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Deep-sea sediments rich in rare earth elements and yttrium (REY) are promising mineral resources that are believed to be associated with the burial of fish debris. However, the nature of the REY enrichment is poorly understood, in part due to a lack of robust age constraints. We report bioapatite U-Pb ages from an Ocean Drilling Program (Leg 199, Hole 1218A) core and a REY-rich sedimentary core from the Pacific Ocean, which yielded U-Pb ages ranging from 22.8 to 18.2 Ma and 6.5 to 2.2 Ma, respectively. The U-Pb fish teeth ages from the 1218A core are consistent with biostratigraphic constraints, shed light on the application of the U-Pb bioapatite chronometer, and yield an absolute time scale for stratigraphy, especially for sequences deposited below the calcite compensation depth (CCD), where there is an absence of fossil carbonate. The successful measurement of U-Pb ages from REY-enriched fish teeth in the REY-rich sediment core suggests the mineralization occurred no later than the Miocene in the western Pacific Ocean. Uranium is positively correlated with REY, suggesting that the U and REY were incorporated into the fish teeth lattice simultaneously, making the bioapatite U-Pb chronometer suitable for constraining the timing of REY mineralization. When combined with published data, our study suggests that the Miocene REY accumulation event in the western Pacific Ocean was influenced by high P2O5 and MnO2 contents correlated with oxic bottom water.

Variations of rare earth element (REE) concentrations in metamorphic garnet are an important source of information of geodynamic and geochemical processes in the deeper Earth. In order to extract this information, the thermodynamic equilibrium and kinetic contributions of the REE uptake in garnet must be distinguished and quantified. Utilizing high-resolution trace element and μ-Raman mapping together with combined thermodynamic–geochemical–diffusion models, we demonstrate that the equilibrium and kinetic aspects of the REE uptake in metamorphic garnet can be discriminated by interpreting 2D trace element mapping in a single sample. The heavy (H) REE (Tb to Lu) zoning in the investigated garnet from a high-pressure blueschist comprises an inner part with an overall decrease from core to inner rim, followed by a concentric zone of HREE enrichment and a drastic HREE decrease towards the outermost rim. The central peak in the garnet core decreases in intensity with decreasing atomic number of the REE. The broad overall shape of this pattern resembles those often observed in metamorphic garnet from different rock types and tectonic settings. Superimposed on this trend is a concentric pattern of minor recurring fluctuations in the HREE concentrations with at least six regularly spaced sets of peaks and troughs along the entire garnet radius. Comparison of the observed inclusion suite, the trace element maps and thermodynamic–geochemical models show that the inner part with decreasing HREE concentrations results from fractional garnet growth in an unchanged mineral assemblage, whereas the REE enrichment zone is caused by the breakdown of titanite. We suggest that the width of the central peak is controlled by the bulk permeability of the interconnected transport matrix and the fraction of matrix minerals that the garnet equilibrates with. The superimposed REE fluctuations result from changing element transport properties of the host rock and mark recurring changes from equilibrium REE uptake to transport-limited REE uptake in garnet. Such fluctuating element transport properties can be best explained by pulse-like fluid fluxes that rhythmically change the interconnectivity of the intercrystalline transport matrix. Increasing numbers of published spatially highly resolved REE analyses show that such trace element fluctuations are common in metamorphic garnet indicating that recurring changes in rock permeabilities due to pulsed fluid fluxes are a common phenomenon during metamorphism.

Spectacular Paleogene uplift and volcanism in Ireland and Britain are thought to be associated with the Iceland Plume but their mechanisms are still unclear, considering, in particular, that the Iceland Hotspot was many hundred kilometres away from the volcanism. We obtain new insights into the mechanisms by combining new evidence from seismic tomography, petrological inversion of seismic data, and the geological data on uplift and volcanism. Optimal resolution tomography is a new approach, developed for surface wave tomography, that allows us to find the optimal resolving length at every point of a tomographic model grid. With this approach we evaluate the posterior model error at a point of the model grid empirically, estimating it by isolating the roughness of the phase-velocity curve that cannot be explained by any Earth structure. We apply this method to the region of Ireland and Britain, using more than 11,000 interstation phase-velocity curves measured at station pairs recording simultaneously, to image the lithosphere and underlying mantle beneath the area. The use of cross-correlation of teleseismic earthquakes and waveform inversion produces measurements in a very broad period range, leads to an unprecedented data coverage of the region, and allows us to unveil exciting new insights into the structure and evolution of the area, from the crust to the deep asthenosphere at a unprecedented level of detail.The composite, optimal resolution phase-velocity maps are inverted for a 3-D VS model, which reveals pronounced, previously unknown variations in the lithospheric thickness beneath the area. The model shows evidence of a robust, low-velocity anomaly beneath the Irish Sea and its surroundings that persists in the models from ~60 to at least 140 km depth, indicating an anomalously thin lithosphere and demonstrating that the assumption of a nearly constant lithospheric thickness across the area, previously adopted, is not valid. Phase velocity data at key locations are inverted using integrated geophysical-petrological inversion, to estimate the thermal structure of the lithosphere-asthenosphere system consistent with the seismic data, surface elevation, and heat-flow. The circum-Irish Sea area reveals a pronounced lithospheric thinning and matches the region of the Paleogene uplift previously suggested to be caused by a lateral branch of the Iceland mantle plume, which may have flowed into thin lithosphere areas surrounded by continental lithosphere during the evolution of the North Atlantic Ocean over the past 60 M.y. Our results show a striking correlation between lithospheric thickness and exhumation thermochronological measurements (as well as proposed underplating thickness, denudation, and the locations of the intraplate volcanism of the enigmatic North Atlantic Igneous Province) suggesting a significant lithospheric control on the volcanism of the area.

Metamorphic garnet can be the ultimate source of information about geodynamic and geochemical processes in the Earth’s crust. Compositionally zoned garnet porphyroblasts preserve records of the host rock’s reaction path, its element transport properties, the fluid-rock interaction during metamorphism as well as absolute ages and rates of these processes. Especially variations of rare earth element (REE) concentrations in garnet are reflecting many of these geodynamic and geochemical processes. In order to extract this information, the thermodynamic equilibrium and kinetic contributions of the REE uptake in garnet must be distinguished and quantified, for which high resolution major- and trace element mappings together with numerical growth simulations are an indispensable tool. Utilizing high resolution trace element and µ-Raman mapping together with combined thermodynamic-geochemical-diffusion models we discriminate the equilibrium and kinetic aspects of the heavy (H) REE uptake in a garnet porphyroblast from a high-pressure/low temperature blueschist from the Dominican Republic. Like many metamorphic garnets from different rock types and tectonic settings, the HREE zoning in the investigated garnet comprises an inner, bell-shaped part with a pronounced central peak and an overall decrease of all HREE from core to inner rim. The central peak in the garnet core decreases in intensity with decreasing atomic number of the REE. This trend is followed by a concentric zone of HREE enrichment and a drastic HREE decrease towards the outermost rim. Superimposed on this common trend is a concentric pattern of minor recurring fluctuations in the HREE concentrations with regularly spaced sets of peaks and troughs along the entire garnet radius.Comparison of the trace element mappings and thermodynamic-geochemical models show that the inner, bell-shaped part results from fractional garnet growth in an unchanged mineral assemblage. The model results further show that the width of the central peak is controlled by the bulk permeability of the interconnected transport matrix and the fraction of matrix minerals that the garnet equilibrates with. The correlation of high resolution µ-Raman mappings of the inclusion suite and the trace element mappings indicate that the REE enrichment zone is caused by HREE redistribution during the titanite-rutile transition.The superimposed REE fluctuations result from changing element transport properties of the host rock and mark recurring changes from equilibrium REE uptake to transport-limited REE uptake in garnet. Such fluctuating element transport properties can be best explained by pulse-like fluid fluxes that rhythmically change the interconnectivity of the intercrystalline transport matrix. Increasing numbers of published spatially highly resolved REE analyses show that such trace element fluctuations are common in metamorphic garnet indicating that recurring changes in rock permeabilities due to pulsed fluid fluxes are a common phenomenon during metamorphism.

Uranium-Pb dating of unusual coarse-grained apatite crystals from hydrothermal dolostone breccia in the barite-rich Magcobar zone at the Silvermines deposit, Ireland, indicates an age of 331 ± 5.6 Ma for hydrothermal alteration. This age is in agreement with an Re-Os age on pyrite-sphalerite but differs from previous estimates that were based on palemomagnetism and sphalerite Rb-Sr geochronology at Silvermines. The new U-Pb age indicates the deposit largely formed epigenetically rather than as a synsedimentary deposit. The trace element composition of the apatite provides additional constraints on the geochemical evolution of the Silvermines hydrothermal system indicating that it was initiated with the expulsion of oxidizing fluids responsible for early hematite-silica precipitation. This was followed by the formation of hydrothermal dolostone breccias containing barite and the apatite dated here. The infiltration of metal-bearing hydrothermal fluids, likely derived from the basement, overlapped and followed the development of hydrothermal dolostone breccias, interacting with Carboniferous seawater during dolomitization and barite precipitation. Near-sea-floor biogenic activity, possibly enhanced due to escape of hydrothermal fluids, resulted in the reduction of seawater sulfate and formation of the sulfide-bearing fluids that facilitated the development of the Silvermines Zn-Pb deposit.

Despite the importance of south Cumbrian sections for the Arundian¿Holkerian (mid Viséan) boundary, beyond the stratotype proposed at Barker Scar in 1976, little else is known regionally about this boundary and its relationship to adjacent formations. We re-evaluate the Dalton Formation, making its upper and lower boundaries regionally more consistent and precisely-defined, in good quality outcrops with associated biostratigraphy. The Dalton Formation is formally divided into the Blackstone Member and overlying Raven's Member. Rich foraminiferal assemblages of the Cf4¿ subzone are recognized in the BlackstoneMember and the lower to mid Raven's Member in nine sections. The Cf4¿¿Cf4¿ boundary is recognized in the underlying Red Hill Limestone Formation in 3 sections. The upper part of the Raven'sMember shows the first appearance of taxa assigned to the Cf5¿ and Cf5ß subzones of the Holkerian in three of the sections. Bentonitic shales in the mid and upper-most part of the Raven's Member were evaluated for zircon and apatite geochronology, although only 4 out of 504 analyses yielded Carboniferous ages, indicating an almost entirely detrital source. This detritus was northerly or northeasterly-derived and predominantly from the Southern Uplands Terrane with subsidiary input from the Lewisian Complex or eastern Greenland sources. Petrographic analysis identified 13 microfacies indicating that the Dalton Formation represents the inner to outer part of a southward inclined shelf, in which east¿west changes inmicrofacies were generated by synsedimentary faulting inherited from northwest¿southeast aligned basement structures., Wearegrateful to the comments by E. Kulagina and an anonymous reviewer. MWHwasinpartfundedbyNERC(grant NE/P00170X/1).PC is grateful to the financial support by the project CGL2016-78738 of the Spanish Ministry ofScienceandInnovation.DC issupportedinpartbya research grant from Science Foundation Ireland (SFI) under Grant Number 13/RC/2092_P2 (iCRAG, the SFI Research Centre in Applied Geosciences).VassilKarloukovski,TerezaKamenikova,DavidMindham, Courtney Sprain and Shihu Li helped collect some of the samples. The log and sampling for Grubbins 2a and 2b sections, was co-measured by Cathy Hollis. Natural England, Cumbria Wildlife Trust, Holker Hall Estate, theArnsideSilverdaleAONB,andtheLandownersofCrosthwaite and Lyth, allowed access, permission and permits to collect samples from these sections.

Multisystem inflammatory syndrome (MIS) is a severe complication described in a minority of patients with COVID-19. Myocarditis has been reported in patients with COVID-19, including MIS. In this study, we compared the clinical characteristics and cardiac magnetic resonance (CMR) findings of COVID-19 myocarditis in patients with and without MIS. In the 330 patients with COVID-19 who were referred for CMR at our institution between July 24, 2020, to March 31, 2021, 40 patients were identified as having myocarditis, MIS myocarditis (n = 21) and non-MIS myocarditis (n = 19). MIS myocarditis was characterized by global myocardial inflammation/edema with significantly elevated native T1, whereas only regional inflammation, and edema were noted in the non-MIS group. Distinct late gadolinium enhancement (LGE) patterns—inferior myocardial involvement in non-MIS myocarditis and septal involvement in MIS myocarditis—were identified. The LGE burden was comparable between the 2 groups (5.9% vs 6.6%, MIS vs non-MIS group, p = 0.83). Myocarditis was diagnosed more frequently by CMR in the MIS group (70% vs 6.3%, MIS vs non-MIS, p

Technologies that recruit and direct the activity of endogenous RNA-editing enzymes to specific cellular RNAs have therapeutic potential, but translating them from cell culture into animal models has been challenging. Here we describe short, chemically modified oligonucleotides called AIMers that direct efficient and specific A-to-I editing of endogenous transcripts by endogenous adenosine deaminases acting on RNA (ADAR) enzymes, including the ubiquitously and constitutively expressed ADAR1 p110 isoform. We show that fully chemically modified AIMers with chimeric backbones containing stereopure phosphorothioate and nitrogen-containing linkages based on phosphoryl guanidine enhanced potency and editing efficiency 100-fold compared with those with uniformly phosphorothioate-modified backbones in vitro. In vivo, AIMers targeted to hepatocytes with N-acetylgalactosamine achieve up to 50% editing with no bystander editing of the endogenous ACTB transcript in non-human primate liver, with editing persisting for at least one month. These results support further investigation of the therapeutic potential of stereopure AIMers.

The LeMay Group accretionary complex of Alexander Island (Antarctic Peninsula) comprises a 4 km thick succession of variably deformed turbidites associated with thrust slices of ocean floor basalts. The depositional age and provenance of the succession is uncertain with estimates ranging from Carboniferous to Cretaceous. The accretion history is also poorly established and whether the LeMay Group developed allochthonously and accreted during an episode of Cretaceous terrane translation. We have examined the geochronology and geochemistry of twenty-two samples from across the entire accretionary complex to determine its depositional, provenance and accretion history. The accretionary complex has been subdivided into four separate groups based on detrital zircon U-Pb age and Lu-Hf provenance analysis. Groups 1 and 2 are interpreted to be a continuation of the extensive Permian accretionary complexes of West Gondwana and have a depositional age of c. 255 Ma, with volcaniclastic input from the extensive silicic volcanism of the Choiyoi Province. Accretion of the LeMay Group to the continental margin developed during the mid-Triassic, potentially related to the Peninsula Orogeny and an episode of flat-slab subduction of the proto-Pacific plate. Group 3 is only identified from an island to the west of Alexander Island and has a mid-Cretaceous depositional age and provenance akin to offshore sequences from Thurston Island. A para-autochthonous origin is suggested, with mid-Cretaceous accretion associated with the melange belts of central Alexander Island. Group 4 is also a distinct unit with an Early Jurassic depositional age and a source more closely related to the Antarctic Peninsula.

Granite typology categorizes granitoid rocks based upon distinguishing characteristics that are interpreted to indicate sources, conditions of generation, and, by implication, tectonic setting. Complexities of elemental and isotopic geochemistry, however, commonly preclude simple typological interpretation and suggest more complex petrogenetic histories. Granitoids from the Songpan-Ganzi terrane in the eastern Tibetan Plateau were emplaced within a short interval (~15 m.y.). They display mineralogical and geochemical characteristics that are consistent with a wide range of proposed typologies (I-, S-, and A-type; high Ba-Sr and adakitic variants). Despite their close spatial and temporal association, these granitoids exhibit diversity in geochemical characteristics that indicates a broad spectrum of contributing sources. Radiogenic isotope data reveal a continuum from primitive to evolved crustal compositions; i.e., 87Sr/86Sr(t) = 0.704–0.715 and εNd(t) = +2 to −11. All granitoid “types” have variable but commonly high zircon δ18O (+4.1‰ to +11.6‰) and low whole-rock Li-B-Mg isotopic ratios compared to mantle and/or seawater (δ7Li = +5.1‰ to −3.2‰; δ11B = −10.7‰ to −16.5‰; δ26Mg = −0.23‰ to −0.59‰). These stable isotopic compositions suggest that the Songpan-Ganzi granitic magmas of all “types” had contributions from sediment, ranging from minor to dominant. The highly variable isotopic compositions of the granitoids rule out a single homogeneous source for these diverse yet contemporaneous granitoids. Their compositional variability may have been significantly influenced by sedimentary contributions, and these results demonstrate the difficulty of straightforward assignment and interpretation of granitoids using conventional typology.

Zircon separates from the contact aureole of the syn-tectonic Dawros–Currywongaun–Doughruagh Complex, western Ireland, are studied to constrain the nature and timing of magmatism associated with the early stages of the Grampian Orogeny. The samples analysed come from the uppermost part of the Dalradian Supergroup in northern Connemara (the Ben Levy Grit Formation), where a laterally extensive (>10 km) package of metamorphosed siliciclastic sedimentary rocks containing heavy mineral seams crops out. The seams mainly comprise magnetite, but zircon is also present in greater than accessory quantities. The seams have been locally reworked at granulite-facies metamorphic conditions during intrusion of the Dawros–Currywongaun–Doughruagh Complex magmas. Here we combine in situ mineral chemical and U–Pb geochronological analyses of zircons from samples of these heavy mineral seams collected at different locations in the Dawros–Currywongaun–Doughruagh Complex thermal aureole. An important finding is that the zircons studied have magmatic trace-element compositions, interpreted here as a function of their growth during contact metamorphic-induced partial melting. The zircons yield a range of U–Pb spot ages whose uncertainties suggest a maximum duration of zircon growth of ˜11 Ma, between 477.1 and 466.1 Ma, though it is likely that zircon growth occurred much more quickly than this. The age constraints revealed here match well with the range of 475 to 463 Ma previously proposed for the Grampian Orogeny overall in Connemara and lend useful support to models that argue for high-intensity, relatively short-lived Grampian orogenesis in the Connemara Caledonides.

Periods of cessation, resumption and enhanced arc activity are recorded in the Cretaceous igneous rocks of the Antarctic Peninsula. We present new geochronological (laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) zircon U–Pb) analyses of 36 intrusive and volcanic Cretaceous rocks, along with LA-ICP-MS apatite U–Pb analyses (a medium-temperature thermochronometer) of 28 Triassic–Cretaceous igneous rocks of the Antarctic Peninsula. These are complemented by new zircon Hf isotope data along with whole-rock geochemistry and isotope (Nd, Sr and Pb) data. Our results indicate that the Cretaceous igneous rocks of the Antarctic Peninsula have geochemical signatures consistent with a continental arc setting and were formed during the intervalc.140–79 Ma, whereas the main peak of magmatism occurred duringc.118–110 Ma. Trends inεHft(zircon) combined with elevated heat flow that remagnetized rocks and reset apatite U–Pb ages suggest that Cretaceous magmatism formed within a prevailing extensional setting that was punctuated by periods of compression. A noteworthy compressive period probably occurred duringc.147–128 Ma, triggered by the westward migration of South America during opening of the South Atlantic Ocean. Cretaceous arc rocks that crystallized duringc.140–100 Ma define a belt that extends from southeastern Palmer Land to the west coast of Graham Land. This geographical distribution could be explained by (1) a flat slab with east-dipping subduction of the Phoenix Plate, or (2) west-dipping subduction of the lithosphere of the Weddell Sea, or (3) an allochthonous origin for the rocks of Alexander Island. A better understanding of the geological history of the pre-Cretaceous rocks of Alexander Island and the inaccessible area of the southern Weddell Sea is required.Supplementary material:A description of the methods used in this study and the complete dataset are available athttps://doi.org/10.6084/m9.figshare.c.6089274

Many orogenic belts in the world exhibit accretionary and collisional orogenic phases to varying extents. How accretion evolves into collision of the Central Asian Orogenic Belt (CAOB), the largest Phanerozoic accretionary orogenic belt, is an intriguing question. In this paper, we present new U-Pb age, geochemical and isotopic data for Permian-Triassic granitoids from middle Inner Mongolia, Northern China in the southeastern CAOB, and delineate the magmatic transition from subduction to (soft) collision. The magmatic record of soft collision is identified and characterized by thickened lower crust-derived high Sr/Y granitoids with a sub-linear distribution along the Solonker suture zone. Granitoids from Early Permian to Late Permian became more enriched in whole-rock Nd and zircon Hf isotopic compositions (eNd(t) values from 2.4 to −19.5, eHf(t) values from 11.6 to −33.7), indicating increasing incorporation of old crust. The change in peak timing of magmatism from west (ca. 264 Ma) to east (ca. 251 Ma) along the Solonker suture zone implies “scissor-like” closure of the Paleo-Asian Ocean. Integrated with previous studies, a three-stage tectonic model from the Permian to Triassic by accretion leading to collision on the south-eastern margin of CAOB is proposed. (1) Early Permian (> ca. 285 Ma): Juvenile magmatism on an active continental margin with double-sided subduction of the Paleo-Asian Ocean; (2) Middle Permian to Middle Triassic (ca. 285–235 Ma): Magma source transition from juvenile to old crust induced by a tectonic switch from arc to “scissor-like” closure and subsequent intra-continental orogenic contraction; (3) Late Triassic (< ca. 235 Ma): A-type and alkaline magmatism in response to post-collisional extension.

Bedding-parallel veins of fibrous calcite (also called “beef”) occur in many sedimentary basins, especially those containing low-permeability strata with organic source material for petroleum. The formation of such veins is commonly linked with fluid overpressure in these source rocks. In this review, we demonstrate that beef veins are most commonly present in foreland basins worldwide or in basins that recorded a compressive tectonic period. The formation of beef veins is related to two main phases: (1) the initiation of bedding-parallel fracture and (2) the infilling of the fracture. Previous structural studies have shown that formation of beef veins occurred during a period of compressive stress activity. This is especially the case for the Wessex Basin (United Kingdom) and the Neuquen Basin (Argentina). In this paper, we provide more observations for other basins: the Cordillera Oriental (Colombia), the Paris Basin (France), the northern Pyrenees (France), the Uinta Basin (United States), the Tian Shan Mountains (central Asia), and the Appalachian Mountains (United States). In the Paris Basin, beef vein formation is dated at 155 Ma (U/Pb calcite method) and is coeval with the compressional deformation in the eastern part of the basin. Because of the timing of generation for such veins and even if the theory and the experiments of fracturing demonstrate that bedding-parallel fractures can be generated only with a distributed fluid overpressure, the formation of beef veins seems to be a consequence of both fluid overpressures and a compressional tectonic stress.

Geological and tectonic analysis of the Eastern Himalayan basins has given rise to a decade-long debate on the geodynamic evolution of the Burmese terrane and on the extent of reorganization of the main SE Asia drainage systems. However, the influence of the Himalayan belt on the Central Myanmar Basin (CMB) system remains poorly documented, although it is key to providing more accurate models for the evolution of the Himalayan-Burmese orogen. In this contribution, we present geochronological, isotopic and geochemical analysis from 2500 zircon, 1700 titanite, 700 rutile and 850 apatite detrital grains from fifteen Cenozoic siliciclastic samples and one Cretaceous igneous rock. The samples were collected within the fore- and back-arc basins of the Central Myanmar Basin domain (CMB) to constrain the provenance, maximum depositional ages, and depositional environments of the west Burma terrane. Nine key lithological units, the Sadwingyi, Ketpanda, Wabo Chaung, Gwegon, Minwun, Padaung, Okmintaung and Irrawaddy formations have detrital age spectra spanning from the Miocene to Paleoarchean. The entire data set has common age peaks at ca. 20, 40, 60, 90, 100 ​Ma, with about 80% of the U–Pb ages younger than ca. 140 Ma and only ca. 1% of the grains predating ca. 3.0 ​Ga. Our results shed light on the current ambiguities on the transport pathways of Himalayan detritus in the CMB. They show that the fore-arc basin was open to the trench and fed by the unroofing of both the Wuntho Popa volcanic arc to the east and possibly from the Burmese basement and/or from Himalayan-derived Bengal Fan detritus to the west during the Eocene, from at least ca. 44 Ma to before ca. 39 Ma. We show that the west Burma Terrane was partitioned into pull-apart basins such as the Minwun Basin, which during the Oligocene recorded the first evidence of a new source contribution into the CMB at ca. 27 Ma. This new source is characterized by detritus highly compatible with the SE Asia basement rocks, which we suggest corresponds to the initiation of the palaeo–Irrawaddy River. This geodynamic evolution does not require any Yarlung Tsangpo-Irrawaddy-Brahmaputra paleodrainage reorganization, since from the Oligocene to the Early Miocene, the Irrawaddy River fed an internally drained basin, and from the Late Miocene onwards, the Yarlung drained into the Brahmaputra in the Bengal Basin.

The pre-Alpine Marmarosh Massif is a tectonically complex unit of the crystalline basement within the Eastern Outer Carpathians. In the eastern (Ukrainian) segment of this massif, two units have been identified-the Bilyi Potok Nappe and the Dilove Nappe. Petrological investigations coupled with zircon U-Pb dating were performed on metavolcanic rocks (porphyroids) and their phyllite host rocks, sampled from three locations within the Dilove Nappe. The geochemical characteristics of the meta-rhyodacite porphyroids revealed a volcanic arc affinity of the protolith, with U-Pb zircon ages of 452.8 ± 1.5 Ma and 461.5 ± 1.6 Ma and zircon saturation temperatures in the range of 823-892 °C. The phyllite host rocks (meta-tuff) yield a U-Pb zircon maximum estimate for the eruption age at 584.7 ± 2.9 Ma. Peak amphibolite-facies metamorphism (M1) was estimated at the pressure of 600-900 MPa with a temperature range of 560-600 °C. Retrogression (M2), possibly related to Alpine nappe stacking and shearing, is assumed to have taken place at 200-250 MPa and 384-222 °C. The volcanic arc is interpreted as an early Caledonian arc that was subsequently accreted to the margin of Baltica during the closure of the easternmost Tornquist Ocean rather than Cenerian (early Paleozoic) orogenic events on the margin of East Gondwana.The online version contains supplementary material available at 10.1007/s00531-022-02228-8.

New palynological results from the Gafo Formation (southern sector of the Pulo do Lobo Domain, South Portuguese Zone) are integrated with recently studied sections and drillholes from the Portuguese and Spanish sectors. A total of 44 samples were studied, 27 of which were positive for palynomorph taxonomy. This research revealed well preserved palynological assemblages, including 73 spore species allocated to 28 genera, four acritarch genera, three prasinophyte algae genera plus common chitinozoan remains. Some additional forms were retained under open nomenclature. From this, the first complete age determination for the Gafo Formation in Portugal and Spain was achieved, indicating a middle Famennian (Grandispora gracilis–Grandispora famenensis, GF Biozone) to a late Famennian (Grandispora echinata, VH Biozone) age. A greywacke sample from the same Gafo Formation was dated by U–Pb zircon geochronology and a maximum depositional age of 369 ± 2.5 Ma was obtained. A correlation between these palynological and U–Pb zircon data and the palynoflora assemblages of previous authors was made, as well as with the ages of felsic volcanic rocks found intercalated in the Gafo Formation, confirming the complex stratigraphy of Pulo do Lobo Domain. The results are consistent with stratigraphic mapping and structural interpretations, allowing a middle–late Famennian age (GF and VH Biozone) to be assigned to the Gafo Formation sedimentary rocks. This work has also contributed to a reinterpretation of Gafo Formation depositional facies correlatives (e.g. the Santa Barbara Group in Spain) as being the same lithological unit. EU/Interreg-VA/Poctep/ 0052_GEO_FPI_5_E Project, Science Foundation Ireland (grant no. 13/RC/2092_P2) info:eu-repo/semantics/publishedVersion

We report a new regional correlation for the Ediacaran succession in the Anti-Atlas belt on the northwestern margin of Gondwana, based on U-Pb LA-ICP-MS zircon geochronology of volcanic rocks in the NE edge of the Saghro inlier. The thick volcano-sedimentary succession comprises a diverse suite of rhyolitic-ignimbrite, basaltic to andesitic lava fields, rhyolitic lava, mafic hydroclastic complex, fallout and surge deposits, pyroclastic dyke, interbedded clastic sediment and subvolcanic bodies. Ten volcanic rocks yield crystallization ages ranging from 573 to 547 Ma, consistent with a lower and upper Ouarzazate Supergroup affinity respectively. Inherited zircon ages range from 623 Ma to 600 Ma, analogous to zircon peaks in the older volcano-sedimentary rocks of the Bou Salda, and Saghro groups in the Anti-Atlas, suggesting the continuity of the Saghro Group beneath the Ouarzazate Supergroup at the NE edge of the Saghro inlier. Rocks with a lower Ouarzazate Supergroup affinity include lithic-poor ignimbrites which yield ages of 573.6 ± 1.9 Ma, 571.8 ± 4.2 Ma, 571.3 ± 2.6 Ma, and 567.4 ± 2.9 Ma, two fallout deposits which yield ages of 563.5 ± 2.1 Ma and 569.2 ± 1.9 Ma, a surge deposit dated at 571.6 ± 2.8 Ma and a rhyolite lava dated at 562.5 ± 3.1 Ma. Two lithic-poor ignimbrites from the upper Ouarzazate Supergroup are dated at 557.3 ± 2.6 Ma and 547.9 ± 3.1 Ma. Volcanic activity at the NE edge of the Saghro inlier is related to West African Cadomian orogenic (WACadomian) activity between 620 and 560 Ma. During this period the Saghro and Bou Salda groups were deposited, followed by the lower Ouarzazate Supergroup. Later extension along the Gondwanan margin took place close to Ediacaran – Cambrian boundary, contemporaneous with upper Ouarzazate Supergroup deposition.

This paper presents an apatite U–Pb and geochemistry archive for exposed plutons and metamorphic rocks of the Kyrgyz South Tian Shan (STS) within the Central Asian Orogenic Belt. Apatite U–Pb dates and trace-element geochemistry are provided for 17 samples from late Carboniferous – early Permian I-type granites in the Terktinsky complex and A-type granites in the Kokshaal Range; early Devonian granites in the Kembel complex; Cryogenian granitoids and tuffs from the Middle Tian Shan and gneisses from the Atbashi metamorphic complex. These samples form a comprehensive selection of igneous and metamorphic rocks within the cores of Mesozoic basement highs that supplied detritus to adjacent basins such as the Tarim, Ferghana and Yarkand-Ferghana Basins. Generally, the granitoid samples preserve primary igneous apatite U–Pb ages that are within uncertainty of previously published zircon U–Pb dates. The apatites from the Atbashi metamorphic complex record anomalous Ordovician dates with large uncertainties that are interpreted as mixing ages between Cryogenian protolith formation and Carboniferous metamorphism. Principal component analysis discriminates apatite samples from the different bedrock terranes in the Kyrgyz STS based on their geochemical fingerprint and categorizes the samples with respect to an extensive apatite geochemical archive. The combined apatite-zircon archive provides a novel framework for provenance studies on the Meso–Cenozoic sedimentary history of the Central Asian Orogenic Belt.

The Late Cenozoic evolution of the major river networks draining eastern Tibet has major tectonic implications for the development of the plateau but remains highly contentious. In this study from the southeastern margin of the Tibetan Plateau, we constrain the evolution of the Paleo-lake Xigeda (recorded by the lacustrine Plio-Pleistocene Xigeda Formation) using combined fission-track (FT) dating, U-Pb and trace-element analysis of detrital apatite, along with U-Pb dating of detrital rutile and zircon. Critically, the detrital apatite U-Pb age data from the Xigeda Formation exhibit a major Late Triassic to Jurassic peak that is also seen in the U-Pb rutile and zircon data. When integrated with apatite fission-track (AFT) age peaks at ca. 60–40 Ma and ca. 20–10 Ma and apatite trace-element analyses, these U-Pb ages support provenance from the Songpan-Ganzi and southern Longmenshan terranes to the north. Thus, the Paleo-Xigeda lake was fed by south-flowing paleo-Dadu and paleo-Yalong rivers during Plio-Pleistocene time. Pliocene tectonic activity on the Xianshuihe-Daliangshan-Xiaojiang fault zone likely formed Paleo-lake Xigeda by damming of the Middle Yangtze River; subsequent capture of the Upper Yangtze by the Middle Yangtze after ca. 1.3 Ma likely breached the Paleo-lake Xigeda.

[Abstract Quartz‐rich sandstones can be produced through multiple sedimentary processes, potentially acting in combination, such as extensive sedimentary recycling or intense chemical weathering. Determining the provenance of such sedimentary rocks can be challenging due to low amounts of accessory minerals, the fact that the primary mineralogy may have been altered during transport, storage or burial and difficulties in the recognition of polycyclic components. This study uses zircon and apatite U‐Pb geochronology, apatite trace elements, zircon‐tourmaline‐rutile indices and petrographic observations to investigate the sedimentary history of mineralogically mature mid‐Carboniferous sandstones of the Tullig Cyclothem, Clare Basin, western Ireland. The provenance data show that the sandstones have been dominantly and ultimately sourced from three basement terranes: older Laurentian‐ associated rocks (ca. 900–2500 Ma) which lay to the north of the basin, peri‐Gondwanan terranes (ca. 500–700 Ma) to the south and igneous intrusive rocks associated with the Caledonian Orogenic Cycle (ca. 380–500 Ma). However, the multi‐proxy approach also helps constrain the sedimentary history and suggests that not all grain populations were derived directly from their original source. Grains with a Laurentian or a Caledonian affinity have likely been recycled through Devonian basins to the south. Grains with a peri‐Gondwanan affinity appear to be first cycle and are potentially derived from south/southwest of the basin. Taken as a whole, these data are consistent with input into the basin from the south and southwest, with the reworking of older sedimentary rocks, rather than intensive first‐cycle chemical weathering, likely explaining the compositional maturity of the sandstones. This study highlights the need for a multi‐proxy provenance approach to constrain sedimentary recycling, particularly in compositionally mature sandstones, as the use of zircon geochronology alone would have led to erroneous provenance interpretations. Zircon, together with U‐Pb geochronology from more labile phases such as apatite, can help distinguish first‐cycle versus polycyclic detritus., This multi‐proxy provenance approach identifies partly recycled sandstones in the mid‐Carboniferous Tullig Cyclothem of the Clare Basin. Taken as a whole, these data are consistent with input into the basin from the south and southwest, with first cycle peri‐Gondwanan grains and recycling of Caledonian and Laurentian grains through Devonian basins to the south. ]

We here present the first U-Pb geochronology from calcites precipitated on fracture and fault surfaces from the passive continental margin of Western Norway. The evolution of passive continental rifted margins is reflected in complex fracture and fault networks which have been activated and reactivated through time. Constraining the timing of fault activity and fracturing can assist in revealing the interaction between tectonic processes and the topographic response onshore. Recently, U-Pb calcite dating has proven to be a useful tool to complement other geochronological methods and to produce more complete records of brittle deformation in different geological settings. In this study, we collected 35 calcite samples from different fault and fracture planes in Western Norway, 14 of which gave reliable U-Pb dates. The onshore field area is located at the junction of the NE-SW trending Norwegian Sea and the N-S trending North Sea. 1) The oldest calcites measured are from the Dalsfjord fault, a complex brittle fault related to the Nordfjord-Sogn Detachment Zone. The ages obtained from a green cataclasite indicate fluid flow and calcite precipitation around 208 ± 25 Ma and 205 ± 6 Ma, whereas a reddish cataclasite and fault gouge zone were dated 142 ± 15 Ma. 2) Two calcite samples from the northern part of the study area were collected along fractures parallel to the Møre-Trøndelag Fault Complex and yield dates of 89 ± 4 Ma and 79 ± 3 Ma. 3) Five samples from variously oriented fractures and faults spread over the field area gave dates of 69 ± 2 Ma, 67 ±15 Ma, 65 ± 2 Ma, 64 ± 2 Ma and 59 ± 2 Ma. These ages can be linked to the base Tertiary unconformity in the offshore stratigraphic record of the northern North Sea interpreted to be caused by onshore uplift. Several processes have been proposed to cause a possible uplift during this time span; a) regional influence of the Icelandic mantle plume, b) rift footwall uplift, c) climatically controlled topographic changes. 4) Five samples from across the field area yield dates of 49 ± 3 Ma, 35 ± 1 Ma, 21 ± 1 Ma, 5.5 ± 4.5 Ma and 0.8 ± 0.1 Ma. All these calcites precipitated on faults and fractures striking NE-SW, and its formation may be related to relaxation along the passive margin. The dated calcites from this study provide Cenozoic brittle deformation ages much younger than previously obtained by other geochronological methods, possibly allowing to decipher the youngest brittle tectonic evolution of the margin in unprecedented detail.

The Limerick Igneous Suite (LIS) in County Limerick, SW Ireland, contains two distinct basaltic igneous units: the Knockroe and Knockseefin, which are expressed as hypabyssal intrusions, porphyritic dykes, diatremes, lava flows, agglomerates and tuffs. These units make up two distinct evolutionary trends: the Knockroe igneous units which range from alkaline basalts to trachyandesites, and the Knockseefin igneous units which range from alkaline basalts to basanites. U‒Pb dating of apatite establishes a primary crystallization age of c. 350 Ma for the Knockroe units. Strontium and Nd isotopes from the least-altered Knockroe bulk rock samples range over 0.70301–0.70454 and 0.512457–0.512493, respectively. The Sr isotopes for the least-altered Knockseefin samples are similar, ranging over 0.70325–0.70386, but the Nd values are slightly more radiogenic, spanning 0.512431–0.512437. Altered samples are buffered against changes in Nd, but some show excursions towards radiogenic Sr, suggesting contamination from Carboniferous seawater and/or introduction of Rb. Rb–Sr calculations conducted on altered Knockroe samples returned ages within uncertainty of the U‒Pb dates. The bulk rock isotope values, normalized trace element plots as well as Zr/Sm, Ce/Pb and Nb/U values demonstrate the LIS is comparable to ocean island basalts and Ce/Y and Zr/Nb values suggest the units likely originated from low degrees of partial melting likely caused by extension related to the amalgamation of Laurussia and Gondwana. Supplementary material: ESM 1, whole rock geochemistry data; ESM 2, apatite chemistry and geochronology data; and ESM 3, supplementary figures are available at https://doi.org/10.6084/m9.figshare.c.6297395

The early exhumation history of the Tauern Window in the European Eastern Alps and its surface expression is poorly dated and quantified, partly because thermochronological and provenance information are sparse from the Upper Austrian Northern Alpine Foreland Basin. For the first time, we combine a single‐grain double‐dating approach (Apatite Fission Track and U‐Pb dating) with trace‐element geochemistry analysis on the same apatites to reconstruct the provenance and exhumation history of the late Oligocene/early Miocene Eastern Alps. The results from 22 samples from the Chattian to Burdigalian sedimentary infill of the Upper Austrian Northern Alpine Foreland Basin were integrated with a 3D seismic‐reflection data set and published stratigraphic reports. Our highly discriminative data set indicates an increasing proportion of apatites (from 6% to 23%) with Sr/Y values 1,000 ppm light rare‐earth elements from Chattian to Burdigalian time. The number of U‐Pb ages with acceptable uncertainties increases from 40% to 59% up‐section, with mostly late Variscan/Permian ages, while an increasing number of grains (10%–27%) have Eocene or younger apatite fission track cooling ages. The changes in the apatite trace‐element geochemistry and U‐Pb data mirror increased sediment input from an ≥upper amphibolite‐facies metamorphic source of late Variscan/Permian age – probably the Ötztal‐Bundschuh nappe system – accompanied by increasing exhumation rates indicated by decreasing apatite fission track lag times. We attribute these changes to the surface response to upright folding and doming in the Penninic units of the future Tauern Window starting at 29–27 Ma. This early period of exhumation (0.3–0.6 mm/a) is triggered by early Adriatic indentation along the Giudicarie Fault System., Science Foundation Ireland http://dx.doi.org/10.13039/501100001602, Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659

Multiple factors (e.g. source rock composition, climate, nature/scale of sedimentary system) influence the volume and composition of sediment delivered to basins. Fluctuations in these parameters produce cryptic source signals which can vary within the same sedimentary system. Bespoke multi-proxy provenance approaches, targeted at minerals of variable stability, allow for an assessment of natural biasing (recycling) and intra-basinal spatial variations. Provenance of fluvial/deltaic sandstones (Mullaghmore Sandstone Formation) in the NW Carboniferous Basin, Ireland, has been constrained using zircon and apatite U–Pb geochronology, trace elements in apatite and Pb-in-K-feldspar analysis. Zircon U–Pb grain populations are consistent with feldspar data, suggesting Proterozoic basement highs offshore Ireland and Scotland were the main contributor with minor supply from Archean–Paleoproterozoic rocks of Greenland/NW Scotland and Caledonian-aged rocks. However, apatite data show a much larger proportion of Caledonian-aged grains of metamorphic origin, suggesting significant sediment was recycled from Neopropterozoic metasedimentary rocks. The spatial variation in provenance indicates that, at onset of clastic input, sediment was being routed to the basin through a complex drainage system, comprising several discrete hinterland catchments, rather than supply from a single, large interconnected sedimentary system. Such complexities can only be identified with the careful application of a bespoke multi-proxy provenance approach. Supplementary material: Tables 1-5 and individual Pb-in-K feldspar plots are available at https://doi.org/10.6084/m9.figshare.c.5536691