The evolution of the cryosphere and climate in northern Patagonia during the late Pleistocene are relatively wellknown thanks to chronologies on ice-marginal features. However, this knowledge mainly represents the magnitude and duration of extreme cold intervals occurring during glacial maxima. Consequently, less is known about the state of the glaciers and climate during transitions between full glacial and interglacial stages. Given that morphometric attributes of glacial cirques are considered as robust indicators of palaeoglacial and palaeoclimate conditions during phases of minor glaciation, examining cirques will yield key insights to assess the typology of glaciers and associated climate conditions during those pivotal periods. In this study, we systematically analyzed the morphology and spatial distribution of 3081 cirques in northern Patagonia between-40o and-45o S. Our findings revealed that circular cirques, reflecting widespread long-lived small glaciers, dominate northern Patagonia. Eastward increase of cirque floor altitude from the coast to the continent along with prevailing east-to-south aspects indicate a key role of westerly-controlled climate and radiative balance in cirque development. Morphometry and spatial distribution of cirques along with statistical analyses indicate that annual total precipitation, minimum temperature, and incoming solar radiation altogether play a major role in cirque development in northern Patagonia, although the relative importance of these factors might vary spatially. Regional lithology exerts a secondary influence mostly in cirque geometry. We conclude that the most frequent state of the cryosphere within the Pleistocene glacial cycles in northern Patagonia is characterized by moderate glaciations similar to that existing during glacial terminations.

The Ararat Depression, at the crossroads of Africa and Eurasia, spans Armenia, Turkey and Iran, providing a unique natural laboratory for studying landscape evolution, hominin lifeways and migration. This research integrates geomorphological mapping and sedimentary analysis with dating techniques such as Terrestrial Cosmogenic Nuclides (10Be-26Al) and Optically Stimulated Luminescence (OSL) to reconstruct environmental history over the past 900,000 years. It investigates the formation and preservation of alluvial landforms in response to climatic fluctuations, Quaternary volcanism and tectonic activity, revealing discontinuities in the archaeological record. Late Pleistocene and Holocene alluvial deposits further illustrate the complex interplay between geomorphic processes and human settlement patterns. Findings indicate that the Middle and Upper Paleolithic occupations were shaped by shifting environmental conditions, with hominin presence fluctuating in response to glacial and interglacial cycles. This study enhances our understanding of how landscape evolution influenced hominin dispersal and adaptation in the Southern Caucasus.

Mount Aragats is one of the largest glaciated volcanoes of the Armenian Highlands (Rwlllwllwb lbnbwZruwnh) and culminating in the Aragats Peak, the highest peak of the Republic of Armenia (4090 masl). Here, prehistoric societies have been present for millennia, so assessing the local influence of past glaciations is a crucial factor to better understand the cultural evolution of this region. Therefore, this work focuses on a detailed study of the morphology and morphostratigraphic succession of Mount Aragats paleoglaciers. Geomorphic-based paleoglacier reconstruction along 36Cl cosmogenic dating (n = 13) of moraines reveal that during the Middle and Upper Pleistocene, a plateau glacier featuring ice lobes covered this area, featuring outlet lobes reaching up to 17 km in length, thicknesses of up to 350 m and descending to 2040 masl. According to the morphostratigraphic succession of ice-marginal features, absolute chronologies and regional correlations, the chronoevolutionary sequence of these glaciers comprises three intervals: (1) The absolute Maximum Ice Extent or Aragats Glacial Maximum occurred during the Penultimate Glacial Cycle within the MIS6e (c. 180 ka). (2) Subsequently, during the Last Glacial Cycle, the Maximum Ice Extent occurred during the MIS5d (c. 111 ka) followed by two secondary glacial maxima stabilizations during the MIS3a (c. 37 ka) and the MIS2 (c. 17 ka). Finally, (3) the Post-Glacial Period (PCP, Holocene, MIS1). The disappearance of the glaciers on Mount Aragats was established at the beginning of the second half of the 20th century by direct observations. The current morphodynamic environment corresponds to active rock glaciers, some neve` moraines and widespread activity of slope processes such as debris flow and debris slides.

Permafrost study in the Spanish Central System (similar to 41 degrees N) has remained elusive in past decades. Although numerous periglacial features have been described, none has yielded conclusive information about the existence/distribution of permafrost across these mountains. This work focuses on integrating light detection and ranging and unmanned aerial vehicle data with geophysical methods and sedimentary records, along with preliminary thermal information, for the comprehensive study of a frost mound. The singularity of this feature resides in its location, currently dominated by a seasonal frost regime, and its size reaching 59 m long, 22.5 m wide and 4 m high, representing the largest landform of this type in Iberia. From top-to-bottom, the internal structure comprises three resistivity units (G1, G2 and G3). The most superficial unit (G1) consists of a sequence of burial soils alternating with sand and silts, with pebbles and gravel at the bottom, followed by a high porous layer that belongs to a landslide deposit (G2), likely composed of gravel and pebbles laying over unit G3 (bedrock). Calibrated C-14 ages suggest this landform formed at least similar to 4300 years ago during the mid-Holocene. Finally, the preliminary surface thermal map indicates the presence of sectors affected by strong thermal gradients likely driven by water table variations. Our results conclude that the dynamics are primarily controlled by the seasonal frost regime influencing local subsurface drainage, which allows us to classify this landform as a hydrodynamic pingo-like structure. We also demonstrate that our approach is suitable for assessing the evolution of this type of periglacial landform. Implementing long-lasting annual monitoring programmes would help to understand local periglacial dynamics better.

The area of Prados del Cervunal (PC) is an intra-morainic topographic depression located at 1800 m asl in the divide or interfluve between Garganta de Gredos and Garganta del Pinar valleys (Central Gredos; Iberian Central System, ICS). Both valleys, along with the adjacent Hoya Nevada, were occupied by glaciers during the Upper Pleistocene, leading to the development of the Prados del Cervunal moraine complexes studied in this work. Using cartographic methods and morphostratigraphic analysis, the three main glacial formations established in the Regional Chrono-Evolutionary Pattern for the ICS, Peripheral Deposits (PD), Principal Moraine (PM) and Internal Deposits (ID), have been identified and mapped in this area. The chronology of these formations has been implemented by Cosmic Ray Exposure (CRE) techniques using 10Be (new data) and 26Cl (previous data, recalculated in this work) in samples from morainic boulders. With these data, the following chrono-evolutionary sequence has been established: (stage 1) local-Maximum Ice Extent (MIE), dated in 25.0 & PLUSMN; 1.4 ka and corresponding to the maximum age obtained in these paleoglaciers; (stage 2) period of oscillations around the MIE, corresponding to the development of the PD Formation between-25 ka and-21 ka; (stage 3) period of readvance and sta-bilisation, dated after-21 ka (average age obtained for the PD moraines attached to PM moraines) and previous to-18 (minimum age obtained for a main crest of the PM formation); and (stage 4) onset of deglaciation dated around to-18 ka (average of ages obtained for the first main crest of the ID forma-tion). During the stages of maximum ice expansion, these three glaciers formed an Ice field whose tongues were interconnected on the PC flat by an ice transfluence system (stages 1 and 2, Plateau Glacier Period). In later stages, the ice masses were partitioned, giving rise to valley glaciers and large moraines forming morainic complexes like those of PC (stages 2, 3 and 4, Valley Glaciers Period). The local MIE and onset of deglaciation stages in this area show a good fit with the ages stablished to global level for the global Last Glacial Maximum (LGM) and the onset of the Last Glacial Termination (Termination I). They also show good correlation at local (with other areas of the ICS), peninsular (with other Iberian moun-tains) and continental (some areas of the Alps and mountains of Central Europe) level. Finally, this evolutionary sequence and its correlations allowed us to adjust and validate some units of the Regional Chrono-Evolutionary Pattern model and propose the Gredos-Pinar-Cabeza Nevada glacial system as benchmark for the glaciation of Marine Isotope Stage (MIS) 2 in the Iberian Peninsula.& COPY; 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

AbstractThis study uses luminescence and 14C accelerator mass spectrometry procedures to date relevant glaciofluvial and glacial deposits from the south-central and southeastern Pyrenees (Andorra–France–Spain). We distinguish two types of end-moraine complexes: (1) those in which at least a far-flung moraine exists beyond a frequently nested end-moraine complex (the most common) and (2) those in which a close-nested end moraine encompasses at least two glacial cycles. Both types formed within six distinctive glacial intervals: (1) A penultimate glacial cycle during Marine Oxygen Isotope Stage (MIS) 6 and older glaciofluvial terraces occurred beyond the range of the luminescence dating method. (2) An early glacial advance in MIS 5d (~97 −15/+19 ka) was followed by glacial retreat during MIS 5c (< 91 ± 9 ka). (3) The last maximum ice extent (LMIE) was in early MIS 4 (~74 ± 4.5 ka). (4) Unexpectedly, glaciers thinned during the second half of MIS 3 (~39 −6/+11 ka). (5) During the MIS 3–2 transition, glaciers subsequently fluctuated behind the LMIE limits. (6) The global last glacial maximum (LGM) started as early as ~26.6 ± 0.365 ka b2k, and the corresponding end moraines were built behind the LMIE limits or merged with it, forming close-nested moraines.

High-mountain peatlands are essential ecosystems for habitats, biodiversity, water, and carbon cycling, but there is little comprehensive information in central Iberia. We present results of research concerning the distribution, geormorphology, floristic, geobotany, and habitat diversity of peatlands in the Gredos Regional Park (Iberian Central System). We identified 72 peatlands covering 117 ha and ranging in size from 0.01 to 17.34 ha. Peatlands occur primarily in the upper orosubmediterranean bioclimatic belt at 1775–2230 m asl. From a geomorphological point of view, 9 different peatland typologies have been defined. Multivariate analyses (agglomerative cluster analysis and principal component analysis) of 103 relevés allowed us to classify the sampled peatland stands into 7 plant communities and 4 European habitats that formed along complex hydrogeomorphic conditions, and to propose a new subassociation of other community previously described (Caricetum echinato-nigrae lycopodielletosum inundatae). The main threat to Gredensean peatlands is pastoral pressure, which affects 15 of them intensively, mainly between the upper supramediterranean and the lower orosubmediterranean bioclimatic belts (~1314–1700 m asl). Seven bryophytes and three vascular plants documented in the Gredos Regional Park peatlands are included in the IUCN Red List. From the point of view of conservation priority, the most threatened correspond to transition mires communities (Habitat 7140) growing in oligotrophic and minerotrophic peatlands (Caricion nigrae vegetation). Particularly, the Iberian Central System endemic Sedo lagascae-Eriophoretum latifolii association is the one that has achieved the highest score in the five criteria considered in this regard because Meesia triquetra, a species with the category of “critically endangered”, inhabits it.

The Sierras de Guadarrama and Somosierra are located at the eastern end of the Central Range, in the center of the Iberian Peninsula, culminating in the Pico de Peñalara (2428 m, 40° 51′ 01″ N and 3° 57′ 17″ W). There are landforms from 79 palaeoglaciers in the Sierra de Guadarrama and 18 in the Sierra de Somosierra. The majority of these palaeoglaciers were cirque and slope glaciers. Plateau and alpine glaciers only appeared in two areas. The moderate altitude of theses Sierras and their continental climate were determining factors that limited the glacial development. However, they house a great variety of landforms that retain most of the chronological information of the complex process that represents the last major deglaciation in Europe. All their glacial landforms come from the Last Glacial Cycle. The most important impact was the LGM, when the largest moraine formations were formed, although some cirques showed earlier major advances. The massive deglaciation started by 19 ka BP, although the recessional moraines in many valleys indicate the existence of advances between 17.5 and 14.6 ka. Later advances during the Younger Dryas are also possible. The glaciers disappeared immediately at the beginning of the Holocene. Some areas of the Peñalara Massif, including important glacial landforms, have been restored recently and are now part of the Guadarrama National Park, the most visited on the Iberian Peninsula.

The Sierra de Gredos forms the central sector of the Central Range and extends for 155 km between the Sierra de Guadarrama to the east and the Sierra de Gata-Peña de Francia to the west, its highest peak being the Pico Almanzor (2591 m, 40° 14′ 46″ N and 5° 17′ 51″ W). The bedrock is mostly made up of granite rocks. The Sierra de Gredos has a Mediterranean–continental climate, with a clear increase in rainfall to the west due to its proximity to the Atlantic. Its glacial landscapes present a great variety of landforms, from small cirques in the massifs of the smaller summits and southern slopes, to large glacial valleys of lengths exceeding 10 km and plateau glaciers in the highest and western-most summits. The glacial evolution during the Late Pleistocene, since the maximum extent occurred before the global Last Global Maximum until the definitive disappearance of the glaciers, just at the beginning of the Holocene, is well known. Phases of glacial advance have also been clearly detected during the Oldest Dryas and, to a much more limited extent, during the Younger Dryas.

Early LiDAR datasets in Spain are available since 2014 (5-m resolution), when the first works were carried out by our team (Fernández-Lozano and Gutiérrez-Alonso Mapping 167:22–29, 2014; Fernández-Lozano et al. J Archaeol Sci 2014:356–373, 2015). The implementation of LiDAR to 1-m resolution was subsequently used and compared by Fernández-Lozano and Gutiérrez-Alonso (J Archaeol Sci 5:509–520, 2016) in combination with UAV-derived (Unmanned Aerial Vehicles) photogrammetry. These works showed different Roman gold mining scenarios that were modeled providing outstanding results even with the poorest resolution LiDAR datasets. Moreover, the implementation of visual enhancement tools, widely used in different fields of archeology, geomorphology, and geology, such as Sky-View, Multi-hillside, Slope, LRM, Openness, and Principal Components have improved notably the interpretation of results in both mining and archeological works. This paper discusses the potential and insights provided by our methodological approach and shows that the results of its application to the study area of Las Miédolas can provide better results than those obtained by Matías and Llamas (Geoheritage 13(2):1–22, 2021).

Geological and geophysical studies in complex valley troughs provide a key record for the reconstruction of paleoenvironmental conditions during the Quaternary. Here we present a study of the sedimentary infill of the El Cervunal kame complex or El Cervunal trough (Sierra de Gredos, Iberian Central System) by means of a combined interpretation of near-surface geophysical techniques supported by geomorphological and borehole data. A set of 1D and 2D near-surface geophysical methods, including electrical (Vertical Electrical Sounding and 2D Electrical Resistivity Tomography), seismic (2D Seismic Tomography and 1D Refraction Microtremor) and Magnetic Resonance Sounding techniques, were used to test their applicability in providing better insight on the infill nature and geometry. Because of greater sensitivity and higher resolution and coverage achieved with resistivity methods, the electrical resistivity has proven to be the most informative physical parameter, while seismic and magnetic resonance methods were complementary. The sedimentary infill was classified into three geophysical units and five sub-units with their geological interpretation. Unit 1 consists of a postglacial sedimentary sequence and includes alluvial-plain and alluvial-fan deposits. Units 2 and 3 below the postglacial unit were interpreted as glacial sequences including kame (glacigenetic and fluvio-glacial) and morainic deposits, respectively. Subsoil information combined with the geomorphological data enabled the partial reconstruction of the map-view geometry of the morainic bodies at the El Cervunal trough. The results suggest a complex evolution of the study area where erosive-sedimentary processes dominate, but also structural factors should be considered. At least five well-differentiated stages can be established to explain the occurrence of the trough infill: pre-glacial, maximum glacial extension, trough obturation, glacial retreat and periglacial-postglacial.

NW Iberia hosts a substantial number of mineral resources. Among them, gold (Au) acquired particular relevance since Antiquity, representing one of the largest Roman Au mining provinces in Europe. While primary deposits associated with orogenic Au have been widely studied in the past years, the Plio-Quaternary Raña Au-bearing placer deposits of the western Duero Basin have received little attention. Besides, the different morphology of Au particles suggests complex processes that may have been responsible for the secondary formation of colloidal particles and Au growth grains from complex geochemical soil interactions and biological activity. In this context, exploring the mechanism by means these secondary deposits developed may contribute to understanding the source of Au (extrinsic or intrinsic factors that rule in within Raña deposits) and the formation of potential mineral exploration sectors. This paper outlines the geochemical analysis of a Cenozoic Raña-like deposit in the Jamuz valley (León), where the source of Au and the main characteristics are established. The correlation matrix showed notable relationships between Au, Fe, Na, K, Ca, Pb and As, among the most important. High values in Fe and As provides direct evidence of Au precipitation. Likewise, a non-linear correlation was found between Au-Na, and Au-Ca, suggesting a direct link to soil formation processes. Finally, the presence of apparent differences in grain roundness and the particles' characteristics ranging from monomineral angular Au to polymineral rounded-shaped particles points towards a complex process affecting the Raña deposits. The ubiquitous rubefaction and top-bottom leaching activity produced during rainwater percolation aided by the extreme drainage affecting this conglomeratic formation have often been argued to be responsible for the transformation of mineral phases in soils. The presence of secondary silicification processes and pH drop due to biological reactions (i.e., presence of P) may have been a triggering mechanism for digestion and reprecipitation of Au colloids in these sediments. Our results have outstanding implications on the mechanisms that may determine the Au enrichment of certain levels within the Raña deposits of the western Duero Basin. This work was funded by the wine company “Fuentes del Silencio”.

espanolEl valle del rio Eria presenta uno de los mayores complejos de mineria aurifera de epoca romana del noroeste de la peninsula iberi- ca. En este trabajo se presenta un estudio geoarqueologico que com- bina un enfoque multidisciplinar basado en el analisis por teledetec- cion con LiDAR aerotransportado, geologia descriptiva y datacion radiocarbonica. La zona estudiada presenta un entramado minero compuesto por una red de canales que dirigian el agua a distinta cota hasta las explotaciones. Los desmontes fueron realizados sobre materiales plio-cuaternarios de tipo rana y cuaternarios constituidos por depositos de ladera, periglaciares y terrazas fluviales. El lavado de los depositos auriferos empleo la fuerza hidraulica para deshacer y arrastrar el sedimento, dando lugar a tres tipos distintos de explo- tacion en funcion de las caracteristicas que presentan los diferentes depositos. Los resultados arrojan luz sobre los materiales geologi- cos explotados y otros aspectos geograficos que condicionaron las tecnicas de explotacion de los yacimientos. El trabajo contribuye a mejorar el conocimiento sobre la mineria aurifera del noroeste y su contexto geologico EnglishThe Eria River valley exhibits one of the largest gold mining com- plexes in NW Iberia from Roman age. In this study, a geoarchaeo- logical work is presented, combining a multiapproach based on air- borne LiDAR remote sensing, descriptive geology and radiocarbon dating. The studied area is characterized by the presence of a mi- ning infrastructure comprised of hydraulic canals driving the water at different levels to the mines. Mining works were associated with Plio-Quaternary rana deposits and Quaternary materials consisting of hillside and periglacial deposits, and fluvial terraces. The washing of the gold deposits used the hydraulic force to break up and drag out the sediment, giving rise to three different types of exploitation depending on the characteristics of the different materials. The re- sults shed light on the geological materials exploited and other geo- graphical aspects that conditioned the exploitation techniques. The work contributes to improving the knowledge about Roman gold mining and its geological context in northwest Iberia

The Iberian Central System (ICS) is a clue region to reveal Mediterranean/Atlantic inferences over Iberia. We present a multidisciplinary study from western Spain conducted in the Navamuno depression (ND), covering the last 16.8 ka (cal BP). A reconstruction of the palaeotemperature from the resulting geochemical data highlights four cold and dry intervals, namely, the Oldest Dryas, Older Dryas, Intra-Allerod Cold Period (IACP), and the Younger Dryas, along with warmer intervals: the Bolling (14.7-14 ka) and the Allerod (12.9-12.6 ka); however, the Greenland Interstadial GI-1c (13.4-13.1 ka) is barely distinguishable in the ND. Despite the shortage of biomass to sustain fire, the earliest charcoals are from similar to 14.4-13.8 ka. Evidence of ash/dust events overprinting the geochemical background starts at similar to 13.8-12.8 ka. Significant fire activity in the Early Holocene at similar to 11.7-10.6 ka affected the ND, matching the westernmost ICS data. This period includes short oceanic spells inferred from Cl peaks at similar to 10.9-10.2 ka and three cold intervals at 11.4, 9.3, and 8.2 ka disrupted the progressive temperature increase. The Mid-Holocene showed a continuously increasing trend towards an arid climate, peaking at 4.2 ka under a pervasive dust influx from North Africa, which has prevailed since almost similar to 7.9 ka. A prominent volcanic event at similar to 6.8-5.8 ka is in Navamuno and Ronanzas (Asturias, N Spain; Gallego et al., 2013) identified from heavy metal-rich layer, synchronous with the last known eruption of the Calatrava volcanic field (South-Central Spain; Poblete-Piedrabuena et al., 2019). This volcanic eruption could affect many other regions half north of Iberia. The pervasive presence of oceanic aerosols in the last three millennia (2.8 ka similar to) allowed the formation of a Cl-rich peat layer during the Ibero-Roman humid period similar to 2.1 ka, before a changing around similar to 0.4 ka toward colder and drier conditions at the Little Ice Age (LIA) period.

Una de las mayores controversias que suscita el estudio geoarqueológico de la minería aurífera romana se refiere al empleo de la amalgama con mercurio (Hg) para la concentración de oro en yacimientos tipo placer, donde éste aparece libre, en forma de pequeñas partículas o pepitas que se acumulan en el sedimento aurífero. A pesar de que el uso y propiedades del mercurio fueron conocidas en época romana, son escasos los trabajos realizados que permiten establecer las condiciones en las que su empleo estaba justificado en la recuperación y beneficio del oro procedente de yacimientos secundarios. En este artículo se ha realizado un estudio geoquímico de suelos para establecer su empleabilidad en la recuperación de oro en este tipo de explotaciones. Para ello, se ha analizado la concentración de Hg en los tramos de canal de lavado (agogae), donde se realizaría la extracción de oro. Los resultados indican que las anomalías observadas están ligadas al acopio y su posterior uso, ya que se concentran en los tramos inferiores de los canales. Esto confirma el empleo de mercurio para el beneficio aurífero en yacimientos de tipo placer, arrojando luz sobre los métodos metalúrgicos empleados en época romana.

The Eria River valley exhibits one of the largest gold mining complexes in NW Iberia from Roman age. In this study, a geoarchaeological work is presented, combining a multiapproach based on airborne LiDAR remote sensing, descriptive geology and radiocarbon dating. The studied area is characterized by the presence of a mining infrastructure comprised of hydraulic canals driving the water at different levels to the mines. Mining works were associated with Plio Quaternary raña deposits and Quaternary materials consisting of hillside and periglacial deposits, and fluvial terraces. The washing of the gold deposits used the hydraulic force to break up and drag out the sediment, giving rise to three different types of exploitation depending on the characteristics of the different materials. The results shed light on the geological materials exploited and other geographical aspects that conditioned the exploitation techniques. The work contributes to improving the knowledge about Roman gold mining and its geological context in northwest Iberia.

ABSTRACT We present a detailed snow avalanche susceptibility map at scale 1:20,000 of the Circo de Gredos in the Sierra de Gredos (Iberian Central System, Spain). This cirque-shaped landscape is one of the most popular spots for winter sports in the region. However, no snow avalanche activity assessment has been conducted to date. We have, therefore, produced a snow avalanche susceptibility map based on aerial and satellite imagery, newspaper reviews and field work, including avalanche features recognition and interviews with frequent backcountry users. We extracted the spatial distribution of necessary and enhancer factors for triggering slab, wet and loose snow avalanches from a digital elevation model. Finally, calculations to evaluate each snow avalanche type susceptibility were performed using a Geographical Information System. By combining our map collection, we concluded that most of the area in the Circo de Gredos is highly susceptible to snow avalanches, especially slab and wet snow types.

We present a detailed geomorphological map of the landform assemblages originated by the two major paleoglaciers of the Sierra de Gredos mountain range in the Spanish Iberian Central System. Based on previous works, our map focused on the features formed by Gredos and Pinar paleoglaciers during the last glaciation and subsequent glacial events. Based on a remote sensing analysis and exhaustive field surveys, we identified with great accuracy the local distribution of glacial, periglacial, mass movement, structural, fluvial, and lacustrine features. We recognized three main glacial geomorphological formations representing: (i) the maximum glacial extension reached (peripheral deposits); (ii) the culmination of glacial conditions (principal moraines) and (iii) the local glacial withdrawal (internal deposits). Our map offers a renewed spatial framework on which to conduct higher-resolution glacial chronologies, especially of Late Glacial and Holocene glacial activity, providing key information for performing future paleoclimatic reconstructions of the northern hemisphere mid-latitudes.