A paleomagnetic study of basaltic lava flows exposed in the northern Neuquén Cordillera, southernmost Central Andes, along the Antiñir-Copahue fault zone (ACFZ), involved 25 sites of the Cola de Zorro Formation (Pliocene–Early Pleistocene) along two different sections. The sites show exclusive normal polarity, corresponding to the Late Pliocene Gauss chron (3.6–2.6 Ma). The angular standard deviation of virtual geomagnetic poles (VGPs; ASD = 14.8°) is consistent with the expected values from recent geomagnetic models, in opposition to anomalously low dispersion found in previous studies in Pleistocene VGPs of reverse polarity from neighboring areas to our study zone. Mean paleomagnetic directions for Bella Vista (Dec = 0.0°, Inc = −50.0°, α₉₅ = 7.6°, K = 36.7, N = 11) and Río Huaraco sections (Dec = 354.9°, Inc = −57.0°, α₉₅ = 7.5°, K = 55.7, N = 8) do not show tectonic rotation around vertical axes. Combining and regrouping our and previous data by area confirmed the absence of tectonic rotations in the Huaraco-Trohunco block and a statistically significant clockwise rotation of 14.4° ± 10.3° of three adjacent tectonic blocks located south of our study locality in Pleistocene times. These results suggest that strike-slip deformation along some sections of the ACFZ was significant in the Pleistocene structural evolution of this region.

In the Sauce Chico Complex (Neoproterozoic–middle Cambrian age; Ventania System, Argentina), polymetamorphosed carbonate xenoliths known as the Loma Marcelo skarn are hosted in an Ediacaran peraluminous granite. The skarn has three types of vesuvianite, namely a, b, and c, with different colors, habits, and/or mineral assemblages. They were studied through petrographic microscopy, electron microprobe, inductively coupled mass and atomic emission spectrometry, Raman and Mössbauer spectroscopy, X-ray diffraction (powder and single-crystal), and fluid inclusion and stable isotope analyses. The average composition of the Loma Marcelo skarn vesuvianite is [...] and corresponds to vesuvianite sensu stricto. Negligible amounts of XNa and TB were detected. Only Zn, Sr, Ce, La, and Sn are in concentrations >50 ppm. Through single-crystal XRD, the crystal structures of vesuvianite types a and b were refined in the P4/nnc space group (domains with P4/n symmetry are also present). Type c vesuvianite could not be satisfactorily refined; however, a P4/n symmetry is suspected. By comparing the Loma Marcelo skarn vesuvianite cell parameters with those of other vesuvianites worldwide, it becomes clear that symmetry does not influence these parameters. Based on Raman, single-crystal XRD data, and structural and chemical characteristics, formation temperatures of 550 °C (type b), 450 °C (type a), and 300–400 °C (type c) were estimated. The δ values of ca. +11.9‰ calculated for these temperatures from δ18O values determined on vesuvianite concentrates and vesuvianite-water fractionation factors are compatible with a peraluminous granitic source. The Loma Marcelo skarn vesuvianite appears to reflect a retrograde process related to the crystallization of the Ediacaran granite hosting the metasomatized xenoliths. During a subsequent protracted Permian tectono-metamorphic event, biphasic secondary fluid inclusions were trapped at ca. 270–339 °C (ca. 250 MPa) from low salinity metamorphic fluids. Stable isotope determinations of H and O on vesuvianite concentrates indicate that the interaction with magmatic and metamorphic aqueous fluids promoted modifications in the 2H/1H ratios of the hydroxyl groups from the W sites, whereas the 18O/16O ratios of the silicate groups were not substantially modified. Notably, the vesuvianite structure is highly stable, remaining unchanged after formation. This stability suggests that vesuvianite-group minerals could serve as a reliable XRD-based thermometer.

A geophysical survey was conducted in the Estancia Valle Daza, Utracán Department, La Pampa Province, within a 5 × 4 km area of mining interest due to the presence of critical minerals, including monazite and metagabbros with nickel anomalies. The study involved gravimetry, magnetometry, gamma-ray spectrometry, and electrical self-potential methods and represents a continuation of previous regional geophysical investigations. Residual gravity data revealed three gravimetric highs, spatially associated with bipolar magnetic anomalies reaching up to 300 nT. The largest of these anomalies is oval-shaped, with a major axis of approximately 2 km. These gravimetric and magnetic features are interpreted as responses to mafic rocks, either sub-outcropping or located at shallow depths within the crystalline basement of the study area. Gamma-ray spectrometry identified two zones with equivalent uranium contents of up to 10 ppm, comparable to the levels recorded in granitic mylonites rich in monazite from this sector. Additionally, the self-potential method was applied along a shear zone characterized by granitic mylonites containing monazite, providing further insight into the area's subsurface features. The results of this integrated geophysical approach highlight the value of combining multiple methods to enhance critical mineral prospecting in Estancia Valle Daza.

At the southern Pampean flat-slab of the Central Andes, Quaternary-active deformation is concentrated at the easternmost thrusts of the Southern Precordillera along the Las Higueras-Las Peñas range (32° 10′-32° 45′S). This range is bounded by the Las Peñas Thrust System (LPTS), which emplaces Cenozoic sedimentary rocks over a suite of Quaternary alluvial deposits under variable shortening rates. This study focuses on the southern part of this range (La Escondida Creek). Here, the east-verging Quaternary-active thrust front has been shifting toward the piedmont area since Pliocene-Pleistocene times, through discrete splays that bound four different morphotectonic domains. To unravel the shortening related to these propagating thrust splays, we applied trishear forward modeling and retrodeformation of geometric markers such as folded and faulted stratigraphic layers and well-preserved alluvial surfaces, supported by detailed topographic surveys. We compare shortening estimations derived from trishear forward models of deformed layers in a propagating thrust exposure with the data obtained from modeling the resulting thrust scarp morphology on an alluvial surface. Shortening rate assessments for the most recent footwall-propagating thrust yielded scattered values; however, the most reliable estimate is likely below 1 mm/a for this Quaternary frontal thrust.

Bioclastic phosphorites composed of linguliform brachiopod shell debris remain largely unexplored from a sedimentological, process-oriented perspective. Understanding the hydrodynamic behaviour of these low-density, platy sediments is essential for elucidating the concentration mechanisms driving their accumulation. The present experimental study delves into this issue through the determination of settling velocity and critical shear velocity of organo-phosphatic bioclasts derived from extant Lingula anatina shells (Brachiopoda: Linguliformea). A total of 137 settling velocity determinations were obtained through stroboscopic photography of the particles' trajectories in a settling tube. In all, 30 critical shear velocity determinations of five sieve fractions were acquired from flow profiles measured in flume experiments. Additionally, L. anatina shell density is here reported for the first time. Organo-phosphatic bioclasts present low particle densities (1040 to 1734 kg/m3), which combined with their platy shape grant them low settling velocities and critical shear velocities comparable to siliciclastic sediments. They thus present a tendency to be easily transported once set in motion coupled with significant resistance to erosion, defining a dual hydrodynamic behaviour like the one reported in platy carbonate sediments. Their resistance to erosion, despite their relatively low submerged weight, is here hypothesized to be explained by shape effects such as elevated intergranular friction forces, large pivoting angles and a low degree of exposure to the flow. In terms of settling, gravel-sized organo-phosphatic bioclasts are equivalent to fine-to-coarse-sized siliciclastic sand; this reflects the textural characteristics of many ancient phosphorite deposits, suggesting that settling equivalence played a role in their deposition and that the common conception of phosphatic particles as a heavy, relatively immobile component is not readily applicable to organo-phosphatic bioclasts. These results shed light on the sedimentology of ancient bioclastic phosphorites and contribute to the still underexplored field of biogenic sediment transport.

A first introduction is presented to the comparison between classical and relativistic gravitational effects related to planetary shape characterization. The Earth and the giant planets are the examples considered. The analysis is mainly devoted to relativistic and classical predictions of periastron shifts for equatorial or almost equatorial orbits around the Earth and the giant planets, which can be used as tools for determinations of the shape and density distribution. The ratios between relativistic (up to the Lense–Thirring order correction) and classical (resulting from the harmonic expansion) effects and their dependence on the orbit parameters are analyzed in order to identify the conditions improving the possibility to resolve mixed effects. In a complementary approach, predictions for freely falling test particles from relativistic corrections and classical harmonic expansions of the Earth and other planets are compared within the same shape characterization framework.

The La Hocha High (LHH), in the Upper Magdalena Basin of Colombia, consists of a crystalline basement overlain by a Triassic to Neogene sedimentary sequence up to 9 km thick. The San Jacinto Fault (SJF), is a dextral NE-SW striking positive-flower structure with subordinate Riedel shears which strikes N-S with subvertical to high dip to the west. It separates two main structural domains: (i) the La LHH and the Tesalia syncline in the western hanging wall block; and (ii) an eastern footwall block with a synclinorium with three north-south trending en echelon anticlines (shows a recumbent, tight, Z-shaped anticline dipping between 45 and 90° to the west), La Cañada and La Cañada Norte oil fields. The LHH has undergone at least five pulses of transpression between the Maastrichtian and present. Variations of the strike orientation have resulted in local flexural segments that are more transtensive to the right and transpressive to the left. Previous structural interpretations based on 2D balanced sections suggested stacking of thrust sheets detached in the basement as a result of orthogonal plate convergence. However, this new 3D interpretation, based on surface geology, well data and a recent 3D seismic survey, shows clear evidence of dextral Andean thrust components on pre-existing normal faults that controlled Triassic-Jurassic rifting.

The Oritupano-Leona Block (BOL) is located along the southern margin of the prolific Maturín Sub-Basin (Eastern Basin of Venezuela). From the available seismic interpretation, a 3D structural model for the Lower Miocene-Pliocene sequence is proposed based on three growth fault systems formed by subordinate segments in the Lower Miocene (17.3 Ma), Middle Miocene (15.35 Ma), and Late Miocene-Pliocene. The structural style is characterized by E-W synthetic normal faults dipping to the North or to the South in a regional counterslope (antithetic faulting) forming tectonic pillars and associated drag folds affected by NE-SW oriented, dextral transpressive faults dipping to the NW with overlapping ends due to lateral and vertical propagation. The faults generated the accommodation for growth strata synsedimentary with variable strengths between the intermediate and central sections of the fault segments, where traps were formed for the sandstones of the Oficina and Merecure formations. The structural morphologies are linked to a dextral transtensive system related to a flexural uplift during Oligocene-Miocene times due to the eastern translation of the Caribbean plate along the northern limit of the South American plate. This analysis provides structural criteria that contribute to the definition of strategies for exploration and development of remaining exploratory targets.

The main seismological characteristics of the Chacopampean region allow the identification of 2 different earthquake clusters: a) a shallow one of low intensity, linked to the Transbrazilian Lineament (LTB) by its intracor-tical transpressional reactivation, and b) another very deep one of higher intensity, located submeridionally in the provinces of Santiago del Estero, Chaco and Formosa, linked to the most distal expressions of the subduc-tion of the Nazca Plate. The spatial coincidence of the recent earthquake of May 31, 2022 at 0:57:06 (UTC) with hipocenter at 10 km (24.761°S and 58.211°W), with the trace of the LTB suggests its linkage by facilitating the release of energy by Andean tectonic faulting reactivation. The TL is a first-order transcontinental suture zone during the consolidation of Western Gondwana prior to the opening of the Atlantic Ocean. It is the boundary of the cratonic environments of Brazil, Argentina and Paraguay and, in its African continuation, the cratonic blocks of Benin, Togo and Algeria. In the Chacopampean region of Paraguay and Argentina, it is associated with the cratonic dextral transpressional convergence of the Rodinia and Rio de la Plata blocks, where the extensive Meso-Cenozoic sedimentary cover prevents its surface expression. However, it can be interpreted in the subsurface from the few exploration wells and geophysical surveys available (2D seismic reflection, magnetotelluric and gravimetric surveys).