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The duration and extent of sediment routing systems are intrinsically linked to crustal‐ to mantle‐scale processes. Therefore, distinct changes in the geodynamic regime may be captured in the detrital record. This study attempts to reconstruct the sediment routing system of the Canning Basin (Western Australia) during the Early Cretaceous to decipher its depositional response to Mesozoic‐Cenozoic supercontinent dispersal. Specifically, we reconstruct source‐to‐sink relationships for the Broome Sandstone (Dampier Peninsula) and proximal modern sediments through multi‐proxy analysis of detrital zircon (U–Pb, Lu–Hf and trace elements) and detrital rutile (U–Pb and trace elements). Multi‐proxy comparison of detrital signatures and potential sources reveals that the majority of the detrital zircon and rutile grains are ultimately sourced from crystalline basement in central Australia (Musgrave Province and Arunta region) and that proximal sediment supply (i.e., Kimberley region) is negligible. However, a significant proportion of detritus might be derived from intermediate sedimentary sources in central Australia (e.g., Amadeus Basin) rather than directly from erosion of crystalline basement. Broome Sandstone data are consistent with a large‐scale drainage system with headwaters in central Australia. Contextualization with other broadly coeval drainage systems suggests that central Australia acted as a major drainage divide during the Early Cretaceous. Importantly, reorganization after supercontinent dispersal is characterized by the continuation of a sediment pathway remnant of an earlier transcontinental routing system originating in Antarctica that provided a template for Early Cretaceous drainage. Review of older Canning Basin strata implies a prolonged denudation history of central Australian lithologies. These observations are consistent with the long‐lived intracontinental tectonic activity of central Australia governing punctuated sediment generation and dispersion more broadly across Australia and emphasize the impact of deep Earth processes on sediment routing systems. [ABSTRACT FROM AUTHOR]

Over 10,000 published detrital zircon ages have been reprocessed (applying a +10% normal and reverse concordance range) and analysed to understand the evolution of the detrital zircon record of north‐west Africa during the Phanerozoic. Using dissimilarity and clustering analysis, shifts in detrital zircon populations allow interpretation of the evolution of source regions and source to sink systems throughout the Phanerozoic within the West Gondwana superfan. Previous thermochronology and field studies conducted across north‐west Africa indicate significant and sustained shifts in source regions in Meso‐Cenozoic times which are not recorded in the detrital zircon geochronology record. This discrepancy is most notable for Mesozoic to modern source to sink studies focused on the evolution of the Atlasic rift and opening of the Atlantic and Tethyan Oceans to the west and north respectively. Our results indicate a high degree of similarity between samples from Cambrian times onwards due to successive phases of sediment recycling. This highlights the need to integrate detrital zircon analysis with other techniques to provide confident reconstruction of sediment routing systems across Morocco. This systematic review also reveals the ubiquitous occurrence of Mesoproterozoic zircons within Moroccan sediment. No basement of this age is known from north‐west Africa—often described as the 'Mesoproterozoic Gap', which was thought to be a diagnostic feature of sediment derived from the West African Craton. However, zircons of this age form 7% of all analysed zircons and are present in sediments from at least 700 Ma. The presence of this population is interpreted as strongly diagnostic of provenance from either the Amazonian Craton or the Eastern Gondwana Orogen within Central Africa. Their presence in the Moroccan detrital record from the Neoproterozoic onwards raises questions about the position of the West African Craton in the Proterozoic, and for the spatial extent of Mesoproterozoic orogeny within north Africa. [ABSTRACT FROM AUTHOR]

The northeastern Siberian craton stores numerous placers of diamonds that differ in morphology and texture, and originate from different types of primary deposits, primarily kimberlites. Analyses of mantle zircons selected from samples of alluvial and coarse clastic sediments in the watersheds of the Olenek and Kyutyungde rivers in the Anabar‐Olenek subprovince of the Yakutian diamond province provide constraints on kimberlite magmatism events in the area. The new U–Pb ages and typical kimberlitic signatures of the Kyutyungde zircons trace‐element patterns reveal three main magmatic events that produced kimberlites: Middle Paleozoic (Late Devonian to Early Carboniferous), Jurassic and Triassic. The Jurassic zircons (177–149 Ma) are mainly related to kimberlites in the proximal Kuoika‐Molodo and Khorbusuon fields. Triassic zircons (240–221 Ma) were probably released during large‐scale erosion of the eastern Anabar shield, however, the presence of such zircons in the Kyutyungde area indicates that kimberlites of the respective magmatic stage may exist within the immediate vicinity of the area. The only Middle Paleozoic zircon sample (358.6 Ma, D3‐C1 boundary) may originate from a proximal kimberlite within the Kyutyungde area. The presence of Middle Paleozoic kimberlitic zircons, along with harzburgite–dunitic pyropes, indicates that the primary deposit of diamonds and related minerals may exist near or within the Kyutyungde area. Late Ediacaran–Early Cambrian (573–473 Ma) mantle zircons found in Early Cambrian conglomerates of the area, along with other mantle minerals including Cr spinel of a diamond assemblage, record another Precambrian event of potentially diamondiferous magmatism in the Kyutyungde basin. [ABSTRACT FROM AUTHOR]

Full‐plate reconstructions describe the history of past continental motions and how plate boundaries have evolved to accommodate these motions. Traditionally, tectonic reconstructions relied on geophysical data from the oceans and paleomagnetism as the primary quantitative constraints. However, these data do not directly constrain the paths of subduction zones or other plate boundaries, so reconstructing the complete configurations of tectonic plates in the past must rely on alternative methods. Here, we investigate the applicability of detrital zircon age spectra to characterize tectonic settings in deep time using a much larger data set than previously considered. We analyzed the proximity between reconstructed plate boundaries and sample sites assigned to different tectonic categorizations based on the proportion of zircon ages close to the depositional age and found that the categorization has an ∼70% success rate in distinguishing convergent settings. Results are not strongly influenced by factors such as the number of zircon grains available within each detrital sample or uncertainty in the depositional age of the sample. The ability of the categorization to define extensional settings, such as rift basins, is less clear. Nonetheless, the broader pattern of results at the scale of Pangea shows that categorized zircon samples form a coherent pattern, where samples with dominantly young zircons lie at the supercontinent periphery while samples in the core of Pangea are dominated by grains much older than the age of deposition. This result suggests that zircon data could help to quantify uncertainties in full‐plate reconstructions and discriminate between competing models for Proterozoic supercontinents. Plain Language Summary: The theory of plate tectonics explains how the continents we live on are in continual motion over geological time. Identifying where plates moved together or apart is a fundamental part of reconstructing Earth history. One novel approach is by analyzing the ages of individual crystals of zircon, a mineral found in many rocks. Previous studies put forward the idea that, in rocks where most zircons are not much older than the rock itself, these rocks likely formed close to the area where volcanos were active. Conversely, rocks formed far from active volcanos would lack these young zircons. We tested this idea using a much bigger data set of rock samples than previously considered. We found that the analysis of zircon ages can fingerprint volcanic activity with a reasonable success rate. Around 300 million years ago, most landmasses on Earth came together to form a supercontinent called Pangea. When viewed at the scale of Pangea, our results show that rocks divided into different groups using their zircon characteristics form coherent patterns distinguishing the periphery of Pangea from the core of it. The same method may help us to study other supercontinents that existed billions of years before Pangea. Key Points: Global plate reconstructions and a large zircon data set are used to quantify the link between detrital zircon age spectra and tectonic settingsAnalysis shows that detrital samples deposited in convergent settings are more likely to be dominated by young zirconsCategorized samples distinguish peripheral regions of Pangea from its core, significant for reconstructing earlier supercontinents [ABSTRACT FROM AUTHOR]

The Cathaysian Coastal Mountains are thought to be an ancient high‐topographic feature that existed along the margin of South China. They are characterised by extensive Jurassic–Cretaceous magmatism; however, their formation mechanism and timing remains uncertain. In this paper, we present sedimentological and detrital zircon analyses from Cretaceous–Eocene strata and drainage sediments from Hainan Island. Our analyses show a change in provenance from a proximal Cathaysian Coastal arc source in Cretaceous strata to a widely distributed intra‐island granite source in the Eocene strata and modern river sediments. Reconstruction of the crustal thickness evolution for the South China margin from Eu/Eu*‐in‐zircon proxy shows significant crustal thickening during the Late Jurassic–Cretaceous, thereby suggesting the existence of the Cathaysian Coastal Mountains. Together with a compilation of detrital zircon U‐Pb ages in the northern basins of the South China Sea margin, we conclude that the Cathaysian Coastal Mountains extended from the Red River region to Taiwan along the South China margin during the Late Jurassic–Cretaceous and then collapsed/eroded from northeast to southwest during the Eocene–Miocene. This large mountain range supplied detrital sediments to the marginal basins in the northern South China Sea and formed a topographic barrier that prohibited moist Pacific air to reach the relatively arid inland area of South China during the Late Jurassic–Cretaceous. [ABSTRACT FROM AUTHOR]

The Lohit Plutonic Complex (LPC) represents Trans‐Himalayan magmatic rocks in the easternmost sector of the Himalayan Orogen. It is divided into leucogranite‐granodiorite‐diorite dominant suite in the NE and the gabbro‐diorite‐granodiorite‐granite–trondhjemite suite in the SE by the Walong Thrust. U–Pb geochronological analyses of euhedral zircon grains from different magmatic phases of LPC reveal episodic magmatism. Zircon U–Pb age of 153.4 ± 1.4 Ma of a garnetiferous granite gneiss suggest that the crustal sourced magmatism was active in Arunachal Trans‐Himalaya during the late Jurassic. U–Pb ages of subduction induced magmatic rocks of LPC range between 117 ± 0.6 Ma and 49.5 ± 0.3 Ma. A significant contribution in crustal recycling during the Oligocene–Miocene is evident from crustally derived leucogranites having U–Pb ages ranging from 35.6 ± 0.3 Ma to 30 ± 0.3 Ma. A comparison of the crystallization ages of the Western Trans‐Himalayan units with those of eastern Trans‐Himalayan units reveals an earlier onset of Tethyan arc magmatism in the eastern sector. The most prominent phase in the eastern sector is during the Late Cretaceous while western and central sector show major activity during the Palaeocene–Eocene. [ABSTRACT FROM AUTHOR]

It is unclear whether the South China blocks have an affinity with continental Gondwana due to a lack of direct Pan‐African magmatic and metamorphic features. In this study, we conducted U‐Pb geochronological and Lu‐Hf isotopic analyses for detrital zircons from a sandstone of the Chang'an Formation of the Nanhua Group in the Longsheng region of northern Guangxi, with the aim of constraining the timing of sedimentation and information as to its source, as well as seeking evidence for Pan‐African events in the South China blocks. The results show that the ages of detrital zircons peaked at 654.7 ± 6.2 Ma, 773.2 ± 4.1 Ma and 821.9 ± 6.5 Ma, with some at 920–870 Ma; the youngest age indicates the existence of the Pan‐African thermal event. The ∊Hf(t) and TDM2 values demonstrate that the study area has experienced three stages of crustal growth at 3.0–2.4 Ga, 2.1–1.5 Ga and 1.3–0.9 Ga. With intensively distributed Neoproterozoic mafic‐ultramafic and granitic plutons emplaced at 830–810 Ma along the southwestern section of the Jiangnan Orogenic Belt and positive ∊Hf(t) values from a large group of zircon grains, it is proposed that the sediments of the Chang'an Formation (of Nanhua Group) were largely sourced from the southeastern margin of the Yangtze block. Comparison with the zircon age spectra of the Cathaysian block shows that about 79% of the Pan‐African aged detrital zircon grains that have TDM2 = 1352–1031 Ma and ∊Hf(t) = 3.68–8.79, were sourced from the recycled Grenvillian crust of the Cathaysian block, suggesting that the Cathaysian block had a close connection with Gondwana. [ABSTRACT FROM AUTHOR]

A study of heavy mineral assemblages, rutile compositions, and detrital zircon age populations in Namurian to Westphalian sandstones in North Wales, deposited in the southwestern part of the Pennine Basin of the United Kingdom, has revealed considerable complexity in their provenance history. The Pendleian to Marsdenian Cefn‐y‐fedw Sandstone Formation, which is known to have been derived from the Wales–Brabant Massif (WBM) to the south on the basis of palaeocurrent and petrographic information, has a heavy mineral assemblage characteristic of this southerly provenance, and includes Late Neoproterozoic zircons apparently of local WBM origin. However, the formation is dominated by zircons that were most probably recycled from sandstones of northern origin from the Caledonian Belt that had been previously deposited over the massif during Late Devonian times, and, as such, has a comparable history to the sedimentologically‐equivalent Morridge Formation of the English Midlands. Heavy mineral analysis shows that sandstones in the Brigantian Minera Formation and Yeadonian part of the Bowland Shale Formation are of similar southern provenance. The Yeadonian Gwespyr Sandstone, previously interpreted as having a northern origin, similar to the time‐equivalent Rough Rock, has variations in heavy mineral analysis and zircon spectrum that suggest a complex provenance history and includes sand bodies with northern, western, and southern origins. [ABSTRACT FROM AUTHOR]

The South Altyn Block (SAB), located along the southern margin of the Altyn Tagh in Qaidam Basin, has a significant relationship with the tectonics of the Qaidam Basin basement. This study presents the petrological features, geochemical compositions, and zircon U–Pb and Hf isotope data of four granitic plutons from the eastern segment of the SAB to constrain the petrogenesis and tectonic setting of this region during the Palaeozoic. Basing on previous U–Pb dating results, the zircon U–Pb analysis in this study suggests that Palaeozoic magmatic events can be subdivided into four episodes: Late Cambrian (approximately 502 Ma), Late Ordovician (approximately 444 Ma), Early Devonian, and Middle Permian (approximately 271 Ma). The Palaeozoic granitoids were derived mainly from Neoproterozoic juvenile crustal components, with minor palaeoproterozoic ancient materials. The S‐ and I‐type granitoids in Late Cambrian indicate a compressional tectonic environment with respect to subduction, and A‐type granitoids suggest post‐collision regime. The Late Ordovician granodiorites of A‐type imply typical magmatism within a post‐collision extensional setting. Ascribing to the subduction of Palaeo‐Tethys Ocean during the Devonian, S‐type granites were emplaced in the Early Devonian accompanied with the crust thickening. The Middle Permian magmatic events include a series of S‐type granitoids, demonstrating the setting of oceanic subduction along with the closure of the Palaeo‐Tethys Ocean. [ABSTRACT FROM AUTHOR]

The South China Block (SCB) has been regarded by many as an integral part of Gondwana, but proposed timing and processes for its accretion to Gondwana vary and remain contentious, largely owing to the lack of reliable Pan‐African age paleomagnetic data and tectono‐magmatic records from the SCB. Integrated in situ U‐Pb ages and Hf‐O isotope analyses of detrital zircons from geochronologically well‐calibrated Ediacaran‐Cambrian sedimentary rocks of western SCB reveal age populations of 2.51, 1.85, 1.20, 0.80, and 0.52 Ga. Detrital zircon age spectra indicate a major tectonic transition for the SCB during 0.56–0.54 Ga, interpreted to reflect the beginning of the collision between SCB‐Indochina and NW India blocks. The collisional event lasted until early Ordovician, leading to the suturing of the SCB‐Indochina to the northern margin of East Gondwana. Plain Language Summary: The South China Block is thought to be a part of the Gondwana superterrane, which was composed of more than half of all continents 650–400 million years ago (Ma). However, questions of when and how the South China Block collided with Gondwana are yet to be answered. In this study, we conducted provenance analyses of sedimentary rocks whose depositional ages were known via radioisotopic dating and chemo‐biostratigraphy in the western South China Block. The results reveal a change in tectonic setting of the South China Block at 560–540 Ma, interpreted as the onset of the collision between the South China Block and India along the northern margin of East Gondwana. Key Points: 1.2‐Ga detrital zircon population is present in age‐calibrated Ediacaran‐Cambrian strata of western South China BlockA major change in tectonic setting of the South China Block occurred in 0.56–0.54 GaThe connection between the South China Block and NW India Block started in the late Ediacaran [ABSTRACT FROM AUTHOR]

To detect the exhumation history of the southwestern South China Block (SCB), we performed fission track (FT) analysis on zircon and apatite grains in granitoid and sedimentary samples. From east to west, the study area includes the Yunkai Massif, Lingshan granitic belt, Shiwandashan Basin, and eastern margin of the Youjiang Basin. The granite sample of the Yunkai Massif has two peaks of 75 and 92 Ma for zircon FT dating. The Lingshan granitic belt samples yield zircon FT central ages from 135 to 132 Ma. The Permian bauxite samples of the Youjiang Basin yield zircon FT central ages from 109 to 93 Ma and display age peaks at ~97–93 Ma. The Yunkai Massif granite sample has two peaks at 74 and 104 Ma for apatite FT dating, while the Lingshan granitic belt sample has two peaks at 81 and 111 Ma. The cooling paths of the Yunkai Massif sample started with an Early Cretaceous (~120–100 Ma) cooling event that brought the granitoids into the apatite partial annealing zone (PAZ). Through comparative studies, we suggest that the southwestern SCB underwent three periods of crustal uplift during ~135–132, ~111–92, and ~ 81–74 Ma, respectively, which is consistent with the regional stratigraphic unconformity and crustal extension. Only the Yunkai Massif and Lingshan granitic belt were uplifted during ~135–132 Ma. During ~111–92 Ma, the southwestern SCB experienced crustal uplift, and the basal conglomerate began to deposit in the Shiwandashan Basin. Late Cretaceous uplifted occurred during ~81–74 Ma, and the Yunkai Massif was uplifted throughout the Cretaceous. From 97 to 92 Ma, the Permian bauxite deposits in the Youjiang Basin were uplifted, which provided the basis of the later transformation to Quaternary bauxite. [ABSTRACT FROM AUTHOR]

Analysing the provenance changes of synorogenic sediments in the Turpan‐Hami basin by detrital zircon geochronology is an efficient tool to examine the uplift and erosion history of the easternmost Tian Shan. We present detrital zircon U‐Pb analysis from nine samples that were collected within marginal lacustrine Middle‐Late Jurassic and aeolian‐fluvial Early Cretaceous strata in the basin. Middle‐Early Jurassic (159–172 Ma) zircons deriving from the southern Junggar dominated the Middle Jurassic sample from the western Turpan‐Hami basin, whereas Permian‐Carboniferous (270–330 Ma) zircons from the Bogda mountains were dominant in the Late Jurassic to Early Cretaceous samples. Devonian‐Silurian (400–420 Ma) and Triassic (235–259 Ma) zircons from the Jueluotage and Harlik mountains constituted the subordinate age groups in the Late Jurassic and Early Cretaceous samples from the eastern basin respectively. These provenance transitions provide evidence for uplift of the Bogda mountains in the Late Jurassic and the Harlik mountains since the Early Cretaceous. [ABSTRACT FROM AUTHOR]

The temporal duration of lunar‐evolved magmatism is still poorly constrained. In lunar meteorite Northwest Africa (NWA) 10049, a melt inclusion‐bearing zircon fragment provides a new tool to understand the composition and age of the melts from which zircon directly crystallized. The studied zircon‐hosted melt inclusions are silica rich and iron poor (e.g., ~80–90 wt% SiO2; <0.5 wt% FeO), compositionally similar with immiscible silica‐rich melts found in Apollo rocks. Nano‐SIMS U–Pb analyses of the zircon yielded a minimum crystallization age of 4,382 ± 40 Ma, older than the ages for Apollo highly evolved alkali suite lithologies (~3.8–4.33 Ga). Our study shows that the melt inclusion‐bearing zircon in NWA 10049 is the oldest microscale evidence for documenting immiscible silica‐rich melts in lunar samples, suggesting that lunar‐evolved silica‐rich melts were prevalent as early as ~4.38 Ga. This work implies that there would be a prolonged silicic magmatism occurred on the Moon. Plain Language Summary: Lunar‐evolved silica‐rich melt is thought to be related to the formation of highly silicic lithologies (e.g., granitic lithologies). These rock types have been observed in Apollo returned samples as lithic clasts and also have been detected by remote‐sensing data as silicic domes. The Apollo‐evolved lithologies give a wide range of crystallization ages from ~3.8–4.33 Ga. However, there is still unclear about the temporal duration of lunar‐evolved magmatism and volcanism. In lunar meteorite breccia NWA 10049, a melt inclusions‐bearing zircon fragment provides a new tool to understand the composition and age of the melts from which zircon directly crystallized. The studied zircon‐hosted melt inclusions are compositionally similar with immiscible silica‐rich melts found in Apollo rocks. Nano‐SIMS U–Pb analyses of the zircon yielded a minimum crystallization age of ~4.38 Ga. This age is older than the ages for Apollo‐returned granites (up to 4.33 Ga) and ancient basaltic volcanism (i.e., up to ~4.37 Ga), making the studied zircon is the oldest microscale evidence for documenting lunar silicate liquid immiscibility. Key Points: A ~200‐μm‐sized melt inclusion‐bearing zircon fragment was found in lunar feldspathic breccia meteorite NWA 10049Melt inclusions in this zircon are compositionally consistent with lunar immiscible silica‐rich meltsThe zircon is 4.38 Ga and provides microscale evidence for ancient immiscible silica‐rich melt on the Moon [ABSTRACT FROM AUTHOR]

The temporal duration of lunar‐evolved magmatism is still poorly constrained. In lunar meteorite Northwest Africa (NWA) 10049, a melt inclusion‐bearing zircon fragment provides a new tool to understand the composition and age of the melts from which zircon directly crystallized. The studied zircon‐hosted melt inclusions are silica rich and iron poor (e.g., ~80–90 wt% SiO2; <0.5 wt% FeO), compositionally similar with immiscible silica‐rich melts found in Apollo rocks. Nano‐SIMS U–Pb analyses of the zircon yielded a minimum crystallization age of 4,382 ± 40 Ma, older than the ages for Apollo highly evolved alkali suite lithologies (~3.8–4.33 Ga). Our study shows that the melt inclusion‐bearing zircon in NWA 10049 is the oldest microscale evidence for documenting immiscible silica‐rich melts in lunar samples, suggesting that lunar‐evolved silica‐rich melts were prevalent as early as ~4.38 Ga. This work implies that there would be a prolonged silicic magmatism occurred on the Moon. Plain Language Summary: Lunar‐evolved silica‐rich melt is thought to be related to the formation of highly silicic lithologies (e.g., granitic lithologies). These rock types have been observed in Apollo returned samples as lithic clasts and also have been detected by remote‐sensing data as silicic domes. The Apollo‐evolved lithologies give a wide range of crystallization ages from ~3.8–4.33 Ga. However, there is still unclear about the temporal duration of lunar‐evolved magmatism and volcanism. In lunar meteorite breccia NWA 10049, a melt inclusions‐bearing zircon fragment provides a new tool to understand the composition and age of the melts from which zircon directly crystallized. The studied zircon‐hosted melt inclusions are compositionally similar with immiscible silica‐rich melts found in Apollo rocks. Nano‐SIMS U–Pb analyses of the zircon yielded a minimum crystallization age of ~4.38 Ga. This age is older than the ages for Apollo‐returned granites (up to 4.33 Ga) and ancient basaltic volcanism (i.e., up to ~4.37 Ga), making the studied zircon is the oldest microscale evidence for documenting lunar silicate liquid immiscibility. Key Points: A ~200‐μm‐sized melt inclusion‐bearing zircon fragment was found in lunar feldspathic breccia meteorite NWA 10049Melt inclusions in this zircon are compositionally consistent with lunar immiscible silica‐rich meltsThe zircon is 4.38 Ga and provides microscale evidence for ancient immiscible silica‐rich melt on the Moon [ABSTRACT FROM AUTHOR]

The Salem Mafic–Ultramafic Complex occurs within the northern part of Cauvery Suture Zone (CSZ), Southern Granulite Terrane (SGT), India. The complex occurs as semicircular to elongated linear body with a thick mantle section and comparatively well‐developed crustal section comprising different lithological units, also referred to as the Chalk Hills of Salem. The major rock types in the complex comprise ultramafic cumulates of dunite, peridotite, wherlite, pyroxenite, and hornblendite, mafic and felsic intrusions of gabbros and amphibolites, and quartzo–feldspathic alkaline rocks together with several ultrapotassic dykes. Geochemical studies of amphibolites from this complex indicate tholeiitic parent magma with enrichment of LIL elements (Rb, Ba, Th, and Sr) and are relatively more enriched than N‐MORB as compared with arc‐related rocks. The enrichment of LIL elements over the HFS elements and with distinct Nb, Ta, and Ti depletion relative to other HFS elements suggest the involvement of subduction‐related components in the depleted mantle source and that the magmatism occurred in an oceanic convergent realm. The mineral chemistry of dunite and peridotite shows high content of forsterite (86.9–92.2) in olivine and high Cr# value (80.85–98.73) for spinel. The tectonic discrimination plots of spinel and olivine mineral chemistry together with clinopyroxene chemistry of amphibolites reveal arc signature typical of Alaskan type of complex. The U–Pb zircon analysis of quartz monzonite intrusion within the hornblendite from the complex yielded a weighted mean age of 819 ± 2.4 Ma, suggesting that the complex formed during the Neoproterozoic and can be correlated to the Alaskan‐type complexes described from the Arabian–Nubian Shield. [ABSTRACT FROM AUTHOR]

Laser ablation inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) U–Pb geochronology of shocked zircon grains in a vesicular‐fluidal impact melt rock from the ≥54 km Charlevoix impact structure, Québec, Canada, suggests an Ordovician to Silurian age of 450 ± 20 Ma for the impact. This age is anchored by concordant U–Pb results of ~450 Ma for a U‐rich, cryptocrystalline zircon grain in the melt rock, interpreted as a recrystallized metamict zircon crystal; the U–Th–Pb system of the metamict grain was seemingly chronometrically reset by the Charlevoix impact, but withstood later tectonometamorphic events. The new zircon age for Charlevoix is in agreement with a stratigraphically constrained Late Ordovician maximum age of ~453 Ma and corroborates earlier suggestions that the impact occurred most likely in the Ordovician, and not ~100 Myr later, as indicated by previous K/Ar and 40Ar/39Ar geochronologic results. The latter may reflect postimpact thermal overprint of impactites during the Salinian (Late Silurian to Early Devonian) and/or Acadian (Late Devonian) orogenies. U–Pb geochronology of zircon crystals in anorthosite exposed in the central uplift of the impact structure yielded a Grenvillian crystallization age of 1062 ± 11 Ma. The preferred Ordovician age for the Charlevoix impact structure, which is partially overthrusted by the Appalachian front, suggests the impact occurred during a phase of Taconian tectonism and an episode of enhanced asteroid bombardment of the Earth. Our results, moreover, demonstrate that (recrystallized) metamict zircon grains may be of particular interest in impact geochronology. [ABSTRACT FROM AUTHOR]

Despite the hazard posed by explosive silicic eruptions, the magma storage conditions and dynamics that precede these events remain controversial. The Laguna del Maule volcanic field, central Chile, is an exceptional example of postglacial (younger than ca. 20,000 years) rhyolite volcanism and sustained unrest driven by a large, shallow, active silicic magma system. New zircon petrochronologic data reveal that compositionally distinct domains developed concurrently within the Laguna del Maule magma reservoir, which produced two episodes of concentrated rhyolitic eruptions at 23–19 and 8–2 ka. Zircon crystallization ages record 160 kyr of magma emplacement resulting in a several hundreds of cubic kilometers reservoir that has been imaged geophysically. The average magma emplacement rate inferred from the zircon geochronology and tomographically defined magma volume is consistent with those required by thermal models to maintain a shallow silicic system. Ti‐in‐zircon temperatures of crystal cores and rims and hiatuses in crystal growth indicates most of this volume persisted in a near‐solidus state. However, consistent patterns of trace element zoning in crystal interiors and crystallization rates derived from a model of diffusion‐limited zircon growth suggest the erupted rhyolite magma batches originated from long‐lived hot zones of extractable mush embedded within the larger, cool reservoir of rigid mush. These contrasting, coeval magma storage conditions obviate a simple hot versus cold storage dichotomy for large silicic magma systems. Plain Language Summary: Elucidating the magma storage conditions and processes that preceded prehistoric eruptions is critical to improving the interpretation of volcano monitoring data. An important, yet controversial, consideration is if long‐term magma storage is dominated by cold, mineral‐rich, and uneruptible conditions or if warm, mobile magma bodies can persist for thousands of years. The mineral zircon is indispensable for reconstructing pre‐eruption behavior because it records the host magma composition and temperature and may be dated at the intracrystal scale. We present ages and chemical compositions of zircon crystals from the Laguna del Maule volcanic field (LdM), located in central Chile. LdM has experienced more than 2 m of uplift since 2007 within a ring of volcanic vents that have erupted repeatedly over the last 20,000 years. The LdM magma reservoir grew over 34,000 to 160,000 years and persisted largely in a cool, crystal‐rich state. However, the erupted magma was derived from hot zones within the larger reservoir that endured throughout this time. These heterogeneous magma storage conditions preclude a simple conceptual framework of magma storage and highlight the need for future integration of forensic investigations of volcanic deposits with models of three‐phase (crystals, melt, and fluid) magma reservoirs dynamics. Key Points: Zircon petrochronology records the accumulation of a large, shallow, heterogeneous silicic magma systemEruptible rhyolite melt was derived from distinct, hot magma mush bodies that resided within a cool, crystalline magma reservoirComposition and thermal variability in time and space is increasingly recognized in shallow silicic magma systems [ABSTRACT FROM AUTHOR]

The article discusses about Zircon U‐Pb Age of the Granodiorite in the Chifeng at Northern Margin of the North China Craton and the Constraints on the Plate Tectonic Evolution. It is concluded that suite of granodiorite was identified in Zhuanshanzi and Yuanbaoshan area in eastern Chifeng atnorthern margin of NCC.

U-Pb geochronology and trace element chemistry of zircons in a microscale analysis were applied to the Ishizuchi caldera in the Outer Zone of Southwest Japan in order to estimate the timescale of the magma process, in particular, the magma differentiation. This caldera is composed mainly of ring fault complexes, major pyroclastic flow deposits, and felsic intrusion including central plutons. Using SHRIMP-IIe, our new U-Pb zircon ages obtained from the major pyroclastic flow deposits (Tengudake pyroclastic flow deposits), granitic rocks from central plutons (Soushikei granodiorite and Teppoishigawa quartz monzonite), and rhyolite from the outer ring dike (Tenchuseki rhyolite) and the inner ring dike (Bansyodani rhyolite) are 14.80 ±0.11 Ma, 14.56 ±0.10 Ma, 14.53 ±0.12 Ma, 14.55 ±0.11 Ma and 14.21 ±0.19 Ma, respectively. Based on the U-Pb ages, the Hf contents and the REE patterns of the zircons, three stages are recognized in the evolutionary history of the magma chamber beneath the Ishizuchi caldera: (i) climactic Tengudake pyroclastic flow eruption; (ii) Tenchuseki rhyolite intrusion into the outer ring dike and central pluton intrusion; and (iii) Bansyodani rhyolite intrusion in the inner ring dike. These results indicate a magma evolution history of the Ishizuchi caldera system which took at least ca 600 kyr from the climatic caldera-forming eruption to the post-caldera intrusions. Our new geochronological data suggest that the Ishizuchi caldera formed as part of the voluminous and episodic magmatism that occurred in the wide zone along the Miocene forearc basin of Southwest Japan during the inception of the young Philippine Sea Plate subduction. [ABSTRACT FROM AUTHOR]

Introduction: The Rochechouart impact structure in the NW part of the French Massif Central (FMC) is characterized by deep erosion that, however, still allows the recognition of a complete suite of impact lithologies, the crater floor, and various target lithologies (e.g., [1]). We present the first results from a project that is aimed at U-Pb on zircon isotope analysis of a representative set of surface and core samples of impact melt rocks and basement lithologies. These results will help to constrain the age of the impact event and provide information about the dynamics of the impact melt formation process in terms of the protolith target rocks for the diverse impact melt rock types. The analysis of the basement samples will improve and complement the current understanding of the FMC evolution in the region of the impact structure. Methodology: Zircons from a reddish impact melt rock from Montoume, a yellow impact melt rock from Recoudert, an amphibolite from Exideuil, and a gray foliated gneiss from Moulin de Laurière have so far been analyzed for U-Pb isotope data with a Neptune Plus Thermo Finnigan LA-MC-ICP-MS coupled with a Photon-Machines 193 nm laser system at the Laboratory of Isotope Geochemistry at the University of Ouro Preto, Brazil. Results: The oldest ages registered in zircons from both basement rocks are Neoproterozoic. The youngest ages from zircons of the gneiss are Silurian (433 ± 15 Ma), and from zircons of the amphibolite we obtained Carboniferous ages (326 ± 5 Ma). The principal age peak recorded from the basement zircons is at ~362 Ma, registered in the amphibolite. Other minor basement age peaks are registered at ~327 and ~449 Ma for the amphibolite; and ~523 Ma and ~544 Ma for the gneiss. The impact melt rocks display a greater variety of ages, from the Neoproterozoic to the Triassic (203 ± 2 Ma) for the Recoudert sample, and from the Neoproterozoic to the Lower Jurassic (195 ± 3 Ma) for the Montoume impact melt rock. The most prominent age peak registered in these impactites is at ~388 Ma and is from the Montoume sample. The Permian ages are obtained principally from the Recoudert sample. Discussion: The basement ages obtained in this study can be broadly correlated with different events of the evolution of the FMC (e.g., [2] and referred therein). Pre-Ordovician ages are probably related to protolith ages of the metamorphic basement. The ~362 Ma age peak is slightly older than the Variscan collision period, and similar ages have been obtained elsewhere in the NW FMC [3]. The ~327 Ma age is probably related to the Carboniferous exhumation period. The most prominent basement age peaks are not registered in the zircons from the two impact melts. Furthermore, these impactites display age peaks that are not found for the basement rocks analyzed to date. This is probably a result of different target rock lithologies involved in the formation of both impact melt rock samples. The age peaks observed for the impact melt rocks possibly record the exhumation of high-grade rocks at ~388 Ma [4] and a Permian granitization phase [5]. Finally, ~204 Ma ages recorded in zircon from both impact melt rocks are in agreement with recent U-Pb estimations of the age of the impact event (204 ± 2.2 and 207 ± 3.6 Ma; [5]). The youngest ~194 Ma ages obtained for the Montoume sample are similar to ~195 Ma ages previously reported for Babaudus impact melt rock [5]. Further textural characterization of these zircons will help in the interpretation of this apparent post-impact age. Conclusions: U-Pb age data for zircon from an amphibolite and a gneiss from the basement of the Rochechouart impact structure show good agreement with known events in the evolution of the FMC. Impact melt rock samples from Montoume and Recoudert show a great diversity of ages, including age peaks not recorded in the basement lithologies analyzed to date, which probably relates to target rocks that still need to be analyzed. Furthermore, the age of the impact event and a younger Lower Jurassic age were obtained. [ABSTRACT FROM AUTHOR]

The Tongshankou Cu-Mo deposit, located in southeast Hubei province, is a typical skarn-porphyry type ore deposit closely related to the Tongshankou granodiorite porphyry, characterized by a high Sr/Y ratio. Detailed in situ analyses of the trace elements and U-Pb and Lu-Hf isotopes in zircons from the Tongshankou granodiorite porphyry were performed. Scarcely any inherited zircons were observed, and the analyzed zircons yielded highly concordant results with a weighted mean 206Pb/238U age of 143.5 ± 0.45 Ma ( n=20, mean square weighted deviation was 0.75), which was interpreted to represent the crystallization age of the Tongshankou granodiorite porphyry. The chondrite-normalized rare-earth element pattern was characterized by a slope that steeply rises from the light-group rare-earth elements (LREE) to the heavy-group rare-earth elements (HREE) with a positive Ce-anomaly and inconspicuous Eu-anomaly, which was coincident with the pattern of the zircons from the Chuquicamata West porphyry, Chile. The analyzed zircons also had relatively low 176Hf/177Hf ratios of 0.282526-0.282604. Assuming t=143 Ma, the corresponding calculated initial Hf isotope compositions ( εHf( t)) ranged from −5.6 to −2.9. The results of the in situ analysis of trace elements and U-Pb and Lu-Hf isotopes in zircons from the Tongshankou granodiorite porphyry suggest that a deep-seated process involving a thickened-crust/enriched-mantle interaction may play an important role in the generation of high Sr/Y-ratio magma and potentially in the generation of porphyry Cu-Mo systems. [ABSTRACT FROM AUTHOR]

This study investigates the behaviour of the geochronometers zircon, monazite, rutile and titanite in polyphase lower crustal rocks of the Kalak Nappe Complex, northern Norway. A pressure-temperature-time-deformation path is constructed by combining microstructural observations with P-T conditions derived from phase equilibrium modelling and U-Pb dating. The following tectonometamorphic evolution is deduced: A subvertical S1 fabric formed at ~730-775 °C and ~6.3-9.8 kbar, above the wet solidus in the sillimanite and kyanite stability fields. The event is dated at 702 ± 5 Ma by high-U zircon in a leucosome. Monazite grains that grew in the S1 fabric show surprisingly little variation in chemical composition compared to a large spread in (concordant) U-Pb dates from c. 800 to 600 Ma. This age spread could either represent protracted growth of monazite during high-grade metamorphism, or represent partially reset ages due to high- T diffusion. Both cases imply that elevated temperatures of >600 °C persisted for over c. 200 Ma, indicating relatively static conditions at lower crustal levels for most of the Neoproterozoic. The S1 fabric was overprinted by a subhorizontal S2 fabric, which formed at ~600-660 °C and ~10-12 kbar. Rutile that originally grew during the S1-forming event lost its Zr-in-rutile and U-Pb signatures during the S2-forming event. It records Zr-in-rutile temperatures of 550-660 °C and Caledonian ages of 440-420 Ma. Titanite grew at the expense of rutile at slightly lower temperatures of ~550 °C during ongoing S2 deformation; U-Pb ages of c. 440-430 Ma date its crystallization, giving a minimum estimate for the age of Caledonian metamorphism and the duration of Caledonian shearing. This study shows that (i) monazite can have a large spread in U-Pb dates despite a homogeneous composition; (ii) rutile may lose its Zr-in-rutile and U-Pb signature during an amphibolite facies overprint; and (iii) titanite may record crystallization ages during retrograde shearing. Therefore, in order to correctly interpret U-Pb ages from different geochronometers in a polyphase deformation and reaction history, they are ideally combined with microstructural observations and phase equilibrium modelling to derive a complete P-T-t-d path. [ABSTRACT FROM AUTHOR]

Laser ablation-inductively coupled plasma-mass spectrometry ( LA- ICP- MS) was examined as a tool for measuring isotopic variation as a function of ablation depth in unpolished zircon from an Archaean metasediment specimen. This technique was able to identify micrometre-thin (> 3 μm) isotopically distinct mineral domains characterised by ca. 100 Myr younger 207Pb/206Pb ages associated with 2 s age uncertainties as low ~ 0.2%, as well as elevated U content relative to grain interiors (up to an order of magnitude). Our calculated drilling rate suggests that each laser pulse excavated depths of ~ 0.06 μm. Ages resolved through the LA- ICP- MS methods overlap the 2 s uncertainties of 207Pb/206Pb ages measured using SIMS depth profiling on the same zircon population. The rims were further evinced by the detection of relative enrichment (> 3 orders of magnitude) in REE in the outermost micrometres of the same zircon, measured using a different and independent LA- ICP- MS depth profiling technique. We propose a LA- ICP- MS U-Pb technique capable of quickly identifying and quantifying rims, which are indication of late, yet geologically significant, fluid events that are otherwise undefined. [ABSTRACT FROM AUTHOR]

Secondary ion mass spectrometry (SIMS) measurements of Pb isotopes and U-Pb elemental ratios in natural minerals are one of the most important methods of measuring geologic time on the million to billion year timescale. Precise and accurate geochronology requires accurate correction of elemental U and Pb fractionation in the SIMS process. The calibration schemes used to correct for this fractionation have been in use since the 1990s. However, the mechanism by which they work remains poorly understood. The independence of primary ion impact energy from the secondary voltage in the sensitive high-resolution ion microprobe (SHRIMP) is used to examine the ionization efficiency of Pb+ in zircon over a range of impact energies from 3.7 kV to 15.7 kV. A plateau of around 34 cps/nA O2−/ppm 206Pb is observed between 5.7 and 10.7-kV impact energy. In contrast, useful yield increases steadily as impact energy is decreased. The use of a primary beam made of 18O2− ions allows the 18O implanted by the primary beam to be differentiated from the 16O in the natural silicate matrix. The oxygen isotopic results, with larger 18O/16O ratios at lower energies, suggest that enhanced oxygen activity at the sputtering surface may be due to progressively lower sputtering efficiency at lower energies. This would increase the Pb+ yield from the sample even as the ion yield per nA of primary beam remains constant, as a nA of molecular oxygen at 5 kV or less sputters a smaller sample volume than at higher energies. The useful yield for Pb increases from 1% to 3% as the primary energy drops. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article presents abstracts on geological topics which include the origin and structure of zircon in metamorphic rocks, the role of fluids during processes involving the continental crust, and geochemical characteristics of granites found in the Dabie Mountains, China.

The article describes research report on Detrital Zircon U-Pb Geochronology of the Triassic Sandstones from the Yanyuan Basin of Southwestern Sichuan, China. Topics discusses include Triassic sandstones in the Yanyuan Basin record different detrital zircon geochronology signals; and supported by the Sichuan Science and technology program the open fund of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology.

The article reports on the discovery of 341 Ma gabbro, that is located inXiongcun copper-gold district at southern margin of Lhasa terrane, Tibet. The methods employed and photographs of Xiongcun gabbro, marble and migmatization gneissare are presented. Zircon U-Pb ages of the gabbro in west of Xiongcun district are 341.55±0.89 Ma

The article reports on the research study on the first Discovery and Zircon U‐Pb Dating of the Early Ordovician Granitoids in the area of Lincang Batholith, Western Yunnan. Implications of Proto‐Tethyan Orogeny in Sanjiang Region, South West China are mentioned. From Petrological and geochronological data it could be concluded that Ordovician magmatism had occured in Lincang batholith.