This article examines a new dataset of radiocarbon dates that provides insights into the progressive installation of Inca infrastructure in the Copiapo Valley, situated at the southern edge of the Atacama Desert in northern Chile. It shows that the Inca imperial expansion in this region was not a linear process and was likely shaped by local negotiations and conflicts. The findings describe three main stages of Inca expansion. The first is the construction of the North–South Inca Road and the establishment of high-altitude mountain shrines. The next stage consisted of a physical intervention in a local village located in the upper valley, including the construction of administrative buildings and public spaces. The last stage involved indirect intervention in local villages, characterized by the presence of isolated administrative buildings that were potentially used for diplomacy and negotiation. I argue that the Inca imperial expansion, characterized by evolving strategies across regions and time periods, not only demonstrates the state's capacity for learning but also suggests the pivotal role of local actors in positions of power who wielded agency to shape these developments.

This article explores how Francisco de Aguirre used the Copiapó Valley encomienda to negotiate political power during the transition from conquest to colonial rule in northern Chile. Simultaneously, we analyze the circumstances of how a native society was incorporated into the Spanish Empire after a decade of fighting and resistance on the fringes of the empire. The strategic use of the fear of native rebellions to close the road from Peru to Chile gave Aguirre enough power to negotiate an important political position, which in the future would clash with the colonial authorities. Copiapó Valley’s peripheral location in the southernmost Atacama Desert constituted a political gray zone for the colonial administration. This space contributed to consolidating power for Aguirre and enabled locals some negotiation power within the possibilities afforded by the colonial system.

Microbiological activities can be detected in various extreme environments on Earth, which suggest that extraterrestrial environments, such as on Mars, could host life. There have been proposed a number of biomarkers to detect extant life mostly based on specific molecules. Because terrestrial organisms have catalytic proteins (enzymes), enzymatic activity may also be a good indicator to evaluate biological activities in extreme environments. Phosphatases are essential for all terrestrial organisms because phosphate esters are ubiquitously used in genetic molecules (DNA/RNA) and membranes. In this study, we evaluated microbial activity in soils of the Atacama Desert, Chile, by analysing several biomarkers, including phosphatase activity. Phosphatases extracted with Tris buffer were assayed fluorometrically using 4-methylumbelliferyl phosphate as a substrate. The horizontal distribution of phosphatase activity and other parameters in soils from the Atacama Desert showed that phosphatase activity was positively correlated with amino acid concentration and colony-forming units and negatively correlated with precipitation amount. We found consistent that biochemical indicators including phosphatase significantly decreased in the extreme hyper-arid zone where rainfall of <25 mm year−1. The results were compared with phosphatase activities detected in extreme environments, such as submarine hydrothermal systems and Antarctic soils, as well as soils from ordinary environments. Overall, our results suggested that phosphatase activity could be a good indicator for evaluating biological activities in extreme environments.

En este trabajo se presentan los resultados de los análisis de isótopos estables (δ13Ccol, δ15Ncol, δ13Capa y δ18Oapa) realizados en huesos de camélidos de sitios de Puripica, Tulán y Salar de Punta Negra (Región de Antofagasta, Chile), dentro de una secuencia que abarca desde el Arcaico temprano hasta el Formativo temprano. Estos datos se cotejaron con datos osteométricos y genéticos de camélidos silvestres y domésticos con el objetivo de comprender el uso de los espacios de caza y pastoreo. Los resultados correspondientes a las muestras de los periodos Arcaico temprano y medio (10.000-5300 aP) obedecen a las características ambientales registradas durante dicho lapso temporal en el área. Para el Arcaico tardío (5300-4000 aP) y el Formativo temprano (3100-2400 aP) se observa una distribución de valores isotópicos relativamente similar. Sin embargo, debido a la alta variabilidad de tamaños dentro de los camélidos domésticos, no es posible definir el uso de ciertas áreas de pastura sobre otras. Al mismo tiempo, los valores isotópicos de carbono y nitrógeno de la fase Tarajne (3700-3200 aP) se muestran poco variables, patrón que se explica por el uso de áreas acotadas para la caza de animales silvestres y/o el pastoreo de animales domésticos.

A través de la morfometría geométrica, este estudio explora la influencia del contexto cronológico y de procedencia en la variabilidad morfológica de 75 anzuelos de concha de Choromytilus chorus provenientes de siete sitios arqueológicos de la comuna de Taltal, en la costa sur del Desierto de Atacama, Chile. Los resultados muestran diferencias significativas en las formas de los anzuelos provenientes de distintos sitios y períodos. El rasgo que explica el mayor porcentaje de variación morfológica es el largo de una de las puntas, seguido por la abertura del anzuelo. Se identifican tres momentos clave en la evolución morfológica de estos artefactos. Entre 8500 y 7500 cal aP aparecen los primeros anzuelos, predominantemente sin vástago y de abertura amplia pero variable. De 7500 cal aP en adelante, la tecnología prolifera y se diversifica: los anzuelos sin vástago y con abertura amplia siguen predominando, pero formas con vástago y abertura media también están presentes en el kit de pesca. Finalmente, entre 5500 y 4500 cal aP el número de anzuelos disminuye, desaparecen las formas circulares y se mantienen las formas con vástago, pero con abertura más estrecha. El caso de estudio de Taltal contribuye a enriquecer el conocimiento sobre la tecnología del anzuelo en concha a lo largo del Pacífico.

A distinct feature of many of the earliest archaeological sites (13,000-11,200 cal yr BP) at the core of the Atacama Desert is that they lie at or just below the surface, often encased in desert pavements. In this study, we compare these sites and undisturbed desert pavements to understand archaeological site formation and pavement development and recovery. Our results indicate these pavements and their soils are poorly developed regardless of their age. We propose that this is because of sustained lack of rain and extreme physical breakdown of clasts by salt expansion. Thus, the core of the Atacama provides an example of the lower limits of rainfall (<50 mm/yr) needed to form desert pavements. At site Quebrada Maní 12 (QM12), humans destroyed the pavement. After abandonment, human-made depressions were filled with eolian sands, incorporating artifacts in shallow deposits. Small and medium-sized artifacts preferentially migrated upwards, perhaps due to earthquakes and the action of salts. These artifacts, which now form palimpsests at the surface, helped – along with older clasts - to restore surface clast cover. Larger archaeological features remained undisturbed on top of a deeper Byzm horizon. The vesicular A horizons (Av horizons) have not regenerated on the archaeological sites due to extreme scarcity of rainfall during the Holocene.

The new mineral antofagastaite, ideally Na2Ca(SO4)2·1.5H2O, was found in the oxidation zone of sulfide–quartz veins at the abandoned Coronel Manuel Rodríguez mine, Mejillones, Antofagasta Province, Antofagasta Region, Chile. It is associated with sideronatrite, metasideronatrite, aubertite, gypsum, ferrinatrite, glauberite, amarillite and an unidentified Fe phosphate. Antofagastaite occurs as prismatic crystals up to 0.5 mm × 1 mm × 5 mm, elongated along [010], typically combined in open-work aggregates up to 1 cm across. Antofagastaite is transparent and colourless, with vitreous lustre. It is brittle; the Mohs’ hardness is ca 3. Cleavage is distinct on (001). Dmeas. is 2.42(1) and Dcalc. is 2.465 g cm−3. Antofagastaite is optically biaxial (–), α = 1.489(2), β = 1.508(2), γ = 1.510(2) and 2Vmeas. = 40(10)°. The IR spectrum is reported. Chemical composition (wt.%, electron microprobe, H2O determined by gas chromatography) is: Na2O 20.85, CaO 17.42, SO3 52.56, H2O 7.93, total 98.76. The empirical formula (based on 8 O atoms belonging to sulfate anions per formula unit with all H belonging to H2O molecules) is Na2.06Ca0.95S2.01O8·1.35H2O. Antofagastaite is monoclinic, P21/m, a = 6.4596(4), b = 6.8703(5), c = 9.4685(7) Å, β = 104.580(4)°, V = 406.67(5) Å3 and Z = 2. The strongest reflections of the powder XRD pattern [d, Å (I, %) (hkl)] are: 9.17 (100) (001), 5.501 (57) (011), 3.437 (59) (020), 3.058 (43) (003), 2.918 (50) (2¯11), 2.795 (35) (013) and 2.753 (50) (121, 201). The crystal structure was solved based on single-crystal X-ray diffraction data, R1 = 5.71%. The structure of antofagastaite consists of ordered and disordered blocks and is related to syngenite K2Ca(SO4)2·H2O. Incorporation of additional H2O molecules in the syngenite-type structure results in disorder of the one of the two tetrahedral sulfate groups occurring in antofagastaite. In addition to the above-reported type material, antofagastaite together with syngenite and blödite occurs in the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia.

A previously undocumented type of wetland is described from the Atacama Desert in northern Chile (3000 m above sea level), sustained exclusively by direct precipitation and perched above the regional water table. Geomorphological mapping, pedostratigraphy, geochemistry, and analysis of contemporary vegetation is used to understand wetland formation and dynamics during historical and present time periods. The paleowetland deposits overlie a Miocene tuff that acts as an impermeable barrier to water transfer and creates conditions for local shallow ground water. These deposits include several paleosols that were formed during periods when precipitation increased regionally at 7755–7300, 1270, 545, and 400–300 cal yr BP. The similarity in timing with other palaeohydrological records for the Atacama implies that paleosols from this wetland are proxies for reconstructing past changes in local and regional hydrological cycle. Archaeological investigations have revealed the presence of two small farms from the Late Intermediate period, i.e., during the earliest wetter phase represented by the paleosols. Both farms are located near the paleowetland deposits, which suggests that local inhabitants exploited these water sources during late pre-Hispanic times. Results of this study improve knowledge of settlement patterns during this and earlier cultural periods.

El Médano-style rock art from the Atacama Desert coast in Chile provides one of the most spectacular and expressive representations of ancient marine hunting and maritime traditions. These red pictographs comprise hundreds of hunting scenes and portray a complex marine hunter-gatherer society. This study presents the discovery of El Médano pictographs from new sites—in particular the Izcuña ravine—and seeks to understand further the processes of marine hunting and the interspecies relationships between hunter and prey. When combined with archaeological evidence, this analysis provides important new information concerning the value and significance of this rock art to those ancient hunter-gatherers.

Pica 8 is a Late Intermediate Period (AD 900–1450) cemetery located in the Atacama Desert. Burials at the site present unexpectedly high variability in δ13C (–8‰ to –16‰) and δ15N (10‰ to 24‰) values in their skeletal tissues, implying highly diverse diets. There are two possible explanations for this variability: the first is diachronic change in diet while the second involves synchronic sociocultural distinctions. To distinguish between them a radiocarbon (14C) dating program (n=23) was initiated. The presumed importance of marine foods adds the complication of a marine reservoir effect. To address this problem, paired 14C dates were obtained on human bone and camelid textiles from nine graves. The results fall into two groups, one showing an average offset of 117±9 14C yr, and the other no statistically significant offsets. We conclude that the contribution of marine foods to bone collagen at Pica 8 was less than previously supposed. Other factors must be invoked to account for the unusually high human δ15N values at the site. Manuring crops with sea-bird guano emerges as a probable explanation. No relationship with chronology is seen implying the presence of considerable diversity in diets and hence lifeways within the Pica 8 community.

We estimated visitors’ willingness to pay (WTP) for a variety of environmental attributes in a protected area of the Atacama Desert, a biodiversity hotspot in northern Chile. By using a choice experiment, WTP was estimated for the protection of the following attributes: animals (mammals, amphibians, reptiles and birds), pollinating insects, plants (cacti and woody shrubs), soil quality and pristine landscapes. Visitors placed economic value on all of the attributes. The marginal mean WTP/visitor for the single levels of variation in the attributes ranged from US$4 (for supporting research on foxes) to US$26 (for maintaining soil quality) per visitor per month. These results can contribute to deciding which attributes are likely to be successful at raising funds for conservation. Our approach may be relevant to protected areas of the world with high conservation values, little funding and a lack of large, charismatic species.

In this study, we present grain-size distributions of the terrigenous fraction of two deep-sea sediment cores from the SE Atlantic (offshore Namibia) and from the SE Pacific (offshore northern Chile), which we "unmix" into subpopulations and which are interpreted as coarse eolian dust, fine eolian dust, and fluvial mud. The downcore ratios of the proportions of eolian dust and fluvial mud subsequently represent paleocontinental aridity records of southwestern Africa and northern Chile for the last 120,000 yr. The two records show a relatively wet Last Glacial Maximum (LGM) compared to a relatively dry Holocene, but different orbital variability on longer time scales. Generally, the northern Chilean aridity record shows higher-frequency changes, which are closely related to precessional variation in solar insolation, compared to the southwestern African aridity record, which shows a remarkable resemblance to the global ice-volume record. We relate the changes in continental aridity in southwestern Africa and northern Chile to changes in the latitudinal position of the moisture-bearing Southern Westerlies, potentially driven by the sea-ice extent around Antarctica and overprinted by tropical forcing in the equatorial Pacific Ocean.

Rodent (Abrocoma, Lagidium, Phyllotis) middens collected from 2350 to 2750 m elevation near Arequipa, Peru (16°S), provide an ∼9600-yr vegetation history of the northern Atacama Desert, based on identification of >50 species of plant macrofossils. These midden floras show considerable stability throughout the Holocene, with slightly more mesophytic plant assemblages in the middle Holocene. Unlike the southwestern United States, rodent middens of mid-Holocene age are common. In the Arequipa area, the midden record does not reflect any effects of a mid-Holocene mega drought proposed from the extreme lowstand (100 m below modern levels, >6000 to 3500 yr B.P.) of Lake Titicaca, only 200 km east of Arequipa. This is perhaps not surprising, given other evidence for wetter summers on the Pacific slope of the Andes during the middle Holocene as well as the poor correlation of summer rainfall among modern weather stations in the central Andes-Atacama Desert. The apparent difference in paleoclimatic reconstructions suggests that it is premature to relate changes observed during the Holocene to changes in El Niño Southern Oscillation modes.

Plant macrofossils from 33 rodent middens sampled at three sites between 2910 and 3150 m elevation in the main canyon of the Río Salado, northern Chile, yield a unique record of vegetation and climate over the past 22,000 cal yr BP. Presence of low-elevation Prepuna taxa throughout the record suggests that mean annual temperature never cooled by more than 5°C and may have been near-modern at 16,270 cal yr BP. Displacements in the lower limits of Andean steppe and Puna taxa indicate that mean annual rainfall was twice modern at 17,520–16,270 cal yr BP. This pluvial event coincides with infilling of paleolake Tauca on the Bolivian Altiplano, increased ENSO activity inferred from a marine core near Lima, abrupt deglaciation in southern Chile, and Heinrich Event 1. Moderate to large increases in precipitation also occurred at 11,770–9550 (Central Atacama Pluvial Event), 7330–6720, 3490–2320 and at 800 cal yr BP. Desiccation occurred at 14,180, 8910–8640, and 4865 cal yr BP. Compared to other midden sites in the region, early Holocene desiccation seems to have happened progressively earlier farther south. Emerging trends from the cumulative midden record in the central Atacama agree at millennial timescales with improved paleolake chronologies for the Bolivian Altiplano, implying common forcing through changes in equatorial Pacific sea-surface temperature gradients.

This study reports the environmental conditions of temperature, moisture and radiation for four years (May 2004 to July 2008) in the area known as Pampas de La Joya in southern Peru, which recently has been considered as a new Mars analogue. The period of evaluation includes the El Niño Southern Oscillation (ENSO) during the months of September 2006 to March 2007, which, despite not having catastrophic effects like its predecessor on 1997–1998, showed an interesting increase in humidity. Our data describe the extreme conditions present in the region and their relationship with the presence of potential habitats that could allow for the survival of micro-organisms. The average environmental temperature was 18.9°C, with a maximum of 35.9°C and a minimum of −4.5°C. The annual average incident solar radiation was 508 W m−2, with high near 1060 W m−2 at noon during the driest period between September and March. The average relative humidity (RH) was 29.5, 20.1 and 20.4% for air, soil and rock, respectively. The RH had higher values at night due to fog during the months of June and August, and during the early morning between December and March. During the months of ENSO event there were four episodes of precipitation (1.1, 1.5, 2.0 and 0.9 mm), of which three increased soil and rock moisture on an average more than 45% and persisted for over 15 days after precipitation, while the atmospheric environment had no significant variations. Finally, quartz rocks and evaporite minerals colonized with micro-organisms were found as the only micro-habitats, in this region, capable of supporting life in this extreme environment.

In this ground-breaking study the author looks at three consecutive styles of rock art, placing them in the social context in which they were produced. Although necessarily succinct, the argument shows that as hierarchy increased and functioned over longer distances, rock art could perform as the organ of pastoralist authority, or the badge of marginalised hunters or, most often, as the imagery of consensus masking social inequality.