The lithostratigraphy of sand injection complexes (SICs) is governed by the architectural and petrological relationships between depositional parent units and intrusive networks. During the formation and evolution of SICs, diverse geological processes can modify mineral assemblages and textures, offering opportunities to evaluate genetic mechanisms and support petrological correlations. This study integrates field mapping with heavy mineral analysis of the Paleogene succession in the San Joaquin Basin, specifically targeting the upper Eocene Tumey Giant Injection Complex (TGIC) to investigate provenance of depositional and intrusive sandstones and processes associated with injection emplacement. Statistical analysis of heavy mineral assemblages and provenance-sensitive indices (MZi, GZi, CZi and RZi) confirms the genetic link between the slope channel-fills of the Kreyenhagen Formation and sandstone intrusions. These assemblages indicate derivation from granitic and metasedimentary sources derived from the Sierra Nevada Province to the east. In contrast, the underlying shallow-marine Domengine Formation reveals mixed sourcing, with significant blueschist-facies minerals (lawsonite and glaucophane) likely supplied by the Franciscan Complex accretionary prism to the west. While low ZTR values in the parent channel-fills and most intrusions indicate mineralogical immaturity, specific intrusive facies exhibit high ZTR and low ATi, suggesting mechanical degradation of less durable grains during sand injection. Qualitative grain morphology analysis reinforces this, showing a higher degree of grain damage within intrusions in comparison to parent unit. Furthermore, density-controlled ZTi index reveals hydraulic segregation, evidenced by the progressive settling of denser zircon grains through a km-scale wing-like intrusion. The petrological signature of the TGIC is thus a function of parent unit composition, intra-granular mechanical interaction, and hydraulic sorting under dynamic fluid-flow conditions. Despite the inherent 3D architectural complexity of the intrusive networks, this study provides robust methodological tools for investigating the evolution of injectites in diverse geodynamic settings.

The Dom Feliciano Belt is one of the most extensive and best-preserved Neoproterozoic orogenic systems, forming a continuous belt from Santa Catarina (southern Brazil) to eastern Uruguay. Its paleogeographic significance within the West Gondwana framework has been refined over the past four decades through integrated structural, geochemical, and geochronological studies. U-Pb zircon dating, along with Sm-Nd and Lu-Hf isotopic systematics, constrain its geodynamic evolution between similar to 900 and 570 Ma. Orogenic history is recorded by metavolcano-sedimentary and metaplutonic units linked to magmatic arcs and Tonian ophiolitic complexes. Pre-collisional magmatism occurred in distinct arc systems, including the intra-oceanic Passinho Arc (900-830 Ma) and the continental S & atilde;o Gabriel (800-730 Ma) and Piratini (800-750 Ma) arcs. Provenance and geochemical data differentiate older, mature passive-margin successions from younger, immature arc-related supracrustal assemblages. These units record syn-depositional volcanism and sedimentation, with detrital input largely derived from Tonian arcs. The Pinheiro Machado Arc (similar to 1000 km long) represents a major Cryogenian expression of syn-to post-collisional plutonic magmatism. It is dominated by potassic granitoids evolving from high-K calc-alkaline metaluminous to peraluminous suites, followed by shoshonitic and late-stage alkaline magmatism. Isotopic data indicate partial melting of Paleoproterozoic basement rocks and contributions from mafic tholeiitic sources, revealing hybrid magmatic origins. Metamorphic ages indicate an initial collisional phase between 730 and 720 Ma affecting the Tonian arcs, followed by a peak metamorphic event between 660 and 620 Ma, marking final oceanic closure and continental amalgamation of the Brasiliano-Pan-African orogenic cycle. Post-collisional magmatism, associated with cataclastic metamorphism, persisted from 610 to 570 Ma. These data provide critical insights into crustal growth and the tectono-magmatic assembly of Western Gondwana.

Basic acid dike swarms of Piratini and Pinheiro Machado areas in the Dom Feliciano belt are intrusive in the Pelotas Batholith. They were emplaced in a shallower crustal level than the batholith. U-Pb age of 560 Ma was obtained for them. We investigated in this paper the origin of these rocks (basic, intermediate, and acid) based on mineral chemistry (K-feldspar, plagioclase, clinopyroxene, amphibole and biotite), and on petrographic and field data. The decrease in TiO2 content from core to edge of clinopyroxene (diopside-augite) suggests that its crystallization occurred from a liquid sub-saturated in silica. The high values of mg# (0.71-0.94) of the core of amphibole crystals of intermediate dikes are comparable to the experimental data of amphiboles equilibrated with primitive basalt magmas. Biotite in the discriminant diagram (FeOtotal versus Al2O3) occupy the fields of the alkaline and peraluminous suites and at the boundary of the calc-alkaline and slightly peraluminous fields. The alkaline character in TAS diagram together with the plot of part of biotite samples in the field of rocks of the alkaline suite of Abdel-Rahman (1994) suggests connection with magmatism of mantle origin that was modified by processes of crustal contamination.

An unprecedented precipitation event in Rio Grande do Sul, Brazil, between April and May 2024 caused widespread floods and landslides. This extreme event impacted 96% of the state's municipalities, affecting approximately 2.4 million people and resulting in 183 deaths. This article reports the magnitude of this extreme event, focusing on the preliminary results of a comprehensive landslide inventory. Our analysis revealed that this event triggered 15,376 landslides across approximately 18,000 km2, with 16,862 landslide initiation points. This event represents the largest landslide occurrence ever recorded in Brazil, measured by quantity. This study provides a scientific analysis of the event's scale, spatial distribution and the associated topographic, environmental and infrastructural conditions.

Geotourism is a form of tourism that uses geology as its main attraction, promoting the preservation of geodiversity and the appreciation of geological and cultural heritage. In urban settings, it connects the history of city development to the materials used in monuments and buildings. Porto Alegre, the capital of Rio Grande do Sul, stands as a true open-air architectural museum, with local rocks incorporated into its Historic Center. This study proposes the creation of a geotrail to highlight the use of rocks in urban development through the analysis of historical buildings and monuments such as the Pal & aacute;cio Piratini, J & uacute;lio de Castilhos Museum, Catedral Metropolitana de Porto Alegre, Pra & ccedil;a Matriz, Pra & ccedil;a da Alf & acirc;ndega, and Farol Santander. The main regional materials identified include Ponta Grossa and Viam & atilde;o granites, rhyolites, diabases, and sandstones from the Botucatu Formation. Jurassic limestones from France and marbles from Espirito Santo were also used. The macroscopic description of the rocks, combined with historical and architectural context, seeks to promote the integration of geology, culture, and society, reinforcing the importance of preserving Porto Alegre's historical and geological heritage.

O metamorfismo termal ocasionado pela intrusão do Granito Jaguari foi investigado através da análise petrográfica das suas unidades encaixantes, que incluiu as rochas metaultramáficas e metavulcano-sedimentares dos complexos Palma, Ibaré, Pontas do Salso, os ortognaisses dos complexos Imbicuí e Cambaí e os basaltos da Formação Acampamento Velho. A análise petrográfica de 126 amostras evidenciou modificações estruturais, texturais e mineralógicas. Os quartzitos e mármores do Complexo Palma, e as rochas metavulcanoclásticas e metassedimentares dos complexos Pontas do Salso e Ibaré, mostraram um aumento da coesão, associado ao desenvolvimento de textura granoblástica poligonal com cristais idioblásticos e com extinção homogênea, indicando ausência de pressão dirigida na recristalização. O metamorfismo termal gerou as texturas decussada, acicular e bow-tie, com o crescimento de porfiroblastos desorientados de clorita, biotita e talco, e agregados fibro-radiados de actinolita, hornblenda, forsterita e tremolita. Em xistos magnesianos e nos serpentinitos a foliação metamórfica foi substituída pela estrutura maciça dos esteatitos, clorititos e tremolititos. Nos gnaisses dos complexos Imbicuí e Cambaí as transformações se restringem a formação de clorita e muscovita com textura decussada, e crescimento de agregados de epidoto sobre os minerais máficos. O grau metamórfico mais elevado equivale a fácies hornblenda hornfels, gradando para a fácies albita-epidoto hornfels na porção mais externa da auréola. Os principais minerais índices definiram as zonas de clorita, biotita e da granada em termos pelíticos, as zonas da actinolita e hornblenda, em rochas de composição quartzo-feldspática, com as zonas da antigorita + talco e talco + forsterita nas rochas metaultramáficas. A extensão da auréola de contato varia entre 15 e 20 km e sua forma acompanha a forma do batólito granítico. Os efeitos termais nas rochas encaixantes indicam que o Granito Jaguari foi a última unidade magmática a se posicionar na região. A colocação do granito esteve relacionada a movimentação de sistemas de falhas de alto ângulo com destaque para a Zona de Cisalhamento Ibaré e da movimentação subordinada da Zona de Falha Cerro dos Cabritos, que limita a porção oeste do Rift Santa Bárbara da Bacia do Camaquã.

The Punta del Este Terrane, located in southeastern Brazil and eastern Uruguay, is a tectonostratigraphic terrane recognized in the Dom Feliciano Belt, the southern segment of Mantiqueira Province (Brasiliano Orogen). The northern sector of the terrane, called here by the Jaguarão Domain, is constituted by Arroio Telho, Arroio Grande, Matarazzo metamorphic complexes, and the Arroio Pedrado Gneisses. The first is composed of low to medium-grade metasedimentary rocks. Metasiliciclastic schists and marbles constitute the second, with serpentinites, magnesian schists, amphibolites, and metagabbros. The Matarazzo Complex comprises pure and siliceous dolomitic marble, metadolerite, and metagabbro. Arroio Pedrado unit comprises granodioritic to monzogranitic augen-gneisses. The rocks of the complexes were poly-deformed and intruded by high-K calc-alkaline peraluminous and metaluminous granitoids. The Pedro Osório, Arroio Grande, and Cerro Amaro dextral shear zones delimited the domain to the north. To the south and east, the units of the Jaguarão Domain were covered by coastal plain sediments. In gravimetric maps, the domain shows a high-density relief in contrast with the rocks of the granite belt (Pelotas Batholith). U-Pb zircon data from garnet-muscovite granites present crystallization ages of 587–568 Ma, which point to a widespread Ediacaran magmatism in the northern Punta del Este Terrane. U-Pb zircon provenance data of the metasedimentary sequences indicate main Meso- to Paleoproterozoic contribution, with subordinate Tonian to Cryogenian age populations. The geochronological results of the supracrustal rocks indicate a sedimentary deposition in an extensional setting, in which posterior deformation and metamorphism/magmatism compatible with a syn-orogenic setting in the context of the Dom Feliciano Belt framework.

Summary Sand injection complexes are important components of petroleum systems. They form sub-vertical and sub-horizontal networks of permeable sandstone reservoirs, which often contain commercial hydrocarbons. In the subsurface, defining the geometry and distribution of sandstone intrusions and their reservoir quality is challenging, and constitutes a high level of uncertainty in subsurface models. The Tumey Giant Injection Complex (TGIC) is a well-exposed, excellent analogue for subsurface injection complexes. Herein, outcrop of a km-scale wing intrusion is used to create a 2D geological template as the basis for static and seismic reservoir models. The 2D and 3D static models combined outcrop geometries, injectite facies, and rock properties data to demonstrate spatial relationship between injectite facies and to derive pore volume and their distribution. Seismic modelling used the geological template and petrophysical well data as input for 2D point-spread function (PSF) based seismic modelling to create 2D synthetic seismic data. Results show that seismic data fail to image substantial "sub-seismic" reserve volumes, and that the reservoir geometry is oversimplified. Our models confirm subsurface experience that sandstone intrusions enhance reserve volumes and recovery factors and show that well placement strategy must be cognisant of intrusion architecture to optimize volumetric estimates and hydrocarbon recovery.

Zircon U-Pb geochronology was applied to investigate the provenance, depositional ages, and paleogeography of the southwestern Gondwana in detrital and ash fall sediments from Carboniferous to Jurassic succession of the southern Paraná Basin. Four detrital age populations suggest provenance from local and distal sources located to the south, southeast, and southwest: (i) Archean to Paleoproterozoic zircons from the Rio de La Plata Craton, Nico Peres and Taquarembó terranes; (ii) Grenvillian zircons from the basement of the Gondwanides and Namaqua–Natal belts; (iii) Neoproterozoic grains from the Don Feliciano Belt; and (iv) Phanerozoic populations from Paleozoic orogenic belts and related foreland systems in Argentina, as well as eroded units of the Paraná Basin. The paleogeographic reconstruction indicates an evolution in three distinct stages: (1) a gulf open to the Panthalassa Ocean during the Carboniferous; (2) an epicontinental sea with the rise of the Gondwanides Orogeny during the Permian; and (3) continental deposits controlled by an intra-plate graben system during the Triassic. Permian–Triassic volcanogenic zircons provide constrained maximum depositional ages and attested persistent volcanism, related to the Choiyoi magmatism and effects of the climate change episodes. During the Triassic, the extensional graben system recorded the uplift of the basement through regional northwest and northeast fault systems, and the recycling of Permian zircons, modifying source-to-sink relationships.

The search for orbital cycles preserved in the sedimentary record is at the forefront of the refinement of the Geologic Time Scale. Semi-enclosed to restricted environments and epicontinental seas are suited for this type of analysis because they are very responsive to the climate conditions around the basin depocenter. This study presents the first astronomical time scale for the late Paleozoic Irati-Whitehill Sea (southern Gondwana - Parana basin) using downhole logging of HV-44-RS. Applying orbital tuning and statistical null hypothesis techniques over the natural gamma-ray, we built two floating astronomical time scales for the same record and anchored them on a new U-Pb (bentonite) numerical age of 280.8 +/- 1.4 Ma. Our results place the Irati Formation be-tween 283.68 and 280.50 +/- 2.98 (orbital tuning) and 284.27-280.47 +/- 1.41 Ma (null hypothesis), giving the vast epicontinental Irati-Whitehill Sea its most precise minimum duration so far of 3.16 +/- 1.02-3.80 +/- 0.1 Myr during the late Cisuralian. Spectral analysis suggests a depositional pattern strongly modulated by long (405-kyr) and short (similar to 100-kyr) eccentricity cycles. As an exercise, we compare one of the produced astronomical age models and recently calculated eccentricity solutions that reach the late Paleozoic interval (ZB20d). Such comparison shows a remarkable correlation in variability and amplitude with this eccentricity solution. Astro-nomical forcing is also related to black shale accumulation with periods of high organic carbon lasting-405 kyr and occurring every two long eccentricity cycles after maximum regressive surface, demonstrating a predictive pattern behind these late Cisuralian regional anoxia. Our approach indicates that the Irati Formation and other correlative southern Gondwana basins are a hotspot for cyclostratigraphy still underexplored. Furthermore, we contribute to verifying astronomical solutions in deep geological time.

The Neoproterozoic supracrustal units of the Dom Feliciano Belt in southern Brazil and eastern Uruguay provide a record of the tectonic evolution of the Brasiliano/Pan-African cycle in terms of sedimentation, deformation, and metamorphism during the western Gondwana supercontinent assembly. From the northern Punta del Este Terrane (Jaguara similar to o Domain) and neighboring Herval Complex were acquired new LA-ICPMS U-Pb and Lu-Hf zircon data from significant samples of metasedimentary rocks and intrusive granites. The central units of the domain are the Arroio Telho and Arroio Grande metasedimentary complexes, which have detrital zircon data ranging in age from 3.2 to 0.7 Ga, with prominent age peaks at 2.2-1.7 Ga, 1.5-1.0 Ga, and 1.0-0.7 Ga. The Herval Complex samples revealed a similar provenance of detrital zircon ages, with two main intervals of 1.5-1.1 Ga and 1.0-0.7 Ga, and also minor Paleoproterozoic (2.0-1.7 Ga) and Archean (2.8-2.4 Ga) ages. The maximum depositional age of the supracrustal complexes is constrained to age populations between 700 and 650 Ma. The mylonitic intrusive peraluminous granites yielded crystallization ages of ca.-570 Ma. The Neo-proterozoic metamorphic zircon overgrowths range from 680 to 570 Ma. The Lu-Hf data from the meso- to Paleoproterozoic zircons have epsilon Hf(t) values ranging from-10 to +10, with the dominance of slightly positive results, and Hf(t) model ages from Paleoproterozoic to Archean. The epsilon Hf(t) values in Neoproterozoic zircons are dominantly negative (-15 to +5) with meso- to Paleoproterozoic Hf(t) model ages. These results demonstrate that sedimentary deposition ceased and underwent metamorphism during the development of the Cryogenian/ Ediacaran arc-related magmatism of the Dom Feliciano belt. Given the scarcity of Mesoproterozoic rocks in the Mantiqueira Province and nearby cratonic areas, the obtained data suggest that these detrital populations originated in southwestern African rocks. The Congo/Kalahari cratons (Africa) are the most likely source area for Paleoproterozoic and Archean detrital zircons. The geological context and isotopic results of the investigated supracrustal complexes point to a prior extensional tectonic setting during the Tonian (-800 Ma), with regional deformation and metamorphism linked with the Dom Feliciano Belt accretionary and collisional stages (660-570 Ma).

The genesis of Precambrian granitic batholiths related to supercontinent assembly is controversial, especially regarding their generating processes and tectonic settings. The present study focused on the Pelotas Batholith (Magmatic-arc domain) of the Dom Feliciano Belt, which comprises the southern segment of the Mantiqueira Province in southeastern South America. New U-Pb and Lu-Hf zircon data from plutonic rocks with evidence of magma mixing and mingling, as well as assimilation of wall rocks, suggest multi-stage magmatism related to flare-up episodes of intense magmatism, potentially triggered by changes in the tectonic setting. U-Pb zircon analyses yielded crystallization ages of granodioritic gneiss xenolith at 691.5 +/- 7 Ma, microgranodiorite xenolith at 645.9 +/- 3.7 Ma, host monzogranite at 634.4 +/- 4.4 Ma, and intrusive syenogranite at 620.1 +/- 4.7 Ma, all intruded by syenogranitic pegmatite at 606.9 +/- 1.7 Ma. Other analyses were performed on calc-alkaline granite (633 +/- 4 Ma) and peraluminous granite (609.6 +/- 2.2 Ma). The Lu-Hf data highlights a model age interval ranging from 1.7 to 1.3 Ga with epsilon Nd values between-4 and 1, except for the pegmatite sample which also includes Paleoproterozoic and Archean model ages (3.3-1.6 Ga) and epsilon Nd values between-33 and-1. Furthermore, the acquired data, together with the gathered dataset Dom Feliciano Belt granites, emphasizes a contribution from slightly juvenile to crustal sources, with model ages ranging primarily from Statherian-Orosirian to Mesoproterozoic. Signature patterns are consistent with sources from African basement rocks.

In the Mesoproterozoic Southern Irumide Belt, Tete Province, NW Mozambique, granulite-facies metavolcaniclastic rocks and orthogneisses from the Chidzolomondo Complex provide new constraints on the subduction and accretionary phases of the belt evolution. The complex comprises a metavolcano-sedimentary succession intruded by syn- to post-orogenic granitoids, charnockites and gabbros. The paragneisses exhibit a calc-alkaline chemical composition akin to intermediate magmatic rocks found in volcanic arcs. They are interpreted as products of a three-component mixture, consisting of pelite-aluminous, quartz, and reworked mafic volcanic rocks. A paragneiss sample contains detrital zircon with ages mainly between 1344 and 1098 Ma and epsilon Hf(t) values between -10 to +7, defining a maximum depositional age of 1121 +/- 2 Ma. A charnockitic gneiss, dated at 1097 +/- 3 Ma, and a metagabbro, dated at 1061 +/- 3 Ma, respectively, represent the syn- and late-orogenic magmatic events. Both rocks exhibit juvenile epsilon Hf(t) signatures ranging from +1.5 to +4.5. The mineral assemblage of cordierite + garnet + orthopyroxene in metavolcaniclastic rocks, and plagioclase + hypersthene + diopside in the metagabbro, provide evidence of the HT-LP metamorphic conditions. Phase equilibria modeling of a paragneiss indicates that the peak metamorphic conditions reached approximately 785-795 degrees C and 3.7-4.2 kbar. By dating of zircon overgrowths in granulite-facies gneisses, we characterized the orogenic (M1) and thermal (M2) metamorphisms that affected the complex. The M1 event records the subduction-type and accretion metamorphism dated between 1092 and 1060 Ma. The M2 event, identified in the metagabbro sample close to the contact with a charnockite intrusion, yielded an age of 1023 +/- 12 Ma for the thermal metamorphism. Intrusive charnockite and a gabbro record the post-orogenic magmatism with ages of 1026 +/- 4 Ma and 1026 +/- 12 Ma, respectively. The results provide a timeline for the last orogenic events of the Southern Irumide Belt, including the maximum depositional age of the Chidzolomondo Complex at ca. 1120 Ma, syn-orogenic magmatism and metamorphism until ca. 1060 Ma, and late- to post-orogenic magmatism and metamorphism between 1050 and 1020 Ma.

The supracrustal rocks from the Zambue and Fingoe Supergroups and the Cazula Group in the Mesoproterozoic Southern Irumide Belt (SIB) of NW Mozambique provides a sedimentation record associated with the Rodinia supercontinent. The Zambue Supergroup comprises a succession of thick massive orthoquartzites and meta-ar-koses, with minor calc-silicatic schists, marble, and a basal complex of ortho-and paragneisses. The FIngoe` Supergroup and Cazula Group are composed of metasandstones, calc-silicatic schists, and metapelites interlay-ered with felsic, mafic, and ultramafic metavolcanic rocks. U-Pb and Lu-Hf isotopic determinations of detrital zircon from five key samples show similar ages for the main source rocks. Detrital zircon from the Zambue Supergroup range between 1208 and 1086 Ma in age, with a restricted contribution of Paleoproterozoic source rocks. The maximum depositional age was established at 1110 +/- 2 Ma. The Fingoe Supergroup shows zircon ages between 1233 and 1106 Ma, with a subordinate contribution of Paleoproterozoic and NeoArchean zircon grains. The calculated maximum depositional age of 1142 +/- 6 Ma is similar to the crystallization age of 1094 +/- 9 Ma obtained from a meta-andesite, and indicates the syn-orogenic nature of these volcanism. In the Cazula Group samples, the zircon ages range between 1164 and 1076 Ma, with minor Paleoproterozoic contributions. The maximum depositional ages were established at 1076 +/- 1 Ma and 1139 +/- 1 Ma. The Lu-Hf data show pre-dominantly positive epsilon Hf(t) values (+2 and +10) and TDM2 ages ranging between 1.75 and 1.50 Ga, indicating isotopic signatures of juvenile sources, with limited older continental crust contributions. The age results, the well-defined young age modes of the detrital zircon associated with the arc magmatism of the Southern Irumide Belt and the Hf isotopic composition demonstrate that the Zambue and Fingoe Supergroups and Cazula Group represent arc-related basins. Structural data indicate a complex and polyphasic evolution, with the development of the metamorphic foliations associated with Mesoproterozoic transpressional oblique tectonics, related to accretionary and collisional phases of the Irumide Orogeny (1200-1000 Ma).

Hartmann and Cerva-Alves (2021) describe a field of silicified Cretaceous Paleodunes of the Botucatu Formation present in southernmost Brazil. In this comment, we explore pressing problems of their study and demonstrate that the authors inadequately use their data to support their conclusions. We evidence that: (1) the methodology misses basic information about the used datasets, as well as petrography and geochemistry data of the Botucatu sandstones; (2) the proposed silicification model is not supported by any petrographic or geochemical data; (3) the interpretations about dune morphology, wind pattern and direction are incorrect and differ from the available eolian record for the study region; and (4) the ‘explosive’ hydrothermal hypothesis for Cerro do Jarau site is based upon a not sustainable hydrothermal model that neglects substantial evidence for an impact origin for Cerro do Jarau and is broadly inconsistent with physical constraints.

The Tonian to Cryogenian Sa similar to o Gabriel Terrane located at the northwestern portion of Dom Feliciano Belt, in southern Brazil, provides sedimentation and magmatism records associated with the Rodinia supercontinent and its subsequent deformation and metamorphism during the West Gondwana assembly. It is composed by a succession of arc-related associations including metavolcano-sedimentary and orthogneisses complexes, accretionary prism associations with mafic-ultramafic complexes (ophiolites) and passive margin metasedimentary associations. New U-Pb analyses by LA-ICPMS on detrital zircon from the supracrustal metamorphic complexes in its type-area indicate two distinct times of deposition, sources and tectonic settings. Arc-related complexes occur as parallel bodies interleaved with the metaplutonic associations- of the Passinho (0.9-0.85 Ga) and Sa similar to o Gabriel (0.78-0.72 Ga) arcs. These complexes have detrital zircon data ranging between 0.94 and 0.70 Ga and depositional age constrained at 0.68 Ga. Passive margin complexes constitute a long and continuous belt located at the eastern and southern borders of the Sa similar to o Gabriel Terrane and were deposited over the Paleoproterozoic basement. These complexes show a wide range of detrital zircon ages, between 3.6-1.62 Ga, and a maximum depositional age of 1.58 Ga. The regional mixed sources and the geological context are consistent with accumulation in a passive margin basin situated on the border of an ancient continental plate represented by the Rio de la Plata Craton. Metamorphic zircon overgrowths indicate that the arc-related complexes were accreted during a Cryogenian (0.71-0.70 Ga) collisional event. The contact between the Sa similar to o Gabriel Terrane and the Paleoproterozoic basement units located to the east and south is tectonic. The distinct geological and geophysical features of this boundary characterize it as a suture zone and emphasize its allochthonous and exotic character.