Early Devonian magmatism in the Minusinsk trough of the Altai-Sayan Large Igneous province provides a critical record of regional geologic history. In this study, we determined the U-Pb baddeleyite isotope age, major and trace element geochemistry, and Sr-Nd isotope composition of igneous rocks in the Uryup sector of Minusinsk trough, with the aim of constraining their magmatic origin. The volcanic succession is divided, from base to top, into three Suites: (1) the Bazyr Suite, composed of basalts, trachybasalts, basaltic trachyandesites, transitional tephrites-trachybasalts, and phonotephrites; (2) the Beresh Suite, consisting of trachybasalts, basaltic trachyandesites, phonotephrites, tephriphonolites, and feldspathoid ijolites; and (3) the Ashpan Suite, comprising basalts, trachybasalts, and basaltic trachyandesites. The Early Devonian age of these Suites, established in previous geological and palaeontological studies, is confirmed here by new U-Pb geochronological data on baddeleyite obtained by ID-TIMS. Rare-element concentrations in all mafic rocks, regardless of alkalinity, vary widely, showing features typical of both oceanic island basalts and island arc basalts. Compared with sub-alkalic counterparts, alkalic mafic rocks contain abundant nepheline phenocrysts (up to 30 wt.%) and are enriched in Na2O, Al2O3, Rb, Ba, Th, U, K, Nb, REE, and radiogenic Sr, while exhibiting similar and only slightly variable radiogenic Nd values. We propose a model in which all Uryup sector rocks were derived from a single sub-alkalic basaltic parental melt generated in the asthenospheric mantle by the influence of a mantle plume on fragments of ancient supra-subduction lithospheric mantle. Geochemical and isotopic variations are inconsistent with a simple comagmatic relationship between sub-alkalic and alkalic rocks or with fractional crystallization as the sole controlling process. Bazyr sub-alkalic basaltic magmas experienced simultaneous fractional crystallization and contamination by silicate crust. Beresh phonotephrites, tephriphonolites, and feldspathoid ijolites formed from differentiated sub-alkalic melts through carbonate contamination, possibly within the continental crust.

In situ U-Pb geochronology, Sm-Nd isotopic analyses, and geochemistry of mafic and ultramafic rocks of Matthews Ridge, NW Guyana: new insights into the geodynamic evolution of the western Paleoproterozoic greenstone belt of the Guiana Shield. We investigated a suite of metamorphosed mafic and ultramafic rocks from Matthews Ridge (MR), NW Guyana, to characterize their magmatic history through geochronology and geochemistry. Three petrographic groups were defined: MR-1 (meta-gabbros), MR-2 (meta-ultramafic cumulates), and MR-3 (meta-basalts). U-Pb SIMS dating of zircon and baddeleyite yields ages of 2100 +/- 35, 2125 +/- 25, and 2152 +/- 42 Ma for MR-1, and 2222 +/- 12 Ma for MR-2. Although undated, MR-3 displays Nd isotopic signatures suggesting coeval formation with MR-2. All petrographic groups exhibit low, uniform Th/La (0.07-0.10) and Sm/La (0.5-1.1), consistent with derivation from a depleted mantle source. Slightly positive initial epsilon Nd values indicate interaction between depleted and enriched mantle reservoirs. Comparisons with other Paleoproterozoic greenstone belts in the Guiana Shield show that western domains, including Matthews Ridge, record less crustal or sedimentary input than those to the east. Tectonic discrimination diagrams reveal little arc affinity, except for two MR-1 samples. Instead, geochemical features support an intra-oceanic origin: MR-3 likely formed at a mid-ocean ridge (similar to 2.22 Ga), whereas high-FeTi rocks in MR-1 and MR-3 reflect mantle plume influence similar to 2.1 Ga. This supports a model where Matthews Ridge magmatism reflects oceanic plateau development, similar to Block B of the El Callao Mining District in Venezuela.

The Tachdamt and Bleida formations from the Bou Azzer-El Graara inlier (Central Anti-Atlas, Morocco) record two distinct Neoproterozoic magmatic episodes that were previously grouped as a single unit. In this study, we present new whole rock major and trace elements geochemistry alongside samarium-neodymium (Sm-Nd) isotopic data for representative volcanic and volcano-sedimentary rocks from both formations. Uranium-lead (U-Pb) zircon dating from previous studies confirms emplacement ages of similar to 883 Ma for the Tachdamt Formation and similar to 700 Ma for the Bleida Formation. The temporal separation and geochemical distinctions between these formations demonstrate two independent magmatic events. The similar to 883 Ma Tachdamt Formation coincides in age with the Munali magmatism (similar to 880-860 Ma) in the Greater Congo Craton; although a direct geodynamic link remains uncertain, this age similarity suggests both events formed during a broader Neoproterozoic extensional phase. Geochemical signatures further differentiate the two pulses. The Tachdamt basalts exhibit tholeiitic affinities, high iron-titanium (Fe-Ti) contents, enrichment in LILE, and positive neodymium isotopic values [epsilon Nd(t) = +3.2 to +4.5], consistent with plume-related magmatism in a Tonian large igneous province (LIP). In contrast, the Bleida basalts display negative niobium (Nb) anomalies, greater geochemical variability, and older depleted mantle model ages (TDM = 1.1-1.3 Ga), indicating an arc-influenced lithospheric mantle source in a foreland basin setting. These contrasting signatures record a geodynamic transition from extensional, plume-driven rifting (Tachdamt) to subduction modified magmatism (Bleida) along the northwestern margin of the West African Craton (WAC). Additional dolerite dykes crosscut both formations, marking a younger magmatic phase and exhibiting orientations similar to the similar to 860 Ma Manso dyke swarm; further U-Pb dating is required to clarify their provenance. Overall, our new geochemical and isotopic dataset refines the Neoproterozoic tectonic evolution of the Anti-Atlas and provides critical constraints on the broader magmatic and rheological history of Rodinia's break-up.

The Imiter Ag District, situated in Morocco’s Anti-Atlas belt in the northwestern edge of the West African Craton, hosts silver-rich base metal mineralization across several sectors, including Imiter I, Imiter II, Imiter South, and Igoudrane. The mineralization is characterized by sub-horizontal ore bodies, steeply dipping north-trending veins aligned with major faults, and low-angle south-dipping veins associated with large-scale fault zones. A key factor in the formation of this world-class and extensive mineralization is the persistent and robust magmatic source, coupled with significant tectonic structures linked to asthenospheric mantle reservoirs. This study combines field observations, electron probe microanalysis, and isotopic data with a review of previously published geochemical and U-Pb zircon ages from magmatic rocks to trace the origin of lead in silver-associated galena. Pb isotopic data reveal three distinct lead signatures corresponding to three geological episodes: Pb1, associated with Late Ediacaran magmatism; Pb2, linked to Hercynian orogenic hydrothermal processes; and Pb3, attributed to Alpine magmatism. The primary mineralization (Pb1) is related to Late Ediacaran high Sr/Y intrusions at Bou Fliou (582 Ma) and Igoudrane (538 Ma), as well as dykes controlled by the crustal-scale Imiter Fault. Precious metal remobilization (Au, Ag) is associated with magma derived from the delaminated lower crust and a former subducted slab during post-collisional processes, with significant mantle-derived magmatic input. Dykes play a role in mineralization by acting as conduits for mineralizing fluids. The formation of magma-related mineral deposits in the Imiter region is attributed to a regional metallogenic event during the Late Ediacaran Large Igneous Province (590–540 Ma), a period of extensive magmatism that was critical for the development of intrusions-related mineral deposits in the Anti-Atlas belt.

Understanding planetary habitability is one of the major challenges of the current scientific era, particularly given the discovery of a large and diverse terrestrial exoplanet population. Discerning the primary factors that contribute to planetary habitability may be extracted through a detailed examination of the terrestrial planets within the Solar System, most particularly Venus, Earth, and Mars, and the evolution of their interiors and atmospheres through time. Here, we provide a detailed description of the fundamental properties of these three planets, the effects of solar evolution, and the potential contributions of these various aspects toward driving their evolutionary pathways. We argue that evolution of Venus, Earth, and Mars provide essential templates from which a more comprehensive approach toward the study of planetary habitability may be derived.

The timing and mechanisms by which the supercontinent Nuna broke up are still enigmatic, although the details have implications for global tectonic activity through Mesoproterozoic periods of alleged quiescence. The proposed breakup time of Nuna has ranged from ca. 1.6 to 1.2 Ga based on the episodic eruptions of large igneous provinces (LIPs) and associated large-scale continental rift systems. Paleomagnetic data from Proterozoic cratons can quantify their motions and directly test these competing inferences. In this study, new paleomagnetic results, which passed baked-contact tests and a reversal test, are reported from 32 dikes from the North China craton (NCC). An isotope dilution-thermal ionization mass spectrometry (ID-TIMS) baddeleyite date from one of these dikes constrains dike emplacement at 1235.6 +/- 2.0 Ma, which provides a new, well-dated paleomagnetic pole (27.7 degrees N, 168.5 degrees E, A95 = 5.0 degrees) for the NCC. Combined with the previously published 1.45-1.04 Ga paleomagnetic and geologic data from Laurentia, the NCC, Baltica, and Australia, the divergence of their apparent polar wander paths suggests that the core of Nuna (Laurentia, Baltica, and Siberia) broke up with East Nuna (Australia and the NCC) at ca. 1.38 Ga. Thereafter, the breakup of East Nuna, denoted by the separation of the NCC and Australia, occurred after ca. 1.32 Ga, and the breakup of the core of Nuna, denoted by the breakaway of Baltica from Laurentia and Siberia, occurred at ca. 1.26-1.22 Ga. The stepwise breakup process of Nuna was similar to that of Pangea, providing evidence for a robust tectonic regime in Earth's middle age.

Theia Mons (centered at 23.4 degrees N, 79.4 degrees W) is the main volcanic center for the Beta Regio plume, of the Beta-AtlaThemis (BAT) region, Venus. Synthetic aperture radar data (SAR) and altimetry data from the 1989-1994 NASA Magellan mission were used to produce a geological map and history of Theia Mons, revealing two distinct magmatic centers (200 km apart), each the focus of basaltic lava flows, extensional lineaments (representing the surface expression of dyke swarms), and associated rift zones. The study area spans 88 degrees W to 72 degrees W, 16 degrees 45 ' N to 29 degrees 45 ' N, and mapping was at 1:500,000 scale. Our detailed mapping makes this area a prime target for the future Venus missions (orbital and lander), also given that Beta Regio is a strong candidate for ongoing volcanic activity. Lava (basaltic) flow units (88 distinguished on the basis of variation in radar backscatter) belonging to Theia Mons volcano were combined into 19 Flow Groups and then into 3 Flow Packages. The lava flows appear to diverge from two distinct magmatic centers, labelled Center 1 (24.5 degrees N, 78.1 degrees W) and Center 2 (23.4 degrees N, 79.4 degrees W), with the older Center 1 being obscured by the volcanism of the younger Center 2. Center 1 consists of flows with low radar brightness and which extend to a maximum to 830 km from the center. Center 2 coincides with the currently preserved central caldera and consists of lava flows of low radar brightness with a maximum length of 620 km, followed by a second pulse of radar-bright flows that are less extensive and concentrated near the center. About 10,000 extensional lineaments (grabens, fissures, and fractures) were mapped and grouped into 19 systems, of which 15 are interpreted to overlie dyke swarms: 2 radiating systems are associated with Centers 1 and 2, and 13 other systems belong to other (older and likely unrelated) magmatic centers in the region. A partial circumferential swarm may also be present, associated with Center 2. Four other extensional lineaments sets are inferred to represent sets of normal faults associated with rift zones (Devana and Zverine, and additional rift zones). These rift zones exhibit two sets of 'triple junction' geometry, which are approximately also focussed on the same Centers 1 and 2, revealed by the lava flows and rift zones. An underlying mantle plume is interpreted to be responsible for the dykes, flows and triple junction rifting. The cause of the shift between Centers 1 and 2 (200 km to SW) is unknown, but plausible mechanisms include a shift of the lithospheric plate above a stationary single plume, or a bending of the mantle plume (e.g. in a mantle wind) between timing of Center 1 and Center 2 activity.

The Imiter deposit is a significant silver-rich base metal deposit. The deposit is primarily composed of sub-horizontal ore bodies located at the contact between the Saghro Group (SG) shales and Ouarzazate Group (OG) volcaniclastics. Silver mineralization occurs as steeply dipping north-trending veins, gently south-dipping veins, and stockwork ore within conglomerates, tuffs, and andesites. The ore mineralogy includes Ag-Hg amalgam, argentite, polybasite, tetrahedrite-tennantite, proustite-pyrargyrite, acanthite, chalcopyrite, arsenopyrite, pyrite, sphalerite, and galena. Lead isotopic data from galena reveal two distinct groups, indicating two origins for mineralizing fluids: one crustal and one mantle-derived. The silver deposits are closely associated with a swarm of mafic to felsic dikes with varying orientations: NE to N70 in the SG and N-S to N10 in the OG. The first group of dikes is characterized by initial Nd-143/Nd-144 ratios of 0.511787-0.511970, moderately negative eNd values (-0.15 to -2.78), and older Nd model ages (1.3-1.7 Ga), suggesting a locally enriched mantle source or enhanced crustal contamination. The second group exhibits initial Nd-143/Nd-144 ratios of 0.511885-0.512075, Nd model ages of 1.00-1.29 Ga, and positive eNd values (0.02-2.84), indicative of a juvenile source.

The Americano do Brasil and Mangabal complexes belong to a cluster of Neoproterozoic mafic-ultramafic intrusions in the southern Goi & aacute;s Magmatic Arc in Brazil. Both complexes were highly deformed and metamorphosed under amphibolite facies, leaving few igneous relict domains. We have documented the mineralogy and texture of the poorly exposed rocks of the Americano do Brasil and Mangabal complexes. We use diverse analytical methods, encompassing petrography, mineral chemistry, geochemistry and thermodynamic modelling, with the principal objective of elucidating the intricacies of secondary alteration processes and offering insights into the complex metamorphic history of the complexes. The rocks of both complexes show intense amphibolitization associated with the most highly metamorphosed rocks. The construction of pseudosections suggests a temperature between 670 and 710 degrees C and pressure up to 7.5 kbar at amphibolite facies conditions. In some amphibolite samples, we note unusual minerals such as kyanite, sillimanite, muscovite, silvialite (a sulfate-rich member of calcic scapolite) and/or anhydrite. We attribute some unusual assemblages to open system behaviour during metamorphism, probably related to metasomatism surrounding diorite veins that are inferred to have released fluids rich in CO2, Ca and SO3. However, this open system behaviour and fluid circulation do not seem to favour Ni-Cu mineralization.

A NNW-trending mafic dyke from the central-western Bastar craton yields a U-Pb ID-TIMS baddeleyite age of 1944 +/- 6 Ma. By correlating additional dykes with similar trend and geochemical characteristics, we identify a previously unrecognized dyke swarm, named herein the Pakhanjore swarm. Geochemical evidence suggests that the studied rocks are derived from partial melting of a spinel-rich, shallow lithospheric mantle source, involving 5-15 % partial melting as indicated by the non-modal batch melting model. AFC (Assimilation and fractional crystallization) modelling further reveals that fractional crystallization with moderate crustal assimilation (r = 0.3) contributes to the overall magmatic evolution. The similarity in trend of the ca. 1.94 Ga Pakhanjore swarm with the 1.89-1.88 Ga Bastanar swarm, and the ca. 1.85 Ga Sonakhan swarm of the Bastar craton suggests their emplacement occurred within a shared tectonic regime and/or paleostress field. Although notable geochemical similarities exist between the ca. 1.94 Ga Pakhanjore swarm and the 1.89-1.88 Ga and ca. 1.85 Ga mafic dykes, a direct genetic linkage remains inconclusive. However, based on available geological, geochronological, and geochemical data, the 1.89-1.88 Ga and ca. 1.85 Ga swarms appear to be part of a shared LIP event, whereas the ca. 1.94 Ga event likely represents an independent magmatic episode. The spatial alignment of all three dyke swarms with the NNW-trending Pranhita-Godavari Basin suggests a potential tectonic connection.

Avanavero mafic dykes and sills are widespread in the Amazonian craton, South America. Although the complete extent of Avanavero magmatism is currently unclear, similar intrusions have been found in places where it had not been previously mapped such as Matthews Ridge, NW Guyana, the focus of this study. We present new geochemical, U-Pb geochronology, and Sm-Nd isotopic data for Matthews Ridge dykes and sills, and a comparison with Avanavero samples from the literature. Our new in-situ U-Pb analysis on baddeleyite grains by SHRIMP yielded an age of 1787 +/- 12 Ma, which overlaps within error both the SHRIMP and the ID-TIMS ages reported in the literature and confirms that the unmetamorphosed dolerites from NW Guyana are part of the Avanavero large igneous province (LIP) event. Geography and geochemistry indicate the presence of two groups of Avanavero mafic intrusions. Group 1 includes occurrences in the north of the Guiana Shield (including the units in Matthews Ridge) and are characterized by mostly low Ti concentrations; Group 2 is limited to occurrences in southern Guiana Shield and have high Ti concentrations. Fractional crystallization pathways differ between the groups, with olivine playing a significant role for Group 1, and olivine + clinopyroxene + plagioclase for Group 2. Distinct Ca/Al ratios may suggest different parental magma and varying degrees of crustal contribution within Group 1. The isotopic data suggest that Group 1 and Group 2 are cogenetic and represent different magma batches that came from the same source by potentially different fractionation paths. The low negative to low positive epsilon Nd values, together with low Nb/Yb, indicate that the samples from both groups are consistent with a continental intraplate setting where primary magmas were contaminated by the lithospheric mantle previously metasomatized during an earlier subduction event.

When an ascending mantle plume arrives beneath a small craton and encounters ambient orogenic extension, what is likely to happen? We explored this scenario through considering the case of the Tarim mantle plume and the mafic-ultramafic intrusions in the southern Central Asian Orogenic Belt (CAOB). This mantle plume, which arrived beneath the Tarim craton, one of the smaller cratons on Earth, lasted from 300 Ma to 270 Ma with peaks at 290 Ma and 278 Ma. Synchronously, the CAOB was at the late orogenic extension stage with an eastwardpropagating, scissor-like closure of the Paleo-Asian Ocean. Ni-Cu sulfide deposits hosted in mafic-ultramafic intrusions are typically associated with mantle plume events. However, an increasing number of Ni-Cu sulfide deposits are recognized as being emplaced in an associated orogenic setting, such as those associated with the southern CAOB. We observed that the number of mafic-ultramafic intrusions decreases with increasing distance from the Tarim craton (from the Tarim plume), and these intrusions show a 7-8-m.y. time lag in their emplacement ages (295-255 Ma, with peaks at 293 Ma, 282 Ma, and 271 Ma) with respect to the timing of Tarim large igneous province magmatism (300-270 Ma) within the Tarim craton. These unusual geochronological and tectonic links suggest that the plume materials were escaping to the northeast along an extensional belt in the southern CAOB, which is perpendicular to the inferred circular boundary of the plume, resulting in the formation of orogenic-style Ni-Cu sulfide deposits and a continuous magma supply from the deep mantle, prolonging the lifetime of the Tarim plume.

The Amazonian Craton is host to one of Earth's largest Proterozoic silicic large igneous provinces (SLIPs), the Orocaima SLIP (ca. 1.98 Ga). Nevertheless, the mechanism(s) responsible for this large-flux felsic magmatic event and its relationships with regional tectonics and/or mantle processes remain debated. New geochronologic and geochemical results from multiple mafic dike swarms in the Amazonian Craton, namely the Guaniamo, Rio Aro, El Manteco-Supamo, and Goboy swarms, reveal a close temporal, spatial, and geochemical association with the Orocaima SLIP. The radiating arrangement of these swarms spanning 90 degrees of arc, their strongly tholeiitic geochemical affinity, and their short-lived emplacement ca. 1.98 Ga including in regions far from any inferred subducting plate margins all strongly suggest: (1) an intraplate, plume-related origin, and (2) a radiating arrangement defining a plume center located at similar to 2.5 degrees N, 61.2 degrees W, near the SW margin of proto-Amazonia at the time and coinciding with the location of the Takutu graben. Discovery of this previously unrecognized radiating swarm array, herein grouped within a proposed Yanomami large igneous province, and its close spatial and temporal association with the Orocaima SLIP suggests a plume-triggered origin for SLIP development, thus arguing against accretionary models for the origin of the Orocaima silicic magmatic belt.

The NASA Magellan Mission (1990 to 1994) produced a valuable resource that planetary geologists continue to use three decades later to unravel the geological characteristics of Venusian Large Igneous Provinces. The ability to be the first to map the surface of Venus is a powerful engagement tool to inspire the next generation of planetary geologists, as illustrated by the size of the Mount Royal University (MRU) Venus geological mapping team (now 25, nearly ¼ of the MRU Geology Major program). MRU is a public undergraduate university. Students are recruited out of 1st and 2nd year courses. In year one (Y1) of the research program students learn how to use the ArcGIS software while being introduced to the geological features of Venus as they map their quadrant, in Y2 or Y3 the students present a poster at an internal research day. The goal by Y4 is for these students to publish a peer-reviewed journal article. Currently one student who ran into pandemic roadblocks through high school could be published while she upgrades her marks, before she is in the MRU Geology Major Program. Such opportunities could prove to be incentives to guide other students past similar roadblocks (we will start working with local junior and high school students in the near future). Collectively we are working towards completing the geological map of the Henie Quadrangle (V-58, south Venus). Detailed mapping (at 1:500,000) revealed that lava canali extend across the entire quadrangle, with evidence for at least three generations of canali. Three canali originate from corona features (e.g. the circumferential dykes around Fotla Corona) suggesting that some canali may be linked to corona formation. The orientation of compressional wrinkle ridges (WR) in northern Henie suggest that these WRs were formed due to strain associated with the formation of the Artemis tectonomagmatic feature which is directly north of Henie. Artemis is possibly the largest such feature in the Solar System. The extent of the Artemis influence is being constrained across the Henie Quadrangle. The source of strain that formed a differently oriented WR swarm to the south of Henie is unknown. There is no evidence for the strain localization into master faults that we see on Earth. More work is needed to develop a model for the formation of the paired Latmikaik-Xacau Coronae and the associated Tellervo Chasma, Sunna-Laverna Dorsae and the Sonmunde-Mdeb-Arubani Flucti. A fissure eruption out of the Sunna Dorsa is proposed as the origin for the surrounding Arubani Fluctus.

Samodiva Mons is a large shield volcano (similar to 240 km in diameter, centered at 13.6 degrees N, 291.0 degrees E) located 1500 km ESE from Beta Regio. Detailed mapping (1:500,000 scale) using radar image and altimetry data from the Magellan mission was used to investigate the geological history of the volcano and its surrounding area. The study area is located in Quadrangle V-29, which extends from 11 degrees to 16 degrees N, 289 degrees to 294 degrees E and covers approximately 291,000 km(2) of which similar to 80,000 km(2) is occupied by Samodiva Mons volcanic materials. Seven geological units were defined, mapped, and characterized: Samodiva Mons lava flows, small shield volcanoes, coronae material, plains material, tesserae, densely lineated plains, and impact craters. Also, we distinguished two structural units: graben-fissure systems (interpreted as dike swarms) and wrinkle ridges. Three geological stages of evolution of the study region are recognized, with Stages 1-2 being pre-Samodiva Mons and Stage 3 that is associated with Samodiva Mons activity. This stage largely postdates the emplacement of regional plains and was culminated by the formation of the Samodiva Mons volcanic construct.