Spatial distribution of Echinolitorina peruviana (Lamarck, 1882) for intertidal rocky shore in Antofagasta (23° S, Chile).

The intertidal rocky shores in continental Chile have high species diversity mainly in northern Chile (18-27° S), and one of the most widespread species is the gastropod Echinolittorina peruviana (Lamarck, 1822). The aim of the present study is do a first characterization of spatial distribution of E. peruviana in along rocky shore in Antofagasta town in northern Chile. Individuals were counted in nine different sites that also were determined their spectral properties using remote sensing techniques (LANDSAT ETM+). The results revealed that sites without marked human intervention have more abundant in comparison to sites located in the town, also in all studied sites was found an aggregated pattern, and in six of these sites were found a negative binomial distribution. The low density related to sites with human intervention is supported when spectral properties for sites were included. These results would agree with other similar results for rocky shore in northern and southern Chile.

Deciphering the Late Paleozoic–Cenozoic Tectonic History of the Inner Central Andes Forearc: An Update From the Salar de Punta Negra Basin of Northern Chile

We integrated new and existing geological, geochronological, thermochronological, and two-dimensional (2D) seismic data from the Salar de Punta Negra Basin to define the Late Paleozoic–Cenozoic tectonic evolution of the inner Andean forearc of northern Chile more precisely. Our results indicate that this region experienced early Late Paleozoic–Mesozoic crustal extension, creating several basement half-graben structures bounded by east- and west-dipping master faults. These extensional basins were filled by Upper Permian to Jurassic volcanic and sedimentary (continental and marine) syn-rift deposits. The genesis of these structures is related to the early breakup of the western Gondwana continent and the development of the large Tarapacá Basin in northern Chile and southern Perú. Subsequently, Late Cretaceous to Paleocene contraction occurred, which led to the tectonic inversion of the pre-existing rift system and the uplift of the Paleozoic–Mesozoic syn-rift deposits. Seismic data show that Upper Cretaceous and Paleocene synorogenic deposits accumulated along and over inversion anticlines, recording the initial contraction and marking the change from an extensional to a contractional tectonic setting. During the final episodes of basin inversion, crustal shortening was accommodated by the Eocene to recent basement reverse faulting accompanied by the rapid exhumation of basement pre-rift blocks, which served as the principal sources for the sediments that filled the pre-Andean basins during the Late Cenozoic. Finally, the exhumed basement pre-rift blocks and the reverse faults compartmentalized the contractional intermontane basins, which constitute the main low topographic relief of the inner forearc of northern Chile.

Ore Mineralogy, Geochemistry, and Dating (Re-Os, Ar-Ar) of the El Volcán Porphyry/Epithermal System, Maricunga Gold Belt, Northern Chile

The El Volcán gold project (8.9 Moz Au @ 0.71 g/t Au) is located in the Maricunga gold belt in northern Chile, on the flank of the large Cenozoic Copiapó Volcanic Complex. Precious metal mineralization is hosted in two zones (Dorado and Ojo de Agua) of (pervasively) altered Miocene porphyry intrusions and lava flows of andesitic to rhyolitic composition, and in breccias. The ore zones reflect an evolving magmatic-hydrothermal system with mineral assemblages of magnetite-ilmenite-pyrite-molybdenite (early), bornite-chalcopyrite-pyrite-rutile (stage I), chalcocite-chalcopyrite-enargite-fahlore-pyrite (stage II), and chalcopyrite-covellite-pyrite (stage III). Alteration is dominantly of Maricunga-style (illite-smectite-chlorite ± kaolinite), partly obscured by quartz-kaolinite-alunite ± illite ± smectite alteration. Powdery quartz-alunite-kaolinite alteration with native sulfur and cinnabar forms shallow steam-heated zones. Early K-feldspar ± biotite alteration is preserved only in small porphyry cores and in deep drill holes. Most gold is submicrometer size and is in banded quartz veinlets, which are characteristic of the Maricunga gold belt. However, some gold is disseminated in zones of pervasive quartz-kaolinite-alunite alteration, with and without banded quartz veinlets. Minor visible gold is related to disseminated chalcocite-chalcopyrite-enargite-fahlore-pyrite. The lithogeochemical database identifies a pronounced Au-Te-Re signature (>100× bulk crust) of the hydrothermal system. Molybdenum-rich bulk rock (100–400 ppm Mo) has an Re-Os age of 10.94 ± 0.17 Ma (2σ). 40Ar-39Ar ages on deep K-feldspar alteration and on alunite altered rock have the same age within error and yield a combined age of 11.20 ± 0.25 Ma (2σ). The formation of the El Volcán gold deposit took place during the establishment of the Chilean flat-slab setting in a time of increasing crustal thickness when hydrous magmas were formed in a mature arc setting. The vigorous nature of the hydrothermal system is expressed by abundant one-phase vapor fluid inclusions recording magmatic vapor streaming through a large rock column with a vertical extent of ≥1,500 m.

Identificação das Dunas do Atacama (Norte do Chile) a partir da avaliação de três algoritmos no Google Earth Engine

As dunas correspondem a processos de sedimentação eólica, que podem estar tanto nas áreas costeiras marinhas, como no interior do continente com algumas diferenças na modelagem. No Sul do deserto do Atacama, no Norte do Chile, há um conjunto de seis campos de dunas intermontanhas chamadas Mar de Dunas do Atacama, as quais têm tipologias complexas de dunas do deserto, que podem ser ativas, semiativas ou estabilizadas. O seu monitoramento é conveniente para conhecer detalhes sobre a possível invasão de areias das dunas ao sul do rio Copiapó. Dessa forma, esta pesquisa tem como objetivo avaliar os métodos de classificação supervisionada Random Forest, CART e SmileCART através de duas metodologias de amostragens, aleatória e estratificada, numa imagem Landsat 5 na plataforma em nuvem Google Earth Engine, a fim de verificar qual método oferece o melhor resultado para o mapeamento do Mar de Dunas do Atacama. Para conseguir este objetivo, foram criados polígonos de classes para a realização da amostragem aleatória estratificada e chave de interpretação para amostragem aleatória simples. O processo de avaliação da acurácia foi feito através de imagem Sentinel 2 com a aplicação dos índices de Simultaneidade Geográfica, Erros de Comissão e Omissão, e Exatidão Global. Observou-se como resultados para os algoritmos testados, que os três algoritmos foram eficientes para o mapeamento das Dunas do Atacama, entretanto, a técnica de classificação supervisionada por CART, com a metodologia da amostragem aleatória simples, representou o melhor desempenho. Identification of the Atacama Dunes (Northern Chile) from the evaluation of three algorithms on Google Earth EngineA B S T R A C TThe dunes correspond to wind sedimentation processes, which can be found both in marine coastal areas and in the interior of the continent with some differences in modeling. In the south of the Atacama desert, in northern Chile, there are a set of six inter-mountain dune fields called Mar de Dunas do Atacama, which have complex types of desert dunes, which can be active, semi-active or stabilized. Its monitoring is convenient to know details about the possible invasion of sand from the dunes south of the Copiapó River. Thus, this research aims to evaluate the supervised classification methods Random Forest, CART and SmileCART through two sampling methodologies, random and stratified, in a Landsat 5 image on the Google Earth Engine cloud platform, in order to verify which method offers the best result for mapping the Atacama Dunes Sea. In order to achieve this objective, class polygons were created to perform stratified random sampling and the interpretation key for simple random sampling. The accuracy assessment process was performed using a Sentinel 2 image with the application of the Geographic Simultaneity indices and the Commission and Omission Errors. It was observed as results for the tested algorithms, that the three algorithms were efficient for mapping the Atacama Dunes, however, the CART supervised classification technique, with the simple random sampling methodology, represents the best performance.

Breeding of a Wild Population of South Pacific Bonito Sarda chiliensis chiliensis (Cuvier 1832) Broodstock under Laboratory Conditions in Pisagua, Northern Chile

The wild population of South Pacific bonito Sarda chiliensis chiliensis, which has a wide distribution in northern Chile, is considered of importance in Chilean aquaculture. The biological feasibility of cultivation of any marine species begins with the establishment of an initial broodstock population to obtain eggs, larvae, and juveniles. In this work, 22 South Pacific bonito fishing campaigns were carried out in Pisagua, Chile, between spring in November 2011 and the summer in January 2012. At least 74 specimens were obtained of which 24 survived the capture and transport processes. Fish were stocked in a recirculating land-based aquaculture system, and at 14 months under captivity, fish began spawning. Eggs were collected, to describe some stages of development, and were placed in incubators at 20 °C and on the third-day eggs hatched. Larvae reached a total length between 1.435 and 1.7 mm, which were accurately characterized during their first morphological changes. This is the first work that describes the capture, transport, and acclimatization in captivity of a breeding population of wild Pacific bonito in Chile.

Hidropolítica neoliberal en Chile y el secuestro hídrico en el Valle de Copiapó: Trayectorias, dinámicas y narrativas en tensión, una perspectiva de coyuntura histórica

Resumen En este artículo, y desde un abordaje regional situado en el valle de Copiapó en la Región de Atacama en el norte de Chile, efectuamos un análisis del periodo de desarrollo del neoliberalismo en clave ambiental como una coyuntura histórica, en la que nos concentramos en el metabolismo económico, material y po­lítico institucional entre sociedad y medioambiente. Específicamente, analizaremos como el agua, es so­metida a un proceso de privatización y mercantilización, constituyendo las silenciosas bases del metabo­lismo extractivo en el marco del desarrollo y transformación de la industria minera y agroindustrial, que implicó una intensificación radical del consumo industrial de agua, paralelo a un aumento exponencial de la acumulación capitalista y a una simultánea hiper-desertificación artificial de una zona ya naturalmente desértica. Hipotetizamos que la acumulación por desposesión hídrica solo fue posible teniendo como condiciones de posibilidad y origen re fundacional, a las transformaciones institucionales radicales reali­zadas sin posibilidad de discusión democrática y en un contexto de represión y violencia política, con lo que el análisis de la dimensión ambiental del presente no puede disociarse de los contextos políticos sub­yacentes y sus trayectorias en términos de un abordaje de análisis de procesos de duración media en términos braudelianos. Palabras clave: hidropolítica; secuestro hídrico; coyuntura; violencia; neoliberalismo. Resumo Neste trabalho, a partir de uma abordagem regional localizada no vale de Copiapó, Região do Atacama, norte do Chile, realizamos uma análise ambiental no período histórico de desenvolvimento do neolibera­lismo no Chile, na qual enfocamos o metabolismo econômico, material e político-institucional entre soci­edade e meio ambiente. Especificamente, analisamos como a água está submetida a um processo de pri­vatização e comercialização, constituindo as bases silenciosas do metabolismo extrativo no quadro do desenvolvimento e transformação da indústria mineira e agroindustrial, o que implicou uma intensifica­ção radical do consumo industrial de água, paralelo a um aumento exponencial da acumulação capitalista e a uma simultânea hiperdesertificação artificial de uma área já naturalmente deserta. Hipotetizamos que o acúmulo por expropriação da água só foi possível tendo como condições de possibilidade e origem refundacional, as radicais transformações institucionais realizadas iniciadas na ditadura e consolidadas nos governos pós-ditatoriais, com as quais a análise da dimensão ambiental do presente não pode ser dissociada dos contextos políticos subjacentes e de suas trajetórias em termos de uma abordagem de análise de processo de média duração em termos braudelianos. Para isso, analisamos o fenómeno desta­cando duas ordens distintas, mas ligadas: 1) uma, relativa às trajetórias político-institucionais sob uma perspectiva histórica, considerando dimensões escalares em dimensiones políticas, econômicas e ambi­entais; 2) outra, sociopolítica e narrativa, ao abordar discursos e narrativas promovidos pelo capital, como formas ideológicas de despolitização da crise, Por outro lado, a emergência de narrativas de contestação desde as comunidades e atores locais, que vão da narrativa do desaparecimento do rio à do sequestro da água. Finalmente, destacamos que, ainda que não haja relação causal entre o sentido semântico obser­vado, tanto o desaparecimento como o sequestro são narrativas que podem estar vinculadas à violência política originária da ditadura y a luta pelos Direitos Humanos, com o desaparecimento e sequestro de pessoas no âmbito da repressão política, paralela aos processos de transformação económica que leva­ram à reconfiguração silenciosa entre capital e meio ambiente no Chile. Em termos de periodização da conjuntura estudada, apesar de não estar estruturada de forma sequencial, se incluem eventos e proces­sos que envolvem o desenvolvimento da conjuntura neoliberal desde a execução do golpe de Estado contra Salvador Allende em 1973, do desenvolvimento de transformações jurídicas e econômicas da dita­dura militar e da consolidação neoliberal na transição pós-ditatorial, até o denominado estallido social de outubro de 2019 e o posterior processo constituinte em 2020/2021 Palavras-chave: hidropolítica; sequestro de água; conjuntura; violência; neoliberalismo. Neoliberal hydropolitics in Chile and the water kidnapping in Copiapó Valley: Trajectories, dynamics and narratives in tension, an historical conjuncture approach Abstract In this work and from a regional approach located in the Copiapó valley in the Atacama Region in northern Chile, we carry out an analysis of the period of development of neoliberalism in an environmental key as a historical conjuncture, in which we focus on metabolism economic, material and institutional political between society and environment. Specifically, we will analyze how water is subjected to a process of privatization and commercialization, constituting the silent bases of the extractive metabolism in the framework of the development and transformation of the mining and agro-industrial industry, which implied a radical intensification of the industrial consumption of water, parallel to an exponential increase in capitalist accumulation and to a simultaneous artificial hyper-desertification of an already naturally desert area. We hypothesize that the accumulation by water dispossession was only possible having as conditions of possibility and re-foundational origin, the radical institutional transformations carried out initiated in the dictatorship and consolidated in the post-dictatorial governments, with which the analysis of the environmental dimension of the present does not it can be dissociated from the underlying political contexts and their trajectories in terms of a medium-duration process analysis approach in Braudelian terms. Keywords: hydro-politics; water kidnapping; conjuncture; violence; neoliberalism.

Earthquake ruptures and topography controlled by plate interface deformation

What controls the location and segmentation of mega-earthquakes in subduction zones is a long-standing problem in earth sciences. Prediction of earthquake ruptures mostly relies on interplate coupling models based on Global Navigation Satellite Systems providing patterns of slip deficit between tectonic plates. We here investigate if and how the seismic and aseismic patches revealed by these models relate to the distribution of deformation along the plate interface, i.e. basal erosion and/or underplating. From a mechanical analysis of the topography applied along the Chilean subduction zone, we show that extensive plate interface deformation takes place along most of the margin. We show that basal erosion occurs preferentially at 15 km depth while underplating does at 35 ± 10 and 60 ± 5 km depth, in agreement with P-T conditions of recovered underplated material, expected pore pressures, and spatial distribution of marine terraces and uplift rates. Along southern Chile, large sediment input favors shallow accretion and underplating of subducted sediments, while along northern Chile, extensive basal erosion provides material for the underplating. We then show that all major earthquakes of southern Chile are limited along their down-dip end by underplating while, along northern Chile, they are surrounded by both basal erosion and underplating. Segments with heterogeneously distributed deformation largely coincide with lateral earthquake terminations. We therefore propose that long-lived plate interface deformation promotes stress build-up and leads to earthquake nucleation. Earthquakes then propagate along fault planes shielded from this long-lived permanent deformation, and are finally stopped by segments of heterogeneously distributed deformation. Slip deficit patterns and earthquake segmentation therefore reflect the along-dip and along-strike distribution of the plate interface deformation. Topography acts as a mirror of distributed plate interface deformation and should be studied systematically to improve the prediction of earthquake ruptures.

Experience tourism: development possibilities in the Bioceanic Corridor

The tourism sector is one of the most powerful generators of economic growth, employment, added value, and services export in the world. In this context, the objective of this article is to discuss tourism and experience tourism possibilities in the region that the Bioceanic Corridor will traverse from the Latin American Integration Route (RILA), involving Brazil, Paraguay, Argentine, and reaching Northern Chile in Antofagasta and Iquique. Regarding methodology, it uses the deductive method and is based on bibliographic and documentary research with access to the articles, indicators, and documents needed. In this regard, regional development issues are presented, followed by experience tourism as a possibility for development, and finally, some indicators and data about tourism are analyzed, seeking an interface with the Bioceanic Corridor. After analyses, it is pointed out that tourism has become one of the fundamental factors for territorial development, presenting new and other values and meanings to the territory, as well as a production resource, discovering another perspective when interpreting rural and natural spaces. Thus, it arises as a new alternative to globalization and, in this context, experience tourism gains prominence considering the significant increase of tourism in the world in 2010, and perspectives until 2030. It is inferred, therefore, that RILA is a great window of opportunity for socioeconomic development through tourism and more specifically experience tourism.