium in Passeriformes. • The haplotype diversity was higher for Plasmodium than Haemoproteus. • Plasmodium and Haemoproteus prevalence were associated with higher avian diversity in the Chilean ecoregions. • Haemoproteus presented more specialist lineages than Plasmodium. • Haemoproteus presented greater genetic differentiation than Plasmodium between the east and west of the Andes mountains. The specialist versus generalist strategies of hemoparasites in relation to their avian host, as well as environmental factors, can influence their prevalence, diversity and distribution. In this paper we investigated the influence of avian host species, as well as the environmental and geographical factors, on the strategies of Haemoproteus and Plasmodium hemoparasites. We determined prevalence and diversity by targeting their cytochrome b (Cytb) in a total of 2,590 passerine samples from 138 localities of Central and South America, and analysed biogeographic patterns and host-parasite relationships. We found a total prevalence of 23.2%. Haemoproteus presented a higher prevalence (15.3%) than Plasmodium (4.3%), as well as a higher diversity and host specificity. We determined that Plasmodium and Haemoproteus prevalences correlated positively with host diversity (Shannon index) and were significantly influenced by bird diversity, demonstrating a possible "amplification effect". We found an effect of locality and the avian family for prevalences of Haemoproteus and Plasmodium. These results suggest that Haemoproteus is more specialist than Plasmodium and could be mostly influenced by its avian host and the Andes Mountains. [ABSTRACT FROM AUTHOR]

Cetina et al. (2019) presented new geochronological, geochemical and isotopic data obtained from volcanic and sub-volcanic rocks exposed in the northern segment of the Western Cordillera of Colombia, which are interpreted as related to a Cretaceous island arc-plateau system. These data are used to come up with a paleogeographic model for the circum-Caribbean realm that may account for the presence of old (Paleozoic – Proterozoic) xenocrystic zircons in the analyzed units. Nevertheless, the authors ignored previously published geological, geochemical, geochronological, thermochronological and provenance constraints from Cretaceous rocks of northwestern Colombia, which refuse the plausibility of their proposed models. Particularly, the occurrence of Cretaceous subduction-related metamorphism, magmatism and construction of marginal sedimentary basins, documented by several published papers in the last decade, renders the paleogeographic reconstructions of Cetina et al. (2019) to be unlikely. We demonstrate that when considering the ignored geological evidences, alternative explanations for the origin of pre-Mesozoic xenocrystic zircons are required. • We comment the recently published paper by Cetina et al. (2019). • Several ignored geological evidences are recalled and discussed. • Paleogeographic models of Cetina et al. (2019) are not plausible. • Alternative explanations for the origin of pre-Mesozoic xenocrystic zircons are required. [ABSTRACT FROM AUTHOR]

This paper evaluates the anaerobic digestion of agricultural waste, manure and slaughterhouse residues of species typical of the Andes, such as llama, vicuña and guinea pig; quinoa, amaranth and wheat straw in order to be able to use them as a renewable energy source and boost rural development in the region. Has been used sludge from a WWTP as inoculum, evaluating the effect of two relationships between the substrate and inoculum (RSI) for both livestock and agricultural waste. The highest cumulative maximum methane production rate was obtained for the residues of flame manure and quinoa straw for an RSI of 1:2 with productions of 376.08 ml CH 4 /g SV and 377.02 ml CH 4 /g SV respectively. In these materials an RSI of 1:2 obtained increases of 22.56% and 37.54% compared to the RSI 1:1. Also, the kinetic analysis showed that the modified Gompertz model is the one that best fits performance, with constant differences of 7.06% between the experimental and predicted values. On the other hand, the modified Gompertz model was adjusted to the experimental results with an r2 of (0.998) and an RMSE of 4.09 ml/g SV at 17.12 ml/g SV. • The addition of an inoculum increased the rate of methane and biogas production. • The camelid manure generated methane yields between 235.49 and 377.02 ml CH 4 /g VS. • The three and four parameter sigmoid prediction models better estimated the BMP tests. • Flame manure residues provided 70.74% biodegradability results. [ABSTRACT FROM AUTHOR]

High-altitude hypoxia is one of many environmental stressors affecting human populations in the highland Andes. Living highland Andeans show adaptive physiological responses to these conditions through both developmental plasticity and natural selection. Given the longevity of human settlement in this region, these same responses ought to have affected ancient Andeans. This paper tests whether developmental plasticity or natural selection best explains the morphological signatures of adaptations to high-altitude hypoxia in ancient highland Andeans. I compare four groups of skeletons: two groups from lowland regions and two groups from high elevations. Previous work shows that the two highland groups have small bodies and voluminous ribs compared with the lowland groups indicating morphological adaptations to high-altitude environments. This paper compares patterns of intrinsic variation and sexual dimorphism in body size, limb lengths, and rib morphology in highland and lowland groups to test if developmental plasticity or natural selection underlies these morphological differences. The four groups share similar patterns of sexual dimorphism and intrinsic variation in body size and limb lengths. The two highland samples show greater degrees of sexual dimorphism in rib morphology than the lowlanders. Patterns of intrinsic variation in rib morphology do not sort by altitude. Both natural selection and developmental plasticity in response to high-altitude hypoxia likely shaped skeletal morphology in ancient highland Andeans. [ABSTRACT FROM AUTHOR]

We use Intermediate-to-short wavelength (20–150 km) gravity anomalies to investigate the role played by crustal scale dense blocks in the genesis of Cu ore deposits along the Andes. These dense blocks are widespread along the margin and located at the fore-arc, arc, and back-arc domains, including depths in the range of 12–18 km, and thickness of 5–8 km. The interplay of these dense blocks with long-lived Trans-Lithospheric-Faults (TLF) controls the emplacement, and most likely, provides the required fertile fluids for the Cu ore genesis. Dense blocks represent impervious crustal domains, surrounded by damage zones at the intersection with TLF systems. Concentration of seismicity, large Vp/Vs ratios, low gravity domains, active volcanism, and structural fabric, demonstrate that these damage zones are in fact the most likely places for magma as well as mineralized flow ascent and emplacement. Basic flow models in porous media show a flow path that migrates horizontally at the base of dense/impervious blocks until the high permeability edge flanks, where pressure gradients provide the ideal conditions for the upward and focusing hydrothermal fluid ascent. Although not fully addressed in this paper, evidence suggests that the interaction of subducting-related fluids and the mafic-dense block might produce a fertile fluid with a concentration of Cu. In contrast with the long-standing view of metallogenic belts of the same age and parallel to the trench axis, we propose a multi-age metallogenic cluster, along the periphery of dense blocks, and organized oblique to the margin, following the trend of a given TLF. • Dense blocks and long-lived Trans-Lithospheric-Faults (TLF) control the emplacement and fertile fluids for Cu ore genesis. • Early Tectonic deformation dependence on crustal heterogeneities. • Multi age metallogenic belts following TLF systems. • Magmatic fluid flow migration depends on the crustal permeability, with flow path not-necessarily vertical. [ABSTRACT FROM AUTHOR]

Given that Land Use and Cover Changes (LUCC) and deforestation are activities with the highest anthropic intervention on ecosystems and increase the loss of biodiversity, this paper explores the LUCC and the main drivers of change in Andean mountains, taking a rural area located between the municipalities of Montenegro and Quimbaya (Quindío, Colombia) (1954–2009), as a case of study. Aerial photographs and geographic information systems (GIS) are used to create maps of LUCC, as well as a systemized search of information on LUCC and main drivers. The results showed that pastureland presented the largest area during all periods, occupying >60% of studied area, while the secondary and mixed forests had a contraction from 23% in 1954 to 9% in 2009. The change rates evidenced a greater affectation for the secondary forest that lost 86% of its initial area through deforestation and transformation processes, while crops gained 410% with respect to their initial area. As for the transition matrix, about 27.8% of the study area presented transformation from land use and cover into other land covers, 14.7% presented deforestation and loss of land cover in their initial area, and 57.5% remained unchanged. It is concluded that socio-economic factors such as livestock farming, agriculture and market prices have been an important driver in the modification of the landscape. [ABSTRACT FROM AUTHOR]

In this paper, static and dynamic analyses were performed considering the reconstituted geometry of a prehistoric 0.1 km 2 rockslide with an exposed stepped-planar failure surface using a distinct element code (UDEC®). The rockslide occurred on the northern slope of the Cerro Catedral mount, located in the headers of the Maipo river drainage basin (Main range of the Andes Cordillera) at the latitude of the Santiago city, Chile, between the Late Pleistocene and the Holocene. The remaining failure surface consists of two distinct sliding planes dipping at an angle of ~37° and connected by a sub-vertical step. The original geometry of the rock slope was estimated from a terrestrial laser scan elevation model (LIDAR), the deposit that remained in the valley, and the hill surface topography. The laser scan of the sliding surfaces and Schmidt hammer field measurements allowed the estimation of the sliding surface mechanical properties, whereas laboratory test results were used to estimate the rock mass material properties. Results from 2D static numerical analyses indicate that the rock slope requires the presence of at least one rock bridge at the sliding surface connecting step in order to be statically stable. Furthermore, we studied the effect of different acceleration time histories recorded during shallow crustal earthquakes, compatible with the regional seismicity, in the rockslide response. The dynamic numerical analyses show that the input earthquake records induce a pronounce topographic amplification in the rock slope, that the rockslide displacement highly correlates with the Arias Intensity, the peak velocity, and the peak acceleration calculated in the rock slope center of gravity, and that the rockslide may have been triggered by horizontal accelerations larger than 0.6 g in the free field. Finally, the slope's response is evaluated under the coupled action of horizontal and vertical accelerations. [ABSTRACT FROM AUTHOR]

The geomorphometric classifications of three groups of volcanoes situated in the Andes Cordillera, Central America, and Mexico are performed and compared. Input data are eight local topographic gradients (i.e. elevation differences) obtained by processing each volcano raster ASTER-GDEM data. The pixels of each volcano DEM have been classified into 17 classes through a K- means clustering procedure following principal component analysis of the gradients. The spatial distribution of the classes, representing homogeneous terrain units, is shown on thematic colour maps, where colours are assigned according to mean slope and aspect class values. The interpretation of the geomorphometric classification of the volcanoes is based on the statistics of both gradients and morphometric parameters (slope, aspect and elevation). The latter were used for a comparison of the volcanoes, performed through classes’ slope/aspect scatterplots and multidimensional methods. In this paper, we apply the mentioned methodology on 21 volcanoes, randomly chosen from Mexico to Patagonia, to show how it may contribute to detect geomorphological similarities and differences among them. As such, both its descriptive and graphical abilities may be a useful complement to future volcanological studies. [ABSTRACT FROM AUTHOR]

Ecuador belongs to the megadiverse countries of the world. However, the high diversity in species, ecosystems and their services are under threat by land use changes, invasive species, overexploitation, pollution and climate change. There is a need to monitor, manage, protect and improve biodiversity and ecosystem services (BES) in Ecuador; however, Ecuador is marginally represented in the international policy-science interface for the protection of BES. We analyzed 266 international peer-reviewed papers that were published between 2000 and 2020 to assess the current impact of human disturbance and climate change on BES in continental Ecuador. We found that there were more studies available on the impact of human disturbance on BES than on climate change effects. Birds represented the most studied taxon in Ecuador (70 studies), whereas the total amount of available international scientific publications for other Ecuadorian plant and animal taxa were rather low (< 34 studies) and spatially and thematically scattered. Among ecosystem services, water provision was analyzed relatively often. Our literature review revealed that there is a need to conduct more studies on impacts of human disturbance and climate change on BES. Further research is needed; particularly in the coastal hinterland, in the central Andes and in the Amazon. We suggest that the investment of time, resources and effort into the documentation, standardization, sharing, and publishing of data are key towards supporting the monitoring and maintenance of BES. [Display omitted] • Analyses of 266 papers on human and climatic impacts on Ecuadorian biodiversity • More studies available on the impact of human disturbance than on climate change • More studies on fauna than on flora; birds in particular • Studies vary in impact, scale, location, species focus, and context. • Documentation, standardization, publishing, and sharing of data needed [ABSTRACT FROM AUTHOR]

We have carried out long-term comparative in a wide latitudinal range of the Andes (29°–37° south), encompassing selected areas that differ in ecology and biogeography. This latitudinal span shows diversity in subsistence modes across time and space, ranging from Andean agro-pastoralists in the north to Patagonian hunter-gatherers in the south. As part of this research, a program of geochemical and archaeological characterization of obsidian sources and distributions is being developed, attempting to assess connections between different biogeographical contexts. This work has allowed recognizing five Andean sources with different geological and topographical properties. Stemming from this macro-regional endeavor, in this paper we present a comparative analysis of the human use of two sources that, based on the intensity of human use on a macro-regional scale, can be interpreted as ‘minor’ sources. This study is framed on GIS least-cost models for human circulation across rugged landscapes allowing access to the sources. We assess temporal and spatial patterns of human occupation of high-altitude Andean deserts and neighboring areas comparing two of obsidian sources: Laguna del Diamante (34° S) and Cerro Huenul (36° S). The results indicate the existence of asymmetric distributions, particularly in the case of Laguna del Diamante. This evidence is used to assess the existence of dominant geographic vectors of human access and use of the Andean highlands. On this basis, we explore the analytical potential of minor sources for the study of human biogeography and organization of technology. [ABSTRACT FROM AUTHOR]

The seismicity studied in this paper is located along the back arc region, between 30°35′ and 31°52' S latitude, in the morphostructural unit known as Eastern Sierras Pampeanas. Seventeen crustal earthquakes could be identified and located, between June 2004 and March 2018, using seismic data recorded by the broadband seismological network of National Institute for Seismic Prevention (INPRES), combined with free seismic data from the Incorporated Research Institutions for Seismology (IRIS). Focal mechanisms were calculated from localized seismicity using the P-wave first motions and interpreted as a strain style on the western portion of Sierras de Córdoba. Overall, the seismicity in this region during the study period was constrained to the upper ∼25 km of the crust and is mostly concentrated along minor structures and not along the major range-bounding faults. Although there is evidence of quaternary activity along the larger structures, the relationship between these displacements and modern deformations is not well developed due to the lack of local seismic stations in the area and the long recurrence interval between earthquakes of significant magnitudes. However, very recent morphometric studies in the Sierras Pampeanas have analyzed the main topography controls and suggested relatively higher uplift rates in the central sectors of the Sierra de Pocho, and a balance between tectonic uplift and erosion rates. Nevertheless, three seismic events showed greater depths around 36 km according to previously proposed geological and geophysical models of crustal thickness and mohorovicic depth. Although focal mechanism solutions show varied results, distributed throughout all the region, it is possible to determine an inverse deformation with an oblique component assigned to regional faults and an area where a normal deformation with an oblique component predominates, near to the Ojo de Agua Lineament. Accordingly with seismological observations, we proposed a model in which the seismogenic structures seem to have detached from deep horizontal intra-crustal interfaces that affects the faults and brittle structures, which document that the Eastern Sierras Pampeanas are actively deforming in response to compression from the convergent margin. • We interpreted two FDTZ based on event relocation and FM analysis. • The normal faults linked to Pocho Volcanic Complex are interpreted as a thrust-lateral ramp-thrust system. • Current deformation of the Sierras de Córdoba is not uniformly distributed along the main faults. [ABSTRACT FROM AUTHOR]

The Río Damas Formation is an Upper Jurassic volcano-sedimentary succession, whose outcrops are largely distributed between 33°S and 35.30°S in Chile and Argentina, as part of the retroarc Neuquén Basin fill. This unit was deposited during an important marine regressive phase of the basin. We studied the Río Damas Formation exposures at the Los Gateados creek valley, in the Alto Atuel depocenter (34°40′S; westernmost Malargüe fold and thrust belt), next to the Argentinean-Chilean border. This area represents a key location where the formation interdigitates with the nonmarine red beds of the time equivalent Tordillo Formation, representing a continentalization episode of the Neuquén Basin. This paper presents a lithofacial characterization of the Río Damas Formation, a new U–Pb igneous crystallization age, and a paleographic reconstruction for this period. The Río Damas Formation in the Alto Atuel depocenter consists of porphyritic basaltic and andesitic lavas, interbedded with fine-grained sandstones, conglomerates, volcanic lithic breccias, and pyroclastic deposits. Based on field and petrographic analyses, we associate the Río Damas Formation with a piedmont environment where sedimentary fluvial and alluvial setting coexisted with volcanic effusive and pyroclastic activity. A regional comparison of the Río Damas and Tordillo Formations along the Argentinian-Chilean border shows that the composition and thickness of these units present important latitudinal and longitudinal variations. The increase in thickness and the volcanic component of the Río Damas Formation towards the west could be associated with the proximity to the Jurassic magmatic arc. • The Río Damas Fm. is a volcano-sedimentary unit outcropping at 33°-35.30°S in Central Andes. • We present the first Late Jurassic U–Pb igneous crystallization age for the unit. • Volcanism include lava flows, dykes and pyroclastic rocks associated with lahar deposits. • Regionally, lithofacial and thickness variations in latitude and longitude are recognized. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we offer a panoramic overview of the development of Andean Spanish and Andean Linguistics, from a theoretical point of view of language contact and universal grammar. We discuss how the notion of Andean Spanish came into existence, the issues under debate, and the consequences of different theoretical positions. We also introduce the contents of the papers included in this special issue, and highlight their key points, framing them in the context of the research on universal grammar. The following five areas are covered: (1) the convergence of Quechua and Aymara, (2) the impact of bilingualism on intonation, (3) the sharing of suffixes in contact situations, (4) the modification of the present perfect tense in Spanish in contact with Quechua, and (5) the properties of the Quechua case system from the point of view of contact varieties. Finally, we provide some remarks on bilingual education, and some suggestions for further directions for future research. [Copyright &y& Elsevier]

Abstract: A useful strategy for improving disaster risk management is sharing spatial data across different technical organizations using shared information systems. However, the implementation of this type of system requires a large effort, so it is difficult to find fully implemented and sustainable information systems that facilitate sharing multinational spatial data about disasters, especially in developing countries. In this paper, we describe a pioneer system for sharing spatial information that we developed for the Andean Community. This system, called SIAPAD (Andean Information System for Disaster Prevention and Relief), integrates spatial information from 37 technical organizations in the Andean countries (Bolivia, Colombia, Ecuador, and Peru). SIAPAD was based on the concept of a thematic Spatial Data Infrastructure (SDI) and includes a web application, called GEORiesgo, which helps users to find relevant information with a knowledge-based system. In the paper, we describe the design and implementation of SIAPAD together with general conclusions and future directions which we learned as a result of this work. [Copyright &y& Elsevier]

Summary: Social movements have been viewed as vehicles through which the concerns of poor and marginalized groups are given greater visibility within civil society, lauded for being the means to achieve local empowerment and citizen activism, and seen as essential in holding the state to account and constituting a grassroots mechanism for promoting democracy. However, within development studies little attention has been paid to understanding how social movements can affect trajectories of development and rural livelihood in given spaces, and how these effects are related to movements’ internal dynamics and their interaction with the broader environment within which they operate. This paper addresses this theme for the case of social movements protesting contemporary forms of mining investment in Latin America. On the basis of cases from Peru and Ecuador, the paper argues that the presence and nature of social movements has significant influences both on forms taken by extractive industries (in this case mining) and on the effects of this extraction on rural livelihoods. In this sense, one can usefully talk about rural development as being co-produced by movements, mining companies, and other actors, in particular the state. The terms of this co-production, however, vary greatly among different locations, reflecting the distinct geographies of social mobilization and of mineral investment, as well as the varying power relationships among the different actors involved. [Copyright &y& Elsevier]

Abstract: The high altitude grasslands of the tropical Andes, known as páramo, are a very fragile and unique ecosystem. Despite increasing human activities, many of its geomorphological and hydrological processes are still very poorly understood. We therefore welcome the paper of Harden [Harden, C.P., 2006. Human impacts on headwater fluvial systems in the northern and central Andes. Geomorphology 79, 249–263.] about “Human impacts on headwater fluvial systems in the northern and central Andes” as a valuable contribution to a better understanding of this complex ecosystem. However, in view of the available literature, we would like to complement the interpretation of the presented results and discuss some of the claims made in the paper. [Copyright &y& Elsevier]

This paper presents a case study in assessment of erosion hotspots in an Andean watershed. To do this, we made use of an interface called Geospatial Modelling of Soil Erosion (GEMSE): a tool that integrates Geographical Information Systems (GIS) with the Water Erosion Prediction Project (WEPP) model. Its advantages are: (i) it is independent of any special GIS software used to create maps and to visualize the results; (ii) the results can be used to produce response surfaces relating outputs (e.g. soil loss, runoff) with simple inputs (e.g. climate, soils, topography); (iii) the scale, resolution and area covered by the different layers can be different among them, which facilitates the use of different sources of information. The objective of this paper is to show GEMSE''s performance in a specific case study of soil erosion in La Encañada watershed (Peru) where the hillslope version of WEPP has been previously validated. Resulting runoff and soil loss maps show the spatial distribution of these processes. Though these maps do not give the total runoff and soil loss at the watershed level, they can be used to identify hotspots that will aid decision makers to make recommendations and plan actions for soil and water conservation. [Copyright &y& Elsevier]

• Distinguish between primary search tasks and ancillary search tasks. • Discuss Web browser support for search tasks and for search services customization. • Let users customize the browser with search services offered by any Web site. • Augment any Web site with external search services and in-context results display. • Discuss new strategies for end-user programming to customize Web search services. This article addresses search tasks, which are the most frequent type of tasks users do nowadays on the Web. We suggest that the customization of search services would improve the user's searching experience, and it also might make search tasks more effective and efficient. We analyze user tasks for performing searches and types of search services. Then, we distinguish between primary search tasks (related to the initial user goal) and ancillary search tasks (those that are performed to find additional information necessary to understand how to achieve a primary search task). We also explain different types of search services, including global search services (which has an extensive search scope, possibly the whole Web) and in-site search services (which has a narrow scope of search focused on a specific Web site or data set). We also discuss features embedded into Web browsers to support search tasks and how Web browsers can support extensions allowing users to integrate customized search services. We propose an approach called ANDES that allows users to integrate into the Web browser new search services that are created by customizing search services offered by existing Web sites. By means of Web augmentation techniques, we demonstrate how users can customize the browser to trigger search services to any Web site and integrate the Web page results. We report on two evaluations showing that end-users can specify and use search services following our approach and that the proposed interaction is more convenient in contrast to traditional mechanisms. Beyond the tool used to demonstrate the feasibility of the ANDES approach, this paper aims to discuss new strategies for end-user programming that allow users to customize search services over the Web. [ABSTRACT FROM AUTHOR]

The hinterland zone of the North Patagonian Andes between 41° and 43°S constitutes a poorly explored sector of the Andes, where no structural studies and scarce geochronological determinations have been carried out. This paper focuses on two isolated volcanic sections hosted at the main Andes, in which field evidence indicates a common synextensional origin. Geochronological data establish that this volcanic event occurred diachronously at the innermost sector of the evolving fold and thrust belt, during middle to late Miocene times. Therefore, the event was briefly coeval and postdated compressive tectonics recognized in the deformational front and correlative to the last phase of pluton emplacement of the North Patagonian Batholith. Local-scale topographic swath profiles performed in this work reveal negative topographic anomalies where normal faults were recognized. Moreover, regional swath profiles show not only a conspicuous depressed zone at the hinterland zone, where the studied sections are located, but also anomalously high altitudes at the foreland zone. In addition, calculated orogenic volumes increase in this sector of the fold and thrust belt, which agrees with recent shortening estimations. These topographic along-strike variations, in association with late Miocene extension following the main compressive stage in the area, are explained by a supercritical stage of the orogenic wedge that would have led to focused extension at the innermost sector of the fold and thrust belt. [ABSTRACT FROM AUTHOR]

A large (>0.1 km 2 ) and complex mass movement in the Central Andes of Argentina (final portion of Cordillera de Olivares, Frontal Cordillera), was studied to identify the triggering factors and understand their relationship with geomorphic, cryogenic and climatic dynamics. This debris-rockslide is composed of clast supported blocks of Permian–Triassic volcanic breccias. In order to characterize this feature, high resolution satellite imagery interpretation was carried out, together with the study of the landslide detachment zones and landslide bodies. These debris-rockslide events could have originated as a consequence of the combination of internal slow deformation and fragmentation under periglacial conditions, followed by a sudden collapse of the rock mass. Pre- and post-slide digital elevation models (DEMs) were created from topographical data with the help of a Geographic Information System (GIS) tool. Approximately 14.89 M m 3 of rock and debris travelled nearly 2 km from an elevation of 5023 m–4325 m asl. Although usually the origin of such catastrophic movements is related to seismically active areas with earthquakes whose magnitude frequently exceed Ms 6, our hypothesis is that this debris-rockslide event has a climatic origin caused by large snow accumulations during winters and subsequent fast meltdown processes during spring, which would have facilitated the sliding. The paper outlines the important role that snowmelt can play in the genesis and evolution of rock displacements and the importance of meteorological data, seismic catalogues, historical aerial photography and satellite images in geomorphological back-analysis. [ABSTRACT FROM AUTHOR]

This paper provides a comprehensive review of the chronostratigraphy of six rock avalanches clustered in the northern extreme of the Cordon del Plata range. These rock avalanches are stratigraphically related to Pleistocene glacial drifts and valley-fill deposits documenting the regional neotectonic activity. We used cosmogenic dating (TCN) to directly date block surfaces of rock-avalanche deposits, as well as optically stimulated luminescence dating (OSL) of paleo-lakes dammed by these rock avalanches. Our new direct dates (17 TCN and 4 OSL) determine the Middle-to-Late Pleistocene age of these collapses. These are in contrast to the previously established chronostratigraphy based on relative dating techniques, paleontological context, and tephrochronology. These new data help to redefine the geomorphological evolution of the Mendoza River valley. Especially, the new data indicate that the glacial stratigraphy earlier proposed must be reconsidered. We redefine this stratigraphy as far as possible with our data and discuss the data in relation with other recently published results. However, it becomes clear that the glacial history of the Mendoza valley has to be studied anew by using modern dating techniques. In addition, our data suggest that the Carrera Fault system bounding the valleys of the Cordillera del Plata has been active more recently than proposed earlier. [ABSTRACT FROM AUTHOR]

The structure of dairy supply chains in developing countries often shows a large diversity of organization usually based on smallholder farmers' involvement. This paper investigates how a dual supply chain combining both formal and informal markets with predominantly smallholder farmers impacts farmer–processor interactions at technical and organizational level in a Peruvian Andean valley. The analysis is based on three complementary field studies conducted between 2009 and 2012. Results show a large diversity of supply channels in formal and informal chains. Milk flows are observed between formal and informal processors based on a mix of competition and complementarity depending on the season of the year and the level of consumer demand. Smallholder farmers can change processors frequently according to the milk price and services offered, since no contracts link stakeholders. This organization allows smallholder farmers to be involved in the dairy sector but with low profitability. While the informal sector shows better profits per liter of milk than the formal ones, it remains sensitive to the State's willingness to apply stricter quality regulations. [ABSTRACT FROM AUTHOR]

Glaciers in the Andes of Chile seem to be shrinking and possibly loosing mass, but the number and types of studies conducted, constrained mainly by data availability, are not sufficient to provide a synopsis of glacier changes for the past or future or explain in an explicit way causes of the observed changes. In this paper, we provide a systematic review of changes in glaciers for the entire country, followed by a discussion of the studies that have provided evidence of such changes. We identify a missing type of work in distributed, physically-oriented modelling studies that are needed to bridge the gap between the numerous remote sensing studies and the specific, point scale works focused on process understanding. We use an advanced mass balance model applied to one of the best monitored glaciers in the region to investigate four main research issues that should be addressed in modelling studies for a sound assessment of glacier changes: 1) the use of physically-based models of glacier ablation (energy balance models) versus more empirical models (enhanced temperature index approaches); 2) the importance of the correct extrapolation of air temperature forcing on glaciers and in high elevation areas and the large uncertainty in model outputs associated with it; 3) the role played by snow gravitational redistribution; and 4) the uncertainty associated with future climate scenarios. We quantify differences in model outputs associated with each of these choices, and conclude with suggestions for future work directions. [ABSTRACT FROM AUTHOR]

The Colombian power sector is highly dependent on hydroelectricity, making it vulnerable to both annual dry seasons and the droughts brought by the El Niño-Southern Oscillation (ENSO). One efficient way to reduce such vulnerabilities is by introducing renewable energies that may complement the availability of hydroelectricity. This paper explores the degree of complementarity between solar and wind resources in Colombia and the country's hydropower sector, on both annual and interannual scales. Various correlation analyses are performed over four climatic variables: water inputs (runoff), precipitation, solar radiation, and wind speed, plus the Oceanic Niño Index (ONI), which helps to characterize ENSO events. The analysis is carried out over different geographic locations and seasons. The results indicate that solar and wind resources, particularly those in the Caribbean Coast and the central Andes regions, complement the hydropower sector during both the dry seasons of the annual climatological cycle and ENSO's warm and cold phases. Also, they show that complementarity varies, not just with the type of sources and location, but also with the seasons of the year and ENSO's stage of development. This paper provides an enhanced perspective on the behavior of renewables and offers an alternative viewpoint for designing the future expansion of power systems. Image 1 • Annual and interannual complementarities between renewable energies are explored. • Solar and wind can complement hydropower during the annual dry seasons and ENSO. • The Caribbean Coast and Andes regions have the largest complementarity potential. • Complementarity varies through yearly seasons and ENSO's development stages. [ABSTRACT FROM AUTHOR]

The Neogene Penitentes basin registers the earliest synorogenic infill in an inner region of the southern Central Andes, between Principal and Frontal cordilleras at 33°S, which contrast with other Neogene basins that are distributed to the east, in the foreland area. In this work, we focused on the study of the first infill of the basin, the Penitentes Conglomerate, which crops out along the Aconcagua fold-and-thrust belt (Principal Cordillera). We carried out sedimentological, geochronological, and structural studies to better understand the genesis and evolution of these synorogenic deposits. We recognized the Penitentes Conglomerate at the Blanco river and the Potrero Escondido creek, located to the south of the previously established boundaries of the basin. We obtained a maximum depositional age of 15 ± 1 Ma (weighted mean 206Pb/238 U age; n = 8; MSDWD = 4.5; error of 95% conf.) for the base of the Penitentes Conglomerate in the Potrero Escondido creek. Based on clast composition and U-Pb detrital zircon ages of the Penitentes Conglomerate base, the provenance analysis reflects the Aconcagua's fold-and-thrust belt exhumation to the west of the basin. The denudation processes that affected the Principal Cordillera generated an unroofing sequence within the Penitentes Conglomerate. In contrast, towards the top of the sequence, the Penitentes Conglomerate has sediment input derived from eastern sources, which indicates that the Frontal Cordillera was exhumed and acted as a sediment source area for the Penitentes basin by the Middle Miocene (~14 Ma). In this sense, the chronology of the uplift of Principal and Frontal cordilleras agrees with the east-vergent orogenic model for the Andes. The structural analyses presented in this paper show a minimum shortening of 62% for the Aconcagua fold-and-thrust belt with an out-of-sequence deformational phase during the mid-late Miocene, after the uplift of the Frontal Cordillera. • We determined the southern extension of the intermontane Penitentes basin. • A maximum depositional age of 15 Ma was obtained for the first synorogenic infill. • The Principal and Frontal cordilleras were source areas for the Penitentes basin. • Our studies show that the Frontal Cordillera was uplifted by the middle Miocene. • The Principal Cordillera had a final contractional pulse at the late Miocene. [ABSTRACT FROM AUTHOR]

[Display omitted] • The meteorological variables are correlated with altitude, latitude and longitude. • Temperature, altitude, latitude and longitude control the δ18O of precipitation. • Unrecorded rainfall in sampling points is obtained by means of correlation models. • These models are useful if the available data are scarce and discontinuous in time. • Aquifer recharge zones are identified by estimating δ18O values with these models. A knowledge of the evolution of isotopic composition of air masses humidity and precipitation in the Western Cordilleras of the Central Andes is still incomplete. This study contributes to a better understanding of the factors that control the δ18O and δ2H contents in precipitation water in the north of Chile, above 2000 m a.s.l.. This paper deals with: (1) the relevant effects and processes that control the spatial (longitude, latitude and altitude) distribution of stable isotope contents of precipitation events in northern Chile, (2) the influence of local meteorological variables: temperature, precipitation and relative humidity on the δ18O and δ2H of precipitation, and (3) the estimation of these meteorological and isotopic variables at specific sites. To achieve these objectives, the relationships between geospatial and meteorological values are identified and analysed, followed by the estimation with empirical models. These estimation models (linear and non-linear) are obtained after examining, validating and calibrating techniques to find the best fit. This results in models for temperature, relative humidity and precipitation for each month of the year. In the same way, three isotopic models are derived from the spatial and meteorological variables (summer, winter and annual). Temperature has been shown to be controlled to a greater extent by altitude and latitude, while relative humidity is by latitude and precipitation in summer is by altitude and latitude. Monthly meteorological variables have been estimated throughout the study area. Precipitation δ18O and δ2H are controlled mainly by temperature and altitude and to a lesser extent by latitude, longitude and precipitation. In the same way, three isotopic models are derived from the spatial and meteorological variables: summer, winter and annual. This opens a new perspective of precipitation and its isotopic contents, but also allows the calculation of runoff and aquifer recharge and the path for linking future precipitation and aquifer recharge through their isotopic composition. [ABSTRACT FROM AUTHOR]

Summary: This paper explores how village level technology usage patterns and bonding social capital (the strength of intra-communal links) mutually influence the individual usage decision of an improved stove in the Peruvian Andes. It shows that the individual usage likelihood is more responsive to village usage patterns if communal bonding links are relatively strong, and that bonding social capital discourages individual usage if the proportion of beneficiaries experiencing usage problems is relatively high. Usage problems were mainly related to faulty stove’s materials, which were likely exogenous to households’ characteristics. Social capital was measured before the intervention, which alleviates reverse causality issues. [Copyright &y& Elsevier]

The mining industry is the largest electricity consumer in Chile. Sustainability reports of Chilean mining companies show that electricity consumption of mining camps is 350–500 kWh/m2 per year. Despite cold climate conditions, mining camps show overheating, and 40% of the miners find them uncomfortable. Mining camps' energy access is difficult because they are located in remote zones. This paper aims to optimize the building envelope and HVAC system to minimize the total energy consumption and eliminate the overheating risk of a real mining camp located at 4400 m.a.s.l. The mining camp is 30,000 m2, built of timber prefabricated lightweight modules and hosts 1700 workers. The electricity consumption of the baseline case is 330 kWh/m2year and shows overheating. Multi-objective optimization is implemented to minimizing the electricity consumption while avoiding overheating. A hybrid multidimensional optimization algorithm implemented in GenOpt, a building energy simulation program (EnergyPlus) and several scripts developed in Pyhthon for optimizing discrete variables and calculating the overheating risk of each thermal zone are coupled. Two different cases are optimized depending on the heating systems: electric heaters (Case I), which is the current situation; and heat pumps with chilled beams with free cooling option (Case II). This paper shows that an efficient HVAC system (Case II) is crucial for achieving thermal comfort and minimizing electricity consumption, which reaches 112.9 kWh/m2year, representing a significant reduction of 66% compared to the baseline case. The optimization process provides not only the optimum set of energy-efficient strategies but also a set of feasible solutions close to the optimum that allows flexibility to choose other strategies based on economic, transportation and on-site construction constraints. • A multi-objective optimization process is proposed to balance thermal comfort and energy use. • An efficient HVAC allows eliminating overheating and energy savings up to 68%. • The optimization process finds the optimum solution despite the complexity of the mining camp. • Solutions close to the optimum let design flexibility to comply with other project constraints. [ABSTRACT FROM AUTHOR]

This paper introduces a novel hybrid finite element (FE) formulation of shell element to enable assembly process simulation of compliant sheet-metal parts with higher efficiency and flexibility. Efficiency was achieved by developing both new hybrid quadrilateral and triangular elements. Quadrilateral element (QUAD+) was formulated by combining area geometric quadrilateral 6 (AGQ6) nodes and mixed interpolated tensorial components (MITC) to model membrane and bending/shear component respectively. Triangular element (TRIA+) was formulated by merging assumed natural deviatoric strain (ANDES) for membrane and MITC for bending/shear component. Flexibility was addressed by developing an open-source C++ code, enhanced by the OpenMP interface for multiprocessing programming. Tests and benchmarks were compiled and executed within Matlab using the MEX API interface. Extensive benchmark studies were accomplished to evaluate the performance of the proposed hybrid formulation and the shell formulations used in three FEM packages - ABAQUS, ANSYS and COMSOL- under static linear elastic condition with small strain assumption. It was observed that the proposed QUAD+ and TRIA+ elements performed better amongst the FE packages, especially when there was in-plane mesh distortion, with errors below 3%. It was also identified that the best efficiency is obtained by adopting dominant QUAD+ elements compared to the TRIA+ when working on complex geometries. This paper also contributes to present a wide set of benchmark studies required to verify new release of FE packages using shell element or evaluate the performance of new shell formulations. • QUAD+ formulation was introduced by combining AGQ6 and MITC models. • TRIA+ formulation was introduced by combining ANDES and MITC models. • Extensive benchmark studies were presented to validate both displacement and stress values. • Comparative studies against multi-purpose commercial suits (ABAQUS, ANSYS and COMSOL) were performed. • Open-source C++ code enhanced by the OpenMP interface for multiprocessing programming. [ABSTRACT FROM AUTHOR]

This paper has been written following the results and reflections of the previously published paper (Viguier et al., 2018) detailing a multidisciplinary assessment of the groundwater resources in the northern part of the Pampa del Tamarugal Aquifer (PTA), at Atacama Desert (Northern Chile). This short note aims to propose an overall review of the PTA conceptual model. Following a brief description of the PTA limit changes over 60 years, the boundary conditions, recharge processes and the 2012–2015 piezometric map are detailed in an updated hydrogeological conceptual model including the northern, central and southern parts of the aquifer. The exploited aquifer contained in El Diablo Fm (Miocene alluvial filling) covers almost 6420 km2, i.e. +87% compared to a previous study. That means that the groundwater resources in the Central Depression are today still underestimated. The Andean Piedmont appears to be a highly interesting target for the groundwater resource exploration and for the long-term water supply in the Central Andes where the regional water demand is continuously increasing. • An overall review of the Pampa del Tamarugal Aquifer conceptual model is proposed. • The updated PTA extent covers almost 6420 km2 (+87%). • Groundwater resources are underestimated in the Central Depression. • The Andean Piedmont is a strategic target for the exploration of groundwater resources. [ABSTRACT FROM AUTHOR]

The Guañacos fold and thrust belt, in the northern Neuquén Andes (37°-38°S; 70°30′-71°10′W), has been studied by many researchers focusing on the Quaternary tectonic activity, from a morphological to a structural perspective. Additionally, this portion of the Andes is quite peculiar due to the numerous geomorphic processes coeval with neotectonic, such as volcanic, mass-wasting, glacial, and fluvial processes. However, it is not yet clear the impact of each one of these processes on landscape evolution. This paper reviews the evidence for the geomorphological modeling of the Guañacos belt and analyses the effects of the various actuating processes over the drainage network, implementing different and novel morphometric indices. We studied the hypsometry of the main basins in the area and identified knickpoints of the trunk of each basin from the stream profile slope-area plot. Besides, we applied morphometric indices such as the k sn and the χ for all catchments to evaluate the state of equilibrium of the stream network and basin divides. Our results show disequilibrium conditions over the entire fluvial network consistent with rockslide deposits and active structures. This study also discusses the usefulness of the applied morphometric indices in an area with low neotectonic slip-rates, great mass-wasting deposits, and glacial erosion. Findings in this matter showed substantial differences in the indices' response whether the analyzed basin was primarily glacial or fluvial carved. Taken together, results in the Guañacos fold and thrust belt suggest that the glacial erosion and the subsequent rockslide deposits are the prime agents for landscape modeling, making it unable to acknowledge the effect of Quaternary tectonic activity. Only when they are absent is it possible to recognize the neotectonic signature over the drainage. • Landscape evolution in Southern Central Andes between 37° and 38° S was analyzed. • K sn and χ maps yield disequilibrium conditions in the stream network. • Slope-area plot reveal knickpoints and concavity more affected by rockslides deposits. • Glacial erosion and rockslide deposits obscure the neotectonic' effects over drainage. • Geomorphic and tectonic processes influence morphometric indices. [ABSTRACT FROM AUTHOR]

Abstract: Over the past few decades, improved firewood cooking stoves have been massively distributed around the world, mainly with the purpose of decreasing fuelwood consumption among rural households. Surprisingly, rigorous “on the field” evidence on the causal impact of these devices is very limited. This paper estimates the impact of an improved stove design distributed in the Northern Peruvian Andes on firewood consumption. To identify the causal effect of improved stoves, it exploits a quasi-experiment related to the improved stove intervention. The evidence indicates that a proportion of households that adopted the new device experienced iron frame failures. These failures were not systematically caused by inadequate usage, installation or maintenance, but by faulty iron frame construction. Moreover, faulty iron frames were randomly distributed, and whether an iron frame was faulty or not, was not ex-ante observable to the beneficiaries. Therefore, an iron frame failure indicator is used as an instrumental variable to identify the causal effect of improved stoves. Improved stove usage appears to reduce firewood consumption by approximately 46% in the study area. [Copyright &y& Elsevier]

Abstract: This work synthesizes results from the application of land cover classification techniques and probability sampling of satellite imagery for estimating forest extent and deforestation in Lake Maracaibo Basin (Venezuela and Colombia). A forest map was produced using a semi-automated supervised classification routine on MODIS 8-day 500-m imagery acquired in January 2010. Results show that forests occupy 29,710 km2 which represents 38% of the basin''s total terrestrial landmass. From this extent, 61% belongs to Venezuela and 39% falls within the Colombian region. Findings indicate a drastic decrease in forest cover as a result of anthropogenic agricultural and urban expansion, especially when compared to its potential extent within the ‘Maracaibo dry forests’ and the ‘Venezuelan Andean montane forests’ ecoregions. Using time series of Landsat imagery, deforestation rates for the 1985–2010 time period were calculated. The analysis was performed on 24 samples blocks of 10 × 10 km2 randomly allocated within previously defined change probability strata. The general spatial distribution of deforestation rates was predicted by a simple regression model between sample blocks and prior change probabilities at the basin scale. Our results indicate that deforestation was low (<0.5%/y) in 85% of the basin, with highly focalized deforestation fronts (intermediate-to-high rates, <2.5%/y) in three regions: a) the Motatán river sub-basin in the Eastern Cordillera, b) the lower slopes of the Catatumbo river sub-basin and c) the submontane regions of the Apón and Santa Ana river sub-basins. The results of this paper lead the way for understanding current patterns in socioeconomic drivers of forest clearing in Lake Maracaibo Basin. The study also demonstrates the feasibility of using alternatives methods to the time-consuming and financially unsustainable methods traditionally used at national and sub-national scale in Venezuela and other Latin American countries. [Copyright &y& Elsevier]

Flat fees in payment for environmental services (PES) schemes promote administrative ease, and are perceived as egalitarian. However, when environmental-service (ES) buyers are heterogeneous in their income and water-consumption levels, this scheme may not be optimal, as total payments might become too low and services under-supplied. This paper estimates willingness to pay (WTP) higher fees from hydrological-service buyers in an ongoing PES initiative in an Andean watershed in Colombia, where small, flat user payments have been introduced. ES users fall into two highly heterogeneous categories: smallholder peasants and recreational-house owners. We perform a contingent valuation analysis in a representative sample of 218 households. For improved water services, ES buyers on average are willing to pay monthly about US$1 premium over current flat PES rate. Users’ heterogeneity, however, affects significantly this outcome: while recreational-house owners are willing to pay monthly on average US$1.61 more than the current fee, smallholders only US$0.41. Spatial variables, such as distance to the water distribution point and to the town center, importantly influence WTP. Results may help designing user-driven PES schemes in line with efficiency and equity objectives. [Copyright &y& Elsevier]

Abstract: The coexistence of a high number of species in the forest is a central issue in tropical ecology. In this paper, we aim to characterise the spatial pattern of woody species in an Andean montane cloud forest to determine whether differences exist among the species in terms of spatial organization and if so, whether these differences are related to the life-form, primary dispersal mode, shade tolerance or the diameter distribution of the species. For this purpose, we analysed the spatial pattern of each species as well as the spatial relationships between young and adult individuals. Almost all the analysed species showed a cluster pattern, followed by a random pattern at larger distances. The cluster size is more evident for the young trees whereas adult trees tended to be more randomly distributed. The shade-tolerant species showed greater distances of aggregation than gap or medium-shade-tolerant species. Species primarily dispersed by wind and small birds showed larger distances of aggregation than species dispersed by mammals or big birds. All the under-story woody plants showed a notable cluster pattern, whereas canopy trees showed a variety of spatial patterns, with clustering at small scales being the most frequent. In the case of emergent trees, association was found between young and adult individuals on a large scale. Positive associations between young and adult individuals predominate at small scales for medium and shade tolerant species and at larger scales for bird-dispersed species whereas negative spatial associations at smaller scales were found for shade tolerant species and wind dispersed species. Our study confirms that conspecific organization varies among the woody plants in the analysed forest, and that the spatial pattern of woody plants is partially linked to shade tolerance, primary dispersal mode and life form of the species. [Copyright &y& Elsevier]

Abstract: This paper presents a synthesis of geological, geochemical, and archaeological information for the Huenul obsidian source located in northern Patagonia (Neuquén Province, Argentina). Important information recently published on other obsidian sources in the South-Central Andes of Argentina and Chile provide the context for this endeavor, allowing evaluation of the role of this lithic source within the network of human mobility and interaction on different spatial scales. It is suggested here that Huenul obsidian is genetically related with the Tilhué Formation, already been mapped in detail. This regional information provides a search model for geoarchaeological surveys. This raw material displays a remarkable supra-regional distribution in the archaeological record, although it is regionally under-represented. Three alternative hypotheses explaining the distribution of Huenul obsidians allow evaluation of technological decisions, marginal vs. nuclear role of certain spaces for past human societies, and territorial organization. [Copyright &y& Elsevier]

Abstract: The availability of in situ measurements of precipitation in remote locations is limited. As a result, the use of satellite measurements of precipitation is attractive for water resources management. Combined precipitation products that rely partially or entirely on satellite measurements are becoming increasingly available. However, these products have several weaknesses, for example their failure to capture certain types of precipitation, limited accuracy and limited spatial and temporal resolution. This paper evaluates the usefulness of several commonly used precipitation products over data scarce, complex mountainous terrain from a water resources perspective. Spatially averaged precipitation time series were generated or obtained for 16 sub-basins of the Paute river basin in the Ecuadorian Andes and 13 sub-basins of the Baker river basin in Chilean Patagonia. Precipitation time series were generated using the European Centre for Medium Weather Range Forecasting (ECMWF) 40year reanalysis (ERA-40) and the subsequent ERA-interim products, and the National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis dataset 1 (NCEP R1) hindcast products, as well as precipitation estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN). The Tropical Rainfall Measurement Mission (TRMM) 3B42 is also used for the Ecuadorian Andes. These datasets were compared to both spatially averaged gauged precipitation and river discharge. In general, the time series of the remotely sensed and hindcast products show a low correlation with locally observed precipitation data. Large biases are also observed between the different products. Hydrological verification based on river flows reveals that water balance errors can be extremely high for all evaluated products, including interpolated local data, in basins smaller than 1000km2. The observations are consistent over the two study regions despite very different climatic settings and hydrological processes, which is encouraging for extrapolation to other mountainous regions. [Copyright &y& Elsevier]

Summary: This paper presents an analysis on the hydrological regimes from several rivers flowing from the western slope of the Andes Cordillera. We compiled a database of 40 unimpaired average monthly streamflow records located in central and southern Chile, spanning the region between latitudes 30°S and 40°S and the period between years 1961 and 2006. River categories encompass snowmelt, mixed and rainfall dominated watersheds. The water year hydrograph center of timing (CT) is used as an indicator of flow regime and as a proxy for streamflow distribution throughout the year. The CT for each river is correlated to local climatic variables such as seasonal temperature and precipitation, and to large-scale circulation indexes. We assess CT trends using the Mann–Kendall test for varying time windows within the study period. Overall results for the 1961–2006 period show a significant (95% confidence level) negative trend (CT date shifting towards earlier in the year) for 23 out of the 40 analyzed series. However, when studying time windows within the entire period there seems to be a break in the trend during the late 1970s, with positive or null changes for the latter half of the study period for most of the stations analyzed. We found that even though the CT is significantly correlated (r >0.5) to temperature indexes in the snowfed watersheds, there has been no significant change in CT timing for most of these watersheds despite documented warming on the region. CT for all types of watersheds present clear correlation to precipitation indexes (r >0.8), and we observed high and significant correlation between CT and ONI, SOI and MEI indexes for all the study region: higher (lower) precipitation amounts during El Niño (La Niña), rather than temperature variations, seem to be the most important factor controlling CT timing during these episodes. In order of importance, the CT showed higher correlation with annual precipitation amounts and timing, MEI, ONI and SOI, mean winter and spring temperature, and finally PDO. The detected trends are consistent only with trends in precipitation, as rivers that showed high correlation to temperature do not show any trend. These conclusions suggest that rivers on the region show a different response to temperature changes when compared to rivers of similar regime in the northern hemisphere, and that precipitation amount and timing are the source of most of the variability in streamflow timing for both snowmelt and rainfall dominated watersheds. Temperature induced variability in streamflow timing should be studied with more precise hydrological models, as the CT has a complex behavior due to multiple climatical dependencies. Studying such behavior using only historical data might be insufficient for drawing more precise conclusions. [Copyright &y& Elsevier]

Abstract: The South American Low-Level Jet Experiment (SALLJEX) provided a unique dataset to investigate the existence of a mesoscale low-level circulation and of a diurnal cycle in its related convergence pattern over the Southeastern South American region east of the Andes, as well as its relationship with deep convection during the warm season. The present paper builds upon high-resolution analyses produced, assimilating the data collected during the SALLJEX field campaign using BRAMS, and explores their capability to reproduce mesoscale circulations not resolved by the low density observational network available in this region. Results of the analyses show a diurnal oscillation signal in the mean boundary layer convergence pattern over the plains with a nocturnal (daytime) convergence (divergence) maximum. These results are coherent with previous findings of a nocturnal phase in the mature stage of organized deep convection and related precipitation in subtropical latitudes east of the Andes during the warm season. The diurnal cycle of convergence/divergence in the boundary layer is described over a 15-day period, during which different synoptic conditions occurred. During weakly forced environments a regime characterized by nocturnal eastward anomaly flow and convergence and daytime westward anomaly flow and divergence related to a mesoscale northwestern mountain–central plain flow regime dominates over the plains between the Andes Mountains, the Parana River Valley, and the southern Brazil mountain range. In contrast, during synoptic conditions dominated by the presence of a deep thermal low over northwestern Argentina and a related low-level jet, convergence at night is mainly accomplished by the predominantly meridional low-level jet, which exhibits an anomalous weak wind speed diurnal cycle with respect to its summer climatological mean. On the other hand daytime divergence is completely produced by the zonal wind component as in the previous synoptic situation. Mesoscale circulations are altered (still effecting mean divergence in the domain, which exhibits a diurnal oscillation) upon the initiation of deep convective circulations in the evening in an increasingly convectively unstable atmosphere driven by a persistent horizontal advection of heat and moisture at low levels and forced by convergence generated by the low-level jet and the presence of a frontal zone. Convection intensifies at night when its related convergence over the plains comes in phase with the convergence related to the nocturnal maximum in the low-level jet. [Copyright &y& Elsevier]

Abstract: A large sedimentary forearc basin developed in Cenozoic times between the present-day Coastal Cordillera and the Western Cordillera of the Central Andes, called Moquegua basin in southern Peru. The basin is filled by Moquegua Group deposits (~50 to 4Ma) comprising mostly siliciclastic mudstones, sandstones and conglomerates as well as volcanic intercalations. Several facies changes both, along orogenic strike and through time, are described and have led to subdivision into four sedimentary units (Moquegua A, B, C and D). In this paper we present a refined stratigraphic scheme of the Moquegua Group combined with the first provenance analysis of the Moquegua basin based on (i) semi-quantitative analysis of heavy mineral abundance, (ii) electron microprobe (EMP) and laser ablation (LA) ICP-MS analyses of single detrital amphibole and Fe–Ti oxide grains, and (iii) comparative analysis of the different potential source rocks to clearly identify the most likely sources. Results allow us to reconstruct sediment provenance and to relate changes of the erosion-sedimentation system in the Moquegua basin to the evolution of the Andean orogen. At ~50 to ~40Ma the Moquegua basin was close to sea level and fed by low energy rivers transporting mainly metamorphic basement and Jurassic-Cretaceous sedimentary detritus from local and distal sources. The latter might be as far as the present Eastern Cordillera. From ~35Ma on the distal sediment sources were cut off by the uplift of the Altiplano and Eastern Cordillera leading to higher energy fluvial systems and increasing importance of local sources, especially the relevant volcanic arcs. From 25Ma on volcanic arc rocks became the predominant sources for Moquegua Group sediments. The 10Ma time lag observed between the onset of uplift-induced facies and provenance changes (at ~35Ma) and the onset of intense magmatic activity (at ~25Ma) suggests that magmatic addition was not the main driver for crustal thickening and uplift in the Central Andes during latest Eocene to Oligocene time. [Copyright &y& Elsevier]

Abstract: Fired glaciofluvial beds in outwash considered to date from the onset of the Younger Dryas Event (~12.9ka) in the northwestern Venezuelan Andes are considered equivalent to the Black Mat deposits described in other areas of North and South America and Europe. It may be equivalent to sediment recovered from other sites containing beds with spikes of cosmic nuclides and charcoal indicating the presence of widespread fire, one of the signatures of the Black Mat conflagration that followed the proposed breakup of Comet Encke or an unknown asteroid over the Laurentide Icesheet at 12.9ka. In the northern Andes at Site MUM7B, sediment considered coeval with the Black Mat contains glassy carbon spherules, tri-coatings of C welded onto quartz and feldspar covered with Fe and Mn. Monazite with excessive concentrations of REEs, platinum metals including Ru and Rh, possible pdf''s, and disrupted/brecciated and microfractured quartz and feldspar from impacting ejecta and excessive heating summarize the data obtained so far. The purpose of this paper is to document the physical character, mineralogy and biotic composition of the Black Mat. [Copyright &y& Elsevier]

Abstract: The structure and tectonics of the retro-arc area of the Andes between 38°30′ and 40°S remains poorly understood because of the scarcity of previous structural studies. This paper analyzes the styles, distribution and timing of the deformation in the eastern flank of the Andes between these latitudes, with focus in the Tertiary tectonics of the area. This Andean section can be divided into an internal and an external domain based on its distinctive structural evolution. The boundary between them coincides with the Bio Bio and Aluminé valleys, which separate sectors of the fold-and-thrust belt with opposite vergence and different structural styles. Structures developed in the external domain during the Andean cycle are associated with a west-verging fold-and-thrust belt which was controlled geometrically by pre-existing normal faults of the Mesozoic rift phase. We also differentiate three segments along the external domain of the inner retro-arc zone at these latitudes. Each segment is associated with a Tertiary depocenter related to the western border of a structural high (Copahue–Pino Hachado Block and Cordilleras de Catan Lil and Chachil) which constitutes an outstanding feature within the study area. The recognition and interpretation of the main structures and the spatial and temporal distribution of the Tertiary sequences allowed us to establish a tectonic model in which the uplift of this NNW-trending block during upper Miocene times, originated a series of intermontane depocenters well represented between 38 and 40°S. As a result of that, syntectonic and synorogenic deposits accumulated in a compressive regime. These depocenters can be integrated in a narrow deposition zone associated with the western slope of the Copahue–Pino Hachado Block and its southward prolongation in the Cordillera de Catan Lil and Cordillera del Chachil. On the basis of tectonostratigraphic controls we define the last Andean contractional phase of the inner retro-arc area at these latitudes, between 11 and 5.67Ma for the northern segment, between 10 and 6.2Ma for the central segment and between 13 to 8 and 4.3Ma for the southern segment. After this short-lived compressional stage, deformation migrated to the west associated with the onset of the Liquiñe-Ofqui strike-slip fault zone along the intra-arc zone. [Copyright &y& Elsevier]