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The longstanding view of Neotropical mountain uplift as a promoter of species diversification has become commonplace in the last decades and could benefit from more specific Earth-Life evolution associations. We now know that mountain formation has contributed to the outstanding levels of richness and endemism of Neotropical mountains. Nonetheless, we are lacking conceptual and empirical frameworks where geological and biological processes are causally linked through testable hypotheses. In this perspective, we present volcanic activity in the Neotropics, not as phenomena occurring “on top of” mountain uplift, the latter being the phenomena of biogeographical interest, but rather as geological processes that directly impact biodiversity and are themselves the phenomenon of biogeographical interest. Volcanoes deserve biogeographical attention because their effects on landscape evolution generate predictable biodiversity process counterparts that can be integrated into biogeographical models enabling hypothesis testing. We review examples in the literature emphasizing the spatio-temporal scale of volcanism’s predicted and recorded effects on biodiversity. We illustrate our perspective by two recent study cases, focusing on wax palms and passerine birds. In the first one, wax palm genomic sampling was used to test 2 hypotheses: that the northern Andes have been disconnected in the past and connected by rapid but repeated eruptions of caldera-forming eruptions in the Colombian Massif fostering episodic dispersal, or alternatively, that they have always been continuous and have gradually uplifted hosting continuous diversification and dispersal through time. In broadly this same area, genetic and phenotypic data revealed the existence of a hybrid zone between species in the warbler genus Myioborus. Because hybridization is likely younger than volcanic activity, topographic connection spurred by volcanism could have also enabled secondary contact between previously isolated species, a hypothesis that merits formal testing. Altogether, we emphasize the pertinence of the volcanic record in offering opportunities for the evaluation of biogeographical hypotheses in the context of Neotropical mountains and their singularly outsized biodiversity.

In the article from the position on the Concept of the Dynamics of the Earth’s Crust Evolution (CDECE) the problems of the origin of volcanoplutonic processes and related endogenous ore formation are considered. It is established that geodynamic forces are created when the Earth rotates around its axis, all global geotectonic processes occur under the influence of these forces. These forces in the face of the Earth spread with certain regularities. Movements of lithospheric masses on the surface of the upper mantle occurs under the influence of these forces. It is known that the geospheres of the Earth have different physical characteristics. Therefore, they react differently to the Earth’s rotation. For this reason, mass shifts occur between the differently characterized geospheres. Because of these displacements between geospheres physical-chemical phase transformations form, where decomposition of mantle matter occurs, which is associated with the increase in the volume of mantle matter, that further, is associated with the formation of primary magma, which is associated with the manifestations of volcanoplutonic processes and earthquakes. These physical and chemical phase transformations theoretically occur in all zones between different geospheres of the Earth. However, the most intensive manifestation of them occurs between the Earth’s crust and upper mantle, associated with the increase in the radius of rotation of the Earth. The speed of movement of lithospheric masses is connected with the regularities of distribution of geodynamic forces, which have differential character of development this is connected with geometrical parameters of the Earth where the directions of movement of lithospheric masses, occur from west to east. In these conditions, the rate of movement in near equatorial zones have a maximum value, and in the direction of the poles reduce to zero. This is due to the fact that the Earth’s radius is located perpendicular to its axis of rotation. Therefore, the velocity of lithospheric masses movement in its equator have maximum values, which in the poles decrease to zero.

The evolution of the Gondwana along the flank of the West African Craton was complex and is far from understood. Subduction-related activity along this margin spanned between c. 750 and 500 Ma. Sections close to African cratons record the earliest stages, while Autochthonous and Allochthonous domains of the Variscan Belt preserve the latest stages of the arc system, essentially between c. 540 and 500 Ma. The geochemistry of the Ediacaran-early Cambrian siliciclastic series deposited along this Cadomian active margin preserves the evolutionary history of their sources, which are related to activity in the arc and nearby continental areas. In this sense, the SW Iberian Massif (Ossa-Morena Complex) preserves a section of this Ediacaran-early Cambrian peri-Gondwanan arc. Its evolution can be tracked through the characterization of the subduction-related magmatism (including the Mérida Massif) and coeval metasedimentary record (Serie Negra Group and Malcocinado Formation) during a time interval spanning almost 100 m.y., from pre-602 Ma to at least c. 534 Ma. This study reveals that arc magmatism is closely linked with synorogenic deposition in a complex way so far unexplored. Arc recycling is revealed by the isotopic equivalence of synorogenic strata to the first magmatic event (pre-602 Ma), and by geochronological data of the arc-building pulses. The earliest magmatic pulses (c. 602–550 Ma) are characterized by significant crustal input, likely favoured by subduction erosion. Subsequently, magmatism evolved towards larger mantle involvement (c. 540–534 Ma), likely associated with progressive variation in the slab angle. These slab-mantle-upper plate interactions generated changes in the arc dynamics leading to an extensional setting with alkaline magmatism during the Cambrian. This review proposes a model of petrogenetic and geodynamic arc evolution between the Ediacaran and the Early Cambrian. The gathered data could improve the accuracy of future palaeogeographic reconstructions for the northern margin of Gondwana. [ABSTRACT FROM AUTHOR]

Alkalic magmatism occurred in the Selwyn Basin, Yukon, Canada throughout the Paleozoic, concurrent with extension during passive margin sedimentation. To examine magmatism associated with this extension, geochemical data were obtained from several locations in the Selwyn Basin (MacMillan Pass, Anvil District, Keno Hill, and the Misty Creek Embayment). Volcanic rocks from the Anvil District and the Misty Creek Embayment are dominated by alkalic basalts with light rare earth element (LREE)-enriched geochemical signatures, whereas metavolcanic and dike samples from Keno Hill comprise subalkaline basalts with enriched mid-ocean ridge basalt (E-MORB) signatures. The Early Ordovician Menzie Creek volcanic rocks of the Anvil District display trace element geochemical signatures intermediate between ocean island basalt (OIB) and E-MORB, whereas the Middle–Late Ordovician volcanic rocks from the Misty Creek Embayment have OIB signatures. Differences in the trace element geochemistry of the sample suites are attributed to the degree of partial melting. The Menzie Creek volcanic rocks formed from large volume melts of enriched mantle that diluted incompatible element signatures in the Early Ordovician. Late Ordovician magmatism produced the Misty Creek Embayment samples, where restricted melt volumes of an enriched mantle source resulted in the most enriched samples geochemically. The Keno Hill samples represent the shallowest melting of the analysed samples and may have resulted from melting of heterogenous subcontinental lithospheric mantle. Magmatic zircons from a Keno Hill metavolcanic sample analysed by chemical abrasion thermal ionization mass spectrometry resulted in a primary deposition age of c. 296 ± 0.36 Ma (Early Permian), during a period with little magmatism in the Selwyn Basin and representing a previously unknown unit in the area. [ABSTRACT FROM AUTHOR]

It was recognized that two magmatic belts in the Lhasa‐Tengchong terrane formed due to the Mesozoic‐Cenozoic Tethyan evolution. Still, their spatiotemporal variations of magmatic flare‐ups/lulls are rarely discussed. Here we use the new U‐Pb and Lu‐Hf isotopic data of captured zircons and a comprehensive data set to show that the flare‐up of northern magmatic belt has peak ages of 110 Ma in central and northern Lhasa and 120 Ma in eastern Tengchong, possibly related to the tectonic transition from Meso‐ and Neo‐Tethyan double subduction to Neo‐Tethyan single subduction. For the southern magmatic belt, the flare‐ups at 100–85 Ma and 65–45 Ma in eastern southern Lhasa indicate obvious juvenile crustal growth, while flare‐ups at 75–45 Ma in western southern Lhasa and Tengchong record ancient crustal reworking. Such flare‐up variations in the southern magmatic belt possibly resulted from asynchronous changes in the Neo‐Tethyan slab dip. Plain Language Summary: The Tethyan slab subduction and following collision of India and Asia produced two magmatic belts in the Lhasa‐Tengchong terrane. How did the magmatic flare‐ups or high‐flux episodes and sources spatiotemporally vary? We combine the new U‐Pb and Lu‐Hf isotopic data of captured zircons (xenocrystic zircons caught by volcanics from country rocks) and a comprehensive data set to show that the peak ages of early Cretaceous flare‐up of the northern magmatic belt are ca.10 Ma younger in central and northern Lhasa than in eastern Tengchong, possibly related to the diachronous closure of the Meso‐Tethys and flat subduction of the Neo‐Tethys. The southern magmatic belt in Tengchong and western southern Lhasa exhibit 75–45 Ma flare‐ups featured by the reworking of ancient crust, different from the eastern southern Lhasa with the flare‐ups at 100–85 Ma and 65–45 Ma which are dominated by the juvenile crustal growth. Such flare‐up variations may be related to changes of the Neo‐Tethyan slab dip. Key Points: The Neo‐Tethyan arc has asynchronous magmatic flare‐ups and diverse magmatic sourcesThe spatiotemporal changes of slab dip triggered the asynchronous flare‐ups of the Neo‐Tethyan arc [ABSTRACT FROM AUTHOR]

The Okinawa Trough is an incipient back-arc basin formed by the subduction of the Philippine Sea Plate beneath the Eurasian Plate and is a natural laboratory for studying basin evolution, magmatism, and crust-mantle interactions during the early stages of back-arc spreading. Back-arc spreading and recent magmatism are occurring mainly in the Middle Okinawa Trough (MOT) and Southern Okinawa Trough (SOT). In order to investigate the magmatism in the Okinawa Trough, volcanic rock samples from the MOT and SOT were analysed for Fe – Sr – Nd – Pb – Hf isotopic compositions. The Fe isotopic compositions of basaltic andesite samples from the SOT are similar to or lower than MORBs. The fluid/melt derived from the subducted slab, especially the fluid dehydrated from slab serpentinites and sediment-derived melts, entered the overlying depleted mantle wedge and participated in magma generation, which resulted in the low δ56Fe values of the SOT basaltic magmas. The δ56Fe values of volcanic rocks from the MOT increase with increasing SiO2 contents, suggesting a gradual enrichment of heavy Fe isotopes during the evolution of the magma as it ascended to the surface. While the Sr – Nd – Pb – Hf isotopic compositions do not vary significantly, suggesting that the different samples are the products of different degrees of crystal fractionation of comagma. The fractional crystallization of olivine, pyroxene, and ilmenite minerals, which enrich in light Fe isotopes, resulted in the gradual increase in Fe isotopic values of magma during its evolution. The dacites and rhyolites from the southernmost Okinawa Trough have the similar δ56Fe values with the basaltic andesite and the basalt from the SOT and MOT, accompanied by significantly lower Nd and Hf isotope ratios relative to basalts, reflecting that the contamination of crustal materials would not change the magma in Fe isotope compositions evidently. Compared with the MOT, the volcanic rocks from the SOT was more affected by subduction components on their underlying mantle, and those from the southernmost experienced more contamination by crustal materials in the evolving magma. [ABSTRACT FROM AUTHOR]

The Late Mesozoic subduction of Izanagi slab beneath East Asia formed large-scale intraplate magmatism in SE South China and subduction mélanges outcropped in SW Japan to eastern Taiwan Island, but the accompanying arc remains uncertain. We conducted LA-ICP-MS U–Pb zircon dating and trace element analyses of proximal sandstones from the SW East China Sea to trace a Jurassic to Cretaceous magmatic arc. Newly acquired data reveal that arc magmatism mostly developed in episodes of 150–124 and 124–102 Ma, exhibiting characteristics of low-T, high Th/U, U/Yb, Sc/Yb, Th/Nb, and low Nb/Yb, Nb/Hf ratios. This magmatic arc, combined with the SE South China intraplate and residual subduction mélanges, spatially forms a Late Mesozoic trench–arc–intraplate architecture responding to the Izanagi subduction. Its identified tectonic scenarios mainly include slab strike-slip subduction (200–170 Ma), slab stagnation and intraplate foundering (170–150 Ma), slab rollback and arc-root removal (150–102 Ma), and arc migration (102–86 Ma). Both the western East China Sea and Cathaysia block share a unified Paleoproterozoic basement that formed at ca. 1.85 Ga, and the Cathaysia-based magmatic arc occurred then. [ABSTRACT FROM AUTHOR]

The western Argentinian sector of Gondwana has been the focus of several recent studies related to the Famatinian orogeny; however, the geologic history of arc activity in hinterland areas remains poorly understood. We present new data from the Monte Guazú Complex that reveal arc-related magmatism in the Sierras de Córdoba, which we consider part of the Famatinian hinterland. Igneous rocks comprise a diorite unit which includes an amphibole quartz-gabbro/diorite and a tonalite unit comprising amphibole- and biotite-bearing tonalites to minor granodiorites. Both units constitute a medium-K calc-alkaline series ranging in composition from metaluminous to moderately peraluminous. Trace-element signatures show Ti and Nb depletion and strong incompatible element enrichments (large-ion lithophile elements, Pb, Th, U, and light-rare earth elements) relative to normal mid-ocean ridge basalts, suggesting that they formed in an arc setting. U–Pb zircon geochronology constrains magmatism to 455–498 Ma, while weighted mean ages of 474–489 Ma are mostly synchronous with the Famatinian arc beginning. We demonstrate that fractional crystallization of mantle wedge-derived melts controlled the early magmatic evolution, while country rock assimilation and anatectic melt mixing were prevalent in evolved rock members. These results spatially extend the Late Cambrian–Late Ordovician Famatinian retro-arc to the southern Sierras de Córdoba. Our findings show that magmatism involved coeval anatexis of host rocks, conversely to previous geodynamic models. Our data have fundamental implications for Paleozoic tectonic and magmatic processes operating along the western Argentinian sector of Gondwana, demonstrating the importance of crustal reworking and the addition of mantle material in the Famatinian arc inboard sector. [ABSTRACT FROM AUTHOR]

Continental topography is dominantly controlled by a combination of crustal thickness and density variations. Nevertheless, it is clear that some additional topographic component is supported by the buoyancy structure of the underlying lithospheric and convecting mantle. Isolating these secondary sources is not straightforward, but provides valuable information about mantle dynamics. Here, we estimate and correct for the component of topographic elevation that is crustally supported to obtain residual topographic anomalies for the major continents, excluding Antarctica. Crustal thickness variations are identified by assembling a global inventory of 26,725 continental crustal thickness estimates from local seismological data sets (e.g., wide‐angle/refraction surveys, calibrated reflection profiles, receiver functions). In order to convert crustal seismic velocity into density, we develop a parametrization that is based upon a database of 1,136 laboratory measurements of seismic velocity as a function of density and pressure. In this way, 4,120 new measurements of continental residual topography are obtained. Observed residual topography mostly varies between ±1 and 2 km on wavelengths of 1,000–5,000 km. Our results are generally consistent with the pattern of residual depth anomalies observed throughout the oceanic realm, with long‐wavelength free‐air gravity anomalies, and with the distribution of upper mantle seismic velocity anomalies. They are also corroborated by spot measurements of emergent marine strata and by the global distribution of intraplate magmatism that is younger than 10 Ma. We infer that a significant component of residual topography is generated and maintained by a combination of lithospheric thickness variation and sub‐plate mantle convection. Lithospheric composition could play an important secondary role, especially within cratonic regions. Plain Language Summary: Plate tectonic theory holds that the horizontal movement of tectonic plates drives crustal thickening and the formation of mountain ranges where plates collide, and crustal thinning in rift basins where plates diverge. The dominance of this process, however, obscures a key secondary source of topographic variation caused by density variations within the underlying mantle. In this study, we compile two new databases. The first is a global compilation of crustal thickness and seismic velocity measurements obtained from seismic experiments. The second is a compilation of laboratory analyses of seismic velocity in crustal rocks as a function of temperature, pressure and density. We combine these data sets to accurately map that component of continental topography caused by crustal thickness and density variations and use it to isolate the secondary, residual component supported by the mantle. We find that a substantial proportion of topography is supported by the temperature and chemical structure of the mantle and is manifest as topographic swells and basins that can occur within interiors of tectonic plates, have amplitudes of up to 2 km, and length scales ranging from hundreds to thousands of kilometers. Independent geologic evidence suggests that some of these topographic features developed over million‐year time scales. Key Points: Continental residual topography estimated using 26,725 crustal thickness and 4,067 seismic velocity constraintsCrustal velocity to density conversion scheme developed to correct for crustal density variationsResidual topography varies from ∼1 to 2 km over ∼1,000 km wavelengths, consistent with a range of geological observations [ABSTRACT FROM AUTHOR]

Despite significant progress in Arctic geological studies, a number of principal questions concerning the Paleozoic collisional events remain unanswered. Therefore, the Taimyr Peninsula, representing the only outcropped high Arctic region where magmatic complexes, formed by Hercynian collision between the Siberian Craton and the Kara Block, are well exposed, is crucially important. In this paper we report new geochemical and geochronological data for intrusions in the poorly studied northeastern part of the Taimyr Peninsula. The obtained results in combination with published data show that supra-subduction magmatism at the southern active margin of the Kara Block continued from ca. 345 to 285 Ma (Early Carboniferous to Early Permian), and was followed by a post-collisional magmatic pulse that affected the whole Taimyr across terrane boundaries at ca. 280 Ma in the Early Permian. After cessation of the post-collisional magmatism at ca. 265 Ma, the Taimyr experienced extension, and voluminous magmatic series associated with a Siberian mantle plume were formed between 251 and 228 Ma during the Triassic. The studied post-collisional and plume-related intrusions of the Northeastern Taimyr are generally classified as evolved high-K I-type granites with adakitic affinity. The latter is a regional feature because the majority of the analyzed plume-related granitoids are geochemically similar to high potassium continental adakites. It is suggested that the adakitic geochemical characteristics of the plume-related granitoids resulted from melting of hydrated mafic lower crustal protoliths and were controlled by the source lithology. Comparison of the new results with data available for adjacent areas allows for correlation of terranes on a regional scale and sheds light on the evolution of the Arctic continental margins in general. In the Early–Middle Paleozoic, the Kara Block was part of a continental terrane that formed at the northern edge of Baltica as a result of Neoproterozoic Timanian orogeny. In the Early Carboniferous, the southern margin of Kara turned into an active margin, while its inferred continuation in the eastern Uralian margin of Baltica remained a passive margin until the Early Permian. This discrepancy can be explained by dextral displacement of Kara relative to Baltica that took place in the Early Carboniferous and was later accommodated by the formation of the Taimyr collisional belt in the course of the Early Permian collision between Kara and Siberia. After collision, the Taimyr was incorporated into the northern Eurasian margin as an uplifted block that experienced surface erosion and supplied clastic material in surrounding basins. [ABSTRACT FROM AUTHOR]

Post‐collisional magmatism contains important clues for understanding the reworking and growth of continental crust, as well as lithospheric delamination and orogenic collapse. Early Devonian magmatism has been identified in the North Qilian Orogenic Belt (NQOB). This paper reports an integrated study of petrology, whole‐rock geochemistry, Sm‐Nd isotope and zircon U‐Pb dating, as well as Lu‐Hf isotopic data, for two Early Devonian intrusive plutons. The Yongchang and Chijin granites yield zircon U‐Pb ages of 394–407 Ma and 414 Ma, respectively. Both of them are characterized by weakly peraluminous to metaluminous without typical aluminium‐rich minerals, LREE‐enriched patterns with negative Eu anomalies and a negative correlation between P2O5 and SiO2 contents, consistent with geochemical features of I‐type granitoids. Zircons from the studied granites display negative to weak positive εHf(t) values (–5.7 to 2.1), which agree well with those of negative εNd(t) values (−6.4 to −2.9) for the whole‐rock samples, indicating that they were derived from the partial melting of Mesoproterozoic crust. Furthermore, low Sr/Y ratios (1.13–21.28) and high zircon saturation temperatures (745°C to 839°C, with the majority being >800°C) demonstrated a relatively shallow depth level below the garnet stability field and an additional heat source. Taken together, the Early Devonian granitic magmatism could have been produced by the partial melting of ancient crustal materials heated by mantle‐derived magmas at high‐temperature and low‐pressure conditions during post‐collisional extensional collapse. The data obtained in this study, when viewed in conjunction with previous studies, provides more information about the tectonic processes that followed the closure of the North Qilian Ocean. The tectonic transition from continental collision to post‐collisional delamination could be constrained to ∼430 Ma, which is provided by the sudden decrease of Sr/Y and La/Yb ratios and an increase in zircon εHf(t) values for granitoids. A two‐stage tectonic evolution model from continental collision to post‐collisional extensional collapse for the NQOB includes (a) continental collision and crustal thickening during ca. 455–430 Ma, characterized by granulite‐facies metamorphism and widespread low‐Mg adakitic magmatism; (b) post‐collisional delamination of thickened continental crust and extensional collapse of orogen during ca. 430–390 Ma, provided by coeval high‐Mg adakitic magmatism, A‐type granites and I‐type granitoids with low Sr‐Y ratios. [ABSTRACT FROM AUTHOR]

The Sanak-Baranof belt includes a series of near-trench plutons that intrude the outboard Chugach-Prince William terrane over ~2200 km along the southern Alaskan margin. We present new petrological, geochronological, and geochemical data for comagmatic microgranitoid enclaves and granitoid rocks from the Crawfish Inlet (ca. 53-47 Ma) and Krestof Island (ca. 52 Ma) plutons on Baranof and Krestof Islands, as well as the Mount Stamy (ca. 51 Ma) and Mount Draper (ca. 54-53 Ma) plutons and associated mafic rocks that intrude the Boundary block at Nunatak Fiord near Yakutat, Alaska, USA. These data suggest that intrusion of the Sanak-Baranof belt plutons is actually a tale of two distinct belts: a western belt with crystallization ages that young systematically from west to east (63-56 Ma) and an eastern belt with crystallization ages ranging from 55 to 47 Ma, but with no clear age progression along the margin. Hf isotope analyses of magmatic zircon from the western Sanak-Baranof belt become increasingly evolved toward the east with εHft = 9.3 ± 0.7 on Sanak Island versus εHft = 5.1 ± 0.5 for the Hive Island pluton in Resurrection Bay. The Hf isotope ratios of eastern Sanak-Baranof belt rocks also vary systematically with age but in reverse, with more evolved ratios in the oldest plutons (εHft = +4.7 ± 0.7) and more primitive ratios in the youngest plutons (εHft = +13.7 ± 0.7). We propose that these findings indicate distinct modes of origin and emplacement histories for the western and eastern segments of the Sanak-Baranof belt, and that the petrogenesis of eastern Sanak-Baranof belt plutons (emplaced subsequent to 57-55 Ma) was associated with an increasing mantle component supplied to the youngest eastern Sanak-Baranof belt magmas. These plutons reveal important information about offshore plate geometries and a dynamic period of plate reorganization ca. 57-55 Ma, but a clearer picture of the tectonic setting that facilitated these Sanak-Baranof belt intrusions cannot be resolved until the magnitude and significance of lateral translation of the Chugach-Prince William terrane are better understood. [ABSTRACT FROM AUTHOR]

Since the Cenozoic, the Tibetan Plateau has experienced large‐scale uplift and outgrowth due to the India‐Asia collision. However, the mechanism and timing of these tectonic processes still remain debated. Here, using apatite fission track dating and inverse thermal modeling, we explore the mechanism of different phases of rapid cooling for different batholiths and intrusions in the southeastern Tibetan Plateau. In contrast to previous views, we find that the coeval granitic batholith exposed in the same tectonic zone experienced differential fast uplift in different sites, indicating that the present Tibetan Plateau was the result of differential uplift rather than the entire lithosphere uplift related to lithospheric collapse during Cenozoic times. In addition, we also suggest that the 5‐2 Ma mantle‐related magmatism should be regarded as the critical trigger for the widely coeval cooling event in the southeastern Tibetan Plateau, because it led to the increase in atmospheric CO2 level and a hotter upper crust than before, which are efficient for suddenly fast rock weathering and erosion. Finally, we propose that the current landform of the southeastern Tibetan Plateau was the combined influences of tectonic and climate. [ABSTRACT FROM AUTHOR]

Mars features a crustal dichotomy, with its southern hemisphere covered by a thicker basaltic crust than its northern hemisphere. Additionally, the planet displays geologically recent volcanism only in its low latitude regions. Previous giant impact models coupled with simulations of mantle convection have shown that the crustal dichotomy can be explained by post‐impact melt crystallization that emplaced a thick crust in the southern hemisphere. In this study, we show that the depleted residue left behind by the original post‐impact crustal formation can spread laterally, potentially persisting beneath the northern hemisphere to the present‐day. Such a large‐scale mantle province would concurrently explain both the prevalence of long‐term magmatism on Mars and its strong preference for localized equatorial regions. Plain Language Summary: Mars has a thicker crust in the southern hemisphere than in the north hemisphere, this difference is named the Martian dichotomy. Various theories have been suggested in order to explain its origin. We focus in the present study on a southern giant impact hypothesis. By using numerical models, we study the fate of a magma pond that is created by a giant impact. As this pond cools, a crust is formed on the top, leaving behind a residue at depth. We show that this residue can spread below the crust to the opposite hemisphere of the planet, that is, the northern hemisphere. We show that this causes, additionally to the dichotomy, also a north‐south difference in both the thermal and compositional structure of the interior of Mars. The advantage of our model is that it can concurrently explain the Martian dichotomy and the location of large and small martian volcanoes near the equator. Key Points: Mantle convection modeling is performed to study the consequence of a giant impact until present dayA thick crust is formed on the impacted hemisphere, suggesting a southern giant impact origin for the Martian crustal dichotomyLong‐lived melting produced preferentially at low‐latitude region in our models can explain the observed Martian volcanism [ABSTRACT FROM AUTHOR]

Post-rift magmatism along continental margins is usually focused on highly stretched basins or aborted rifts. Adjacent microplates with relatively thick lithosphere are not expected to exhibit intense postrift magmatism. This study identifies 20 mounded structures and associated pathways using two-dimensional, multichannel seismic data and ocean bottom seismometer (OBS) data across the southeastern Xisha Massif of the northwestern South China Sea. This massif is a relatively thick (>20 km) region of crust that forms a microplate between two rift branches. The mounded structures are interpreted as volcanoes, based on their seismic reflections and morphological characteristics. Detachment faults that extend into the middle crust captured the magma and provided pathways for vertical migration. During the rise of magma into the sedimentary stratum, detachment faults still served as the main channels of magmatic migration. The rigidity differences between the basement and the overlying sediments, as well as the stress field, facilitated subordinate pathways for magmatic migration, particularly at the depocenters and flanks of half-grabens. Consequently, larger volcanoes are present above the basement highs, while smaller volcanoes are located in the centers of half-grabens. This study provides criteria for identifying submarine mounded structures of different origins that are applicable beyond the study area. Moreover, this study highlights that detachment faults play a key role in the volcanic systems of the relatively rigid microplates of heterogeneous crustal structure. It also promotes our understanding of post-rift magmatism and the dynamic evolution of continental margins, and the results could be applicable to other areas with similar geological settings. [ABSTRACT FROM AUTHOR]

The late Mesozoic destruction of the eastern North China Craton (NCC) resulted from intense crust-mantle interaction, culminating in the formation of world-class gold deposits in the Jiaodong Peninsula at ca. 120 Ma. We present zircon U-Pb geochronological data, Hf isotopic compositions, whole-rock major and trace element, and Sr-Nd-Pb isotopic compositions for two suites of granitoids: one (the Linglong suite) that hosts significant mineralization and the other (the Weideshan suite) that is largely unmineralized. The Linglong suite was emplaced in the Late Jurassic at 160 ± 3 Ma to 155 ± 3 Ma, whereas the Weideshan suite was emplaced in the Early Cretaceous at 121 ± 2 Ma to 118 ± 1 Ma, coeval with gold mineralization. Geochemical data indicate the Linglong suite was derived from the melting of thickened lower crust of the NCC, mixed with material from the Yangtze Craton (YC) and intervening Su-Lu Orogenic Belt, whereas the Weideshan suite was formed from the partial melting of lower continental crust, with the addition of enriched lithospheric mantle components. The Late Jurassic magmatism was associated with crustal growth resulting from the continental collision between the NCC and YC and subsequent subduction of the Paleo-Pacific Oceanic Plate (PPOP). In contrast, Early Cretaceous magmatism was triggered by rapid lithospheric thinning and asthenospheric upwelling resulting from slab roll-back and stagnation of the PPOP beneath the NCC. Lithospheric delamination induced the widespread development of secondary structures associated with the major Tan-Lu Fault, providing favorable loci for the accumulation of auriferous fluids. [ABSTRACT FROM AUTHOR]

The nature and tectonic evolution of the Bangong-Nujiang Tethyan Ocean remain unresolved, which seriously restricts our understanding of the role of this ocean in the Tethys tectonic domain and hinders in-depth study of the geodynamics of the Tethyan tectonic evolution. The study of intraplate oceanic-island fragments in the Bangong-Nujiang Suture Zone of Northern Tibet, which are remnants of the oceanic crust, is important for determining the nature and tectonic evolution of the Bangong-Nujiang Tethyan Ocean. Here, we present a combined analysis of petrological, geochronological, geochemical, and Sr-Nd isotope data for the five intraplate oceanic-island fragments preserved in the Bangong-Nujiang Suture Zone. The oldest intraplate oceanic-island fragment in the Bangong-Nujiang Suture Zone is of Late Permian-Triassic age, and the underlying oceanic lithosphere is Late Permian or older, which indicates the development of the Bangong-Nujiang Tethyan Oceanic basin at this time. The opening time of the Bangong-Nujiang Tethyan Ocean must be even earlier than the Late Permian. At least four Triassic intraplate oceanic-island fragments have been recognized in the Bangong-Nujiang Suture Zone, and their assemblages and geochemistry are mostly similar to present-day oceanicisland basalts that erupted onto the thick lithosphere of mature oceanic basins. All of these observations indicate that the Bangong-Nujiang Tethyan Ocean evolved into a mature oceanic basin during the Triassic. The youngest intraplate oceanic-island fragments are of Late Jurassic-Early Cretaceous ages, which effectively argues for the continued presence of the Bangong-Nujiang Tethyan Ocean at this time. The abundant data of the intraplate oceanic-island fragments provide strong evidence that the Bangong-Nujiang Tethyan Ocean was a broad oceanic basin that separated Cimmeria from Gondwana during the Permian-Early Cretaceous and experienced complex evolution over at least 160 m.y. [ABSTRACT FROM AUTHOR]

We present results of a geochronological and geochemical study of the Kaniksu batholith, located in northern Idaho and Washington near the Canadian border. This batholith occurs at the southern end of the Omineca Belt and forms an integral part of the Priest River metamorphic complex. The Kaniksu batholith is compositionally diverse, but granitoids can be grouped into a volumetrically major peraluminous and metaluminous suite and a volumetrically minor alkalic suite based on lithology and major-element composition; additional compositionally similar alkalic plutons extend far to the south of the main footprint of the batholith. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb zircon dating revealed that most granitoids of the batholith formed in the Early Cretaceous between 120 Ma and 100 Ma, although magmatism continued until ca. 73 Ma. The dominance of Early Cretaceous ages closely matches magmatic age distributions elsewhere in the Omineca Belt. There is no clear relationship between age and suite assignment or other geochemical characteristics. Whole-rock Sr, Nd, and Pb isotope data along with zircon Hf isotope data suggest that the alkalic and metaluminous suites can largely be explained as mixtures of partial melts from the Mesoproterozoic Moyie sills and metasedimentary rocks of the Belt Supergroup, whereas a third component, perhaps Paleoproterozoic or Neoarchean metaigneous basement, is required to explain the origin of the peraluminous suite. All of these granitoids formed well behind the Cordilleran arc front in an area characterized by multiple episodes of crustal thickening. As there is little evidence of contemporaneous mantle-derived magmatism, crustal thickening was probably the main driver of batholith formation. [ABSTRACT FROM AUTHOR]

We report three sets of newly identified late Mesoproterozoic mafic intrusions in the southwestern Yangtze Block, China. Secondary ion mass spectrometry (SIMS) baddeleyite and zircon U-Pb analyses yield crystallization ages of ca. 1.15 Ga for the Boka dolerites, ca. 1.07 Ga for the Lanniping gabbros, and ca. 1.06 Ga for the Tong'an mafic dikes. These are tholeiitic to alkaline rocks with enriched mid-ocean-ridge basalt (E-MORB)-like trace-element patterns and superchondritic εNd(t) values, indicating a partial melting origin from the asthenospheric mantle. These results, along with existing data, define two episodes of late Mesoproterozoic, rift-related mafic magmatism in the southwestern Yangtze Block: an early phase at 1.17-1.14 Ga and a late phase at 1.07-1.02 Ga. Initiation of the two episodes of extensional events in the southwestern Yangtze Block coincided with high-grade Grenville-aged metamorphism in Hainan Island and possible early collision of Cathaysia with the southwestern Yangtze Block, indicating an impactogen model. Therefore, we interpret the observed two episodes to have resulted from local collision between the southwestern Yangtze Block and the Cathaysia Block (including Hainan Island), which was possibly a part of western Laurentia during the assembly of Rodinia. [ABSTRACT FROM AUTHOR]

Exploring the nature of Archean plate tectonics is crucial for understanding the geodynamic evolution of early Earth. While previous studies have focused on (ultra-)mafic metavolcanic and tonalite-trondhjemite-granodiorite (TTG) rocks, the crust-mantle interactions of Archean intermediate magmatism have received much less attention. Mesoarchean (ca. 2936-2855 Ma) dioritic and tonalitic-trondhjemitic magmatism occurred in the Jiaobei terrane, North China Craton. While low-silica (65.67-68.82 wt%) TTG magmatism persisted throughout the entire magmatic period, both the high-silica (69.79-74.54 wt%) TTG and biotite dioritic (MgO of 1.52-2.45 wt%) magmatism were transient (ca. 2922-2901 Ma). They were mainly sourced from metabasaltic crust, though the biotite dioritic and low-silica TTG rocks show variable mantle input. In comparison, the hornblende dioritic magmatism (MgO of 2.07-5.00 wt%) occurred later (ca. 2912-2865 Ma) and was derived from melt-metasomatized mantle sources. Spatially, the magmatism became younger from northeast to southwest. Combined with increasing crustal melting pressures after ca. 2920 Ma and mildly elevated zircon δ18O (up to +6.8‰) of TTG rocks, a Mesoarchean nascent subduction zone is proposed for the Jiaobei terrane that is featured by the recycling of supracrustal basaltic rocks to thickened lower crust (forming high-pressure and high-δ18O TTG) and subsequent meltrelated mantle metasomatism (forming relatively high-Mg hornblende dioritic rocks). The recycled supracrustal materials may have lubricated the basal part of the thickened crust and then triggered the opening of a nascent mantle wedge. Further compilation of data from global Archean dioritic and TTG rocks reveals chemical discontinuities at ca. 3.6-3.5 Ga and after ca. 3.0 Ga; these periods are marked by the occurrence of both high-Mg (median MgO >3 wt%) dioritic magmatism and high-(La/Yb)N (median >30) and high-δ18O (median >5.9‰) TTG magmatism. These data, along with independent geological evidence, suggest that the nascent subduction processes may have initiated locally at ca. 3.6-3.5 Ga but globally after ca. 3.0 Ga. [ABSTRACT FROM AUTHOR]

In this paper, we have synthesized the information derived from more than 20 papers and PhD theses on the anisotropy of the magnetic susceptibility (AMS) of 19 Variscan granite plutons, spanning the period between 320 Ma and 296 Ma. The AMS data are obtained from 876 sampling sites with more than 7080 AMS measurements and a re-interpretation is proposed. The studied granites exhibit a magnetic susceptibility (Km) ranging from 30 to 10,436 × 10−6 SI units. Most granites typically exhibit Km values below 1000 × 10−6 SI, indicative of paramagnetic behavior. Biotite serves as the main carrier of iron (Fe), emphasizing the reduced conditions prevalent during the formation of granite melts in the Variscan orogeny. The AMS fabrics of the studied granite plutons record the magma strain, expressing the chronologic evolution of the stress field during the orogeny. This chronologic approach highlights the magmatic events between around 330 and 315 Ma, occurring in an extensional regime, in which the Borralha pluton is an example of a suite that recorded this extensional AMS fabric. Plutons with ages between 315 and 305 Ma show AMS fabrics, pointing out their emplacement in a compressional tectonic regime related to the Variscan collision. The plutons, younger than 305 Ma, record AMS fabrics indicating that the tectonic setting for emplacement changes from a wrench regime to an extensional one at the end of the collision stage. This is evident as there is a chronological overlap between the granites that exhibit AMS fabrics indicating extension and the ones that have AMS fabrics indicating a wrench regime. [ABSTRACT FROM AUTHOR]

The Huayangchuan U-polymetallic deposit in the Qinling Orogen is a newly verified carbonatite-hosted deposit on the southern margin of the North China Craton (NCC) in Central China. Granitic magmatism is extensively developed in the Huayangchuan deposit area and is lacking analysis on the reasons for these situations; however, its ages, petrogenesis, and relationship with uranium mineralization are not well constrained. Zircon U–Pb ages for the hornblende-bearing granite porphyry and medium-fine-grained biotite granites in close proximity to carbonatite rocks are 229.8 ± 1.1 and 135.3 ± 0.6 Ma, respectively. High-K calc-alkaline series and weakly peraluminous Triassic hornblende-bearing granite porphyry are slightly enriched in light rare earth elements (LREE) with flat heavy rare earth element (HREE) patterns, enriched in Ba and Sr, and depleted in Nb, Ta, P, and Ti, i.e., geochemical characteristics similar to those of adakite-like rocks. The Early Cretaceous medium-fine-grained biotite granites are characterized by LREE enrichment and flat HREE patterns, which belong to high-K calc-alkaline series, and metaluminous belong to weakly peraluminous I-type granite, with U and large ion lithophile element (LILE) enrichment and high field strength element depletion. The high initial 87Sr/86Sr ratios and enriched Nd (εNd(t) = −10.7 to −9.5 and −19.9 to −18.9, respectively) and Hf (εHf(t) = −21.8 to −13.0 and −30.5 to −19.0, respectively) isotopes revealed that both granitic rocks from the Huayangchuan deposit mainly originated from lower crustal materials, generated by partial melting of the ancient basement materials of the Taihua Group. Triassic hornblende-bearing granite porphyry is significantly different from the mantle origin of the contemporaneous U-mineralization carbonatite. In combination with tectonic evolution, we argue that the Qinling Orogenic Belt was affected by the subduction of the North Mianlian Ocean during the Late Triassic. The ongoing northward subduction of the Yangtze Craton resulted in crustal thickening, forming large-scale Indosinian carbonatites, U-polymetallic mineralization, and contemporaneous intermediate-acid magmatism. Additionally, due to the tectonic system transformation caused by Paleo-Pacific Plate subduction, intracontinental lithosphere extension and lithospheric thinning occurred along the southern NCC margin in the Early Cretaceous. Intense magma underplating of the post-orogeny created a large number of magmatic rocks. The tremendous heat could have provided a thermal source and dynamic mechanism for the Yanshanian large-scale U-polymetallic mineralization events. [ABSTRACT FROM AUTHOR]

Magmatism on continental lithospheres induced by mantle plumes is more complex compared to oceanic intraplate volcanism owing to the heterogeneous nature of continental crustal and lithospheric structures. Substantial evidence points to the deep-oriented Hainan mantle plume beneath the Lei–Qiong region, the southernmost of the South China block. In this study, we present a detailed shear wave velocity model of the crust and uppermost mantle in the Lei–Qiong volcanic region, derived from 3-year seismic data (2016–2018) from 34 stations and the use of the ambient noise tomography method. An evident columnar low-velocity anomaly was imaged in the crust and uppermost mantle beneath the Wushi Sag (WSS), Beibu Gulf, potentially suggesting that the center of either one branch or the entirety of the Hainan mantle plume impacts the crust here. This low-velocity anomaly is overlaid by a local Moho deepening, indicative of underplating beneath the existing crust. The Maanling–Leihuling Volcanic Field (MLVF) in northern Hainan Island, previously considered the center of the hotspot, does not exhibit such distinct velocity anomalies. Instead, subtle lower crustal anomalies beneath the MLVF are linked with the upper mantle low-velocity zone beneath the WSS. Additionally, the high-conductivity bodies beneath the MLVF indicate lateral magma transport. Earthquake swarms and deep-seated seismic events beneath the WSS further support the presence of magmatic processes. This study indicates that in the Lei–Qiong region, the interaction of the continental crust with the mantle plume centered in the WSS results in magma exhibiting both vertical ascent and lateral migration, leading to a dual low-velocity shear wave pattern in the upper crust, which significantly influences the surface volcanic activity. [ABSTRACT FROM AUTHOR]

The start of the Paleoproterozoic supercontinent cycle is typically taken as the initiation of orogenesis at ca. 2.1 Ga leading to the assembly of Earth's first supercontinent, Columbia. However, the dearth of ca. 2.5–2.2 Ga geological records makes it difficult to deduce tectonic factors during the onset of the Paleoproterozoic supercontinent cycle. The petrogenesis of tonalite–trondhjemite–granodiorite (TTG) provides useful proxies for tracing prevailing geodynamic regimes of early continental evolution. However, marked decreases of TTG and other magmatism occurred across the Archean–Paleoproterozoic transition and have previously precluded forming testable hypotheses. Early Paleoproterozoic TTGs have been identified in the North China Craton (NCC) and other cratons, which may represent the last major pulse of TTGs globally. Here we present low δ18O and δ30Si ca. 2.3 Ga TTGs from the NCC, together with thermodynamic modeling and compilation of stable O and Si isotopes for TTGs globally through time. The ca. 2.3 Ga TTGs were derived from the partial melting of Archean basaltic crust and give lighter average zircon δ18O (3.15 ± 0.35‰) and whole‐rock δ30Si values (−0.17 ± 0.08‰) than most Archean TTGs. Considering coeval mafic‐felsic igneous rocks, and lithospheric thinning since ca. 2.5 Ga based on estimated crustal thickness through the Neoarchean–Paleoproterozoic, we posit the onset of an intraplate rifting consistent with the anomalous low‐δ18O magmatism. Continental rifting of Archean cratons/supercratons plausibly hints at the formation of rifts driving subduction initiation as the veritable onset of the Paleoproterozoic supercontinent cycle. Plain Language Summary: The Earth's first supercontinent, Paleoproterozoic–Mesoproterozoic Columbia, likely began to form during ca. 2.1 Ga (billion years ago) orogenesis. However, the limited record of ca. 2.5–2.2 Ga magmatism makes it difficult to establish how exactly the Paleoproterozoic supercontinent cycle commenced. The tonalite–trondhjemite–granodiorite (TTG) series of felsic rocks forms the backbone of Archean cratons and can provide key constraints on the Earth's early tectonic evolution. Some early Paleoproterozoic TTGs occur in North China and other cratons, which may represent the last major TTG event globally, presenting the possibility to fulfill this role. Here we carry out zircon O and bulk‐rock Si isotopic analyses and thermodynamic modeling for these ca. 2.3 Ga TTGs, together with Si‐O‐Hf data compilation of TTGs globally through time. These ca. 2.3 Ga TTGs show lighter zircon O and bulk‐rock Si isotopes than those of Archean TTGs. They might be formed within‐plate, associated with lithospheric thinning and mantle‐crust remelting to form mafic‐felsic magmatism. We propose an intraplate rift setting for this early ca. 2.3 Ga magmatism, which drove the mobilism that led to the subsequent 2.1–1.8 Ga orogenesis and should be posited as the real start of the Paleoproterozoic supercontinent cycle. Key Points: Ca. 2.3 Ga tonalite–trondhjemite–granodiorite (TTG) in the North China Craton (NCC) shows the affinity of low‐pressure (LP) TTGs and contains low zircon δ18O and bulk‐rock δ30Si valuesCa. 2.3 Ga low δ18O and δ30Si TTG and coeval low‐δ18O magmatism herald the initiation of an intraplate rift settingSuch intraplate rifting hints at the formation of rifts driving subduction as the real onset of the Paleoproterozoic supercontinent cycle [ABSTRACT FROM AUTHOR]

The Southwestern Laurentia large igneous province (SWLLIP) comprises voluminous, widespread ca 1.1 Ga magmatism in the southwestern United States and northern Mexico. The timing and tempo of SWLLIP magmatism and its relationship to other late Mesoproterozoic igneous provinces have been unclear due to difficulties in dating mafic rocks at high precision. New precise U-Pb zircon dates for comagmatic felsic segregations within mafic rocks reveal distinct magmatic episodes at ca. 1098 Ma (represented by massive sills in Death Valley, California, the Grand Canyon, and central Arizona) and ca. 1083 Ma (represented by the Cardenas Basalts in the Grand Canyon and a sill in the Dead Mountains, California). The ca. 1098 Ma magmatic pulse was short-lived, lasting 0.25-0.24 +0.67 m.y., and voluminous and widespread, evidenced by the ≥100 m sills in Death Valley, the Grand Canyon, and central Arizona, consistent with decompression melting of an upwelling mantle plume. The ca. 1083 Ma magmatism may have been generated by a secondary plume pulse or post-plume lithosphere extension. The ca. 1098 Ma pulse of magmatism in southwestern Laurentia occurred ∼2 m.y. prior to an anomalous renewal of voluminous melt generation in the Midcontinent Rift of central Laurentia that is recorded by the ca. 1096 Ma Duluth Complex layered mafic intrusions. Rates of lateral plume spread predicted by mantle plume lubrication theory support a model where a plume derived from the deep mantle impinged near southwestern Laurentia, then spread to thinned Midcontinent Rift lithosphere over ∼2 m.y. to elevate mantle temperatures and generate melt. This geodynamic hypothesis reconciles the close temporal relationships between voluminous magmatism across Laurentia and provides an explanation for that anomalous renewal of high magmatic flux within the protracted magmatic history of the Midcontinent Rift. [ABSTRACT FROM AUTHOR]

The Eocene Yulong porphyry copper belt (YPCB) in eastern Tibet contains more than 10 Mt of Cu metal, associated with subvolcanic to volcanic porphyry systems intruding Cenozoic sedimentary basins. Geochemical data analysis shows that all samples belonged to high-K calc-alkaline and shoshonite series with metaluminous–peraluminous characteristics, light rare earth elements and large ion lithophile elements enrichment, high field strength elements depletion, and share geochemical similarities to adakitic rocks. We have established a spatiotemporal evolution framework through geochronological data analysis, combined with calculated bulk zirconium saturation temperature, calculated crustal thickness and geophysical evidence. We identified three magmatic processes triggered by asthenospheric upwelling and thermal erosion of thickened crust: (1) ultrapotassic magma derived from metasomatized mantle; (2) coeval ultrapotassic melt that promoted the partial melting of eroded lower crust and the generation of high-K adakitic felsic melt; high-K and Mg# adakitic fertile magma was formed by interaction between the eroded sulfide-rich juvenile lower crust-derived melt and mantle peridotite; (3) high-K adakitic fertile magma was derived from sulfide-rich juvenile lower crust, triggered by injecting hydrous ultrapotassic magma into thinned lower crust. The difference between deposit size in the north/south section of Yulong belt may be caused by the temperature of magmatic source and the volume of coeval potassic–ultrapotassic magmatism. Our analysis of the YPCB suggests that magmatism after 175 Ma within Intermontane arc complex of the Canadian Cordillera has high potential for porphyry deposits. [ABSTRACT FROM AUTHOR]

Iron oxide-copper–gold (IOCG) deposit genesis is often genetically linked to magmatism due to temporal association between granite and mineralization and participation of magma-derived components. In the Carajás Mineral Province, NW Brazil, a set of ca. 2.6–2.5 Ga IOCG deposits has been interpreted to be genetically linked to contemporary granite, which are located along the Cinzento Shear Zone, in the northern part of the province. Despite the apparent temporal correlation, the understanding of ca. 2.5 Ga ages as magmatic may be misleading, since ca. 2.6–2.5 Ga reset ages have been previously reported for deformed and hydrothermally altered granites crystallized at ca. 2.74 Ga. We studied the morphology, texture, and composition of 2.74–2.73 Ga, 2.68 Ga, 2.64–2.62 Ga, and 2.59–2.55 Ga zircons from variably deformed and metasomatized granites located along the Cinzento Shear Zone. Our study reveals re-equilibrated magmatic, deformed, and newly grown zircon domains with compositional changes (Ta, U, Y, and LREE enrichment relative to chondrite) that inconsistently follow textural patterns. The overprint arises from diffusion–reaction, coupled-dissolution-reprecipitation processes, and alteration of metamict zircons, likely aided by alkaline (Na–K-rich) and F-Cl-rich hydrothermal fluids that circulated regionally in the Carajás Province. Such processes account for disturbances and resetting of the U-Th-Pb isotopic system in zircon; therefore, the geochronological record in granites from our study can be associated with the first (ca. 2.72–2.68 Ga) and the second (ca. 2.6–2.5 Ga) IOCG-forming hydrothermal events rather than to igneous crystallization. In this context, we rule out a temporal link between granitic magmatism and the IOCG deposits at Carajás. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The problem of hyperbasites origin is one of the widely discussed topics in geology. This is because they often appear when no expected. Their development does not correspond to the general regularities of the geological complexes’ development. Therefore, when problematic instances of hyperbasites appear, discussion is inevitable. This is due to the imperfections of existing concepts, which are not without flaws. The essence of this concept lies in the fact that during the rotation of the Earth around its axis, geodynamic forces are formed. The hyperbasites complex by its nature belongs to deep igneous formations formed at the initial stage of development of volcano-plutonic processes, where the composition of magmatic products was not subject to decomposition. In general, the origin of igneous rocks is associated with deep anomalous processes, which were formed under the influence of geodynamic forces, where decompression of mantle matter occurs, causing a catastrophic increase in the volume of mantle matter, as well as the associated development of volcanoplutonic processes. Hyperbasites are formed both in divergent and convergent zones of the Earth’s crust. The main factor for their formation is high pressure – deep thermodynamic conditions, where there are no favorable thermodynamic conditions for the complete separation of magmatic melts by composition. The emergence of hypermafic rocks on the surface is associated with geotectonic or denudation processes. Denudation processes can expose only those hypermafic formations that are located at the site of formation. These zones include ancient platforms, sheets, terranes, etc., which were cut by deep erosion processes. As for those hyperbasic formations that are classified as alpinotype hyperbasites, they were moved to the structure of the Alps-Himalayan folded zone from the basement with a collision with subsequent geotectonic processes, where they formed in the bed of the Paleotethys Ocean, both in the process of divergence and convergence. The noted pattern of formation and the mechanism of formation of alpine-type hyperbasites clearly corresponds to the patterns of development of geodynamic forces in the face of the Earth, also with natural laws, which are the main factors in the evolution of the Earth’s crust. From the standpoint of KDEZK, the origin, mechanism of formation, as well as the form of distribution of alpinotype hypermafic rocks of the Lesser Caucasus occurred in the Paleotethys bed, under different thermodynamic conditions and at depths. Further, as a result of the collision, it participated in the formation of folded zones of the Lesser Caucasus. Within the Lesser Caucasus, two genetic types of hypermafic rocks are exposed. Some of them correspond to the convergent zone of the Tethys paleocean, while others correspond to divergent zones. In terms of ore content, the most promising are those hypermafic rocks that are genetically related to convergent zones.

Triassic intermediate-mafic igneous rocks are sporadically exposed in the East Kunlun Orogen Belt (EKOB), and their petrogenesis and geological implications for the Paleo-Tethyan orogeny are not well constrained. Geochronologic and geochemical data for the gabbro, gabbroic diorite and quartz diorite in Qingshuihe pluton are presented here to constrain their ages, petrogenesis and geodynamic settings. LA-ICP-MS zircon U-Pb dating indicates that the gabbro, gabbroic diorite and quartz diorite were formed at 239.8 ± 2.1 Ma, 238.4 ± 1.1 Ma and 235.7 ± 1.1 Ma, respectively. The studied samples span a wide range in geochemical compositions with SiO2 content of 47.55–63.93 wt%, exhibiting low-K tholeiitic to high-K calc-alkaline affinities. All samples have trace element compositions resembling typical arc magmas, however, from gabbro, gabbroic diorite to quartz diorite, the fractionation degree of rare earth elements gradually increases ((La/Yb) N = 2.08–2.52, 2.20–9.23 and 7.15–17.95, respectively), and the enrichment in large ion lithophile elements (e.g., Rb, Ba, Th and K) and the depletion in high field strength elements (e.g., Nb, Ta, and Ti) are also more obvious. These geochemical features, combined with their enriched Sr-Nd-Hf isotopes ((87Sr/86Sr)i = 0.709694–0.71445, εNd(t) = -7.9 – -4.7, εHf(t) = -3.65–3.79, respectively), unanimously indicate their parental magma was derived by partial melting of an enriched lithospheric mantle, followed by cumulation of tabular plagioclase and prismatic amphibole generating the appinitic gabbro, and subsequent certain degree of magma mixing and fractional crystallization forming the evolved gabbroic diorite and quartz diorite. This study therefore not only demonstrates that mantle-derived arc magma underplating followed by crust-mantle mixing and fractional crystallization is an important mechanism of continental crust growth, but also confirms that the East Kunlun Paleo-Tethyan oceanic subduction lasted at least until 235 Ma.

This cutting-edge study delves into regional magmatism in northern Taiwan through advanced 3-D P- and S-wave frequency-dependent attenuation tomography. Positioned at the dynamic convergence boundary between the Philippine Sea Plate and the Eurasian Plate, Taiwan experiences moderate earthquakes and intriguing volcanic activity, with a focus on the Tatun volcano group. Employing the Formosa seismic array for high-resolution results, our research identifies high-attenuation anomalies (low Q) beneath the northern Taiwan volcanic zone (NTVZ) and offshore submarine volcanoes, indicative of potential hydrothermal activities and magma reservoirs at varying depths. Additionally, we explore low-attenuation anomalies (high Q) in the forearc region of the Ryukyu subduction zone, suggestive of partial saturation linked to serpentinization processes resulting from seawater infiltration or forearc mantle hydration. These findings shed light on the complex geological features and provide essential insights into the crustal properties of northern Taiwan, contributing to a deeper understanding of its magmatic evolution and tectonic processes. [ABSTRACT FROM AUTHOR]

During the Permian-Triassic transition, dramatic environmental changes occurred, including the segmentation of Pangaea and the beginning of the Alpine orogenic cycle with widespread magmatism and tectonic activity. The Permian-Triassic succession deposited in the northern (palaeo-) Gondwana is now exposed in the inner Northern Apennines where it crops out discontinuously in the Middle Tuscan Ridge, a NS-oriented morphotectonic feature mainly formed by blue-schist and green-schist facies metamorphic rocks. In this paper, we describe a previously unreported late Palaeozoic succession exposed in the central part of the Middle Tuscan Ridge: the Montagnola Senese Ridge. This succession provides information concerning the enigmatic late Palaeozoic units exposed in southern Tuscany, and permits the age constraint of continentalization at the Permian-Triassic boundary with associated magmatism. Specifically, by integrating stratigraphic, structural, and petrographic data, we describe a siliciclastic, volcanoclastic-to-carbonate succession which recorded the transition from marine sedimentation to the typical continental, red-beds of the Verrucano tectofacies. Additionally, deformational features, metamorphism and age of the succession are discussed in terms of its tectono-sedimentary evolution and implications for the Palaeozoic-Triassic setting of the central Pangaea sector currently exposed in southern Tuscany. The results allow us to recognize a middle-late Permian pre-Verrucano succession, and to date the transition to continental facies as latest Permian. The microflora permits correlation of the pre-Verrucano succession to the late Palaeozoic units of the inner Northern Apennines, and establishes the diachronous nature of the Verrucano tectofacies exposed in the inner Northern Apennines. Finally, the thermal maturity of the organic matter indicates a maximum temperature of 387 ± 30°C attained during metamorphism. [ABSTRACT FROM AUTHOR]

During the Late Cretaceous, a magmatic arc extended from the Lesser Caucasus through the northern margin of the Pontides into Srednogorie, Timok, Banat, and Apuseni (ABTS) in the Balkans for a distance of 2700 km. We studied the arc volcanic rocks in three regions in the Western Pontides and reviewed the geological data on the Lesser Caucasus-Pontide-ABTS magmatic arc, which shows several common features. Prior to the start of the arc magmatism, the region underwent uplift and erosion. New and published geochronologic and biostratigraphic data show that magmatism in the Lesser Caucasus-Pontide-ABTS arc started in the Turonian (ca. 93 Ma) peaked in the middle Campanian (80–78 Ma) and became rare and sporadic after the late Campanian (ca. 75 Ma). Magmatism was dominantly calc-alkaline to high-K calc-alkaline and shows typical subduction geochemical signatures. Late Cretaceous volcanism took place in a submarine and extensional environment. In the Lesser Caucasus-Pontide-ABTS belt, the arc volcanic rocks are overlain by Maastrichtian to Palaeocene marine limestones and sandstones, marking the end of the main phase of arc magmatism. However, in the Kefken region in the Western Pontides, Maastrichtian limestone sequence includes a volcanic horizon with a U-Pb zircon age of ca. 71 Ma. The Maastrichtian volcanic rocks show a more varied geochemistry than the older arc volcanic rocks, and include alkaline basalts, calc-alkaline basalts, and adakites. The coeval start of arc magmatism in the 2700-km-long Lesser Caucasus-Pontide-ABTS belt is related to the inception of the Africa-Eurasia convergence at ca. 96 Ma, which is also independently indicated by the beginning of intra-oceanic subduction, inferred from the ages of sub-ophiolite metamorphic rocks in Anatolia. The end of magmatism is linked to a marked decrease in the convergence rate during the Campanian, which was also partitioned between the northern and southern Tethyan subduction zones. [ABSTRACT FROM AUTHOR]

Based on an analysis of global digital models, the distribution of fracture zones of the oceanic crust, global and regional models of evolution, and published geological and geophysical data, the structural features of the ocean floor in the junction area of the Indian and Atlantic oceans are considered. Tectonic zoning of the region's crust has been carried out. Heterogeneous blocks of the lithosphere with crust formed on different spreading ridges, separated by structural boundaries, which are pseudofaults, fixing traces of propagating rift zones, jumping and cessation of spreading ridges are identified. The main stages in the evolution of the lithosphere associated with the activation of plume magmatism and kinematic reorganizations of plate boundaries are identified. [ABSTRACT FROM AUTHOR]

This report analyzes original geological materials on the Magellan Seamounts in the Pacific Ocean, obtained by the authors on numerous cruises of the R/V Gelendzhik. This chain of guyouts does not have a common volcanic basement and apparently formed in the second half of the Early Cretaceous on the oldest (Middle–Late Jurassic) fragment of the Pacific Plate. The main viewpoints on the genesis of the Magellan Seamounts are as follows: either they originated at the intersection of fracture zones or the Pacific Plate moved them from the Southern Hemisphere to their present-day position. Because of their high degree of study, the Magellan Seamounts are one of the key sites for understanding the mechanism underlying the origin of linear chains in the ocean. A comprehensive analysis of new geological data on the Magellan Seamounts has established the important role of magmatism and tectonics in the formation of the modern morphological forms, sedimentation, and influence on the paleoceangraphy. The periodic reactivation of these processes from the Early Cretaceous to Late Cenozoic can be traced in the cyclicity of sedimentation, the continuous growth of ore crusts, and the formation of secondary volcanic domes and cones. [ABSTRACT FROM AUTHOR]

The study of the magnetic susceptibility of igneous rocks from the Sikhote-Alin orogenic belt has shown that zones with the predominant development of ilmenite- or magnetite-series rocks formed during the Albian–Cenomanian magmatic stage. This zonation is independent of the petrochemical composition, type, and age of rocks and has been preserved until at least the Paleocene. It also shows no correlation with terranes. According to the authors, the redox zonation in the post-Cenomanian period was mainly determined by the granite-metamorphic layer of the new continental crust of the Sikhote-Alin orogen, which formed at the beginning of the Late Cretaceous. [ABSTRACT FROM AUTHOR]

A geochronological and isotope–geochemical study of alkaline basalts from three areas of young magmatism within the northeastern part of the Arabian Plate (Southeastern Turkey), Batman, Kurtalan and Alemdağ, was carried out. The obtained isotope data have indicated that the volcanism in the studied region developed over a 5-Ma period from the end of Miocene to the middle Pleistocene during four pulses separated by breaks in magmatic activity: 6.1–4.9 Ma (Batman area, hawaiites), ~3.0 Ma (Alemdağ plateau, phase I, basalts), 2.0–1.9 Ma (Alemdağ plateau, phase II, tephrites), and 1.5–1.3 Ma (Alemdağ plateau, phase III, basalts; Kurtalan area, basalts). A comparison of spatial–temporal changes of magmatic activity evolution in the studied part of the Arabian Plate and within the largest basalt plateau of Arabian foreland, Karacadağ Plateau, located to the west, was carried out. The results of Sr–Nd–Pb isotope–geochemical studies show that the development of young basalt volcanism in the Arabian Plate was characterized at different time by the contribution of various mantle sources in magma generation under this region. Initial pulses of magmatic activity are associated with melting of Arabian subcontinental lithospheric mantle (SCLM). The processes of fractional crystallization combined with crustal assimilation (AFC) have played an important role in the petrogenesis of lavas as well. Later, a deep mantle source (PREMA) with a depleted isotopic composition played a leading role in the formation of basaltic magmas of increased alkalinity. The melts generated by this source were mixed with the SCLM material in various proportions at different stages of magmatism with a limited participation of AFC processes in the petrogenesis of the rocks. It was concluded that young basalt volcanism of increased alkalinity in the northeast of the Arabian Plate is not related to the collision of the Eurasian and Arabian plates genetically, but presumably manifested here as a result of the migration of the initial rift geodynamic setting from the Red Sea basin to the north along Levantine and East Anatolian transform faults due to directed convection flows in the lower part of mantle under this part of the Earth. [ABSTRACT FROM AUTHOR]

The relationship between deep crustal structure and the deformation in the overlying sedimentary wedge in Santos basin, Brazil is not well understood, and the origin and evolution of the salt‐related "Albian Gap (AG)" remain a topic of debate. We investigate the deep structure using three‐dimensional inversion of full tensor marine magnetotelluric (MT) data (of 10−1 to 104 s period bandwidth) from 92 stations along three NW–SE lines in 50–1,700 m water depth, one crossing the Cretaceous hinge line (CHL), AG, and Cabo Frio Fault (CFF). The geological validity of the resulting MT resistivity models was determined using resistivity logs from 11 wells and seismic data. The model shows two regionally persistent electrically conductive layers (C2 and C3) related to key Cenozoic and Cretaceous unconformities in the upper part of the sedimentary wedge. Beneath this wedge, the resistive continental crust is ∼35 km thick across the CHL until the 200 m isobath and thereafter thins rapidly seaward to ∼21 km over a lateral distance of ∼80 km defining a domain of highly extended and faulted crust. Our models show a mantle‐associated basement high and evidence of significant uplift of the lower part of the sedimentary wedge at 100–150 km distance along our central profile which spatially coincides with the AG and a previously proposed Moho high. This implies a mantle‐driven deformation of the crust and basin fill. We propose that mantle flow and magmatism may have played a significant role in the inferred displacement at the AG. Plain Language Summary: How the deformation observed in the sedimentary wedge of Santos basin, Brazil is related to deep crustal and/or upper mantle processes is not well understood. We investigate the deep structure beneath Santos basin using a three‐dimensional magnetotelluric resistivity model crossing the Cretaceous hinge line (CHL), Albian Gap (AG), and Cabo Frio Fault (CFF). The geology‐calibrated resistivity model shows a top electrically conductive sedimentary wedge, underlain by the resistive crust that thins seawards as a result of basin evolution through continental rifting and extension characteristic of passive margin basins. The resistive continental crust is ∼35 km thick across the CHL and thins rapidly seaward to ∼21 km beneath the CFF, defining a domain of ∼80 km with highly extended and faulted crust. Our model suggests a mantle‐associated basement high and shows evidence of significant displacement over a wide zone across a proposed Moho high and the AG implying a coupled deformation of the basement and the sedimentary wedge. It is proposed that magmatism or lower crustal flow may have played a significant role in the inferred significant dislocation of strata at the AG. Key Points: Electrically resistive continental crust is ∼35 km thick near‐shore and thins rapidly seaward to about 21 km over a distance of ∼80 kmResistivity models show a 50 km wide zone of heavily faulted thin crust and shallow mantle that is spatially coincident with the Albian Gap (AG)We propose that the vertical movement and the enigma of the AG may be related to mantle‐driven uplift and magmatism in this zone of highly extended crust [ABSTRACT FROM AUTHOR]

In the south Eastern Desert of Egypt, two contrasting types of magmatism (mafic and felsic) are recorded in the Wadi Kalalat area, and form the Gabal El Motaghiarat and Gabal Batuga intrusions, respectively. The two intrusions post-dates ophiolitic and arc associations represented by serpentinite and metagabbro-diorite, respectively. The mafic intrusion has a basal ultramafic member represented by fresh peridotite, which is followed upward by olivine gabbro and anorthositic or leucogabbro. This mafic intrusion pertains to the Alaskan-type mafic–ultramafic intrusions in the Arabian–Nubian Shield (ANS) being of tholeiitic nature and emplaced in a typical arc setting. On the other hand, the Gabal Batuga intrusion comprises three varieties of fresh A-type granites of high K-calc alkaline nature, which is peraluminous and garnet-bearing in parts. A narrow thermal aureole in the olivine gabbro of the mafic intrusion was developed due to the intrusion of the Batuga granites. This results in the development of a hornfelsic melagabbro variety in which the composition changed from tholeiitic to a calc-alkaline composition due to the addition of SiO2, Al2O3, alkalis, lithosphile elements (LILEs) such as Rb (70 ppm) and Y (28 ppm) from the felsic intrusion. Outside the thermal aureole, Rb amounts 2–8 ppm and Y lies in the range < 2–6 ppm. It is believed that the Gabal Batuga felsic intrusion started to emplace during the waning stage of an arc system, with transition from the pre-collisional (i.e., arc setting) to post-collisional and within plate settings. Magma from which the Gabal Batuga granites were fractionated is high-K calc-alkaline giving rise to a typical post-collisional A-type granite (A2-subtype) indicating an origin from an underplating crustal source. Accordingly, it is stressed here that the younger granites in the ANS are not exclusively post-collisional and within-plate but most likely they started to develop before closure of the arc system. The possible source(s) of mafic magmas that resulted in the formation of the two intrusions are discussed. Mineralogical and geochemical data of the post-intrusion dykes (mafic and felsic) suggest typical active continental rift/within-plate settings. [ABSTRACT FROM AUTHOR]

The Early Paleozoic tectono-thermal event was a significant orogenic activity during the Phanerozoic era, which had a profound impact on the early crust of the South China Block (SCB) and established the foundation for later tectonic activity. The Wuyi-Yunkai orogenic belt in Southeastern China was extensively exposed to Early Paleozoic magmatism, the genetic mechanism of which remains controversial. To shed light on this issue, detailed petrological, geochemical, and zircon U–Pb–Hf isotopic studies were carried out on two granitoids, namely the Yuntongshan pluton and the Gaoqiao pluton, identified in the central Wuyishan. Zircon U–Pb chronology of the Yuntongshan and Gaoqiao bodies yielded ages of 437 ± 4 Ma (MSWD = 2.2) and 404 ± 2 Ma (MSWD = 12), respectively, indicating that they were emplaced during the Early Silurian and Early Devonian periods. These granitoids are primarily composed of biotite-granite and biotite-monzonitic-granites, with high concentrations of SiO2 (73.59–75.91 wt%), K2O + Na2O (8.31–8.73 wt%), and low contents of MgO, CaO, Cr, Ni. They are classified as high-K calc-alkaline and weakly metaluminous-strongly peraluminous S-type granites. These granitoids are enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs) and depleted in heavy rare earth elements (HREEs) and high field strength elements (HFSEs) with arc affinity. The εHf(t) values of − 3.3 to − 15.4 with two-stage Hf model ages ranging from 2829 to 1644 Ma, combined with the presence of Neoproterozoic inherited zircons, suggest that the primary magma of these granitoids was derived from the partial melting of Neoproterozoic crust with a Paleoproterozoic crustal model age. These findings, combined with the spatio-temporal distribution of regional magmatism, reveal that the late Early-Paleozoic granitoids formed in the intraplate orogenic background originating from the subduction of the proto-Tethys Ocean and proto-Pacific Ocean around the margin of the east Gondwana supercontinent. [ABSTRACT FROM AUTHOR]

The Palaeozoic magmatic history of Central Iran is related to the subduction of the Proto‐Tethys Ocean and the amalgamation of Gondwana continental fragments. This study presents whole‐rock geochemistry, Sr–Nd isotope and zircon U–Pb–Hf ages of shoshonitic plutonic rocks (e.g., monzonite–syenite) from the north Posht‐e‐Badam (NPB) district with a view to constrain their petrogenetic and tectono‐magmatic evolution during the Palaeozoic. The geochemical data show moderate enrichment in large‐ion lithophile elements and Ti, large positive Pb anomalies, and depletion or moderate enrichment in high‐field‐strength elements (e.g., Nb and Ta), typical of continental arcs. Zircon LA–ICP–MS U–Pb ages are in the range of 444–428 Ma. The Sr–Nd–Hf isotope data, for example, (87Sr/86Sr)i = 0.7073 to 0.7089, εNd(t) = −1.4 to −0.2, and εHf(t) = −3.6 to +7.7, indicate derivation of the magma from a mantle source. The numerical modelling shows a contribution of less than 10% crustal assimilation and ~3% sediment into the melt‐derived mantle. We propose that metasomatic enrichment occurred during the subduction of Proto‐Tethyan Ocean between the Iranian microcontinents, leading to the formation of a shoshonitic melt. We infer that the recorded ages coincide with a continental rift episode followed by a rear arc tectonic region that spread along the northern active margin of Gondwana. Further, the change in magma affinity from calc‐alkaline (~474–512 Ma) to shoshonitic (444–428 Ma) in Central Iran is probably related to the gradual steepening of the slab dip angle and trench‐ward migration of the front arc into the region above metasomatically enriched rear arc mantle. [ABSTRACT FROM AUTHOR]

Frequent magmatism was a major event causing the mass extinction across the Permian/Triassic Boundary. In the current study, we determined magmatism characteristics from the Pingdingshan section at the Permian/Triassic Boundary using conodont-based geochemical proxies at a high-resolution scale (~ 50 kyr). Integrated trace elements (Mn, Sr, Rb, and Th) and stable/radioactive isotopes (δ18O, δ13C, and 87Sr/86Sr) revealed that conodonts provided an ideal proxy for chemostratigraphic signatures of ancient seawater. The conodont-based, high-resolution 87Sr/86Sr isotopes from the studied interval (250.50–252.00 Ma) displayed three decreasing cycles upwardly against a long-term increasing background, reflecting three episodes of magmatism. As a contrast, the conodont-based, high-resolution δ18O isotopes from this interval exhibited no episodic pattern, indicating that the δ18O isotopes of conodonts were limitedly influenced by marine magmatism. The high-resolution δ13C values of micrites displayed a pattern consistent with the trend of long-term background, revealing that the δ13C signatures of episodic magmatism were not inherited by micrites. The magmatism associated with the EPME event exerted great influences upon the Chihsian source rocks by introducing massive heat through hydrothermal fluids and causing pervasive oceanic anoxia. [ABSTRACT FROM AUTHOR]

Determining the volume and timing of magmatism during rifting and breakup is challenging due to the similar density and seismic velocity of inherited continental crust, magmatic additions and serpentinized mantle; and the difficulty of dating magmatic additions. Here rules of thumb to estimate these are proposed based on the characteristics of the top basement and Moho on seismically imaged margins. A simple kinematic model is used to generate first‐order crustal shapes of margins as a function of magma volume and timing of emplacement, which are successfully compared to a representative number of rifted margins. It appears that 'magma‐rich margins' require melt emplacement in advance of crustal thinning but not necessarily enhanced melt volume, while margins with exhumed mantle require a delay in melt emplacement but not necessarily a low magmatic volume. An alternative classification for the magma‐poor/magma‐rich dichotomy is proposed to better represent the crustal shape variability of rifted margins. [ABSTRACT FROM AUTHOR]

Our study of boreholes, seismic survey and magnetic data from the region between the Baltic Basin and the Lublin Basin indicates the existence of numerous buried intrusions and effusive complexes, most of them unnoticed so far, together with a few igneous massifs. They are of alkaline character and developed in a time span of c. 348 to 338 Ma. Deep seismic data reveal the presence of large sills (up to 100 km long) within the crystalline basement and the overlying sedimentary cover, at depths of 7–14 km and 5.5–6.5 km, respectively. All these igneous rocks occur in the coherent region and constitute a hitherto unrecognized Lublin–Baltic Mississippian Igneous Province (>120,000 km2). Its denudation is evidenced by the Mississippian volcaniclastic formations of high thickness, developed in the adjacent basins. Igneous activity was triggered by thermal anomaly and/or mantle decompression caused by stress field reorganization, induced by the Variscan collision. [ABSTRACT FROM AUTHOR]

A relation between tectonics and arc magmatism has been proposed in the west Pacific‐type accretionary orogens, but the specific mechanism remains unclear. This study examines the Cretaceous records in NE Asia in order to unravel this link. Two tectono‐magmatic episodes, namely the Early and Late Cretaceous, are recognized. The first episode was under (trans‐)extension, consisting of both mafic and felsic, depleted and enriched, and deep‐ and shallow‐derived arc magmas. The second episode experienced several compressive events with highly evolved and shallow‐derived (mid‐crustal level) arc magmas. We propose that (trans‐)extension thinned the arc crust, facilitating deep mafic magmas to ascend and cool rapidly, maintaining their geochemical diversity. Compression led to magmatic emplacement around the middle crust; and the warm crust allowed highly‐evolved granitoids to form. Therefore, tectonic setting controls arc magmatism in NE Asia, and is likely representative of other west Pacific‐type orogens. Plain Language Summary: Arc magmas are produced where oceanic plates subduct into the mantle. Their chemical composition varies in different tectonic settings, but the specific mechanism is unclear. We explore this question using the NE Asian setting during the Cretaceous. Here, the Early Cretaceous arc magmas reveal diverse compositions when in a setting undergoing extension. However, the Late Cretaceous magmas uniformly contain high silica contents when the continental crust was under compression. This implies that thin arc crust under extension facilitated the ascent of deeply‐derived magmas and these cooled rapidly and kept their chemical diversity. In contrast, crust under compression prohibited the ascent of deep magmas, instead inducing crustal melting and slower cooling in the middle crust, thus increasing the silica content. Therefore, tectonics strongly affected the nature of arc magmatism in NE Asia, and possibly other west Pacific‐type orogens. Key Points: Cretaceous magmatism in the NE Asian arcs was diverse during extension, but highly evolved under compressionExtension induced deep magmas to ascend and cool rapidly; Compression restrained deep magmas and extended coolingArc magmas were controlled by alternating extensional and compressional regimes during subduction retreat in west Pacific‐type orogens [ABSTRACT FROM AUTHOR]