Marine sediment samples were collected from Quebrada la Higuera, Chile to provide a record of planktonic and benthic foraminifera as a means of reconstructing the paleo-bathymetry and paleo-environment of the Quebrada la Higuera basin. The research area is located in northern Chile, south of Caldera in Quebrada la Higuera (S 27° 16.443, W 70° 54.887). The Quebrada la Higuera basin rests unconformably atop Mesozoic gabbroic basement, which is locally exposed, representing fault-bounded horsts and grabens. At the base of the section, diatomaceous sediment within the sequence suggests intervals of high productivity. The co-occurrence of the shallower water benthic species Nonionella miocenica and Epistominella pulchella with deep-water species Bolivina tumida, Uvigerina peregrina, Globobulimina auriculata, and Bolivina subfusiformis, at 10-23 m above the base of the section and again at 44-62 m, within fining-upward sedimentary packages suggests possible turbidites caused by transgressive-regressive cycles. Additionally, the occurrence and high abundance of these species are indicative of high productivity. A 30-40 cm Late Miocene phosphatic bed consisting of vertebrate and invertebrate fossils lies unconformably atop a poorly consolidated sand ~42 m from the base of the section. This phosphatic bed suggests that upwelling was occurring off the coast of Chile earlier than previously believed. The hyperaridity of Chile's Atacama Desert has been the result of the cold upwelling Peru-Chile current, which is further intensified by the rain-shadow effect of the Andes and the cold, dry descending Hadley cell. The occurrence of planktonic foraminifer Globigerina bulloides at the base of the section establishes the maximum possible lower age limit of 15.97 Ma (Middle Miocene). At 47 m, the co-occurrence of Globorotalia margaritae, Globorotalia crassaformis, and Dentogloboquadrina altispira establishes a maximum age limit for that horizon of ~3.6 Ma (Early Pliocene), providing an age range for the Quebrada la Higuera section from Middle Miocene through Early Pliocene. This study provides a record of planktonic and benthic foraminifera as a means of reconstructing the paleohistory of Quebrada la Higuera and more broadly through the Caldera region. The analyses address interactions between uplift, atmospheric conditions, sea level, and upwelling within the region from interpretations of the composite section, including facies relationship between sediments and occurring foraminifera species. These observations, along with the foraminiferal record, help broaden the understanding and development of the Quebrada la Higuera Neogene record.

Dans les zones arides, la grande variabilité des eaux de surface a conduit les Hommes à exploiter les eaux souterraines. Cependant, afin de préserver durablement cette ressource, une bonne connaissance des processus de recharge est nécessaire. Ces travaux de thèse ont pour objectifs de caractériser les facteurs de contrôle de la recharge et des écoulements souterrains en zone de piedmont aride et hyper-aride. Dans le Nord du Chili, l’activité minière et les villes nouvelles associées aux déplacements de populations depuis quelques dizaine d’années ont engendré une surexploitation des ressources en eaux souterraines contenues dans l’Aquifère de la Pampa del Tamarugal. Cet aquifère régional est l’une des principales ressources en eau de l’ensemble du Nord du Chili, ce qui en fait une ressource stratégique. Le contexte hyper-aride de cette zone de piedmont (extension nord du Désert d’Atacama) semble suggérer que la recharge actuelle de l’aquifère ne permet pas de soutenir son bilan hydrologique.Afin d’identifier et de caractériser les facteurs de contrôle de la recharge et des écoulements souterrains de l’Aquifère de la Pampa del Tamarugal, une approche multidisciplinaire a été utilisée. Cette approche est basée dans un premier temps sur la caractérisation géologique et géomorphologique de la Dépression Centrale et notamment du Piedmont Andin entre 19,5°S et 20°S. Celle-ci a permis d’identifier le rôle du substratum pré-Oligocène sur l’organisation de la couverture fin-Cénozoïque (i.e. axes de drainages, barrières sédimentaires & paléovallées) et sur les circulations souterraines au niveau du piedmont. Dans un second temps, une approche hydrogéophysique et hydro(géo)logique a été utilisée afin de caractériser et d’identifier les conditions aux limites ainsi que l’évolution spatiale de la piézométrie au sein de la plaine de la Pampa del Tamarugal et du piedmont. De nombreux sondages de résistivité, réalisé par TDEM, ont permis d’identifier un contraste bien défini et corrélé avec le niveau piézométrique de la nappe libre. Des relevés hydro(geo)logiques ont permis de valider les échanges rivière-nappe (zones de recharge) qui ont été déduits à partir de l’étude géophysique. Dans un troisième temps, la caractérisation géochimique et isotopique des eaux souterraines de la zone d’étude a permis d’identifier les origines, les circulations ainsi que les processus de recharge de l’aquifère. La distribution des âges de l’eau de la zone saturée a permis d’identifier les grandes phases de recharge paléoclimatiques de l’Holocène. Dans un quatrième temps, une approche exploratoire par la modélisation des écoulements au sein de la zone non saturée, basée sur un modèle à base physique (Hydrus-1D) et complétée par des relevés de terrain, ont permis d’évaluer la recharge induite par une crue au niveau des cônes alluviaux. L’analyse des chroniques piézométriques a apporté de nombreuses informations sur la quantification de la recharge.Sur la base des résultats de cette étude multidisciplinaire, ces travaux de recherche ont permis de définir, au niveau de l’Aquifère de la Pampa del Tamarugal (Nord Chili), les facteurs de contrôle de la recharge et des écoulements souterrains en zone de piedmont aride et hyper-aride. / In drylands, the scarcity of surface waters has led the population to mainly extract the groundwater resource for water supply. To preserve the groundwater resource of the over-exploitation, the understanding of the groundwater recharge processes is required. The present work aims to assess the factors of control on both the groundwater recharge and the groundwater circulation in dryland piedmonts.In Northern Chile, since a few tens of years, mining activities and the associated population movements have induced an over-exploitation of the Pampa del Tamarugal Aquifer. This regional size aquifer is one of the main groundwater resources of Northern Chile as a whole.In order to assess the controls on the groundwater recharge processes that allow recharging the Pampa del Tamarugal Aquifer as well as the groundwater circulation in the Andean Piedmont, a multidisciplinary approach was carried out in the endorheic catchment of the Pampa del Tamarugal (i.e. lowlands and piedmont) between 19.5°S and 20°S. Firstly, the study is based on a geological and geomorphological assessment of the Central Depression sedimentary basin with a focus on the Andean Piedmont. This work allowed identifying the control of the pre-Oligocene bedrock on both the late-Cenozoic piedmont cover (i.e. alluvial drainage axis, sedimentary barriers, and paleovalleys) and the groundwater circulation. Secondly, a hydrogeophysical (resistivity soundings, via TDEM) and hydrogeological characterization of the vadose zone and the saturated zone of the aquifer was carried out. These measurements allowed identifying a well-defined contrast of resistivity that is correlated with the water-table. This allows to better define the boundary conditions of the aquifer and to shift eastwards (i.e. in the piedmont) the oriental limit of the aquifer. Hydrological surveys allowed to validate the identification of groundwater recharge areas where the rivers fed the aquifer. Thirdly, the study is based on the assessment of the geochemical, isotopic and dissolved gas content of the groundwater. This approach allowed identifying the origin and also the groundwater circulation of the aquifer. The characterization of the groundwater distribution ages allowed to identify the main stages of recharge during Holocene and late-Pleistocene times. Fourthly, an exploratory approach was carried out in order to address the recharge fluxes in the vadose zone. Based on Hydrus-1D model and soil sampling carried out in the field, the recharge fluxes induced by one flood in the alluvial fans were estimated. The behavior analysis of water-table on time series of a few years were also used to estimate the recharge in the lower part of alluvial fans according to the surface geomorphology features.Based on this multidisciplinary approach, these works (performed in Northern Chile) allow defining the controls on the groundwater recharge and circulation in arid and hyperarid piedmont areas.

Ceramics, Textiles and the Tiwanaku Integration of Chile's "Norte Grande"In this paper we explore Tiwanaku's iconography of power and its role in integrating south-central Andean frontier areas such as the Azapa Valley and oasis of San Pedro de Atacama, in northern Chile. It is presumed that Tiwanaku's expansive processes, like the powers that maintained its central hierarchy and the strategies that integrated peripheral and ultra-peripheral areas with the center, were ideological and political. This ideological and political nature was expressed materially in the stone sculptures of Tiwanaku, and widely distributed in portable art objects that generated and integrated Tiwanaku's interaction sphere. This idea motivates a reexamination of collections from the nuclear and peripheral areas, including the extreme south of Peru, south-central Bolivia, and northern Chile. Focusing on Chile's Azapa Valley, and San Pedro de Atacama, the authors seek to determine from iconography and artifacts the degree of integration between center and periphery, in hegemonic and territorial terms. / En este trabajo se explora la iconografía del poder en Tiwanaku y su rol en la integración de zonas de frontera del área centro-sur andina, como lo son el valle de Azapa y San Pedro de Atacama, en el norte de Chile. Se asume que en el proceso expansivo de Tiwanaku, las sanciones que apoyaron la jerarquía central y las estrategias empleadas para integrar las zonas periféricas y ultraperiféricas al centro fueron de naturaleza ideológica y política, lo que se manifestaría materialmente en la iconografía que reproduce las imágenes de la litoescultura del lago, y que se distribuyó en objetos portátiles que integraron o generaron su esfera de interacción. Esta idea motivó la revisión de colecciones arqueológicas de las zonas nucleares y marginales de la esfera de influencia tiwanaku, comprendidas entre el extremo sur del Perú, centro-sur de Bolivia y norte de Chile. Aquí, en particular, los autores se referirán a los textiles y a la alfarería del valle de Azapa y de San Pedro de Atacama para, a través de las relaciones iconográficas y artefactuales, intentar determinar el grado de integración centro-periferia, ya sea en términos hegemónicos o territoriales.

Funerary ritual in San Pedro de Atacama: evidence for Tiwanaku interment?Given the homogeneous nature of mortuary practices among the Prehispanic residents of San Pedro de Atacama, Chile, atypical graves have been interpreted as evidence for foreigners buried among the local dead in San Pedro cemeteries. This study reexamines graves generally attributed to colonizers from Tiwanaku (AD 500-1000). Emphasizing contexts with gold and silver, detailed comparison is made between the mortuary practices of San Pedro and Tiwanaku. These analyses and data coincide in challenging the efficacy of the colonization model, and support instead the model of indirect Tiwanaku presence that Berenguer (1998) termed "clientage". Confirmation of Tiwanaku tombs similar to the San Pedro graves is lacking, given the importance of Tiwanaku pottery in altiplano tombs, in comparison with the placement of individual Tiwanaku objects in San Pedro graves that otherwise contain only objects of local origin, as well as the possibility that gold and silver objects found in San Pedro graves came from places other than Tiwanaku, it is premature to assign Tiwanaku identity to San Pedro's atypical tombs. / Dada la homogeneidad de las prácticas funerarias de los habitantes prehispánicos de San Pedro de Atacama, Chile, los entierros de carácter excepcional han sido interpretados como producto de la presencia de individuos foráneos en la zona. El presente trabajo retoma los casos y objetos típicamente asociados a la colonización tiwanaku (entre 500 y 1000 d.C.), y poniendo énfasis sobre todo en los contextos con oro y plata, hace una comparación detallada entre los patrones funerarios sanpedrinos y tiwanaku. Los datos presentados coinciden para rechazar el modelo colonizador y apoyan al modelo indirecto de presencia tiwanaku de "clientelaje" (Berenguer 1998). Se establece que, dada la escasez de información sobre prácticas funerarias estatales, la importancia de la cerámica en los entierros altiplánicos recuperados cuando los ejemplos sanpedrinos carecen de la misma, la incorporación casi exclusiva del material cultural tiwanaku en contextos de carácter local y la posibilidad de que los objetos de oro puedan proceder de otros lugares no basta para confirmar una identidad tiwanaku a estos entierros excepcionales.

EditorialThe text doesn't have an abstract / El texto no presenta resumen