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.

Generic Mapping Tools (GMT) is a well-known set of software originally developed for geosciences, allowing scientists in climate and solid earth disciplines to routinely create publish-ready maps and graphics. However, GMT users rarely make animations despite their undeniable benefit for understanding and teaching dynamic processes. As reading habits shift from print to digital, capitalizing on animations for illustrating scientific concepts is more accessible than ever. In the latest GMT version (6.5), we have added and refined the movie-making modules, alleviating the time-consuming steps that would hinder GMT users from making such animations. In this paper, we will explain how GMT's “movie” module works and provide six representative examples, from basic to more advanced, to show some of its key features. We hope our presentation will encourage the masses to routinely create animations for their publications.

The Patagonian Andean foreland system includes several intermountain basins filled with a Miocene non-marine record deposited under syn-tectonic conditions related to the Andean uplift and a regional climate change triggered by a rain shadow effect. Many of those basins, such as the Collón Cura basin in Neuquén Province, Argentina, present a well-preserved fluvial record (i.e. the Limay Chico Member of the Caleufú Formation). Sedimentological and palaeomagnetic studies have allowed the interpretation of coeval transverse distributary fan and axial mixed-load fluvial systems deposited between 10.6 ± 0.2 and 12.8 Ma. The basin infill arrangement shows that, while the axial mixed-load fluvial system exhibits an aggradational stacking pattern, the transverse distributary fluvial fan system denotes three different orders of stratigraphic patterns: (i) large-scale progradation of the transverse fluvial fan system over a time scale of 106 year; (ii) intermediate-scale progradational–retrogradational transverse intra-basinal fluvial fan episodes over a time scale of 105 year; and (iii) small-scale transverse lobe progradation over a time scale of 105–104 year. These patterns were interpreted as transverse sediment flux variations triggered by variable external forcings. To decouple those forcings, we estimated the Collón Cura basin equilibrium time at 3–5 × 105 year and compared it with the time scale over which different external forcings varied in the Patagonian Andean and foreland regions during Miocene times. Large-scale progradation is linked to an increase in sediment flux triggered by a long-term tectonically driven exhumation forcing associated with the Miocene Patagonian Andean contractional phase. Intermediate-scale progradational–retrogradational episodes are linked to variations in sediment flux due to a mid-term tectonic forcing associated with the western fault system activity. The small-scale fan lobe progradation is related to increases in sediment flux triggered by indistinguishable short-term autogenic processes and/or high-frequency tectonic and climatic forcings. This contribution shows the applicability and limitations of the basin equilibrium time concept to decouple external forcings from the geological record, considering their magnitude, nature and time scale, as well as the basin characteristics.

The spectacular fossil plant assemblage preserved in the non-marine Mount Flora Formation of the northern Antarctic Peninsula represents the diverse Jurassic fora that once covered the Gondwanan continents at high paleolatitudes. The depositional facies of the formation plays a key role in the tectonic interpretations and basin evolution models that attempt to reconcile large igneous province magmatism, continental break up, and magmatic arc development throughout the Jurassic and Cretaceous. Limited U–Pb in situ geochronology reported from the Mount Flora Formation and adjacent units lack the necessary resolution to overcome ambiguous correlations and biostratigraphic discrepancies. We present two high-precision U–Pb zircon ages (CA-ID-TIMS method) from a distinct tufaceous interval of the Mount Flora Formation at Hope Bay, which document a terminal Middle Jurassic age (Callovian Stage) for the formation and its paleofora. In excess of 1400 new collected fossil plant specimens exhibit a highly diverse Jurassic plant association that dominated the Antarctic Peninsula nearly 17 million years after its disappearance from northern Patagonia. This suggests similar paleoecological conditions were established diachronously throughout basins of southern Gondwana, possibly facilitating foral migrations in response to local climate change. The depositional facies of the Mount Flora Formation, its age proximity to the marine Nordenskjöld Formation in the Antarctic Larsen Basin and its coincidence with a regional unconformity in the northern Patagonia point out to a complex interplay among magmatic arc development, tectonic extension and continental break up that dominated the geologic and paleoenvironmental evolution of southern Gondwana near the end of the Middle Jurassic.

Micropaleontological analyses from the western South Atlantic core AU_Geo02_GC20 (45° 55' S; 58° 30' W, 2589 m water depth) revealed changes in the primary productivity and sea surface temperature (SST) during MIS 3 that point to significant changes in the Brazil Malvinas Confluence Zone dynamics. These changes led to a marked increase in the SST and the primary productivity between 44.0–36.1 ka BP, as indicated by the quantitative reconstruction of the subsurface temperature and the high relative abundance of the planktonic foraminifera Globigerina bulloides and the eutrophic index. The increase in the SST and the primary productivity could indicate frequent or more persistent southward penetration of subtropical waters over the north Patagonian margin due to a southward extension of the Brazil Current and a weakening of the Malvinas Current. The high primary productivity resulted in the intensive use of phosphate during spring. Conversely, benthic assemblages do not reflect high surface productivity. The dominance of calcareous nannoplankton over diatoms as primary producers, which allows inferring the shoaling of the nutricline and the thermocline, justifies the decoupling between planktonic and benthic communities as a consequence of reduced efficiency of the biological pump. The deposition of the pelagites during the period of enhanced primary productivity indicates a slowing down of the bottom circulation, probably due to a weakening of the Atlantic Meridional Overturning Circulation.

A paleomagnetic study performed in Plio-Pleistocene volcanic rocks of two localities in the Southern Central Andes is presented. The region corresponds to the transition zone between the Central and the Patagonian Andes. In the latter, deformation is almost exclusively controlled by the dextral-strike slip Liquiñe-Ofqui Fault Zone, that extends from ∼47 °S to ∼38 °S and accommodates the deformation generated by the oblique subduction of the Nazca Plate below South America. To the north of ∼36 °S, deformation is mainly contractional. Our study was carried out in the transition zone between both tectonic regimes. Sampling consisted of 31 paleomagnetic sites distributed in two localities: the Loncopué (∼38.0 °S, 70.7 °W) and Andacollo (∼37.2 °S, 70.8 °W) areas. We sampled Pliocene and Pleistocene volcanic rocks with ages younger than 5 Ma. After stepwise demagnetization and principal component analysis, site mean remanence directions were computed. Both localities show non-significant clockwise rotations of 1.7° ± 14.4° (Loncopué) and 8.1° ± 8.4° (Andacollo). Although the presently available database does not support significant tectonic rotation of the Andacollo lavas, preliminary results obtained from upper Miocene volcanics in a nearby area indicating ∼20° of clockwise rotation, encourage further studies to improve the resolution of the paleomagnetic data to determine if crustal block rotations have been, or still are, part of the Andean deformational processes. A revision of previously published paleomagnetic data in the northern Patagonian Andes suggests that, against original claims, no significant tectonic rotations associated to the Liquiñe-Ofqui Fault Zone, between ∼39 and 37.5 °S, can be unambiguously demonstrated.

The mineralogical and geochemical characterization of sediments of the Reconquista River allows analyzing the geochemical partition of trace elements in one of the most polluted water courses of Argentina. The low dissolved oxygen and high ammonia contents, together with the high chemical oxygen demand, attest to the poor water quality. Ammonia, Cd and Cu content in surficial water exceeds the maximum guidelines for freshwater in Argentina. The recent sediments of the uppermost bed are enriched in organic matter (OM), sulfur, Zn, Cu and Pb. The enrichment factor is moderate, and the geoaccumulation index (Igeo) for Cu and Pb indicates uncontaminated to moderately contaminated sediments. The positive and significant correlation between As, Cr, Pb and Zn with the iron content suggests that their retention is controlled by the amount of iron oxy (hydr)oxides in the sediments, probably combined with the silt + clay abundance. In comparison with its tributary, the Las Catonas Stream, the Reconquista River, has less OM and trace elements in the sediments and more dissolved trace elements in the interstitial water. We interpret that OM is the main sorbent of the trace element. In the absence of OM, the iron oxy (hydr)oxides and the silt + clay fraction are a less efficient substitute. Consequently, the interstitial waters of the Reconquista River are enriched in these elements. Therefore, minor changes in the environmental conditions may generate significant release of hazardous trace elements from the sediments to the interstitial water and, in turn, to the surficial water of the river. As most of the big cities and the agricultural activities of Argentina are developed on the loessic substrate, the understanding of its interaction with polluted waters is crucial.

Geological evidence indicates that the deformation along the southwest Gondwana margin began during the Middle-to-Late Devonian (the Acadian-Cháñica orogenic phase in Argentina). It has been interpreted that this deformation occurred as a consequence of the collision of Chilenia from the west and Patagonia from the south-southwest with Gondwana. As both Chilenia and Patagonia collided at the same time, in this study, we proposed that these continental blocks conform to the same allochthonous drift terrain, named here as CHIPA. The geological evolution of this margin is still under debate. Field work, paleomagnetic studies, and anisotropy of magnetic susceptibility (AMS) studies were integrated from different localities along this paleomargin in Argentina. In Permian rocks, all the geological indicators show a clear regional NW-SE elongation signature and NE-SW shortening direction. The middle Devonian to Permian patterns are more complex as the result of stress interference and the overlapping of orogenic activities with different intensities and ages. The deformation that started as the product of the CHIPA collision with Gondwana during the Middle Devonian continued through the Permian (the Hercinian-San Rafael orogenic phase in Argentina) as post-collisional compressive deformation, consequence of the paleogeographic re-organization of Gondwana and Laurentia, which moved toward the Equator from the south and the north, respectively, to form the Pangea supercontinent during the Triassic.

Historical and instrumental seismicity from 1845 to the present was compiled for the Pampean regions of Argentina and Uruguay and the adjacent continental platform. These data were analyzed using the Gapped Wavelet Transform (GWT) with the aim of investigating recurrence patterns in the time series.

The GWT analysis reveals the existence of periods of seismic activity and periods of seismic silence within the considered area. A 22-year period was determined as the main pattern of seismic activity, during which earthquakes are registered only in 11 years. Based on these results, a probabilistic earthquake forecasting model was created using the Bayesian Machine Learning method, which suggests that the current seismically active period spans from 2011 to 2023 ± 1, with a cessation until 2034 ± 1, while the next seismically active period would begin in 2034 ± 2 ending in 2046 ± 2.

These periods or recurrence patterns are interpreted as intervals during which stress accumulates throughout intracrustal faults in the studied area, being then released through various events within the established temporal interval. The accumulation and release mechanisms are still a subject of debate. However, the earthquakes distribution suggests a sublatitudinal arrangement that tends to confirm some correspondence with the controlling faulting of the Quilmes Trough and others transtensional regional lineaments.

Anomalous paleomagnetic data have been found worldwide during the Ediacaran period, giving rise to several non-actualistic hypothesis. In order to get more information about this period, paleomagnetic, magnetic fabric and rock magnetic studies were carried out in the Avellaneda Formation (∼570–560 Ma) from two drill cores of the Alicia quarry in the Olavarría area of the Tandilia System, in the Río de la Plata craton (Argentina). Anisotropy of magnetic susceptibility studies indicate a pre-tectonic origin for the magnetic fabric of this Formation. Rock magnetic studies suggest the presence of magnetite and hematite in different proportions as the main ferromagnetic minerals carrying the remanence. After stepwise thermal demagnetization, two different characteristic remanence directions were obtained for the same unit, one corresponding to the marls (“b1”) of the lower section of the Avellaneda Formation, and the other from the claystones (“b2”) of the upper section of this unit. These results were combined with the remanence directions obtained by
Franceschinis et al. (2022)
for the same unit at La Cabañita quarry, located 10 km away. This procedure allows the calculation of two paleomagnetic poles for the Avellaneda Formation. The AV1 pole is located at: 2.0° S, 311.1° E, A95: 5.0°, N: 58 while the AV2 pole is at: 3.3° N, 348.9° E, A95: 11.7°, N: 7. These results confirms that the Rio de la Plata craton also presents anomalous paleomagnetic data during the Ediacaran, implying extremely fast movements in very short periods of time. This can be interpreted as evidence of two inertial interchange true polar wander events during this time, as was already proposed by other authors. An alternative possibility suggests a non-actualistic behaviour of the Earth Magnetic Field, switching from axial to equatorial positions, with an intermediate stable position between them. The likelihood and implications of these two hypotheses is discussed.