Analysis of high-resolution seismic profiles from the central Beagle Channel enabled the recognition and characterization of several post-glacial subaqueous mass transport deposits in the subsurface of Bahía Ushuaia, offshore the city of Ushuaia (Argentina). These deposits are located at different stratigraphic levels and are embedded in the stratified sedimentary sequence within a deep trough, suggesting a recurrent occurrence. Up to eleven deposits have been identified, with four major events that involved estimated sediment volumes ranging from 12 to 57 million m3. The latter are associated with megaturbidite deposits up to 10 m thick. Two of the largest events postdate the early Holocene unconformity of marine transgression. The seismic data suggest a different dynamic behaviour of these four main events, with erosional, strongly disintegrating and longer-lasting pre-marine transgression mass transport events compared to the post-early Holocene deposits. Several of the deposits appear to have a common origin due to earthquake-induced failures of submerged glaciofluvial deposits or from tributary deltas. In addition, a preliminary analysis of the potential generation of tsunami waves associated with the largest submarine failures was carried out using numerical models. The results show that at least three of them would have the potential to generate dangerous waves with maximum heights of up to 1–2 m in the port of Ushuaia and estimated run-up heights between 2 and 8 m. Although further detailed analysis is recommended, particularly with regard to a more sophisticated modelling approach and refinement of the resolution of bathymetric and topographic data for strategic areas.

The tungsten-bearing veins of San Román and La Puntana mines constitute a series of quartz biextended bodies along about two km with potencies of the sub metric order that were exploited between the 40s and 70s through trenches and subsurface works. They are arranged in parallel on the contact of the metamorphic host of the San Luis Formation with the La Escalerilla Granite assigned to the lower Paleozoic, both units of the crystalline basement of the Sierra de San Luis. It is proposed that volumetric changes occurred during its late emplacement favored thermotectonic phenomena linked to the structural control of the mineralization by developing potential spaces subparallel to the vicinity of its controlled contact by the pre-existing planar anisotropies of its shale host rocks. In addition, the differential thermal contraction of the quartz during the passage from b to a, with respect to the other mineralogical constituents of the granite dome, produced during its cooling, a decrease in pressure with boiling of the pneumatolytic hydrothermal fluids enriched in immiscible elements. This mechanism generated in the domes of the La Escalerilla granite porosity and the concentration of fluids enriched in tungsten that migrated towards the overlying veins with a significant absence of greissinification and pegmatization. It is proposed that the power of the veins is related to the volumetric decrease of the intrusive throughout its contact and that they tend to thin out as they move away from the contact of the intrusive body.

The Punta Rasa Natural Reserve encompasses a system of small coastal lagoons, which are developed in a sand spit that limits with the coast of the southern end of the outer estuary of the Río de la Plata. The aim of this work is to estimate the discharge flow of groundwater from the environments of beach ridges and dunes adjacent to the coastal lagoons and evaluate how it influences the hydrochemistry of the associated lagoons and marshes. For this, a monitoring network was defined covering sampling points in the sea/estuary, coastal lagoons, and groundwater located in transects that perpendicularly cross the main body of the coastal lagoon. In each transect, water levels, pH, electrical conductivity, and 222Rn were measured in situ and samples were collected to determine the major ions. The analysis of groundwater flow profiles and 222Rn values allowed the identification of the existence of groundwater discharge flows in the three coastal lagoons. It was also possible to estimate the different components of the groundwater discharge flow and the velocity and discharge flows. Regarding chemistry, although coastal lagoons and marsh water are saline and show Na-Cl hydrochemical facies that reflect tidal flow contribution, in the areas of groundwater discharge from the dunes and beach ridges there is a decrease in the electrical conductivity of the marsh water associated with an increase in the concentration HCO−3+CO−23. This is because the water from the dunes and beach ridges is fresh to saline and has higher concentrations of HCO−3+CO−23 than sea water. Hydrodynamic differences in the three lagoons are associated with the relationship between tidal flow contributions—groundwater discharge responds to morphological changes owing to the evolution of the sand spit that encompasses the lagoons.

Our recent echo-character analysis of the Tierra del Fuego Continental Margin, focusing on Sloggett Canyon and the interfluve with Valentín Canyon, provides insights into contemporary sedimentary processes. Utilizing high-resolution seismic profiles obtained from the R/V Austral in 2017, we categorized sub-bottom echoes into 10 distinct types, shedding light on various processes such as hemipelagic deposition, mass wasting events, glacial influence, and the impact of bottom water masses. By integrating data from the GLORYS12V1 model (1993–2020), CTDs from the World Ocean Database, and sediment samples, we analyze the interaction between bottom currents, seafloor topography, and sediment characteristics. We conclude that the flow of the Subantarctic Water Mass acts as an active transport of coarser sediment from the continental shelf into the canyon, maintaining the Sloggett Canyon's activity, while the flows of the Upper and Lower Circumpolar Water Masses contribute to contourite formation along the eastern canyon flank and the erosion of the lower interfluve, leading to the generation of distinctive longitudinal scours. Additionally, in the continental rise, the interaction of water masses with the seafloor influences the redistribution of the deep-sea fans from the Sloggett and Valentín canyons towards the northeast. This study significantly enhances our understanding of the sedimentary dynamics in this area, establishing the basis of the sedimentary distribution for future interdisciplinary studies and for setting a new baseline in marine protected areas.

Stabilized and active dunes and sand sheet deposits abound in a small lake-dotted semi-arid region of the Western Pampean Dunefield, Argentina. Here, a multi-scale and multi-proxy study of three sites, across a hydrologic gradient from lakes to a dryland with groundwater levels at more than 25 m depth, analyzes calcareous and ferruginous rhizoliths, calcareous crusts, hypocoatings, pedogenic carbonate and amorphous Mn-oxide precipitates within blowout dunes. These palustrine-related features indicate significantly wetter conditions that allowed the development of shallow lakes and expanding wetlands during the Pleistocene–Holocene transition, limited by associated optically stimulated luminescence ages between ca. 14.7 and 11.6 ka. These wetter conditions, also identified in other nearby proxy records, may be associated with a strengthened South American Monsoon System, potentially during the Younger Dryas Chronozone, though other geological, ecological and climatic forcings cannot be ruled out with available data. Such a scenario lacks a modern analogue, since current hydrologic excess, evidenced in the formation of lakes and new rivers, is not observed in the localities which record paleolakes. This study underlines the variable conditions for pronounced hydrologic excess in semi-arid eolian environments in western Argentina with complex ecological, anthropogenic and climatic linkages.

We present a projectile point recovered from the archaeological locality of El Alto, province of Córdoba, Argentina. Its techno-morphological characteristics and the raw material used in its preparation are described. The results allow it to be included in the typological group of Fell projectile points. The data provided enrich the discussion about the first stages of occupation in the region, characterized by a meager archaeological record belonging to the final Pleistocene and the beginning of the Holocene.

Samborombón Bay is located on the Bonaerense coast, in the estuary of the River Plate. It has a characteristic semicircular morphology, approximately 100 km long, between Punta Piedras (to the north) and Cape San Antonio (to the south). The coincidence with the underlying Salado Basin makes it possible to trace time-space relationships between its morphology and its tectonosedimentary history. Andean exhumation brought sediments to the Atlantic passive margin. In the Pliocene there was a decrease in the rate of sedimentation due to the filling in of the environments of the Pampean Plain. The interposition of the Córdoba alluvial fan against the San Guillermo High generated the Mar Chiquita Lagoon and changes in drainage. Thus, the Las Chilcas Formation (Maastrichtian-Paleocene) sedimentation rate of ~0.09 mm/year is reduced to ~0.005 mm/year of the Puelches Formation (Pliocene-Pleistocene), with an average of 0.042 mm/year for the Eocene Los Cardos and Olivos formations. The progressive negative balance between the rate of sedimentation vs. subsidence determines that the Salado Basin is a hungry (highly receptive) depocenter that has led to the advance of the sea inland into Samborombón Bay. In this way, there are conch strands, wetlands, shallows and marshes where the development of highlands from the south favored progressive continentalization.

The Urcuschún hill is located in the morphostructural unit of the Central Precordillera, in the central-west region of La Rioja province, Argentina. In this hill, an intrusive body called the Urcuschún Pluton outcrops, which induces contact metamorphism and metasomatism in the limestones of the San Juan Formation and in the basal levels of the Paganzo Group. As a result, meta-sediments are generated from the transformation of sedimentary protoliths, along with a Fe and Mo skarn in the Ordovician limestones and, primarily, in the calcareous conglomerate at the base of the Paganzo Group.
The objective of this study is to present the petrographic and geochemical characterization of the Urcuschún Pluton. Additionally, its crystallization age was determined using the U/Pb method on zircons, resulting in a Permian age (270.39 ± 0.45 Ma).

We contribute to the definition of the mineral extraction and process-ing phases of the operational chain of pre-Hispanic mining in the west of Tinogasta (Catamarca, Argentina). We develop macro and micro scales to characterize geologically and geo-chemically the mineral resources of mines in the Los Árboles and El Salto creeks on the western and eastern slopes of the Sierra de Fiambalá. We present new ways of processing mineral ores at the El Salto-1 site, characterized by presence of rock en-gravings associated with mortars with deep cavities and heavy pounders. The methodology articulates: (i) new surveys for sample collecting and to record potential mineral extraction sites or old pits and, (ii) geochemical analyses of rock samples and a lith-ic artefact (pounder), to integrate the results with the existing and available geological background of the Sier-ra de Fiambalá. We posit that these mortars were used for crushing rocks to separate the minerals with eco-nomic value.

The Termas de Río Valdez is a low-enthalpy geothermal area located in the southernmost South America, Argentina. The area is characterized by a geologic history of changing tectonic regimes that resulted in superimposed structures. The mechanism and pathway for fluid migration of the thermal springs remains uncertain. A geophysical survey of electrical resistivity tomography profiles combined with magnetometric measurements and lineament mapping were aimed at modelling the shallow structural setting of the area. Data suggest that the springs are controlled by two systems of fractures and faults affecting the bedrock and that the rising of the thermal waters is due to transtensional structures.