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The distribution of vos 'you' and uno 'one' in generic messages is studied in a corpus of female speakers of Spanish (Argentina).The question was how it is possible that the form vos , so clearly defined as the pronoun to refer to the interlocutor, could have an impersonal reading, alongside the indefinite pronoun uno , which seems much more fit to do the job. The alternation between the generic use of the forms vos and uno cannot be, in our view, the result of chance nor a merely stylistic tool, but corresponds to the communicative strategies that speakers utilize in each and every context. This paper studies the different factors that play a role in the selection of each of the pronouns. • Vos 'you' and uno 'one', used in generic messages, have different meanings, resulting in different interpretations. • Linguistic forms have single meanings, but may have different interpretations in different contexts. • The single meaning is a clue for a given interpretation. • Generic vos 'you' refers to the hearer: 'you in my place'. •Generic uno 'one' refers to the speaker: '(some)one like me'. [ABSTRACT FROM AUTHOR]

In order to understand the paleogeographic evolution of Viedma Lake (252 masl) sedimentary sequences with glaciolacustrine and lacustrine strata between 307 masl and 266 masl and bathymetric fluctuations between 27 ka. and 2.4 ka. were identified. The paleoenvironmental interpretation of the stratigraphic profiles was carried out based on the analysis of facies and their associations. The oldest age was recorded at 301 masl (27 ka) and the youngest corresponds to 266 masl (2.4 ka). The record of 27 ka was compared with another dated record of the Tar-San Martin Lakes basin showing that Viedma – Tar-San Martín Lakes were formed at similar ages. Taking into account that the deposits of Bahía Túnel are located at 266 masl and that the level of the lake would be above this height, it is proposed that this lake level would have restricted the movement of hunter-gatherer populations along the coast and to the west. From 2.4 ka on a new space started to be available for these populations broadening the wintering grounds (≤400 masl). The chronology of the archaeological record found in this new space fits the proposed paleogeographic evolution. This paper complements the research on the evolution of lacustrine systems in the Patagonian Mountain range and broadens the discussion of human mobility in the Viedma Lake basin during the Holocene. [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]

• New mathematical model that couples biophysical and biotic interactions was generated. • We performed numerical simulations of the dynamics of 12 rodent species from Patagonia. • The model showed population dynamics combining information on species with field data. • The composition of species is driven by predation and interspecific competition. • Species were showed different on its own than in presence with other species. Species distribution models (SDM) are the spatial surrogate of the suitability of a species in the biophysical aspect, since they are based on predicting their presence using climatic and environmental indicators. SDMs are satisfactory at regional scales, where biological interactions such as predation and competition do not influence distribution. However, at the local scale, they are incomplete for characterizing the ecology of a species since the algorithms do not include information about biotic variables. In this paper, we present a mathematical model that couples biophysical and biotic interactions in a spatially explicit way. We used a distributional database of 12 species of sigmodontine rodents from Argentine Patagonia as a study case. We performed numerical simulations of the dynamics of each rodent from a stochastic and spatially explicit population model. The biophysical suitability of each species was modeled using Maxent, which generated an indicator of its patch colonization capacity. The vegetation cover of each patch was characterized with remote sensing indices, associating the coverage with the pressure of aerial predation. The effect of interspecific competition was modeled from the assembly rules. The initial occupation conditions for each species were proposed as known sites of occurrence, and the temporal evolution of these systems was compared with that obtained from using random initial occupation conditions. The obtained results not only enrich the characterization of the studied ecosystems but also underscore a remarkable predictive capacity. Aerial predation and competition for resources, in accordance with assembly rules, dynamically modify populations and their distributions, revealing intricate interdependencies among species. This novel modeling tool holds promise for forecasting potential ecological scenarios, providing valuable insights into the intricate web of species interactions and their influence on distribution patterns. [ABSTRACT FROM AUTHOR]

The Magallanes-Austral Foreland Basin preserves an important record of orogenesis and landscape evolution in the Patagonian Andes of Chile and Argentina. This paper evaluates the comparison between the thick Paleogene sequences in the Chilean Peninsula Brunswick (Chorrillo Chico and Agua Fresca formations) and the reduced Paleogene sequence (La Barca Formation) in the Punta Ainol locality, Argentina, by taking account of palynological and geochemical analyses. Warm and humid subtropical conditions (Subtropical Gondwanic Paleoflora) are inferred for the late Paleocene-Eocene interval studied. A new record of Lactoridaceae in the La Barca Formation expanded the known fossil range of this family in Patagonia. During the late Paleocene the Chorrillo Chico and La Barca formations would have been deposited mainly from hyperpycnal flows and this accumulation process continued until the Lutenian in the La Barca Formation. A relative rise in the sea level in the early Eocene would be recognized in both sections. In the middle Eocene a relative fall in the sea level would have occurred with increased terrigenous influx. The rate of sedimentation was similar in both sections during the Thanetian and Ypresian intervals according to the ages assigned by biostratigraphy, suggesting that the sedimentation rate would have been controlled mainly by relative changes in sea level during the Paleocene-Eocene transition. Paleoenvironmental changes during the Paleocene-Eocene transition were characterized at the La Barca Formation of the Punta Ainol section, considering the new geochemical and palynological data provided in this contribution. • A new register of early Paleogene flora of Patagonia. • Paleogeographic changes based on palynological and geochemical data. • New geochemical inferences of the Paleocene-Eocene transition in South America. • A new Paleocene-Eocene record from Southern Hemisphere. [ABSTRACT FROM AUTHOR]

Due to its high efficiency and zero direct greenhouse gas emissions, the direct utilization of geothermal energy could play a crucial role in addressing climate change. Low-enthalpy geothermal projects, such as geothermal heat pumps (GHPs), have the potential to contribute to greenhouse gases reduction and replace polluting systems like wood burning, which are extensively used in countries such as Chile. The implementation of this technology presents various challenges, encompassing not only economic and technical aspects but also cultural and social factors. This paper addresses the latter two, providing empirical findings from a social and qualitative perspective by examining three GHP projects in educational spaces in Chilean Patagonia. An inductive approach was employed to describe the social perception of GHP projects in three public buildings, specifically educational facilities, located in the Aysén region of Chile. The questions that guided the research were how users interact with technology in these environments and what factors influence their acceptance. Data were collected through various methods, including in-depth interviews and participant observation, with a focus on social perceptions and everyday practices. The paper argues that there is a general lack of information regarding GHP technology. This type of system is often perceived as an 'elegant' and almost 'untouchable' technology. Nevertheless, motivational factors such as preventing deforestation and reducing air pollution were identified as the primary drivers supporting this type of initiative. One of the cases studied, which demonstrated sustainability over time, revealed that the participants' main motivation was to see themselves as agents of change. This allowed them to build a coherent narrative around the project. Consequently, the cultural meaning attached to the new practice became central for change and sustained adoption of social practices. • There is a social distance between GHP technology and local communities. • There is a low level of information about geothermal energy. • Sustainable adoption of GHP requires cultural and social changes. • GHP projects require the development of new skills and monitoring activities. [ABSTRACT FROM AUTHOR]

Abstract The main aim of this paper is to evaluate if certain processes that were documented in a specific area of Central-Southern Patagonia during the Late Holocene were also registered in a broader spatial scale. Previous investigations carried out in our study area located in Central-Western Santa Cruz province, Patagonia, have stated that climatic fluctuations during the Late Holocene (last 2500 years) were the cause of a reduction of hunter-gatherers' residential mobility. The new climatic conditions were characterized by important environmental droughts, which increased during the Mediaeval Climatic Anomaly, circa 900 years BP. This reduction in mobility resulted in concentrations of populations in low altitude basins and increased logistical and seasonal mobility, defined as a process of extensification. In this paper we take a broad spatial perspective to evaluate to what extent the low residential mobility identified in our research area had a correlation in a larger regional scale. Also we assess if this lead to a regional differentiation among hunter-gatherer populations, previous to European contact (450 years BP). In order to achieve these aims, we undertake a coarse grain analysis, using available data published on the composition and distribution of the archaeological record for Central-Southern Patagonia, an area of about 450.000 km2. Specifically, we consider evidence about technology, zooarchaeology, rock art, mortuary record and paleodietary studies. The analysis indicates that a reduced residential mobility could have occurred in certain areas of the study region, linked to the aforementioned climatic changes. On the issue of regional differentiation, the archaeological record highlights the complexity of this process. There are a variety of arguments both for and against the idea of a process of regionalization in Central-Southern Patagonia in the Late Holocene. We propose a process of differentiation of populations with low residential mobility which nonetheless remained connected through the circulation of goods, information and people. [ABSTRACT FROM AUTHOR]

In June 1986, the news on the discovery of high critical temperature superconductivity at IBM, Switzerland, by the physicists Bednorz and Müller, reached the laboratories at the Bariloche Atomic Center in the Argentine Patagonia. The expertise in experimental techniques at low temperatures led by Paco de la Cruz and his team and also in crystal growth led by Daniel Esparza and his group, were important to reproduce the results in a question of a few months. This discovery produced enormous enthusiasm in the community and incentivized research in these materials in other laboratories and theoretical groups at the Bariloche Atomic Center, which had already a vast experience and trajectory in materials science. In this paper I will delve on how this striking discovery fostered theoretical and experimental research in Bariloche which lasts until today. [ABSTRACT FROM AUTHOR]

Well-preserved and diverse Early Cretaceous palynological assemblages were studied from an outcrop section of the Springhill Formation at the Río Correntoso locality (PRC), close to Ghío Lake, in Santa Cruz Province, Patagonia, Argentina. The studied log corresponds to the northernmost outcrops known for the Springhill Formation in the Austral Basin. Most of the palynomorphs algae (Botryococcus, Sphaeroplea, Lecaniella, Zygnema, Pseudoschizaea, Schizosporis, Ovoidites), and some angiosperm pollen grains (Proxapertites , Longapertites, Arecipites) are distinctive and characterize the palaeoenvironment and palaeoclimate of PRC, which was dominated by estuarine coastal margin sedimentites deposited under warm and humid conditions. These angiosperm pollen grains correspond to the earliest record of these group in Patagonia, represented by diverse monosulcates and one rare tricolpate type. This new record of angiosperm pollen in the Springhill Formation provides further evidence that one of the earliest diversifications of angiosperms started at least during the early Cretaceous in Patagonia. Sergio Archangelsky provided an invaluable expertise in the field of paleobotany in multiple ways. His knowledge transcended not only through his papers but also through his exceptional oratory skills. His talks were always enriching in every aspect, combining an engaging historical account with a vision towards the future. "...La paleobotánica un placer, debe ser algo agradable, es decir uno cuando trabaja en paleobotánica le gusta lo que hace, y cuando uno está describiendo, uno se va, y es lo mismo que componer una pieza musical, te perdés, te perdés en todo y lo hacés con gusto, con pasión..." "...The paleobotany is a pleasure, it should be something enjoyable, meaning that when you work in paleobotany, you love what you do. And when you're describing, you get lost, just like composing a musical piece. You lose yourself, in everything, and you do it with pleasure, with passion...". The file with the voice of Sergio Archangelsky is in Supplementary file under Sergio_Archangelsky.mp3. • The palynoflora of the Springhill Formation includes algae and land plants. • Pollen records show features of early members of some taxa (monocots and eudicots). • Angiosperm pollen grains provides evidence for early radiation of some basal taxa in Patagonia. • Palynoflora studied indicates freshwater palaeoenvironment, warm and humid climate. [ABSTRACT FROM AUTHOR]

Several foodborne diseases have been described in coastal populations from the past, many of them including parasitic infections related to marine diets. Considering this background, the strong relationship between hunter-gatherers from Patagonia and the marine species implies a possible source of parasitic infections and zoonotic risk. However, marine parasitic species have not been identified in archaeological sites from Patagonia so far. The aim of this paper is to propose the potential parasitic infections produced by the consumption of marine molluscs, fishes, birds and sea mammals by human populations from Patagonia during the Holocene, considering the current parasitic species identified in the Southern Atlantic Ocean. We searched in journal articles and book chapters for references of archaeological remains of molluscs, fishes, seabirds and marine mammals recorded in archaeological sites from the Atlantic coast below the 42nd parallel South. Afterwards, we surveyed all the macroparasites of marine origin identified by current parasitological research in the same species found in the archaeological record. We found that most of the marine species in the zooarchaeological record of Patagonia are currently hosts of many parasites. Some species of molluscs, fishes and pinnipeds are highly infected by larvae that are potentially hazardous for human health. Some of them are responsible for acute or chronic zoonotic diseases, with severe consequences depending on how the food was cooked, the amount of consumed parasites and the immune response of the host, in this case, humans. Fishes are host of several parasites related to anisakidosis and corynosomiasis. Sea lions species were also a potential source of the same zoonosis but also diphyllobothriasis. Molluscs are hosts of several parasitic species, but with less severe consequences for human health. On the other hand, birds are infected by adult parasites, without direct zoonotic importance. These findings, although limited by temporal and environmental variability, can provide a speculative overview about the potential influence of marine diets in the health of past hunter-gatherers of Patagonia, particularly if fishes, molluscs or marine mammals were consumed inadequately cooked. [ABSTRACT FROM AUTHOR]

Central Western Patagonia (CWP) is a key area for assessing long-distance procurement of high-quality obsidians throughout the Holocene given that almost all relevant types represented in the archaeological record are exotic to this region. By using surface and stratigraphic obsidian artifacts from archaeological sites compared to standards from known sources in Patagonia, this paper discusses the spatial and temporal distribution of this lithic material. Sampling was oriented to assemblages from deposits with radiocarbon-based time frames (10,700 − 300 cal BP). This paper presents geochemical (ICP-MS) analyses of 178 samples from 58 archaeological sites at 11 surveyed areas located along the Pacific coast, the Andean forest, and eastern steppe. Out of six potential sources, the Chaitén Volcano source (Los Lagos Region, Chile) dominates exclusively the occurrence of obsidians along the coastal fringe, while the Pampa del Asador source (PDA, Santa Cruz Province, Argentina) largely dominates (86% of samples) obsidian in the eastern steppe and the forest/steppe ecotone. This broad distribution is explained by the presence of the densely forested Andean mountain range acting as a biogeographical barrier. East of the Andes, we recorded an absolute dominance of PDA south of 45°30′S, while more variability prevailed north of this point. The highest diversity of obsidians was recorded in the Cisnes River valley, probably because it is located closer to other alternative northern sources (Telsen/Sierra Negra, Sacanana and Angostura Blanca, all in Chubut Province, Argentina) and because it also hosts a local low-quality obsidian type. Based on this distribution, we discuss obsidian procurement behaviors by considering obsidian frequency and tool/debitage-class representation with increasing distance. We use the analysis of fall-off curves based on the distance of studied locations from the sources and include the use of least-cost paths for providing the most likely procurement routes. No obsidian diversification was recorded during the Holocene, hence the main driver for its procurement seems to be the distance from the source rather than the antiquity of its knowledge. Alternative procurement behaviors are discussed, specifically direct acquisition, exchange, and/or sporadic visits as mechanisms for explaining the archaeological patterns throughout the Holocene. [ABSTRACT FROM AUTHOR]

Factors affecting cetacean preservation and distribution in ancient sedimentary successions are not well understood. Actualistic studies have focused on coastal and deep marine examples, and little is known about taphonomic processes occurring within shelf environments. In this paper, we integrate sedimentological, taphonomic and palaeontological data for the cetacean-bearing lower Miocene Gaiman Formation from Patagonia, Argentina, to analyse which factors affected the distribution and preservation of cetaceans in several localities of the Southwestern Atlantic. Facies analysis shows that the formation represents a transgressive-regressive stratigraphic cycle, with palaeoenvironments including coastal, storm-dominated shoreface, inner shelf embayment and open inner shelf. Cetacean remains show preservation styles varying from isolated elements to articulated specimens, with nearly all remains restricted to both embayment and open marine inner shelf settings. Two fossil cetacean assemblages are recognized: Assemblage A comprises small-sized odontocetes dominated by Platanistoidea, preserved mostly in inner shelf embayment deposits; and Assemblage B comprises large-sized odontocetes and mysticetes, dominated by Physeteroidea and Balaenopteroidea, preserved mostly in open inner shelf deposits. Cetacean preservation style is controlled by a combination of palaeoenvironmental conditions, such as energy and sedimentation rate, and by biological factors, such as cetacean body plan and its impact on carcass buoyancy. Ecological factors may also explain the stratigraphic distribution of cetaceans between coastal and oceanic assemblages. This novel integrative and multidisciplinary analyses improves our knowledge of cetacean taphonomy in shelf environments. • Four coastal and shelf marine facies are identified for the lower Miocene Gaiman Formation of Argentina. • Cetaceans are mostly recorded in inner shelf deposits. • Cetacean preservation style is controlled by environmental and biological factors. • Cetaceans distribution is mostly controlled by palaeoecological factors. [ABSTRACT FROM AUTHOR]

Drylands occupy 31% of the South America. Although diverse, the soils in these environments are fragile and highly vulnerable to anthropogenic pressures. In this study, bibliometric techniques were used to analyze 3309 papers published on soil science in the Caatinga, Patagonia, Gran Chaco, and Atacama Desert, aiming to understand the evolution, map the produced knowledge, and identify future trends of soil science research in the dry environments of South America. The database was obtained from the Web of Science Core Collection, considering the period 1992–2022. Data analysis was performed using regression analysis, descriptive statistics, and cluster analysis. The results indicated that the Caatinga was the biome with the highest number of publications on soil science (n = 1203), followed by Patagonia (n = 1096), Atacama (n = 644), and Gran Chaco (n = 366). EMBRAPA in Caatinga (16.2%), CONICET in Patagonia (55.2%), and the Gran Chaco (42.9%), and NASA in Atacama (15.9%) were the institutions with the highest number of published studies. Citation analysis indicated the strong influence of soil science research conducted in the Atacama for global scientific research, especially in studies related to geochemistry, soil microbiology, and the existence of life on other planets, given the physical-climatic similarity between this environment and the planet Mars. In the Caatinga, research was more related to agriculture (58.0%), while in Patagonia (41.9%) and Gran Chaco (37.4%), research was related to environmental sciences and ecology, as a result of the high level of environmental degradation observed in these environments. In general, the development and use of biological indicators of soil quality and health, subjected to various degradation types (agriculture, overgrazing, deforestation, burning, mining) and climate change, as well as the biotechnological potential of the soil microbiota found under conditions of greater water deficit (arid and hyper-arid regions), can be considered as the main trends of soil science research in the studied environments. The results of this study may be useful for conducting new research and collaborations that contribute to the sustainable use of soils in the dry environments of South America. • Soil science research in the dry environments of South America was reviewed. • Soil science research in the Caatinga accounted for 36.6% of the total studies. • Gran Chaco soils have been the least studied. • Soil science research in the Atacama has shown greater global interest. • Soil microbiology can be considered as the main research trend. [ABSTRACT FROM AUTHOR]

The present paper reports the first paleoparasitological results obtained from coprolites of fossil rodent middens and demonstrates the potential of rodent middens as a source of paleoparasitological evidences in South America. Ten fossil rodent middens from northwestern Patagonia, Argentina, were studied. Five coprolites of each midden were fully processed, rehydrated, homogenized, subjected to spontaneous sedimentation, and examined through light microscopy. Eight of the 10 examined rodent middens contained parasite eggs. The eggs of parasites were assigned to Heteroxynema ( Cavioxyura ) viscaciae Sutton & Hugot, 1989 and Helminthoxys sp. (Nematoda: Oxyuridae), Trichuris sp. (Nematoda: Trichuridae) and one unidentified nematode. Fossil rodent middens were assigned to Lagidium viscacia (Caviomorph: Chinchillidae). The excellent preservation of parasite remains in coprolites from fossil rodent middens provided an opportunity to perform paleoparasitological inferences. The results of this papers demonstrates that fossil rodent middens offer an excellent opportunity for the recovery of parasite remains for future paleoparasitological studies in the southwest of South America. [ABSTRACT FROM AUTHOR]

The Cenomanian–Turonian is considered the warmest interval of the last 150 million years. It was characterized by major disturbances to the global carbon cycle, resulting in elevated pCO 2 levels and global temperatures, and witnessed the rise to dominance of angiosperms floras. In this paper, we assess changes of fossil floras during the Cenomanian–Turonian interval based on palynological studies of two distantly-spaced localities in high southern paleolatitudes: the Mata Amarilla Formation of Patagonia, southern South America and the Tupuangi Formation of the Chatham Islands, New Zealand. Richness estimations for each stratigraphic unit and cluster analysis were conducted to assess the vegetation changes. Palynological dominance and the presence/absence of taxa were compiled for these units and compared with others from the Cenomanian of southern Gondwana. We recognize a peak in richness during the Mid-Cenomanian Event in Patagonia, with a fall in richness after the event due to species being displaced by dominant taxa. Several richness peaks are also recognized in New Zealand, but the lack of stratigraphic control prevents correlation with marine-based events. Oceanic Anoxic Event 2 is not recorded in either study area. The inclusion of Gondwanic palynological records demonstrate that the Tupuangi Formation cluster with sites from the Antarctic Peninsula and south-eastern Australia conforming a 'polar cluster'. However, this area has its own palynological signature, constituting a newly proposed Taxodiaceaepollenites Subprovince. The abundances of key plant groups of the Mata Amarilla Formation cluster with those of Bathurst Island (northern Australia), but also show important differences, likely owing to their geographic separation and latitudinal difference. In summary, our paper presents a new scheme for the mid-Cretaceous palynological provinces of Southern Gondwana and provides novel data sets for Patagonia and New Zealand, which can be used as reference points for palynological and paleoecological studies of coeval floras worldwide. • A peak of richness is described for the mid-Cenomanian Event in Patagonia. • After the mid-Cenomanian Event Patagonian palynofloras show a decrease in richness. • Five richness peaks are described for the Cenomanian–Turonian of New Zealand. • The Taxodiaceaepollenites Subprovince is proposed for New Zealand palynofloras. • Angiosperms are small portion of Gondwana palynofloras during Cenomanian–Turonian. [ABSTRACT FROM AUTHOR]

Abstract Glacial Lake Outburst Floods (GLOFs) have become increasingly common over the past century in response to climate change, posing risks for human activities in many mountain regions. In this paper we document and reconstruct the sequence of events and impact of a large GLOF that took place in December 2015 in the Chileno Valley, Patagonia. Hydrograph data suggests that the flood continued for around eight days with an estimated total discharge of 105.6 × 106 m3 of water. The sequence of events was as follows: (1) A large debris flow entered the lake from two steep and largely non-vegetated mountain gullies located northeast of the Chileno Glacier terminus. (2) Water displaced in the lake by the debris flow increased the discharge through the Chileno Lake outflow. (3) Lake and moraine sediments were eroded by the flood. (4) Eroded sediments were redistributed downstream by the GLOF. The post-GLOF channel at the lake outlet widened in some places by >130 m and the surface elevation of the terrain lowered by a maximum of 38.8 ± 1.5 m. Farther downstream, large amounts of entrained sediment were deposited at the head of an alluvial plain and these sediments produced an ~340 m wide fan with an average increase in surface elevation over the pre-GLOF surface of 4.6 ± 1.5 m. We estimate that around 3.5 million m3 of material was eroded from the flood-affected area whilst over 0.5 million m3 of material was deposited in the downstream GLOF fan. The large debris flow that triggered the GLOF was probably a paraglacial response to glacier recession from its Little Ice Age limits. We suggest that GLOFs will continue to occur in these settings in the future as glaciers further recede in response to global warming and produce potentially unstable lakes. Detailed studies of GLOF events are currently limited in Patagonia and the information presented here will therefore help to inform future glacial hazard assessments in this region. [ABSTRACT FROM AUTHOR]

This paper presents the paleogeographic reconstructions of flooded areas of the Tar - San Martín lacustrine system during the late Pleistocene - Holocene. The dimensions of lacustrine and glaciolacustrine levels of this basin are higher than the current levels of the lakes. The organic matter of lake levels recorded on stratigraphic profiles was described, sampled and dated using AMS, while other paleobathymetric indicators were also identified (height of the fan-delta apex and paleo-coast levels). Deriving out of the reconstruction of flooded areas it was established that the lake system was formed before 28 ka ago and would have reached its maximum expansion around 12 ka ago. The first hunter-gatherer occupation of the basin (11 ka) corresponds to the period of initial contraction of the lake system and the composition of the current configuration of the coastlines. This scenario would have allowed the exploration of western areas and the gradual incorporation of the forest to the action range of hunter-gatherer populations. Similarly, the levels of lakes Tar and San Martín would not have hindered the movement of human populations through the steppe throughout the Holocene. [ABSTRACT FROM AUTHOR]

Satellite Image Time Series are becoming increasingly available and will continue to do so in the coming years thanks to the launch of space missions which aim to provide a high spatial resolution coverage of the Earth every few days. Bio-optical characteristics and their variation over time have been poorly studied in the Patagonian shelf. In this paper, we present the trends of time series analysis from satellite images that allows us to interpret the variations of bio-optical properties throughout time and their implications for planktonic organisms. The annual and seasonal trends of six variables were analyzed for two different gulfs, Nuevo and San José, in northern Patagonia from January 2003–December 2021. We present the dynamic temporal changes of chlorophyll a (Chl a -sat) , phytoplankton absorption (Ab_phy), detritus absorption as well as environmental features changes for the sea surface temperature (SST), depth of the euphotic zone (Z_eu) and photosynthetically active radiation (PAR). We found positive trends for SST, Ab_phy at 443 nm and PAR, but negative for Z_eu in Nuevo and San José gulfs. The positive trendlines for SST and negative for Z_eu suggest less availability of nutrients and light. These trends could change the bloom phenology and modify the phytoplankton community structure with implications for the entire food web and the ecosystem services in the VBR. • The last two decades of satellite inherent optical data showed trends for a marine protected area of global importance. • Positive relationships were found for increased SST, PAR and phytoplankton absorption over time in VBR waters. • In contrast, a decrease in the depth of the euphotic layer was found with multiple possible explanations. [ABSTRACT FROM AUTHOR]

In this paper, the analysis of a radiocarbon database of the North Coast of Santa Cruz (central Patagonia, Argentina), is presented. Dated archaeological samples were obtained from 56 different types of archaeological sites (open-air -residential sites and burials-, and also rock shelters). The objective of this paper is assessing the continuities and discontinuities in the chronological signal of the area and identifying tendencies along the Holocene. The database currently contains 75 radiocarbon dates falling between ca. 8000 and 300 BP. The radiocarbon data base provides information on the chronological, spatial and contextual variability of the archaeological record of North Coast of Santa Cruz. By means of different analysis of sum of probabilities, we present three different chronological moments of human use of the coast and intermediate zone can be identified. A first moment is represented by early evidence of settlement during Middle Holocene. A second moment corresponds to a hiatus between ca. 5800 and ca. 3900 BP without archaeological evidence. Finally, a third moment is where an increasing of chronological signal occurred, related to greater artifactual variability and an increase in the intensity of human settlement in the Patagonian region. The causes that could have influenced in the discontinuity of the chronological signal of the study area, and the characteristics of the different moments identified are discussed. [ABSTRACT FROM AUTHOR]

Patagonia features the most extensive glaciers of the Southern Hemisphere, excluding Antarctica, and a vast inventory of glacial landforms, so it is thought to have played a key role in (paleo)glacier studies since the late 19th century. However, no systematic attempts to characterize the specific research trends and the scientific community focused on Patagonian cryosphere have been conducted so far. To fill this gap, we analyzed the metadata associated to 305 articles compiled from the Web of Science database following a bibliometric approach covering the period between 1976 and 2020. Our results point to an irregular but net increase on the number of contributions on Patagonian (paleo)glaciers. Mass balance analyses based on satellite data of present-day glaciers and the reconstruction of past glacier activity by dating glacial landforms formed during the Last Glacial Termination, were the most addressed topics during the analyzed period. Patagonian (paleo)glacier studies are mostly published in generic Earth Sciences publications, followed by Quaternary and glaciological journals. Most of the studies were led by scientists from the United Kingdom, followed by Chile, Argentina and United States. In terms of collaborations, these studies can be divided into two main clusters, one composed by researchers from United States, Chile and Argentina institutions, and another mostly composed by British researchers. So far, the most prolific authors are nearly equally distributed in nationality, yet gender inclusion and international collaborations are still caveats that must be solved. Even though our query on the Web of Science missed highly influential (so-called) grey literature, such as local scientific journals and technical reports, the reviewed scientific literature unambiguously indicates that Patagonia is a privileged location for (paleo)glaciers studies worldwide and that it will continue offering vast opportunities to tackle critical questions related to global cryosphere and past-to-present climate changes. • Patagonia is a privilege site for studying present and past glacier dynamics and the evolution of climate changes at hemispheric and global scale. • Glacier dynamics during the 20th century and and the Last Glacial Termination are the most common topics addressed in past decades in the WOS. • Patagonian (paleo)glacier studies has contributed to the development or improvement of diverse analytical techniques. • United Kingdom, United States, Chile and Argentina produced the largest number of WOS-listed papers on (paleo)glaciers in past decades. • The related scientific community is fairly heterogeneous. Although, inclusion and international collaboration issues still need to improve. [ABSTRACT FROM AUTHOR]

In this paper, we analyze the lithic assemblages from three sites from the Central Plateau of Santa Cruz in the Argentine Patagonia. Functional analysis was combined with a techno-morphological and distributional approach, the investigation on raw materials and the study of the technological strategies of production and consumption. The significance of combining functional analysis with other research methods involving lithic remains is emphasized. By articulating different methodologies, it is possible to understand the systems of technological organization. Two sites refer to Final Pleistocene occupations (Cerro Tres Tetas 1 and Casa del Minero 1). The integration of approaches showed the diversity of strategies developed in the production and use of tools, as well as the existence of activity areas within the sites. The third site is a Middle Holocene context (Cueva 13 of Los Toldos). The combination of perspectives allowed a redefinition of the toolkit structure and showed that blade production was part of a standardized technological system. [ABSTRACT FROM AUTHOR]

This paper presents the first attempt at qualitatively and quantitatively evaluating the sedimentary contribution of the Puna plateau to the loess and soils of the Argentinean Pampas. The origin of the Pampean sediment has been traditionally ascribed to northern Patagonia, but new evidence supports a dual supply: western Central Andes/North Patagonia and Puna/Altiplano Plateau. Three different lines of evidence show here that Puna dust supply is active and produces significant sedimentary deposition up to places like Buenos Aires city. The first evidence is meteorological and we show here one event related to an abnormal rainfall that deposited large quantities of a reddish-brownish silt eroded out from the Puna, calling the attention of the environmental agency of Buenos Aires city. The second evidence is the sampling of active wind transport collecting extremely coarse material carried out in the saltation layer, suggesting the fine grained material escapes the area as fugitive dust. This also demonstrates that observed gravel-bearing bedforms of the Puna are active, and that the transport system seems to be activated by polar fronts only. Results show that the saltation curtain is abnormally thick and coarse, suggesting that the kinetic energy peaks ca. 7–10 times higher than for normal saltation, while the transported grain size coincides with the lagged sediment in this basin composing different bedforms, varying between sandy gravel and gravelly sand. The third evidence is the quantification of the exported material by defining a reference surface as the initial time of evolution, and the present day surface. The initial surface is an alluvial surface of an estimated age of 11–12 ka. BP. Volume balance was achieved by a detailed topographic, stratigraphic and geophysical survey, reconstructing old alluvial and present surfaces. Two gridding methods were used, and more conservative results of the volume balance, indicate a total erosion of ca. 3.386 hm 3 of sediment in 72 Ha, spliced in 0.963 hm 3 of sediment that was left within the place forming gravel dunes, while the remaining volume of ca. 2.423 hm 3 is sediment truly exported from the surveyed area. Results imply a continuous blanket of ca. 4 m thick of sediment exported out of this basin in the Holocene. These findings prove that the Puna contribution to the Chaco-Pampean plain is significant, although not unique. Thus, true proportions of sediment contribution to soils and loess from these multiple sources should be better evaluated in future studies. [ABSTRACT FROM AUTHOR]

Even though mohair production in Argentina is well known, data about fibre production from double-coated regional native goats—generically referred to as Patagonian Cashmere-remains scarce. The aim of this paper was to determine the production of down fibres and to assess the quality and variability of the fleece characteristics of the Northern Patagonian Creole goats. From late winter to early spring of 2005–2008, 2397 fibre samples were collected from five areas of NW Neuquén in Northern Patagonia. The average of down fibre diameter (DFD), down fibre length (DFL), down weights (DW) yields to dehairing (Y%), ratio of coarse fibre length (CFL) on down fibre length (DFL) (R:CFL/DFL), crimp/cm and the degree of curvature (C°) of the fibre were measured. For DFD an average of 20.4 ± 3.6 μm, DFL of 7.9 ± 3.2 cm and C° of 38.1 ± 5.8°/mm, a Y% of 32.5 ± 13.9% and a DW of 255.7 ± 66.0 g were obtained. In an attempt to reduce the variability of the fibre variables studied, locality, herds, age, fleece types and fineness were included as external effects in ANOVA. All the variables measured were greatly affected by style: long cashmere (LC) was the most frequent style (41.5%) followed by cashgora (CG) (22.2%). The most common grade of fineness (57.5%) was >19.0 μm, indicating that 42.5% of the fibre was below 19 μm in DFD. The other variables were significantly different within LC, short cashmere (SC) and intermediate cashmere (IC) styles when the grade of fineness was compared. The styles with lustre effect (CG and L) showed very low crimp as compared to the other styles. Taking styles as numerical, a Spearman's rank correlation coefficient ( r s ) was calculated with numerical grade of fineness ( r s = 0.45), DFD ( r s = 0.58), DFL ( r s = 0.56) Y% ( r s = 0.61), R: CFL/DFL ( r s = −0.60); DW ( r s = 0.56); C°/mm ( r s = −0.27). It was concluded that the classification by styles and fineness could determine more than 42% of fleece complies with the cashmere textile industry requirements. [ABSTRACT FROM AUTHOR]

In this paper we focus on the regional/local scale of the archaeological record of the Central-West area of Chubut (Argentinean Patagonia) through the characterization of its regional taphonomy, considered from an archaeological perspective. We focus our research in the comparison of three different landscape situations: 1) a slope leading to highlands, 2) an azonal vegetal community (wetland or mallín ), and 3) a salt lake. Our main goal is to compare those situations, in order to determine the main taphonomic factors that regulate the archaeological material distribution in those locales. The ultimate goal is to address how past hunter–gatherers inhabited these landscapes. We depart from the assumption that distributions of artifacts are mainly explained by the action of post-depositional processes. To evaluate this assumption first we postulate a series of hypothesis and expectations for each locale, considering the main post-depositional agents present in them, and we evaluated if the patterns of material distributions can be explained by one or many of those processes. Only if explanation cannot be achieved by them, we recurred to human depositional activities. As a result we managed to explain most of the archaeological distributions in terms of post-depositional processes. Only in two cases we propose that human deposition occurred. [ABSTRACT FROM AUTHOR]

Permo-Triassic magmatism is widespread in the eastern North Patagonian Massif and has been related to the Gondwanide orogeny. Although a magmatic arc setting is widely accepted for the Permian plutonic rocks, the origin and geotectonic setting for the Triassic plutonic and volcanic rocks are still unknown. A NW-SE Triassic dyke swarm composed of andesites and latites with minor rhyolites was previously described in the Sierra Grande – Rincon de Paileman area. The dyke swarm was associated with extensional tectonics which was linked to a postorogenic process. In this paper we present new geochemical data of the rocks that form the swarm. Trachyandesites and rhyolites were separated based on their geochemical characteristics. Both groups may be considered originated from different sources. On the other hand, the content of incompatible elements (LILE and HFSE) indicates a strong relation between the swarm and an active continental margin. The samples also show a transitional signature between continental-arc and postcollisional or anorogenic settings. The new geochemical data on the dyke swarm support the idea of a magmatism that was linked to a postorogenic extensional tectonic regime related to a continental magmatic arc. Such an extension started in the Paleopacific margin of Pangea during the Anisian and might indicate the beginning of the Pangea break-up. [ABSTRACT FROM AUTHOR]

The May 22nd, 1960 Valdivia earthquake, Chile (Mw 9.5) triggered a series of subaqueous mass-wasting processes (debris flows and slides) in Lago Nahuel Huapi (Argentina), generating a tsunami-like wave that hit the coasts of San Carlos de Bariloche. Aiming to provide a first preliminary insight into tsunami hazards for the lakeshore communities, in this paper we identify and characterize the subaqueous landslides at the populated distal basin of the lake. Swath bathymetric and seismic profiling surveys were carried out and high-resolution digital elevation models were derived from these data to perform a landslide inventory map. A series of morphometrical parameters (including the landslide area, the volume of displaced materials and the run-out distance, among others) were estimated upon selected events. The results indicated that landslide activity at the distal basin of Lago Nahuel Huapi has been concentrated in the vicinity of Bariloche (massive landslide triggered by the 1960 earthquake) and within steep delta fronts where the slope failures typically initiate at shallow waters (9–11 m depth). The sliding mass frequently travels basinward along a great distance (≥ 1000 m). At the delta fronts, the volume of material removed by landslides can reach ~ 40 × 10 4 m 3 , leaving scar areas of up to 13 m thick. The periodic occurrence of rotational–translational mass movements initiating at the upper edge of the delta fronts, with vertical displacements of the mobilized materials reaching ~ 200 m, probably represents a potential tsunami hazard for the nearby populated coasts. [ABSTRACT FROM AUTHOR]

Abstract: This paper compares two zooarchaeological sub-samples, each of which comes from a different area (North chamber and South chamber) of Maripe Cave Site (Santa Cruz, Argentina). In previous papers, each chamber was interpreted as a particular microenvironment based on their specific environmental and geoarchaeological features. In both areas, hunting–gatherer society occupations were recorded since the Pleistocene–Holocene transition to late Holocene. This paper investigated and discussed the different agents and processes involved in the formation of each assemblage, with the aim of assessing the taphonomic variability between the two areas and discussing their integrity. Bone specimens of Lama guanicoe (guanaco), the most common species on the site, were analyzed. The bone surfaces of specimens were studied by naked eye observations and binocular magnifying to 10×, which allowed recognition of different patterns of modification. The representation of guanaco anatomical units was also discussed at each chamber according to economic utility and BMD values. The results indicate that while there was involvement of different natural agents and processes acted differently in each sector, the main accumulating agent in both sets was human. Differences between both chambers are observed in the representation of anatomical units, in processing marks, in the conservation of specimens, and in the number and intensity performed by each natural agents and process in each sector. Each chamber indicates a different taphonomic history: the North Chamber records greater conservation and archaeological integrity, while the South Chamber shows a more complex taphonomy. [Copyright &y& Elsevier]

Abstract: Chilean Patagonia is one of the most extended fjord regions in the world that covers nearly 240,000km2 with an extremely complex coastline and topography in one of the least densely populated areas of the country (1–8 inhabitants every 10km2). In recent years, the area has been undergoing somewhat intense pressure since several commercial projects in hydroelectricity, tourism, and commercial salmon and mytilid cultures have been developed, or are in progress. Concomitantly, several large research programs have been devised to study the physical, chemical, and biological environment of Patagonia, such as the CIMAR FIORDO, and recently COPAS Sur-Austral based at Universidad de Concepcion, that attempts to close the bridge between oceanographic knowledge and its use by society. In this introductory article we summarize the collection of papers comprising this Special Issue of Continental Shelf Research. These papers deal with aspects of regional oceanography and geology, inorganic and organic geochemistry, ecology of pelagic and benthic organisms, and past changes in productivity. [Copyright &y& Elsevier]

Understanding the timing of past glacial advances in Patagonia is of global climatic importance because of the insight this can provide into the influence on glacier behaviour of changes in temperature and precipitation related to the Southern Westerlies. In this paper we present new luminescence ages determined using single grains of K-feldspar from proglacial outwash sediments that were deposited by the Patagonian Ice Sheet around Lago Buenos Aires (∼46 °S), east of the contemporary Northern Patagonian Icefield. The new luminescence ages indicate that major outwash accumulations formed around ∼110 ± 20 ka to 140 ± 20 ka and that these correspond to the Moreno I and II moraine ridges, which were previously dated using cosmogenic isotope dating to 150 ± 30 ka. Luminescence dating at Lago Buenos Aires has also identified outwash sediments that were deposited during glacial advances ∼30.8 ± 5.7 ka and ∼34.0 ± 6.1 ka (MIS 3) that are not recorded in the moraine record. Younger outwash accumulations were then deposited between ∼14.7 ± 2.1 and 26.2 ± 1.6 ka which correspond to the Fenix I – V moraine ridges. The combined chronology suggests that glacial advances occurred ∼110 ± 20 ka to 150 ± 30 ka (MIS 6), ∼30.8 ± 5.7 ka to ∼34.0 ± 6.1 ka (MIS 3), and ∼14.7 ± 2.1 to 26.2 ± 1.6 ka (MIS 2) at Lago Buenos Aires. Overall luminescence dating using single grains of K-feldspar has excellent potential to contribute towards the ever-increasing geochronological dataset constraining the timings of glacial advances in Patagonia. [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]

The purpose of this paper is to begin to understand human mobility through rock transport at different times in two areas with different environmental characteristics: the Southern Deseado Massif and the basaltic canyons north of the Santa Cruz River. We focus on obsidian, which has a clear geochemical signature and an uneven distribution. Additionally, we use macroscopic information on siliceous rocks, which at present have only been identified in northern areas, although they may also be recovered randomly and in low frequencies in southern ones. During the initial peopling of the Southern Deseado Massif (ca. 10,800 BP), inhabitants were transporting black obsidian as well as translucent chalcedony, probably as part of the individual gear. During the Late Holocene, the number of obsidian artifacts decreased in the Southern Deseado Massif, related to a better knowledge of the high-quality local lithic resources and/or to the existence of higher population densities. Obsidian artifacts are more abundant in the northern Santa Cruz River basin than in the southern Deseado Massif, suggesting the existence of a relationship with areas located to the northwest, close to the obsidian source, as other lines of evidence suggest. In addition, the presence in the basaltic canyons of artifacts made from high-quality siliceous rocks, more abundant and predictable in northern areas, could also be the result of human movements following a north-south direction. [ABSTRACT FROM AUTHOR]

Paleoparasitology is the study of parasite remains from archaeological and paleontological sites. Raptor pellets can be used as source for paleoparasitological information in archaeological sites. However, this zooarchaeological material has been scarcely studied. Epullán Chica (ECh) is an archaeological site in northwestern Patagonia. This cave yielded remains from more than 2000 years before present. The aim of this paper was to study the parasite remains found in owl pellets from the archaeological site ECh, and to discuss the paleoparasitological findings in an archaeological context. Twenty two raptor pellets were examined for parasites. The pellets were whole processed by rehydration in a 0.5% water solution of trisodium phosphate, followed by homogenization, filtered and processed by spontaneous sedimentation. Eight out of 22 bird pellets examined were positive for parasites from reptiles and rodents. Representatives of 12 parasite taxa were recorded; nine of this parasitic species were reported for the first time from ancient samples from Patagonia. This is the first time that pellets give evidences of ancient reptile parasites from archaeological contexts. It is noteworthy that Late Holocene hunter-gatherers of the upper Limay River basin, could have been exposed to some of these zoonotic parasites. Future paleoparasitological studies on owl pellets may reflect even more the parasitological diversity of all micromammal and reptile species presents in ancient times. [ABSTRACT FROM AUTHOR]

• Glaciomarine environmental stress produce a decreasing in the OM availability. • Sedimentation of terrestrial OM contributed with a significant fraction of total OM. • Soft-bottom benthic communities exhibited a species richness longitudinal gradient. • The C/N ratio in benthic fauna suggest preferential organic carbon use. The benthic community in the Chilean Patagonia is as rich and highly diverse as the spatial variation of its habitats and food sources. Environmental stress from glacier melt and river discharge are known drivers of benthic community dynamics. Here, we analyze longitudinal patterns of soft-bottom benthic communities across transects of glacier-marine environments and how these habitats may respond to changes in the environmental conditions. To assess the relationships between environmental heterogeneity (marine and glacial habitats) and benthic biodiversity, this paper reviews biological (mega- and macroinfauna) and sedimentological dataset from multiple oceanographic campaigns in Chilean Patagonian fjords. Furthermore, we analyze isotopic compositions of epibenthic and macroinfaunal organisms (δ13C/δ15N and C/N) to determine particulate organic carbon (POC) and particulate organic nitrogen (PON) availability and organismal stoichiometric budgets within each benthic community. Our results showed that glaciomarine and glaciofluvial environmental stress negatively affected nutrient reservoirs and organic matter (OM) availability, and hence produced changes in benthic diversity and trophic structure throughout the fjords. These conditions shaped the benthic community where small-bodied polychaetes and opportunistic species dominated. Additionally, we found a strong relationship between OM and nutrient availability with faunal isotopic composition, but a decoupling in C/N ratios between fauna and sediment OM, suggesting preferential organic carbon use under limited nitrogen in fjord sediments. [ABSTRACT FROM AUTHOR]

Lama guanicoe (Müller, 1776) is one of the most important South American large mammal species for both biologists, ecologists and archaeologists, and body size of modern and prehistoric populations of guanaco has been one of the most studied parameters. In this paper, we evaluate the latitudinal differences in body size of different modern populations of guanaco from Argentinean Patagonia based on osteometric data of their long bones. The osteological sample is made of 110 fully-fused individuals drawn from three different guanaco populations from continental and insular Patagonia covering the latitudinal interval from S40° to S54.5°. Quantitative data for the four long bones selected are analyzed with univariate and multivariate parametric statistical techniques. Apparently consistent with Bergmann's rule, results show that guanaco specimens from S53–54.5° are bigger on average than those from S48–52° which are, in turn, bigger than those from S40°. We observe a high and significant covariation between different environmental variables (maximum temperature, net primary production, and winter precipitation) and body size of the guanaco populations. Nevertheless, when the temporal factor is incorporated into the analysis of this geographical gradient of body size the scenario becomes more complex. We conclude that the current clinal pattern observed in Patagonia is the result of several microevolutionary and biogeographic processes related to an adjustment of body size to different environmental and ecological drivers and to the consequences of isolation in Tierra del Fuego that occurred around the Pleistocene-Holocene transition. [ABSTRACT FROM AUTHOR]

Archaeological radiocarbon databases are being increasingly used as a proxy of past demographic trends. In this paper we compile and analyze an extensive database of paleoecological information and 14 C dates from archaeological sites in northwestern Patagonia (Argentina, South America). On this basis, we assess the regional distribution of human populations since the late Pleistocene, and their relation with the evolution of Patagonian climate and landscapes. We explore the spatial and temporal distribution of evidence and discuss sampling biases affecting the record in different ecological contexts. The analysis is set in the frame of three main ecological regions that have implications for human subsistence: Andean forest, grass steppe, and shrub steppe. The intensity of the archaeological signal differs among these regions through time, being stronger and more homogeneous in the grass steppe. In the Andean forest and the shrub steppe the signal is weaker and even absent during short periods of the middle Holocene. We suggest likely sampling biases contributing to these tendencies, since these three regions present variable research cover and intensity. On the other hand, we also suggest that these differences may reflect variations in the intensity of human occupation, in favor of more attractive environments for hunting (i.e., areas where guanaco are generally more abundant). This macro-regional synthesis of the paleoecology and archaeology of northwestern Patagonia provides a platform for developing future oriented research. [ABSTRACT FROM AUTHOR]

This paper summarizes and discusses the main results achieved over three decades of research on paleodemographic aspects of Late Holocene hunter-gatherers in Northwestern Santa Cruz (Argentina). Research has been guided by a model of regional settlement that proposes that, as a result of the progressive aridization process recorded in Patagonia during the Late Holocene, human groups would have reduced their residential mobility and concentrated their settlements in low altitude basins with water availability, such as Lake Cardiel and Lake Salitroso. Paleodemographic questions derived from the model relate to population regional continuity and dynamics and were tested using several lines of research at regional and local scales. The assessment of the chronological information and temporal trends of the archaeological record at the regional level allowed for a coarse grain paleodemographic approach, and acted as a mean to support hypotheses related to changes in mobility and land use strategies. Building on this, several lines of bioarchaeological evidence were used to address paleodemographic aspects of the model, including temporal, distributional, and compositional studies of the mortuary record, isotopic, morphometric and DNA analyses and the sex and age structure of the skeletal samples recovered in Lake Salitroso basin. Results point to a biological and cultural population continuity in the region during the Late Holocene. Also, a reduction in residential mobility would have favored a slight population growth of Lake Salitroso populations during the last millennium. [ABSTRACT FROM AUTHOR]

The archaeo-paleontological site of Pilauco (southern Chile) has one of the richest Late Pleistocene mammal records of the northern Chilean Patagonia, with at least nine forms dominated by gomphothere remains. This site has a complex taphonomic history due to postdepositional processes that affected the integrity, frequency, and distribution of the fossil bones. One of these processes is the action of large carnivores, indicated by tooth marks recorded exclusively in gomphothere bones. In this paper, we describe Gomphotheriidae fossil remains and give a detailed description of carnivore tooth marks detected in the sample. The absence of diagnostic fossil specimens does not allow genus or species assignment. The type, location, intensity, and dimensions of the tooth marks are compatible at least with a large felid, which probably scavenged a partially exposed carcass. The record of this taphonomic feature is important in order to understand the postdepositacional history of the Pilauco site, in which natural and cultural agents are involved. [ABSTRACT FROM AUTHOR]

• Dryline formation is favoured by the advection of mid-level dry air from the Pacific. • Local circulations impact the dryline movement and strength in quiescent conditions. • Nocturnal LLJ and local circulations reinforce the moisture gradient at night. • In synoptically active periods, dry advection and diurnal mixing are more important. Drylines are a frequent feature of the atmospheric circulation in Argentina. Recent work described their climatological characteristics and synoptic-scale processes associated with their formation. However, little is known about the mesoscale processes that are relevant for their life cycle. In this paper, we investigate the influence of these mechanisms on the formation and movement using a case-study approach. Also, the relationship between these mechanisms and convective initiation near the dryline is investigated. A typical northern Patagonia dryline is simulated using the Weather Research and Forecasting (WRF) with an horizontal resolution of 3 km. The FLEXible PARTicle dispersion-WRF is also used to study some of the processes from a Lagrangian perspective. During the quiescent period corresponding to dryline formation and intensification, the dryline strengthens along the axis of a thermally-induced surface trough that promotes differential moisture advection. Also, convergence along the dryline is enhanced during night-time by the inertial oscillation ahead of the dryline and by the development of a thermally-driven circulation between the elevated terrain in northern Patagonia and the adjacent plains. These two mechanisms contribute to enhancing the intensity of the moisture gradient and to trigger deep moist convection. Under a period of stronger synoptic forcing, the dryline intensifies in response to the confluence induced by the deepening surface trough and moves away from the terrain elevations. Its movement during this period is driven by horizontal dry advection and the vertical mixing enhanced by the entrainment into the boundary layer of extremely dry air, whose origin can be traced back to the mid-levels over the Pacific Ocean. When the magnitude of the low-level westerly winds increase, moister air from lower levels cross the barrier, contributing to weakening the moisture gradient at the dryline. [ABSTRACT FROM AUTHOR]

Discoveries of Jurassic pterosaurs in the Southern Hemisphere are extremely unusual. In Argentina, pterosaurs from the Upper Jurassic (Tithonian) have only been found in the Northwest of Patagonia (Neuquén Basin). These come from marine deposits and three specimens have been discovered up to the present. In this paper, we report a new finding from the Neuquén Basin. This material is identified as a tibiotarsus, which probably belonged to an osteologically adult individual and represents a new species of a pterodactyloid pterosaur of medium size. This discovery provides new evidence that at least two different species of pterodactyloid pterosaurs may have coexisted in Los Catutos Member, Vaca Muerta Formation, from the shallow marine deposits of the Neuquén Basin. [ABSTRACT FROM AUTHOR]

Abstract: The boring bivalve Lithophaga patagonica (d'Orbigny, 1842) is a locally abundant inhabitant of hard substrata in the coastal waters of the Southwestern Atlantic. In this paper, we describe the growth, age and mortality of three intertidal rock-boring populations of L. patagonica and one subtidal oyster shell (Ostrea puelchana) boring population. An analysis of acetate peel replicas of shell sections showed that L. patagonica slows down its growth during autumn–winter, which leads to changes in the direction and rate of shell deposition and the formation of conspicuous annual (low temperature induced) clefts in the shell margin. Cleft counts and Von Bertalanffy growth analyses indicated that maximum age varies from 4years in the oyster-boring population to 13years in a rock-boring one (longevity estimates varied between 6.5 and 15years, respectively). Maximum asymptotic length (L∞) and Von Bertalanffy growth constant (K) were also variable between populations (L∞ between 14.76 and 36.95mm and K from 0.20 to 0.90yr−1 respectively). Mortality rates were higher at the two southernmost populations. Type (rock vs. oyster), composition and hardness of the substrata are likely the main factors controlling the observed differences between populations. [Copyright &y& Elsevier]

In this paper, we present new palaeontological data regarding plant remains (palynomorphs, mesofossils, and leaves) from the uppermost part of the Lago Colhué Huapi Formation (Maastrichtian), at the headwaters of the Río Chico, Golfo San Jorge Basin. We also suggest a palaeoenvironmental reconstruction of these deposits, taking into account the information reported herein and previous palaeontological and sedimentological studies. Several spores of bryophytes, lycophytes, and monilophytes (ferns) as well as zygospores of Zygnemataceae form part of the freshwater aquatic ecosystem. The new species of Palmae affinity, Spinizonocolpites riochiquensis sp. nov. is described in this paper. Besides, we present the first record of leaf fragments with probable Palm-affinity in the Upper Cretaceous of Patagonia, which could reassert the presence of the Arecaceae in the basin. The palaeoflora recognized in the upper Lago Colhué Huapi Formation contributes to interpreting palaeoecological and palaeoclimatic conditions of a stratigraphic interval close to the Cretaceous/Paleogene extinction event, at the latitude of Patagonia. • Maastrichtian plant remains from the Golfo San Jorge Basin. • A new species of Spinizonocolpites is described in the Lago Colhué Huapi Formation. • Monocot fragmentary leaves are reported from the Maastrichtian of Patagonia. • A reconstruction of a terrestrial environment close to the K/Pg boundary is proposed. [ABSTRACT FROM AUTHOR]

This paper describes differences between Medieval Climate Anomaly (MCA) and present-day temperatures in the area composed of the Antarctic Peninsula, southern Patagonia, and the surrounding southern oceans. The investigation is conducted with the simulation results from the Community Earth System Model Last Millennium Ensemble (CESM-LME) considering the impact of each natural (volcanic activity and solar variability) and anthropogenic (greenhouse gas, ozone-aerosols and land use/land cover) individual forcing relative to the full forced simulations. Model results show generalized warming during the MCA in the study area. However, the simulated MCA temperatures are significantly colder than present-day mean values due to the influence of increased atmospheric greenhouse gas concentrations since the beginning of the modern Industrial Era in the ∼1850s. In fact, model runs in which only natural forcings were applied show that, in the absence of greenhouse gas forcing, present-day temperatures in the Antarctic Peninsula and southern Patagonia would be lower than or similar to those during the MCA. The study demonstrates the value of paleoclimate proxy–model comparisons but also highlights the limitations of current available proxy information to perform that integration in the study area. • CESM-LME model simulations describe last-millennium climate evolution. • Temperature changes over Antarctic Peninsula and Patagonia are analyzed. • The impact of each natural and anthropogenic individual forcing is described. • Limitations of current available proxy information are showed. [ABSTRACT FROM AUTHOR]

Alectopsylla unisetosa (Ischnopsyllidae) from Santa Cruz province represents the second report of the species after 45 years. This new distributional record extends this species distribution 1350 km further south than previously documented. Moreover, Alectopsylla unisetosa infesting Myotis chiloensis constitutes a new flea–host association. This finding provides new insights into the biogeography and host associations within the family Ischnopsyllidae. • Alectopsylla unisetosa is recorded for the second time after 45 years. • The paper provides images with the diagnostic characters of specimens male and female. • This finding provides new insights into the biogeography and host associations within the family Ischnopsyllidae. [ABSTRACT FROM AUTHOR]

The western slope of Cerro Domuyo in northern Patagonia is characterized by thermal springs with boiling waters, Quaternary silicic domes, and pyroclastic deposits that suggest the existence of a geothermal reservoir. According to geochemical studies, the reservoir may have a temperature of 220 °C and one of the largest advective heat fluxes reported for a continental volcanic center. In this paper, we propose a more refined conceptual model for the Domuyo geothermal area, based on a geological survey supported by U Pb, U Th, and Ar Ar geochronology and by magnetotelluric and gravity surveys. Our study indicates that the Domuyo Volcanic Complex (DVC) is a Middle Pleistocene dome complex overlying middle Miocene to Pliocene volcanic sequences, which in turn cover: 1) the Jurassic-Early Cretaceous Neuquén marine sedimentary succession, 2) silicic ignimbrites dated at ~186.7 Ma, and 3) the Paleozoic metamorphic basement intruded by ~288 Ma granite bodies. The volcanic cycle in the DVC is distinctly bimodal, characterized by the emplacement of massive silicic domes and less voluminous olivine basalts on its southern slope. A major collapse of the central dome at ~600 ka produced a voluminous (19.4 km3 and 133 km2) block-and-ash flow, and associated pyroclastic flows, that filled a valley to the southwest at distances up to ~30 km from Cerro Domuyo summit. This was followed by a period of intense effusive activity that formed the Cerro Guitarra, Cerro Las Pampas, Cerro Domo, and Cerro Covunco silicic domes. The last two domes are the youngest and largest edifices, dated at 0.50 Ma (Ar Ar age) and 0.25 Ma (U Th age). Pre-Cenozoic successions were affected by N-S reverse and thrust faults that were later displaced by an ENE-WSW-trending transtensional belt. The basement rocks at the northern termination of the Cordillera del Viento anticlinorium were also displaced towards the east-northeast by this belt, which is observed NNW of Cerro Domuyo. The DVC was emplaced within this zone of crustal weakness. The integration of geologic observations with magnetotelluric and gravity data, allowed us to develop an updated conceptual model of the geothermal system. The geothermal reservoir is inferred at a depth of less than 2 km within pre-Pliocene fractured rocks, bounded by ~WSW-ENE trending faults and sealed by the pyroclastic deposits and rhyolitic lavas of the DVC. The location of most thermal springs is not directly controlled by faults. Instead, flows emerge at the contact between the fractured and faulted basement and the caprock. • The Domuyo Volcanic Complex (DVC) is a silicic dome complex formed in the Pleistocene. • The central dome collapsed at ~600 ka producing a voluminous (19.4 km3) pyroclastic deposit. • The youngest domes were emplaced at ~500 ka and 250 ka. • The DVC was emplaced within a ENE-WSW trending transtensional zone of crustal weakness. • The geothermal reservoir is hosted in pre-Pliocene rocks sealed by the DVC pyroclastics and lavas. [ABSTRACT FROM AUTHOR]

The South Atlantic coast in Argentine Patagonia is an area where semi-arid to arid conditions predominate and coastal populations present serious water supply problems. The aim of the work was to evaluate the factors that condition the salinization processes of coastal aquifers from a hydrochemical and isotopic analysis of the groundwater located in Pleistocene and Holocene littoral ridges in the northern sector of Patagonia in Bahía San Blas. A geomorphological characterization of the area was carried out using digital elevation models, satellite image interpretation and field surveys. Groundwater chemistry was analyzed in 40 shallow wells and 2 tidal water samples. At each point, electrical conductivity, temperature and pH of water were measured and samples were taken for analysis of major ions and stable isotopes. The salinization processes were analyzed by means of ionic and isotopic relationship graphs and were subsequently modeled using free software. The results obtained allowed the identification of the factors that determine the salinization of coastal aquifers. Particularly in the Pleistocene coastal ridges, the cementation of the most superficial sediments reduces permeability conditioning rainwater infiltration. This, together with the presence of soluble salts on the surface and the mixing with sea water, determines the salinization of the groundwater. In contrast to these, in the Holocene coastal ridges without cementation, rainwater infiltrates forming freshwater lenses where salinization processes occur only at the edges of the lenses where the saltwater wedge is located. The data provided in this paper are useful in prospecting freshwater sources along the arid coast of Patagonia where freshwater availability is scarce. They can also be extrapolated to other sectors worldwide with similar geological and climatic environments. • Water supply problems exist in the arid coastal zone of Patagonia Argentina. • Freshwater lenses are formed in Pleistocene and Holocene littoral ridges. • Groundwater salinization is recognized in lenses of Pleistocene littoral ridges. • Salinization processes are due to cementation, salts dissolution and marine intrusion. [ABSTRACT FROM AUTHOR]

The general trend of glacial retreat since the Little Ice Age has shown an acceleration during the last decades in Southern Argentine and Chilean Patagonia. The Fuegian Andes climatic records report an irregular mean annual temperature increase since 1970, with acceleration from 2015, and the Chato Glacier, as other regional cirque glaciers, has undergone a rapid ice front retreat. A detailed mapping of the proglacial area of the Chato Glacier allowed the identification of a landform assemblage related to the glacier retreat during the last decades. In this paper morphological and sedimentological features of this peculiar landform assemblage, generated in an intense glacial ablation environment, are described and the causes of their origin are discussed. Among the most remarkable landforms annual moraines, hummocky moraines, esker-like landforms, flutes, kettle ponds, dirt cones, glacifluvial deposits, pronival ramparts and collapsed moraines are found. The multitemporal analysis of the Chato Glacier retreat allowed us to interpret that most of these landforms were generated when the landscape became ice-free after 2005. The Chato Glacier cirque floor gentle slope, the thin-ice thickness and the occurrence of a rocky threshold near the glacier front would have promoted the rapid glacier thinning and the disconnection of dead ice. This context, together with the sediments and meltwater availability, would have favored the development of this landform assemblage which is ephemeral due to its high susceptibility to erosion. • Proglacial landforms developed since the final Little Ice Age in a glacial cirque. • Multitemporal glacier retreat analysis and landforms associated. • Temperature increase and glacier retreat acceleration in Fuegian Andes since 1970. • Ephemeral landforms due to poor consolidation, intense meltwater and precipitation. • Satellite images and a photomosaic derived from unmanned aerial vehicle (UAV). [ABSTRACT FROM AUTHOR]

Abstract: A scanning and transmission electron microscopy-based ultrastructural study of Arcellites humilisVillar de Seoane and Archangelsky, 2008, from the Kachaike Formation and Piedra Clavada Formation (Albian-Cenomanian) from several localities in Patagonia (Argentina), is presented in this paper. TEM-photographs of thin-sectioned specimens show a thick spore body wall composed of three layers: a thin and dense exine, an inner granular perine sublayer with irregularly disposed small channels and lacunae, and an outer alveolate perine sublayer with channels perpendicular to the external surface. Transverse sections of the A. humilis wall are compared with fossil and extant species of Marsileaceae. We show that the wall ultrastructure is similar in A. humilis, A. santacrucensis, A. disciformis, A. stellatus and Regnellidium upatoiensis. However, the body wall and acrolamella of A. humilis are more similar to those of R. diphyllum Lindman than to those of the Marsilea L. or Pilularia L. species. Water ferns such as members of the Marsileaceae played an important role in aquatic or semi-aquatic niches in Patagonian Cretaceous floras, suggesting that high humidity and temperature prevailed during the Albian-Cenomanian in this region of Argentina. [Copyright &y& Elsevier]

Abstract: Lower Cretaceous trackways assignable to xiphosurids were recently found in tidally influenced marginal-marine deposits of the Agrio Formation (Patagonia, Argentina). The aim of this paper is to describe these trace fossils in detail, discuss their conditions of preservation, make palaeoecological and taphonomic inferences from them, and analyse the importance of their palaeogeographic location. These trace fossils are assigned to Kouphichnium, and five track morphotypes are established. Microbially induced sedimentary structures (MISS) are associated with the trackways. Scanning electron microscope (SEM) studies document the involvement of microbial mats in the preservation of the trackways by the presence of cyanobacteria-like filament sheaths. The microbial mats enabled preservation of the tracks by binding and biostabilisation of the sediment surface. The mostly likely producers of the trackways are from the subfamily Limulinae. The studied surface could represent a high-tide mating ground associated with a very shallow water deposit on a warm Cretaceous tidal flat. These records are the first convincingly documented trackways produced by xiphosurids in the Early Cretaceous worldwide and the second fossil record of this group from the Cretaceous in the Southern Hemisphere. [Copyright &y& Elsevier]

Abstract: Archaeological deposits in continental Patagonia that allow an adequate discussion of the exploitation of seabirds, particularly the Spheniscidae, are scarce. In many cases, characteristics of bone assemblages seem to indicate the natural incorporation of penguin bones into archaeological contexts. This suggests it is not always possible to support the argument that the presence of penguin remains indicates, a priori, consumption by humans. The Bajada de los Pescadores (BP2) site, San Matías Gulf (Río Negro, Patagonia, Argentina), provides a case study that allows the origin of these deposits and their contents to be evaluated in terms of the exploitation of penguins and other marine resources by hunter-gatherers during the Late Holocene. This paper discusses the origin of the archaeological deposit, its context, and the agents involved in its formation. The analysis used criteria formulated previously in the framework of actualistic taphonomic observations, with the aim of assessing the integrity of this sample, and evaluating its contribution towards clarifying the role of penguins in the subsistence of people on the northern Patagonian coast. [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]