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• U–Pb data from fast pulse LA-ICP-MS is equivalent with conventional U–Pb analysis. • Provenance of the largely unexposed Yeneena Basin revealed. • Exotic sources support a transcontinental transport system across Rodinia. Over ten thousand detrital zircon U–Pb analyses on thirty four samples were undertaken using a fast pulse laser ablation protocol from the Neoprotoerozoic rocks of the largely unexposed Yeneena and northwestern Officer Basins in Western Australia. In addition, conventional laser ablation detrital zircon U–Pb geochronology was carried out on three of the samples. A comparison of the two datasets demonstrated that no statistical significant difference was observed in the detrital zircon spectra between the two techniques. The results of the detrital zircon analyses reveal that after an intial pulse of material dominated by Archean detritus the sediment are dominated by Mesoproterozic sources. This indicates that there is little variation in source materials within and between the identified formations. The major age peaks coincide with magmatic rock ages from within Australia. The results indicate that either the Palaeoproterozoic and Mesoproterozoic terranes remained sources throughout the deposition of the Yeneena and northwestern Officer Basins during the Neoproterozoic, or that recycling of zircons occurred within a quasi-closed system for the duration of sedimentation. The remaining 10 % of grains are difficult to reconcile with magmatic suites of any significant volume within Australia. However, when considering the broader palaeogeographic context at the time the sediments are inferred to have been deposited, rocks from Dronning Maud Land and the Kalahari Craton can supply grains of appropriate ages and are consistent with the known paleocurrent directions. This work demonstrates that there is no significant disadvantage in the application of the fast pulse technique when applied to the collection of U–Pb detrital zircon datasets for the purpose of detrital zircon fingerprinting. However, there is a large upside related to the significant amount of data that can be collected for a given amount of time compared to other more conventional techniques. [ABSTRACT FROM AUTHOR]

In situ U–Pb dating of carbonate minerals and Rb–Sr dating of illite was carried out on the Yata sediment-hosted disseminated-type gold deposit in the Youjiang basin, South China. The new study determines the timing of gold mineralization and clarifies the geological conditions required for the successful application of in situ U–Pb dating of alteration-related carbonate minerals. The results suggest that the Yata gold deposit likely formed during two metallogenic episodes. Illite Rb–Sr ages of 178.6 ± 5.8 Ma (MSWD = 1.2) for the 2–0.5 μm fraction and 171.3 ± 3.4 Ma (MSWD = 0.62) for the 0.5–0.2 μm fraction constrain an earlier episode of gold mineralization to >178.6 Ma. Hydrothermal carbonate minerals within the Yata gold deposit are associated with organic matter. In situ U–Pb dating of paragenetically early ankerite and later calcite veins yields ages of 149.0 ± 10.4 Ma (MSWD = 2.0) and 147.3 ± 32.6 Ma (MSWD = 1.8), respectively. These mineral ages and their petrographic relationships provide unequivocal evidence that another episode of gold mineralization occurred in the Early Cretaceous. Importantly, this study demonstrates in situ U–Pb dating is applicable to low-temperature deposits consisting of organic-rich hydrothermal carbonates characteristic of relatively high common Pb. Such deposits potentially include hydrothermal antimony, Carlin-type gold deposits, gold‐uranium, and carbonate-hosted uranium deposits. • Carbonate U–Pb dating constrains the age of late mineralization to ca. 150 Ma. • Illite Rb–Sr ages constrain the early stage of gold mineralization to ca. 178–172 Ma. • U–Pb isotope analysis can provide reliable ages for U-rich hydrothermal carbonates. [ABSTRACT FROM AUTHOR]

Knowledge of temporal patterns of past explosive eruptions is necessary to understand possible future eruptive behavior. However, volcanic records based on geological reconstructions remain incomplete. This inference is true not only for remote and sparsely populated areas like the Aleutian or Kurile-Kamchatka arcs, but also for Europe, where past large explosive events are continuously recognized in the geological record. Here we report the first age and geochemical data on the violent middle to late Pleistocene explosive eruptions from the Elbrus volcanic center (Greater Caucasus), which towers over the densely populated regions in southern Russia and Georgia. We attribute six disparate ash deposits found in the terrestrial and marine sediments along the SE European margin to the Elbrus volcanic center based on major and trace element compositions of individual shards of volcanic glass and radiogenic Sr-Nd-Pb isotope compositions of bulk tephra. We suggest that these deposits represent products of five different eruptions that were dispersed over distances of more than 150–560 km from their source. Three of four eruptions are dated at 522 ± 36, 258 ± 13, and 84.6 ± 7.4 ka by a combined zircon U–Th–Pb and (U–Th)/He approach. One sample revealed an overdispersed spectrum of single crystal (U–Th)/He dates with an average of 176 ± 40 ka. Zircon characteristics and statistical deconvolution of the geochronology data suggest that this sample contains zircon crystals from two different eruptions tentatively dated at 156.5 ± 7.7 ka and 222.8 ± 13 ka. These eruption ages represent the first recognition of a suite of large pumiceous eruptions from the Elbrus volcanic center postdating the previously known explosive activity, documented by ∼800 ka old welded tuffs. These data also provide the first geochemical and geochronological characterization of both proximal and distal Elbrus tephra glasses and contribute to the global tephra database, permitting the identification of Elbrus tephras in distal terrestrial and marine paleoenvironmental archives and hence their use as paleoclimate and archaeological markers. We consider the significance of the identified tephras for paleoenvironmental research and show their potential for tephrochronological studies in the East European Plain and adjacent areas. • First age and geochemical data on tephra from the Elbrus volcanic center (Caucasus). • Four large silicic explosive eruptions from Elbrus identified between 500 and 85 ka. • Elbrus tephra deposits found at distances of 150–560 km from the source. • Dated Elbrus tephras may serve as markers for paleoenvironmental research. [ABSTRACT FROM AUTHOR]

• The Rogaland Anorthosite complex took about 100 Myr to form. • Anorthosite emplacement involved different processes in an evolving stress regime. • The distribution of UHT rocks reflects differential tectonic exhumation. • At no point during orogeny did the crust in the study area thicken significantly. • Long-lived extension was interrupted by intermittent compression. The tectonic setting and mechanisms and duration of emplacement of Proterozoic massif-type anorthosites and the significance of typically associated ultrahigh-temperature (UHT) host rocks have been debated for decades. This is particularly true of the Rogaland Anorthosite Province (RAP) in the SW Sveconorwegian Orogen. Earlier studies suggest that the RAP was emplaced over 1–3 Myr around 930 Ma towards the end of orogenesis, resulting in an up to 15–20 km-wide contact metamorphic aureole. However, our structural observations show that the RAP is located in the footwall of a 15 km-wide extensional detachment (Rogaland Extensional Detachment, RED), separating the intrusions and their UHT host rocks from weakly metamorphosed rocks in the hanging wall. U–Pb zircon dating of leucosome in extensional pull-aparts associated with the RED yields ages of 950–935 Ma, consistent with Re–Os molybdenite ages from brittle extensional structures in the hanging-wall block that range between 980 and 930 Ma. A metapelite in the immediate vicinity of the RAP yields a 950 Ma U–Pb age of matrix-hosted monazite, and part of the RAP was intruded by the Storgangen norite dike at ca. 950 Ma, providing a minimum age of emplacement. These ages are consistent with Ar–Ar hornblende and biotite ages that show rapid cooling of the footwall before 930 Ma, but slow cooling of the hanging wall. Field and geochronologic data suggest that the RAP formed and was emplaced over a long period of time, up to 100 Myr, with different emplacement mechanisms reflecting an evolving regional stress regime. The distribution of UHT rocks around the RAP reflects differential extensional exhumation between 980 and 930 Ma, not contact metamorphism. The duration and style of orogenic activity and externally (as opposed to gravitationally) driven extension suggest that the RAP formed in a continental back-arc setting. [ABSTRACT FROM AUTHOR]

• First geochronological data from the southern Mount Isa Terrane under deep cover. • Ages of ca. 1865 and 1800–1760 Ma are linked to the Kalkadoon-Leichhardt Complex and Leichhardt Superbasin. • The southwestern Mount Isa Terrane can be correlated to the eastern and northern Gawler Craton. • Archean lithosphere is present under the Mount Isa Terrane. • Archean detritus in the Mount Isa Terrane may be derived from then-proximal Gawler Craton. The parts of the Mount Isa Terrane that crop out have been instrumental in deciphering the configuration of the supercontinent Nuna. In addition, these rocks host prolific base and precious metals. Further south, the Mount Isa Terrane is buried by >800 m of Phanerozoic cover that, to date, has primarily been investigated via geophysical surveys. Here, we present zircon U-Pb and Hf isotopic data of granitoids, metabasalts and metasedimentary rocks from seven >1 km deep drill holes that provide a window into the basement geology of the southern parts of the Mount Isa Terrane. The oldest rocks, intersected in two of the drill holes, are a series of granitic gneisses dated at ca. 1865 Ma, corresponding to the Kalkadoon-Leichhardt Complex. The majority of the encountered lithology in the drill holes are metasedimentary rocks with associated volcanic rocks and intruding granitoids, which bracket the remaining stratigraphy to ca. 1800–1760 Ma, corresponding to the lower and middle parts of the Leichhardt Superbasin. The ca. 1865 Ma Kalkadoon-Leichhardt Complex and ca. 1800 Ma granitoids have unradiogenic Hf isotopic signatures that necessitate an Archean lithosphere underneath the Mount Isa Terrane. Detrital zircon from the Leichhardt Superbasin may have been derived locally but also share age and Hf isotopic signatures with the eastern and northern Gawler Craton, implying possible long-distance transport. Metamorphic events recorded in discrete zircon grains and rims reveal punctuated tectonic activity at ca. 1760–1750 Ma and ca. 1720–1710 Ma in the southern Mount Isa Terrane, related to the pre-Wonga Event and the second stage of the Wonga Orogeny. The stratigraphy and events in the southern Mount Isa Terrane can be correlated to the northern and eastern Gawler Craton in South Australia, which may only have been ∼500–1000 km from the Mount Isa Terrane at the time of deposition. Ultimately, the results from these new drill holes reveal the extent of the Mount Isa Terrane under deep sedimentary cover and strengthen the links between the North and South Australian Cratons during the protracted assembly of the supercontinent Nuna. [ABSTRACT FROM AUTHOR]

[Display omitted] • 4344 magmatic U-Pb ages (2300-800 Ma) compiled. • Active external margins of Laurentia, Baltica and Amazonia in Columbia. • Baltica-Amazonia magmatic correlation strongest, others poor. • Global Grenville-age orogens also including Kalahari and western Australia. • Magmatism ceased at ~950 to 900 Ma as most areas became inboard in Rodinia. A total of 4344 magmatic U-Pb ages in the range 2300 to 800 Ma have been compiled from the Great Proterozoic Accretionary Orogen along the margin of the Columbia / Nuna supercontinent and from the subsequent Grenvillian collisional orogens forming the core of Rodinia. The age data are derived from Laurentia (North America and Greenland, n = 1212), Baltica (NE Europe, n = 1922), Amazonia (central South America, n = 625), Kalahari (southern Africa and Dronning Maud Land in East Antarctica, n = 386), and western Australia (n = 199). Laurentia, Baltica, and Amazonia (and possibly other cratons) most likely formed a ca. 10 000-km-long external active continental margin of Columbia from its assembly at ca. 1800 Ma until its dispersal at ca. 1260 Ma, after which all cratons studied were involved in the Rodinia-forming Grenvillian orogeny. However, the magmatic record is not smooth and even but highly irregular, with marked peaks and troughs, both for individual cratons and the combined data set. Magmatic peaks typically range in duration from a few tens of million years up to around hundred million years, with intervening troughs of comparable length. Some magmatic peaks are observed on multiple cratons, either by coincidence or because of paleogeographic proximity and common tectonic setting, while others are not. The best overall correlation, 0.617, is observed between Baltica and Amazonia, consistent with (but not definitive proof of) their being close neighbours in a SAMBA-like configuration at least in Columbia, and perhaps having shared the same peri-Columbian subduction system for a considerable time. Correlation factors between Laurentia and Baltica, or Laurentia and Amazonia, are below 0.14. Comparison between the Grenville Province in northeastern Laurentia and the Sveconorwegian Province in southwestern Fennoscandia (Baltica) shows some striking similarities, especially in the Mesoproterozoic, but also exhibits differences in the timing of events, especially during the final Grenville-Sveconorwegian collision, when the Sveconorwegian evolution seems to lag behind by some tens of million years. Between the other cratons, the evolution before and during the final Grenvillian collision is also largely diachronous. After 900 Ma, magmatic activity had ceased in all areas investigated, attesting to the position of most of them within the stable interior of Rodinia. [ABSTRACT FROM AUTHOR]

Zircon double-dating utilises (U–Th)/He dating coupled with U–Th disequilibrium or U–Pb dating to determine eruption ages for volcanic rocks between ca. 2 ka to 1 Ma. This approach depends on understanding the crystallisation history of each zircon crystal analysed. For lack of better constraints, zircon crystallisation is generally assumed to be represented by a single crystallisation age, which is routinely determined on the rim of the grain by spot analyses. While zircon crystallisation is often protracted, interrogating the crystallisation history of a zircon crystal usually requires grinding the grain, which can introduce uncertainty to the alpha ejection (Ft) correction, critical for accurate (U–Th)/He ages. Grinding a zircon crystal to exactly 50% of its original width, to a plane of symmetry, leaves the Ft correction factor unchanged relative to that of the whole crystal. This is verified by a new computer program – GriFt, which also allows the calculation of accurate Ft correction factors for a range of different grinding depths, opening the opportunity to measure both the core and rim crystallisation ages and integrate these into a more robust disequilibrium correction of (U–Th)/He data. The feasibility of this approach is tested here in a case study of zircon crystals with protracted crystallisation histories from the Shikotsu-Toya volcanic field in Hokkaido, Japan. A maximum of 15% difference in overall eruption age is calculated between rim- and core-corrected (U–Th)/He ages. Eruption ages were determined for two tephras – Kimobetsu 1 (59–79 ka) and Kimobetsu 2 (96 ± 5 ka, 2σ). The geological implication from these dates is that a regionally important tephra, Toya, may be younger (<96 ± 5 ka) than previously reported (109 ± 3 ka). In addition, the maximum eruption ages determined from crystallisation age distributions calculated for samples from eruptions at Shikotsu and Kuttara (48 ± 17 and 49 ± 21 ka, respectively) are within uncertainty of previous measurements (44–41 ka and >43 ka, respectively). [ABSTRACT FROM AUTHOR]

Corundum, including the variety ruby, is found in numerous locations in the North Atlantic Craton of southern Greenland where high-grade metamorphic lithologies of contrasting chemistry interact. This study constrains the conditions of corundum formation and the compositions of the fluids involved for the Storø and Maniitsoq localities using thermodynamic modelling of mineral and mineral-fluid equilibria, and mineral solubility. Metasomatism took place at 650–725 °C and 7 kbar, which is indistinguishable from peak metamorphic conditions, and involved an acidic metasomatising fluid of low f O 2 , low X(CO 2), and rich in B. Aqueous concentrations of Al are low and indicate that corundum saturation is the result of residual enrichment rather than Al mobilisation. An evolved magmatic intrusion is the likely source of B, and U Pb dating of rutile inclusions is consistent with a temporal link between corundum formation and emplacement of the Qôrqut granite. Interaction with metadunite, and metapelite-hosted Fe-sulfides modified the granite-derived oxidized fluid, introduced SO 4 , and produced the required reduced, low pH, high X Mg and high K/Na fluid as constrained from the corundum-bearing samples. These results highlight the complex interplay among lithologies involved in corundum-formation in a high-grade metamorphic-metasomatic setting, but also demonstrate that corundum formation is a predictable part of the geological history where a magmatic intrusion sends a pulse of fluid through a high grade, lithologically heterogeneous carapace that includes aluminous and Si-deficient units. [Display omitted] [ABSTRACT FROM AUTHOR]

• Fangmayu chromitite formed in the Early Paleoproterozoic (ca. 2.42 Ga). • Apatite closed to Pb diffusion (ca. 1.80 Ga) during post-collisional cooling. • Parental melts from supra-subduction zone with a high degree of melting. • Parental melt composition shows an island-arc setting with high-Ti IAB affinity. The study of chromite from chromitite-bearing layered intrusions can provide significant insights into their petrogenetic origin and tectonic setting. The Fangmayu Alaskan-type ultramafic intrusion in the North China Craton contains layered and massive chromitite associated with a serpentinized ultramafic suite. This study presents zircon and apatite geochronology, chromite mineral chemistry, platinum-group element (PGE) and Re-Os isotopic data for the purpose of constraining the origin, evolution, and composition of the Fangmayu chromitite parental melts. Zircon U-Pb data from the chromitites define various age populations, with oldest age component (>2.49 Ga) interpreted to represent xenocrystic grains incorporated from crystalline basement. A dominant age component (~2.42 Ga) may represent the age of magma emplacement. Ages in the range of 2375–2068 Ma likely represent variable partial radiogenic Pb-loss during subsequent thermal events. Zircon ages in the range of 1.96–1.90 Ga record metamorphic events, potentially related to the collision between the Eastern Block and Western Block in the North China Craton. Ages of 1.85–1.81 Ga likely represent zircon growth during retrograde metamorphic process in a post-collisional setting; near contemporaneous apatite (~1.8 Ga) tracks cooling through ~500 °C. High Fo contents in olivine (Fo 90-92) and high Cr# in chromite (72–77) suggest a low Al 2 O 3 ultramafic parental magma formed by a high degree of partial melting. However, total concentrations of PGEs are abnormally low, and the Re-Os system indicates multiple disturbances during later metamorphic events. Experimental data are used to recover the compositions of parental melts to the chromitite, the calculations yield parental melts with 10–11 wt% Al 2 O 3 and 0.7–1.1 wt% TiO 2 , which define the arc and IAB affinity. The high Cr#s, low Al 2 O 3 (8–10 wt%), and high TiO 2 (0.58–0.96 wt%) contents of chromite, combined with calculated parental melt compositions, suggest that the parental magma of Fangmayu stratiform chromitites was a high-Ti island-arc basalt origin and formed within supra-subduction zone setting. [ABSTRACT FROM AUTHOR]

Models of volcanic eruption periodicity are vital for hazard prediction, but require an understanding of the past pattern of melt evolution and transport. Zircon double-dating combines (U-Th)/He methods with U-Pb or U-Th disequilibrium geochronology to determine the timing of volcanic eruptions for rocks with a particular emphasis on those younger than ca. 1 Ma. This paper focuses on the Jeju Island intraplate volcano in South Korea, and compares a previously proposed model for trachyte eruption with new zircon double-dating results. The results document four episodes of trachyte eruption on Jeju. The oldest trachytes were erupted at ca. 750–477 ka, followed by an episode at ca. 97–53 ka. Two further eruptive episodes occurred at ca. 31–23 ka and ca. 2 ka. This ca. 2 ka eruption age is the first geochronological documentation of such young eruptive activity from the island. In addition to the new eruption ages, there is evidence for three separate stages of zircon crystallisation, which are correlated with the three oldest eruption stages. The strong temporal correlation of zircon crystallisation and eruption on Jeju points to a simple magmatic plumbing system. These observations have important implications for hazard monitoring and mitigation on Jeju Island by highlighting the historical trachyte eruptions and the magmatic tempo for this system. • Zircon double-dating is used to determine eruption ages of trachytes on Jeju Island. • We propose a revised age model of trachyte eruption comprising four eruptive stages. • Geochronology identifies trachyte volcanism on Jeju occurring at 2.0 ka. • Zircon crystallisation age spectra suggest minimal magma mixing. [ABSTRACT FROM AUTHOR]

We report the development of a SIMS analytical method for in situ Sr isotope analysis of the mineral apatite at an analytical scale of 15 μm or less. Experiments were conducted on a series of reference apatites of widely differing Sr contents at three different mass resolution settings: low (3000), moderate (4200) and very high (16000), using a large-geometry CAMECA 1280 ion microprobe retrofitted with a HyperionTM oxygen plasma ion source. Peak-stripping algorithms tailored to the different mass-resolution settings were developed to correct for significant interferences on the target strontium isotope species in the mass spectra, namely Ca dimers, CaPO, Rb and SrH, and for instrumental mass fractionation. The most consistently accurate and precise 87Sr/86Sr ratios were achieved at the 3000 mass resolution setting with appropriate energy filtering and use of a cold trap. On average, corrected 87Sr/86Sr ratios by this method were elevated by ~0.8‰ above equivalent TIMS and solution ICPMS data, with consistent behaviour across the range of Sr concentrations. Individual spot precision of ± 0.001 to 0.004 (2SE) was achieved, depending on Sr content. The key advantages of SIMS analysis compared to existing LA-MC-ICP-MS methods are the high spatial resolution, low sample consumption, and the high mass resolution that allows for the elimination of problematic isobaric interferences. Our approach is particularly useful for the analysis of small or valuable targets, such as mineral inclusions or meteoric samples, and for apatite with high REE contents. However, the much larger volume of material consumed during LA-MC-ICP-MS analysis allows for substantially better precision than the SIMS method presented here. The highly variable trace element composition of natural apatites, involving both cationic and anionic substitutions, necessitates careful characterisation of prospective targets prior to any in situ analysis, in addition to matching to appropriate reference materials. • Development of new SIMS method for in situ measurement of 87Sr/86Sr in apatite. • Isobaric interferences overcome by high mass resolution, peak-stripping algorithm. • High spatial resolution ideal for targeting mineral inclusions. [ABSTRACT FROM AUTHOR]

Mylonitic shear zones crosscutting homogenous granitoids can retain evidence of fluid-driven metasomatic retrogression and reactivation. However, the relationships between fluid-rock interaction, retrogression, deformation and mylonitisation, and the timing thereof, are often cryptically recorded. This study focuses on the granulite-facies Boothby Orthogneiss from the Reynolds Range, central Australia, which contains a large scale mylonitic shear zone with an apparent record of structural inheritance, fluid infiltration and reactivation. The chosen site provides an ideal natural laboratory in which to investigate the timing of deformation, associated fluid flow and mass transport. U Pb isotope analyses of monazite indicate an average Pb recrystallization age of c. 1560 Ma, demonstrating that the orthogneiss fabric developed during the Mesoproterozoic Chewings Orogeny (1590–1550 Ma). Structural mapping suggests that this shear zone represents a Riedel branch of larger structures that were subsequently reactivated during the Paleozoic Alice Springs Orogeny (450–300 Ma). The timing of reactivation and fluid flow is constrained by U Pb dating of apatite, which is present as a stable U-bearing mineral in both orthogneiss and mylonite. Modelling of apatite radiogenic-Pb retention ages, accounting for a wide potential range in common Pb compositions, demonstrates at least some growth and/or recrystallization at c. 1500 Ma and c. 400 Ma, confirming apatite precipitation during Alice Springs shearing and the reactivation of Chewings-age structures. In addition, Alice Springs-aged apatite is found along pre-existing fabrics in the orthogneiss in the vicinity of the shear zone, indicating pre-kinematic fluid flow across the shear zone boundary and into country rock that was otherwise largely unaffected. The combined datasets demonstrates that integrated apatite and monazite U Pb geochronology is an effective method to unravel the record of superimposed fluid-flow and deformation events. This includes the detection of an 'inverse younging relationship', where younger ages are preferentially recorded in the wall rock as rather than in the reactivated shear zone. Such effects are potentially common where deformation is driven by pre-kinematic fluid-rock interaction, with subsequent deformation enhancing the removal of replacement assemblages in more deformed rocks and favouring their preservation in less deformed rocks. • Apparent inverse younging relationship between wall rock and mylonite sheds light onto shear zone history. • Cryptically recorded sequence disentangled by combined monazite and apatite geochronology • Temporal constraints on mass transport, fluid-rock interaction and reactivation of shear zones during deformation • Pre-kinematic fluid influx was recorded in the country rock, not shear zone [ABSTRACT FROM AUTHOR]

• 1340–1140 Ma extension in SW Fennoscandia resulted in fragmentation of the margin. • 1140–920 Ma Sveconorwegian orogeny resulted from reamalgamation of this margin. • The Sveconorwegian orogeny reflects tectonic processes similar to today. The Sveconorwegian orogeny encompasses magmatic, metamorphic and deformational events between ca. 1140 and 920 Ma at the southwestern margin of Fennoscandia. In recent years, the tectonic setting of this nearly 200 Myr-long evolution has been debated, with some workers arguing for collision with an unknown continent off the present-day southwest coast of Norway, and others advocating accretionary processes inboard of an active margin. Recently, it has been suggested that orogeny may have been gravity-driven by delamination and foundering of heavy subcontinental lithospheric mantle in an intraplate setting, in some ways similar to proposed sagduction processes in the Archaean. Resolving the tectonic setting of the Sveconorwegian orogen has implications for correlation with other orogens and Rodinia supercontinent reconstructions and for assessments of the evolution of plate tectonics on Earth, from the Archaean to the present. Here, we present new mapping and geochronological data from the Bamble and Telemark lithotectonic units in the central and western Sveconorwegian orogen – the former representing a critical region separating western parts of the orogen that underwent long-lived high- to ultrahigh-temperature metamorphism and magmatism from parts closer to the orogenic foreland that underwent episodic high-pressure events. The data show that the units constituting the Sveconorwegian orogen most likely formed at the southwestern margin of Fennoscandia between ca. 1800 and 1480 Ma, followed by fragmentation during widespread extension between ca. 1340 and 1100 Ma marked by bimodal magmatism and sedimentation. A summary of Sveconorwegian magmatic, metamorphic and depositional events in the different units shows disparate histories prior to their assembly with adjacent units. The most likely interpretation of this record seems to be that episodic, Sveconorwegian metamorphic and deformational events in the central and eastern parts of the orogen represent accretion and assembly of these units. This process most likely took place behind an active margin to the southwest that sustained mafic underplating in the proximal back-arc, resulting in high- to ultrahigh-temperature metamorphism in the western parts. In this interpretation, all features of the Sveconorwegian orogen are readily explained by modern-style plate tectonic processes and hypotheses involving some form of vertical, intraplate tectonics are not supported. [ABSTRACT FROM AUTHOR]

Understanding the provenance of megaliths used in the Neolithic stone circle at Stonehenge, southern England, gives insight into the culture and connectivity of prehistoric Britain. The source of the Altar Stone, the central recumbent sandstone megalith, has remained unknown, with recent work discounting an Anglo-Welsh Basin origin 1,2 . Here we present the age and chemistry of detrital zircon, apatite and rutile grains from within fragments of the Altar Stone. The detrital zircon load largely comprises Mesoproterozoic and Archaean sources, whereas rutile and apatite are dominated by a mid-Ordovician source. The ages of these grains indicate derivation from an ultimate Laurentian crystalline source region that was overprinted by Grampian (around 460 million years ago) magmatism. Detrital age comparisons to sedimentary packages throughout Britain and Ireland reveal a remarkable similarity to the Old Red Sandstone of the Orcadian Basin in northeast Scotland. Such a provenance implies that the Altar Stone, a 6 tonne shaped block, was sourced at least 750 km from its current location. The difficulty of long-distance overland transport of such massive cargo from Scotland, navigating topographic barriers, suggests that it was transported by sea. Such routing demonstrates a high level of societal organization with intra-Britain transport during the Neolithic period., (© 2024. The Author(s).)

Argyle is the world's largest source of natural diamonds, yet one of only a few economic deposits hosted in a Paleoproterozoic orogen. The geodynamic triggers responsible for its alkaline ultramafic volcanic host are unknown. Here we show, using U-Pb and (U-Th)/He geochronology of detrital apatite and detrital zircon, and U-Pb dating of hydrothermal titanite, that emplacement of the Argyle lamproite is bracketed between 1311 ± 9 Ma and 1257 ± 15 Ma (2σ), older than previously known. To form the Argyle lamproite diatreme complex, emplacement was likely driven by lithospheric extension related to the breakup of the supercontinent Nuna. Extension facilitated production of low-degree partial melts and their migration through transcrustal corridors in the Paleoproterozoic Halls Creek Orogen, a rheologically-weak rift zone adjacent to the Kimberley Craton. Diamondiferous diatreme emplacement during (super)continental breakup may be prevalent but hitherto under-recognized in rift zones at the edges of ancient continental blocks., (© 2023. Springer Nature Limited.)

Earth is the only planet known to have continents, although how they formed and evolved is unclear. Here using the oxygen isotope compositions of dated magmatic zircon, we show that the Pilbara Craton in Western Australia, Earth's best-preserved Archaean (4.0-2.5 billion years ago (Ga)) continental remnant, was built in three stages. Stage 1 zircons (3.6-3.4 Ga) form two age clusters with one-third recording submantle δ 18 O, indicating crystallization from evolved magmas derived from hydrothermally altered basaltic crust like that in modern-day Iceland 1,2 . Shallow melting is consistent with giant impacts that typified the first billion years of Earth history 3-5 . Giant impacts provide a mechanism for fracturing the crust and establishing prolonged hydrothermal alteration by interaction with the globally extensive ocean 6-8 . A giant impact at around 3.6 Ga, coeval with the oldest low-δ 18 O zircon, would have triggered massive mantle melting to produce a thick mafic-ultramafic nucleus 9,10 . A second low-δ 18 O zircon cluster at around 3.4 Ga is contemporaneous with spherule beds that provide the oldest material evidence for giant impacts on Earth 11 . Stage 2 (3.4-3.0 Ga) zircons mostly have mantle-like δ 18 O and crystallized from parental magmas formed near the base of the evolving continental nucleus 12 . Stage 3 (<3.0 Ga) zircons have above-mantle δ 18 O, indicating efficient recycling of supracrustal rocks. That the oldest felsic rocks formed at 3.9-3.5 Ga (ref. 13 ), towards the end of the so-called late heavy bombardment 4 , is not a coincidence., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Zircon U-Pb geochronology places high-temperature geological events into temporal context. Here, we present a comprehensive zircon U-Pb geochronology dataset for the Meso- to Neoarchean Maniitsoq region in southwest Greenland, which includes the Akia Terrane, Tuno Terrane, and the intervening Alanngua Complex. The magmatic and metamorphic processes recorded in these terranes straddle a key change-point in early Earth geodynamics. This dataset comprises zircon U-Pb ages for 121 samples, including 46 that are newly dated. A principal crystallization peak occurs across all three terranes at ca. 3000 Ma, with subordinate crystallization age peaks at 3200 Ma (Akia Terrane and Alanngua Complex only), 2720 Ma and 2540 Ma. Metamorphic age peaks occur at 2990 Ma, 2820-2700 Ma, 2670-2600 Ma and 2540 Ma. Except for one sample, all dated metamorphic zircon growth after the Neoarchean occurred in the Alanngua Complex or within 20 km of its boundaries. This U-Pb dataset provides an important resource for addressing Earth Science topics as diverse as crustal evolution, fluid-rock interaction and mineral deposit genesis.