Andes Research Articles

Optical–Physical Characteristics of Low Clouds and Aerosols in South America Based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation

Clouds and aerosols, as important factors in the Earth’s climate system, have significant impacts on the atmospheric environment and global climate. This study investigated the optical and physical properties of clouds and aerosols over South America from 2006 to 2021 using CALIPSO Level 2 products. South America was divided into four regions: A (Western Andean Mountains), B (Northern Orinoco and Amazon plains), C (Southern La Plata Plains), and D (Eastern Brazilian Highlands). Seasonal variations in the optical properties of low clouds and their interactions with the lowest-layer aerosols were analyzed and compared. The results indicate that Region C had the highest OPlc (probability of low clouds) and AODlc (AOD (Aerosol Optical Depth) of low clouds, likely due to its flat terrain and westerly influences. Both AODlc and OPlc were higher in September–November compared to other seasons. DRlc (depolarization ratio of low clouds) values were higher in Regions C and D, particularly in September–February, possibly due to topographic effects and more precipitation and higher humidity during this period. The elevated CRlc (color ratio of low clouds) in Region A may be attributed to the Andes blocking warm, moist air, leading to increased precipitation and cloud particle content. HLlc (top height of low clouds) and BLlc (base altitude of low clouds) were positively correlated with geographic elevation, while Tlc (thickness of low clouds) was greater at night, potentially due to enhanced atmospheric stability. Furthermore, strong correlations among certain parameters suggested significant interactions between aerosols and clouds.

A phylogenetic analysis and new delimitation of the Neotropical genus Werneria (Compositae, Senecioneae)

AbstractThe genus Werneria was first described from six species found in the northern Andes in 1818 by Karl S. Kunth. By 1970 the number of species increased to around 50. Werneria is mostly distributed in the Andean highlands with a single species, W. nubigena, reaching as far as southern Chiapas, Mexico. Today, the genus Werneria encompasses 28 species with its center of diversity located in Peru and Bolivia. It is defined, in part, by having involucral bracts fused at least halfway and lacking a well‐developed calyculus at the base of the head. Further research indicated that there was considerable variability between Werneria species, and several species were transferred into the related genera Anticona, Misbrookea, Senecio, and Xenophyllum. Recently, it has been brought to light that the type of the genus Werneria is W. rigida, an effective lectotypification made by Rockhausen that previous authors working on this group overlooked. Since W. rigida has been accepted so far as a member of the genus Xenophyllum, Rockhausen's typification has resulted in: (1) Xenophyllum a superfluous name for Werneria; (2) Werneria a name to be applied to the species treated thus far as Xenophyllum; and (3) describing the new genus Rockhausenia to place the “traditional” Werneria species. Instead of proposing to conserve the name Werneria to avoid the aforementioned undesirable disruptions in the interest of nomenclatural stability, 30 new combinations have been made. Herein, we present the first comprehensive phylogenetic study based on ITS, trnL, ndhF, matK, and psbA sequence data involving 29 out of the 51 known species of Werneria and Xenophyllum (including the monotypic genus Misbrookea). The results indicate that: (1) the treatment of Misbrookea as a distinct genus is well supported; and (2) Werneria and Xenophyllum are each clearly not monophyletic. This, in addition to the fact that there are no diagnostic morphological synapomorphies to support either of the two genera, suggests treating them as members of a single genus. Moreover, the type of W. subg. Anactis appears to be nested in the genus Senecio. The three species belonging to this subgenus are accordingly transferred to Senecio. Finally, two subgenera are here proposed for facilitating species identification: (1) W. subg. Werneria, including species previously treated under Xenophyllum; (2) W. subg. Rockhausenia comb. & stat. nov., including the “traditional” Werneria species centered around W. nubigena.

Invading extreme environments: status of the invasion of the European hare Lepus europaeus in the Atacama Desert and the Andean highlands of the Southern Cone of South America

Invading extreme environments: status of the invasion of the European hare Lepus europaeus in the Atacama Desert and the Andean highlands of the Southern Cone of South America

Contrasting topography-vegetation relationships at natural and human-influenced mountain treelines in the Peruvian Andes

ContextThe tropical Andes have a long history of human land use, which has affected vegetation patterns especially at high elevations. However, reference patterns to quantify these effects are missing due to lacking data from mountain ranges unaffected by humans.ObjectivesWe compared landscape-scale patterns of forest distribution in the largest tropical Andean mountain range without high-elevation human occupancy, the Cordillera de Vilcabamba, and a nearby range with a long land-use history, the Cordillera de San Miguel, in Peru.MethodsWe quantified topographical positions (exposition, slope, wetness index) of 12.5 × 12.5-m2 pixels with and without forest cover in 100-m elevational bands and compared the study regions.ResultsIn the undisturbed range (Vilcabamba), forest consistently occurred on steeper slopes than non-forest, differing little in other topographic metrics except a slight preference for the less sunny South- and West-facing slopes. In the disturbed range (San Miguel), forest showed little preference for any landscape position at elevations below 3500 m, but at higher elevations patterns were very clear: forest was more restricted to valley bottoms, as indicated consistently by higher topographic wetness and lower slope and topographic position indices, and to the less sunny South-facing slopes.ConclusionsLand-use has a strong influence on landscape-level forest distribution in this part of the tropical Andes. Similar effects are likely in other tropical mountains, although no reference areas are available in most of them. The patterns described here can support the use of remote sensing to detect minimally disturbed tropical alpine-treeline ecotones, which should be focal points for conservation and research.

Early Human Foraging Paleoecology in the Highlands of Potosí, Bolivia

For centuries the Cerro Rico of Potosí in the South American Andes has been known as the richest silver mine in the world but also as a notoriously challenging place for human habitation due to its extreme elevation. Nevertheless, little is known about the temporal depth and socioecological dynamics associated with the initial occupation of this region. In this paper, we present an archaeological and paleoecological assessment of the earliest human peopling of Potosí and the eastern south-central Andes. Systematic surveys in two neighboring regions complemented by test excavations, artifact analysis, and radiocarbon dating revealed evidence of foraging occupations dating to the Early Holocene as well as by agropastoralist communities during the Late Holocene. Local paleoenvironmental records suggest that periods of increased humidity might have fostered ecological productivity that incentivized settlement in this high elevation setting. The nature of the occupations and associated technological organization is consistent with findings from sites elsewhere in the arid Andes.

Genome‐Wide Diversity in Lowland and Highland Maize Landraces From Southern South America: Population Genetics Insights to Assist Conservation

ABSTRACTMaize (Zea mays ssp. mays L.) landraces are traditional American crops with high genetic variability that conform a source of original alleles for conventional maize breeding. Northern Argentina, one the southernmost regions of traditional maize cultivation in the Americas, harbours around 57 races traditionally grown in two regions with contrasting environmental conditions, namely, the Andean mountains in the Northwest and the tropical grasslands and Atlantic Forest in the Northeast. These races encounter diverse threats to their genetic diversity and persistence in their regions of origin, with climate change standing out as one of the major challenges. In this work, we use genome‐wide SNPs derived from ddRADseq to study the genetic diversity of individuals representing the five groups previously described for this area. This allowed us to distinguish two clearly differentiated gene pools, the highland northwestern maize (HNWA) and the floury northeastern maize (FNEA). Subsequently, we employed essential biodiversity variables at the genetic level, as proposed by the Group on Earth Observations Biodiversity Observation Network (GEO BON), to evaluate the conservation status of these two groups. This assessment encompassed genetic diversity (Pi), inbreeding coefficient (F) and effective population size (Ne). FNEA showed low Ne values and high F values, while HNWA showed low Ne values and low Pi values, indicating that further genetic erosion is imminent for these landraces. Outlier detection methods allowed identification of putative adaptive genomic regions, consistent with previously reported flowering‐time loci and chromosomal regions displaying introgression from the teosinte Zea mays ssp. mexicana. Finally, species distribution models were obtained for two future climate scenarios, showing a notable reduction in the potential planting area of HNWA and a shift in the cultivation areas of FNEA. These results suggest that maize landraces from Northern Argentina may be unable to cope with climate change. Therefore, active conservation policies are advisable.

Biotic and abiotic drivers of seedling density in Polylepis rugulosa forests across east- and west-facing slopes in the Peruvian Andes

ABSTRACT Background Polylepis forests are highly endangered tropical high Andean ecosystems. P. rugulosa has had the most significant decrease in spatial distribution compared to other Polylepis species and requires adequate restoration measures. Aims This study evaluated the relationship between P. rugulosa seedling density and biotic and abiotic factors across east- and west-facing slopes to identify optimum conditions for the regeneration and restoration of the species. Methods We assessed structural, edaphic, and topographic variables in 58 plots of 600 m2, microsite characteristics in 204 quadrats of 1 m2 and related them observed to P. rugulosa seedling density. Results The density and basal area of P. rugulosa adults were higher on west-facing slopes than on east-facing slopes. On both aspects, seedling density was positively related to the height and basal area of the adult trees and negatively related to sand content and the cover of ground vegetation (shrubs and herbs). Seedling density on east-facing slopes was positively related to soil organic matter content, and it was negatively related to it on west-facing slopes. Regarding microsite characteristics, the height of the nearest adult tree and litter cover were positively related to seedling density. Conclusions Restoration of P. rugulosa should consider the contrasting effects of abiotic and biotic factors on seedling density on east- vs. west-facing slopes to optimise the recruitment and growth.

Ecological drivers of coloniality in Oreotrochilus chimborazo chimborazo (Chimborazo Hillstar), a hummingbird endemic to the High Andes of Ecuador

Ecological drivers of coloniality in <i>Oreotrochilus chimborazo chimborazo</i> (Chimborazo Hillstar), a hummingbird endemic to the High Andes of Ecuador

Gross primary productivity estimation through remote sensing and machine learning techniques in the high Andean Region of Ecuador.

Accurately estimating gross primary productivity (GPP) is crucial for simulating the carbon cycle and addressing the challenges of climate change. However, estimating GPP is challenging due to the absence of direct measurements at scales larger than the leaf level. To overcome this challenge, researchers have developed indirect methods such as remote sensing and modeling approaches. This study estimated GPP in a humid páramo ecosystem in the Andean Mountains using machine learning models (ML), specifically Random Forest (RF) and Support Vector Regression (SVR), and compared them with traditional models. The study's objective was to analyze the strength and complex nonlinear relationships that govern GPP and to perform an uncertainty analysis for future climate projections. The methodology used to estimate GPP showed that ML-based models outperformed traditional models. The performance of ML models varied significantly among seasons, with the correlation coefficient (R) ranging from 0.24 to 0.86. The RF model performed better in capturing the temporal changes and magnitude of GPP in the less humid season, displaying the highest R (0.86), lowest root mean squared error (0.37g C*m-2), and percentage bias (-3%). Additionally, the analysis indicates that solar radiation is the primary predictor of GPP in the páramo biome, rather than water. The study presents a method for deriving daily GPP fluxes and evaluates the impact of various variables on GPP estimates. This information can be employed in the development of vegetation prediction models.

Effect of bottle storage on the color, chemical composition, antioxidant activity, and physicochemical parameters of wild Andean blueberry (mortiño) wine

Andean blueberry (Vaccinium floribundum Kunth) wine, produced in the high Andean regions of Ecuador, presents a novel and promising alternative to traditional grape wines. This study aimed to characterize its physicochemical properties and chemical composition, as well as the effect of bottle storage aging on these characteristics. Results showed color shifted from deep red to yellow, over 24 months of bottle storage, reflecting changes in phenolic compounds. During storage, pH, titratable acidity, and sugar content decreased. Total phenolic content and anthocyanins decreased initially but stabilized after the first year. Antioxidant activity, measured by FRAP, increased over time, indicating potential health benefits. LC-MS/MS analysis revealed a complex phenolic profile, including anthocyanins, procyanidins, quercetin derivatives, and chlorogenic acid. This study provides new insights into the evolution of Andean blueberry wine during bottling, demonstrating that its chemical evolution is similar to that observed in blueberry wines from other varieties and geographical regions. Notably, this investigation extends beyond the previously reported 12-month stability studies for these wines, analyzing physicochemical properties and stability for up to 24 months of bottle storage. Future research could explore the effects of longer aging periods and various winemaking techniques to further enhance the wine's quality and appeal.

Experimental Center El Remanso ECER in Choachi-Colombia. A Laboratory Eco-Village to Learn and Co-build a Circular Learning

AbstractThe purpose of this article was to show the progress in the implementation of an Eco-Village that incorporated elements of bioconstruction with the use of bamboo-guadua cane framed in a circular design and integrated planning approaches for the increasing resilience in an area of high seismic risk in the Colombian Andes Mountains. Likewise, it included energy transition elements advancing towards decarbonization with the use of solar panels for electricity generation and water heating. At the same time, it integrated clean production linked to regenerative agriculture and circular bioeconomy using closed water circuits from bioprospection purification processes in internal treatment plants, equally, waterless toilets that allow the use of human waste as an input for composting and urine mixed with water for nitrogen fixation in permaculture gardens. Likewise, Experimental Center El Remanso ECER has allowed the application of Interdisciplinary education related to Ecological Engineering Education. The project is framed in the concepts and theories of bioeconomy and degrowth (Georgescu-Roegen, Latouche). An exploratory qualitative methodology was considered based on the participatory action research PAR proposals of Fals Borda. In addition to, the meeting with the traditional knowledge of the indigenous people and the peasant communities of the area in the production and cooking of food and the recovery of soils and ecosystems, as well as, the implementation of associativity processes related to the design and execution of tourist routes. As result of the research, the importance of co-creation, respect for ancestral knowledgement and the dialogue of knowledges are recognized, among others. The used of the small sample size of the different information access instruments were recognized as a limitation in the research. However, future actions linked to the results of the implementation of the PAR are been planned.

Mapping Polylepis Forest Using Sentinel, PlanetScope Images, and Topographical Features with Machine Learning

Globally, there is a significant trend in the loss of native forests, including those of the Polylepis genus, which are essential for soil conservation across the Andes Mountain range. These forests play a critical role in regulating water flow, promoting soil regeneration, and retaining essential nutrients and sediments, thereby contributing to the soil conservation of the region. In Ecuador, these forests are often fragmented and isolated in areas of high cloud cover, making it difficult to use remote sensing and spectral vegetation indices to detect this forest species. This study developed twelve scenarios using medium- and high-resolution satellite data, integrating datasets such as Sentinel-2 and PlanetScope (optical), Sentinel-1 (radar), and the Sigtierras project topographic data. The scenarios were categorized into two groups: SC1–SC6, combining 5 m resolution data, and SC7–SC12, combining 10 m resolution data. Additionally, each scenario was tested with two target types: multiclass (distinguishing Polylepis stands, native forest, Pine, Shrub vegetation, and other classes) and binary (distinguishing Polylepis from non-Polylepis). The Recursive Feature Elimination technique was employed to identify the most effective variables for each scenario. This process reduced the number of variables by selecting those with high importance according to a Random Forest model, using accuracy and Kappa values as criteria. Finally, the scenario that presented the highest reliability was SC10 (Sentinel-2 and Topography) with a pixel size of 10 m in a multiclass target, achieving an accuracy of 0.91 and a Kappa coefficient of 0.80. For the Polylepis class, the User Accuracy and Producer Accuracy were 0.90 and 0.89, respectively. The findings confirm that, despite the limited area of the Polylepis stands, integrating topographic and spectral variables at a 10 m pixel resolution improves detection accuracy.

Terminal Pleistocene–Early Holocene human occupation in north-central Chile

While a clear human presence may be recognised in the Andes by 12 000–11 000 cal BP, most archaeological research has focused on occupation of the Andean highlands. To understand the initial occupation of inland areas of South America, the authors consider regional connections and spatial exploitation strategies of hunter-gatherers highlighted in a recent survey of Andean sites. Focusing on north-central Chile, artefacts and radiocarbon dates from three rock shelters suggest sporadic and brief occupation during the Terminal Pleistocene–Early Holocene. Co-occurrence of marine and montane resources, the authors argue, demonstrates a strategy of high mobility and local adaptation in early Andean occupation, using rock shelters as landmarks to navigate and learn new landscapes.

Negotiating Collective Land Rights in the Andes: Insights from contrasting trajectories on the Bolivian-Chilean altiplano, 1880s–1930s

Abstract This article develops a historicising and comparative perspective on the transformation, formalisation, and negotiation of collective land rights in the Andean Highlands. It discusses and compares the trajectories of two highland areas situated across the Bolivian-Chilean border within the context of globally and nationally shifting frontiers of market and state integration since the late 19th century. The case studies demonstrate a striking divergence in the context of the breakthrough of liberal land legislation in Latin America. Communities in the Bolivian province of Carangas were able to resist privatising pressures, while communities of the Arica highlands, once annexed and incorporated in Chile after the War of the Pacific, adjusted to a more homogeneous regime that left little room for communal land relations. Despite the stark contrasts, this article questions simplistic dichotomic framings of the unchallenged “survival” of communal land rights in Bolivia versus complete “disappearance” of communal arrangements in Chile. Empirical archival and ethnographic data point to the social reconfigurations and creative strategies through which the community as a collective legal entity and daily practice transformed. The article sheds light on the causes and longer-term implications of these regional trajectories within the context of a globalising land regime.

Unraveling the Geodynamic Evolution of the Pre– and Early–Andean Margin: Insights From Numerical Modeling

AbstractAn outstanding question in the geological evolution of the Chilean Andes is the cause of the westward shift and relocation of magmatism from the High Andes (HA) to the Coastal Cordillera (CC) during the Late Triassic, Pre–Andean stage. The spatiotemporal distribution of Permian–Triassic–Jurassic igneous rocks in northern‐central Chile (20°S–32°S) reveals a significant westward magmatic shift of ∼120 km during the Norian time. Despite diverse proposed models, the precise geodynamic mechanism behind this shift remains unclear. To address this, we used 2D numerical modeling to investigate two contrasting scenarios: (a) subduction rollback and (b) subduction transference/jump and reinitiation by terrane accretion. Our modeling results strongly support Scenario B, where mantle density and the size of the oceanic plateau are crucial for triggering subduction jump and reinitiation. This model aligns with geological and geophysical evidence and offers new insights into unraveling the Pre– and Early–Andean evolution.

Joining to the web. Predation of Heterophrynus sp. (Amblypygi: Phrynidae) on a catfish Astroblepus sp. (Siluriformes: Astroblepidae), in a premontane river of the northern Andes of Colombia

Riparian food webs are linked by cross-boundary resource fluxes, including the consumption of terrestrial invertebrates and vertebrates by fish and the consumption of aquatic vertebrates by terrestrial invertebrates, mostly arachnids. Amblypygids prey upon a wide array of vertebrates, but no records on fishes are known. Here we report an interesting predation event of an adult Heterophrynus sp., upon a catfish Astroblepus sp. in the Rio Manso, northern Andes of Colombia, and summarized the published information of trophic interactions of this river in a food web framework. A high prey-size ratio (0.87) respect to Heterophrynus sp., highlight that fishes could represent an important food item for amblypygids. This datum, besides other published before, indicates that the consumption of terrestrial and aquatic vertebrates by terrestrial invertebrates can be a substantial cross-boundary flux link in tropical montane streams deserving future ecological studies.

Unravelling the distribution of mycorrhizal plants in the Colombian páramos

AbstractThe tropicalpine páramo stands out as a unique biodiversity hotspot located in the northern Andes. Over the last decades, páramo plants and animals have been increasingly studied, yet a critical knowledge gap remains on their microbial ecology. Given the crucial importance of mycorrhiza in structural and functional communities, our study aimed to explore their geographic distribution in the Colombian páramos. Specifically, we used information about their host plants as a proxy and modelled their current distribution to unravel spatial patterns related to mycorrhizal status and mycorrhizal types. We constructed species distribution models for 440 vascular plant species representatives of the Colombian páramos using a combination of climatic and edaphic variables. Then we stacked the models following species classification into their mycorrhizal type: arbuscular, ectomycorrhizal, ericoid, orchid, and non-mycorrhizal. Our results suggest that the abundance of mycorrhizal species decreases with increasing elevation and in the west-to-east direction. The arbuscular type of mycorrhiza is chiefly dominant and spreads out widely throughout the Colombian páramos. The other types showed singular patterns, with (i) species having ericoid mycorrhiza being abundant in both the southern (Nariño–Putumayo) and the northern páramos (Sierra Nevada–Perijá); (ii) species with orchid mycorrhiza being abundant in the Western Cordillera and overall at low elevations, (iii) ectomycorrhizal species being absent, and (iv) non-mycorrhizal species being widely spread and reaching high elevations. Our study highlights the potentially high level of mycorrhization of this alpine system and contributes new spatial and environmental information towards a better understanding of mycorrhizal biogeography in tropical mountains.

Spatial Connectivity Through Mountains and Deserts Drove South American Scorpions Dispersal

ABSTRACTAimThe aim of this study is to infer the geographic dispersal paths and the environmental conditions that shaped the historical biogeography of Brachistosternus scorpions in South America. We evaluated the role that altitude and aridity had on the geographic distance that each species dispersed from the location of the genus common ancestor. Based on the previous studies, we evaluated the hypothesis postulating that species geographic expansion was promoted by arid conditions in high altitudes.LocationSouth America.TaxonBrachistosternus genus.MethodsWe integrated two methodological approaches in this study, the phylogenetic Geographical model and the Conductance model, considering the uncertainty associated with the phylogenetic relationship and the species classification. The Geo model infers the locations of ancestral species in a phylogenetic tree, assuming a spherical space and using samples of georeferenced locations for every species as input data. It allows us to estimate the species dispersal routes and distances from the location of the genus common ancestor. The Conductance model is based on the circuit theory and infers the geographic route and distance of least resistance between an origin and destination point. We defined the origin as the location of the genus common ancestor obtained from the Geo model and a destination point as the current geographic location of each species. This model infers the geographic routes with the least cost of resistance for dispersal in a landscape of varying altitude and aridity. Finally, we evaluated the correlation between the two dispersal distances each species have moved from the location of the common ancestor, that is, the distance inferred from the Geo model and from the Conductance model.ResultsThe Geo model shows that Brachistosternus's geographical origin was most likely along the coast of south Peru, and central Chile. From this location, extant species dispersed thorough routes ranging from 873 to 2800 km in average. The Conductance model that considers the routes with least resistance to elevation and aridity simulated dispersal distances that are highly correlated with the species dispersal distances obtained from the Geo model.Main ConclusionsWe revealed the geographic dispersal routes, with the least resistance to the pressures imposed by changes in altitude and aridity, that 55 species of scorpions have probably followed in the last 30 million years in South America. These geographic routes that went along the Andean Mountains and the arid zones of South America shaped the current spatial distribution of the genus Brachistosternus.

Mapping Tropical Dry Forest Gradients in an Andean Region with High Environmental Variability

Tropical Dry Forest (TDF) is one of the most threatened terrestrial environments in the neotropics because of high rates of conversion to agriculture. Despite this high degree of threat, many regions lack detailed maps on the actual extent and boundaries of their TDFs, which is fundamental information for their conservation. We developed a methodological framework to map TDF at 10 m in regions where they grade into other forest types. The approach uses climate variables, altitude, soil properties, and remote sensing data (multispectral and SAR − Synthetic Aperture Radar-SAR imagery) to predict TDF in the Department of Caldas, Colombia. Accuracy of the resulting map was confirmed with field observations (Overall Accuracy = 0.88, Kappa = 0.73, Area Under the Receiver Operating Characteristics Curve = 0.87, and True Skill Statistic = 0.73). We estimated ∼ 54 km2 of TDF, which represents 9.2 % of its potential area of occurrence in the study area. TDF gradually transitions to Tropical Moist Forest (TMF) from two main low altitude river valleys to higher altitudes in the Andes Mountains. With modification, our methods could be applied for mapping TDF in other tropical regions.

Petrogenesis and tectonic setting of mafic magmatism within the Laguna Amarga Metamorphic Complex, Andes of Catamarca, Argentina: Insights into the opening of the Cuyania/Precordillera terrane from the Ouachita rift

Neoproterozoic crystalline basement rocks are exposed as fault-bounded blocks over the high Andes of Catamarca. The crystalline basement is stratigraphically grouped into the unique Laguna Amarga Metamorphic Complex and represents the northern extension of the Cuyania/Precordillera terrane. Tabular bodies of meta-mafic rocks are widespread in the basement interspersed within a thick sequence of meta-sedimentary rocks derived from siliciclastic, calc-silicate, and limestone protoliths. Overall, the geochemical characteristics of meta-mafic rocks are in the compositional range of Normal-Mid Ocean Ridge Basalt (Normal-MORB), reflecting a common depleted-mantle source with varying degrees of partial melting. While preserving the typical bulk chemistry of MORB magmatism, some mafic magma underwent differentiation at emplacement, leading to the development of high-Ti mafic rocks. New U-Pb zircon geochronology reveals three distinct age peaks, with two coinciding with ages identified in the metasedimentary host rocks. The dominant Mesoproterozoic age cluster is linked to inherited zircon crystals assimilated within a single meta-mafic rock. In contrast, zircon ages from the late Ordovician to early Devonian are attributed to metamorphic overgrowths. Notably, the third age cluster, delineates a Late Neoproterozoic magmatic event, indicating the temporal span of mafic magmatism. The finding agrees with the best available age (576 ± 17 Ma) for mafic magmatism on the Precordillera Mafic-Ultramafic Belt. Stratigraphic relationships and geochemical fingerprints enable correlation among the meta-mafic rocks from Laguna Amarga, tracing a belt of mafic magmatism with an oceanic affinity that extends southward. Building upon previous works, this study reaffirms that the rift-drift transition of the Cuyania/Precordillera terrane, linked to the Ouachita rift opening from southeastern Grenville, evolved during the latest Neoproterozoic.