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Metasedimentary rocks from nine sampling sites in southern Finland and an intermediate dyke in one of these sites were sampled for analysis of U-Pb zircon age and geochemical composition. The zircons of the metasedimentary rock samples yield 207Pb/206Pb dates ranging from 3281 to 1810 Ma. The nearly concordant dates from apparent detrital zircon cores indicate a prominent source with age around 2.1-2.0 Ga. The maximum depositional ages estimated for six of the metasedimentary rock samples span from 1.96 to 1.89 Ga. The data from zircon rims and overgrowths and metamorphic zircons in the metasedimentary rock samples indicate regional metamorphic events in the study area at least at ca. 1.89 and 1.84 Ga, and possibly also at ca. 1.87 Ga. The minimum age of the deposition (=1.89 Ga) was estimated based on the ages of the regional metamorphism and the intrusive rocks. Some zircon rims and overgrowths yield 21.91 Ga 207Pb/206Pb dates, which are considered to possibly represent metamorphic events in the source areas. [ABSTRACT FROM AUTHOR]

The crustally derived Tungsten Plutonic Suite (TPS) in the northern Canadian Cordillera is responsible for several of the world's most important tungsten (W) resources, but the actual source rocks to these exceptionally metallogenic magmas have never been identified. Detrital zircon studies have improved our knowledge of exposed supracrustal packages in the region, such that a U-Pb study of inherited zircon cores in the TPS provides an opportunity to determine the age and provenance of the melt source to these magmas. The TPS is dominated by Neoarchean to Paleoproterozoic inherited zircons that are typical of a northwest Laurentian "cratonic" detrital zircon signature (e.g., 2.8-1.8 Ga). Cross-correlation statistical analysis of detrital zircon populations combined with whole-rock neodymium isotopic compositions indicate that mid- to late Cambrian sedimentary rocks in the Selwyn Basin are the most likely melt source for the TPS magmas. Despite the presence of prospective intrusions across the Selwyn Basin, world-class W metallogeny is limited to the narrow belt of TPS plutons in the eastern Selwyn Basin near the ancient continental margin, possibly due to depositional or structural controls on the source strata. Today, the early Phanerozoic melt source to the TPS must be present at depths of at least 15-17 km and is notably younger than suggested by current geophysical interpretations for the middle crust, requiring a reconsideration of the crustal architecture in the northern Canadian Cordillera. [ABSTRACT FROM AUTHOR]

The Sijiaying iron deposit is located in the Eastern Hebei area of the southern section of the northern margin of the North China Craton (NCC) and is the largest single iron deposit in China. The deposit contains many banded iron formations (BIFs) and was proven to have more than 3 million tons of high-grade iron ore resources. This study carried out geochemistry and zircon U–Pb analysis of normal-grade iron ore, high-grade iron ore, and wall rock (biotite–leptynite, chlorite–sericite schist) in the Sijiaying deposit and discussed the genesis and metallogenic age of high-grade iron ore. BIFs have low concentrations of Al2O3 and TiO2 and high field strength element (HFSE) depletion, indicating almost no contamination via terrestrial debris. The standardized post-Archean Australian shale (PAAS) rare earth element (REE) distribution pattern indicates that the iron formation exhibits positive Eu, Y, and heavy rare earth element (HREE) anomalies and lacks negative Ce anomalies, indicating that the Sijiaying BIF was enriched with iron sources via high-temperature hydrothermal fluids from the seabed and deposited in an anoxic ancient marine environment. In addition, geological field work identified two types of high-grade iron ore in the mining area: primitive sedimentary and hydrothermally altered high-grade iron ore. Further ore geochemical research showed that the primitive sedimentary-type iron ore is similar in geochemistry to the BIF. In addition to low Eu/Eu* values, the hydrothermally altered high-grade iron ore shows geochemical characteristics similar to those of the BIF, suggesting that they share the same iron source but did not form at the same time. The total large ion lithophile element (LILE) (Sr, Ba, Pb) contents in primitive sedimentary-type high-grade iron ore are higher than those in hydrothermally altered high-grade iron ore, indicating that LILEs are carried away via fluids during the hydrothermal alteration process in normal-grade iron ore. The geochemical characteristics of biotite–leptynite and chlorite–sericite schist include high contents of SiO2 and Al2O3, light rare earth elements (LREEs), LILE enrichment (Rb, Ba, Sr, Zr), and HFSE depletion (Nb, Ta, P, Ti), characteristics that are similar to island arc volcanic rocks. The reconstruction of the original rock indicates that the wall rock is a product of volcanic sedimentary cycles in an island arc setting. Zircon cathodoluminescence images and LA–ICP–MS zircon U–Pb dating can be divided into four age groups (3283 Ma, 2547 Ma, 2500 Ma, and 2407 Ma), which correspond to the earliest volcanic activity in eastern Hebei, the main mineralization age of the Sijiaying BIF (the mineralization age of primitive sedimentary high-grade iron ore), a regional tectonic–metamorphic event, and the occurrence of migmatization (the mineralization age of hydrothermally altered high-grade iron ore), respectively. Therefore, the Sijiaying BIF and primitive sedimentary high-grade iron ores were deposited and mineralized at 2547 Ma, and the iron orebody was later altered via the hydrothermal solution at 2407 Ma, forming large-scale high-grade iron ores. [ABSTRACT FROM AUTHOR]

Two samples of zircon concentrate by local manufacturers were investigated for the first time for their rare earth elements (REE) content by instrumental neutron activation analysis (INAA) and energy dispersive X-ray fluorescence analysis. Comparator variant of INAA based on an external standard (Fe) and two internal standards (Th, La) was used to determine the elements divided into three groups depending on the detector type, radionuclide half-lives, and suitable comparator. High Y and heavy REE contents of the samples exceeding their crustal averages up to two orders of magnitude confirmed significance of the zircon concentrate as an important source of these elements production as a by-product. [ABSTRACT FROM AUTHOR]

LA-ICPMS U-Pb isotope analyses are presented for zircons from a thin granite sheet intersected in a borehole drilled into the upper Transvaal Supergroup wall rocks to the Molopo Farms Complex in southern Botswana. Many of the zircons have irregular or angular grain margins, and some have rounded cores. Approximately half of the analysed grains yielded concordant 207Pb/206Pb ages ranging between 2 282 ± 29 and 2 113 ± 16 Ma. Assuming that these grains were inherited from the surrounding upper Transvaal Supergroup sedimentary strata, the youngest zircon age provides a maximum depositional age for these sediments. Importantly, these zircon ages coincide with dates from detrital zircons in upper Transvaal Supergroup strata in the eastern Kaapvaal Craton and in the Magondi Supergroup in western Zimbabwe. Hf isotope analyses of the rounded zircons suggest that these grains were sourced from a variable mixture of an old basement and more juvenile material. A younger age of 2 060 ± 12 Ma was obtained from a single subhedral zircon grain from the granite sheet. This is interpreted as the granite’s emplacement age, making it coeval with the adjacent Molopo Farms Complex that forms part of the Bushveld Large Igneous Province. [ABSTRACT FROM AUTHOR]

Zircon samples of loess detritus were taken from Qugang loess profile in Maizhokunggar area, southern Tibetan Plateau. Based on the experimental analysis of zircon morphology, trace elements and zircon U–Pb age, provenance information and formation model of Qugang loess were discussed in combination with regional geological, topographic and geomorphological characteristics. The information of zircon morphology and trace elements suggests that the clastic zircons are of magmatic origin and proximal sedimentary characteristics. Zircon U–Pb age spectrum shows that the provenance information is significantly different from loess in the Loess Plateau and the northeastern Tibetan Plateau, related to the distribution of bedrock in regional geology, and corresponding to the Gangdese magmatic activity. The loess sediment development has a "Rock-Valley detrital material-Loess" model. [ABSTRACT FROM AUTHOR]

The present study is focused on the analysis of zircon inclusions found in pink to purple sapphires from Ilakaka (Madagascar) with an optical microscope, Fourier-transform infrared (FTIR), and micro-Raman spectroscopy in order to update previous knowledge and find insights to separate heated from unheated samples. In total, 157 zircon inclusions in 15 unheated samples and 74 zircon inclusions in 6 heated samples are analysed using micro-Raman spectroscopy with standardised parameters. The full width at half maximum (FWHM) of the main Raman band due to anti-symmetric stretching vibration ν3 of the SiO4 tetrahedron in the zircon structure has been carefully measured. In the unheated samples, it ranges from 6.26 to 21.73 cm−1 with an average of 10.74 cm−1, a median of 10.04 cm−1, and a standard deviation of 2.84 cm−1. On the other hand, it is lower in the heated samples, ranging from 4.83 to 14.97 cm−1 with an average of 7.23 cm−1, median of 7.06 cm−1, and standard deviation of 1.63 cm−1. In our unheated samples, the FWHM was rarely below 7 cm−1. In our heated samples, the FWHM was rarely above 12 cm−1 but mostly below 8 cm−1, with a variation restricted to less than 3 cm−1 in the same sample. The present work will hopefully further contribute to more accurately identifying the low-temperature heat treatment of pink sapphires from Ilakaka, Madagascar. [ABSTRACT FROM AUTHOR]

The recently discovered 460 Gaodi porphyry Mo-Cu deposit is a sub-economic deposit characterized by low Mo-Cu grades, dispersed mineralization, and separated Mo- and Cu-ore bodies. This study aims to elucidate the factors underlying this type of sub-economic mineralization. Electron-microprobe analyses of biotite from ore-related granite porphyry yielded Ti-in-biotite crystallization temperatures of 677–734 °C (an average of 719 °C) and biotite phenocryst crystallization depths of 6.0 to 12.9 km. LA-ICP-MS analyses of zircons from the same sample revealed average zircon Ce4+/Ce3+ ratios of 299.7 and elevated zircon lg(ƒO2) ratios, with an average ΔFMQ of +6.6 ± 1.9. These discoveries suggest that the magma responsible for ore formation boasts a high degree of oxidation, yet also possesses a magma chamber located at a significant depth within the upper crust. This implies an extensive exsolving depth for fluids. Furthermore, our microthermometry analysis of fluid inclusions reveals that a portion of the fluid experiences considerable conductive cooling as it ascends along the conduit, owing to the depth of fluid exsolution. This process results in the ore fluids remaining in the liquid-only region without undergoing boiling, which is conducive to the enrichment of metals. We emphasize the fact that fluid-exsolving depth plays a critical role in determining the metal grades and economic value of a porphyry deposit by regulating the P-T evolution path of the ore fluids [ABSTRACT FROM AUTHOR]

Late Cretaceous granitoids are developed in the eastern and western districts of the Gejiu ore district, but tin deposits mainly occur in the eastern district, and the reasons for the difference in mineralization between the eastern and western districts are still controversial. Considering the main factors controlling granite Sn fertility, the whole-rock geochemical characteristics of granites on both sides are compared. LA-ICP-MS zircon U-Pb analyses of the Gejiu granites yielded two age periods: the early phase from 79.2 to 83.3 Ma and the later phase from 73.8 to 75.6 Ma. The western district granites have higher zircon εHf(t), CaO/Na2O, Ba, and Sr concentrations and lower Rb/Sr ratios than the eastern district granites, indicating that the western district granites have more mantle-derived materials in the source than the eastern district granites. Results of oxygen fugacity show that the western granites have a higher oxygen fugacity condition. More depleted Ba, Sr, P, Eu and Ti characteristics with obviously negative Eu anomalies in the eastern granites also have high Rb/Sr ratios and low Nb/Ta and Zr/Hf ratios, indicating that the eastern granites experienced highly magmatic differentiation, attributed to high volatile F contents that can reduce the viscosity and solidus of magma. Combined with the differences in field observations and structural styles, on the whole, the western district granites have higher oxygen fugacities and lower F contents and magmatic differentiation than those in the eastern district granites, indicating that the western district granites are not conducive to mineralization. [ABSTRACT FROM AUTHOR]

Fluvial sediments are the product of erosion, weathering, and transport of bedrock within a well-defined catchment area, and their constituent grains may therefore record valuable information about the lithological and geochemical properties of geologic units within the upstream drainage. Analysis of U-Pb ages and Lu/Hf isotopic values in detrital zircon grains from major rivers in the eastern United States characterizes these parameters within broad areas of the Appalachian orogen. In this study, five modern fluvial sediment samples, collected across ∼1500 km and representing 216,000 km2 of total catchment area, reveal that the relative proportions of Mesoproterozoic to Paleozoic U-Pb crystallization ages vary widely across the former Laurentian margin. However, εHf t values in the same samples are largely consistent regardless of their geographic location. Mesoproterozoic (Grenville orogen) zircons display a more limited range of εHf t values (approximately 0 to +10 εHf t units) compared with the more negative, more variable values (−15 to +10) found in grains from the Paleozoic orogenies. Compared with other published modern detrital samples from the Gulf Coastal Plain, Appalachian samples show more similarity to each other and to the Pleistocene of Florida than to those from the Mississippi River mouth, likely because the latter also sources sediments from the Cordillera of western North America. More negative εHf t values in Paleozoic zircons may be genetically related to older Mesoproterozoic grains, as they are compatible with the continued isotopic evolution of Lu/Hf derived from the mantle between 1.2 and 2.0 Ga. Hafnium geochemistry in detrital grains may therefore have some utility in discerning sediment provenance between the Appalachians and other regions and may also provide useful information regarding the nature of crustal generation through time. [ABSTRACT FROM AUTHOR]

The Bacajá domain, southeastern Amazonian craton, comprises Mesoarchaean and Siderian terrains reworked during the Transamazonian cycle. Combined analyses of zircon LA-ICP-MS U-Pb and Lu-Hf with whole-rock Sm-Nd from the northeast portion of this domain made it possible to propose an evolutionary sequence between ca. 2.60 and 2.06 Ga. Gneisses with an igneous protolith age of 2630±15 Ma show negative signatures (εHf(t) = -0.3 to -1.7 and εNd(t) = -3.08 to -2.98) and a Mesoarchaean formation (Hf-TDMC and Nd-TDM model ages range from 3.0 to 3.2 Ga). Rhyacian granite genesis lasted about 40 million years (2.10-2.06 Ga) and was divided into two magmatic periods. The first is represented by deformed granitoids with zircons yielding crystallization ages between 2.10 and 2.09 Ga and model ages (Hf-Nd) at about 2.5 Ga. The second event is represented by granitoids with preserved magmatic texture, crystallization ages of 2.06 Ga, and Siderian model ages (Hf-Nd) of around 2.3 Ga. The overall Hf isotopic analyses of this Rhyacian granite genesis exhibit a spread of εHf(t) values between 1.8 and -2.9, which show a probably underestimated mantle-derived contribution in this period. [ABSTRACT FROM AUTHOR]

In recent decades, blue and fancy-colour sapphires have been gathered from secondary deposits derived from Tertiary basalts in the Muling area of north-eastern China. In this article, zircon inclusions in the blue sapphires were studied to characterise their morphology and structure, as well as to obtain the age of the host sapphires. The zircon inclusions in the studied samples were euhedral and transparent, and their dominant morphology was similar to that of typical zircon inclusions in sapphires associated with alkali basalts. Raman spectroscopy of the zircons showed only slight radiation damage, and cathodoluminescence images revealed two distinctive zoning patterns (in their cores and rims). LA-ICP-MS analyses of the zircon rims showed typical magmatic Th/U ratios. In situ U-Pb dating of the zircon rims yielded ages of 9 to 8 Ma--which is the inferred upper limit of the formation age of the host sapphires--while cores had much older ages that exceeded 110 Ma (i.e. an inherited age component). The 9-8 Ma sapphire age coincides with Late Miocene basaltic eruptions in the Dunhua-Mishan graben. Age dating of zircon inclusions in the Muling sapphires helps elucidate their geological origin and provides useful information for the provenance determination of gem corundum. [ABSTRACT FROM AUTHOR]

Integrated U-Pb, O and Lu-Hf isotopic analyses of detrital zircons, collected from fourteen European river sands and one beach sand from northern Germany, were carried out to study the evolution of the preserved European continental crust. The drainage area of these sand samples covers large areas in eastern and western Europe, which evolved independently until their amalgamation during the Paleozoic. U-Pb ages of detrital zircons from eastern and western Europe generally match the ages of the major magmatic events in the two tectonic regions. The combined histogram of 2403 zircon U-Pb ages, obtained for this study, shows five major periods of zircon crystallisation: 2.80–2.65, 1.95–1.35, 1.25–0.85, 0.65–0.40, and 0.40–0.25 Ga, which correspond broadly with the timing of supercontinent assembly. The correlation could be due to enhanced granitoid magmatism and zircon growth during the supercontinent amalgamation, or the high preservation potential of igneous rocks generated during continental collisions. The O and Hf isotopic data of the analysed European river zircons show wide spreads in δ18O and ε Hf (t) values at ca. 1.9 Ga and 650–250 Ma, contrasting with the limited range for the Mesoproterozoic zircons. This indicates that extensive reworking of pre-existing crustal rocks occurred during the late Paleoproterozoic and Paleozoic in the evolution of the European continental crust, whereas the formation of new crust played an important role during the Mesoproterozoic. Arc mantle Hf model ages for the detrital zircons were calculated to estimate when European juvenile crust was extracted from the mantle. Model age uncertainties were estimated using the bootstrap method, considering three sources of uncertainty: (i) uncertainty in the Hf isotopic composition of the mantle reservoir, (ii) uncertainty in the 176Lu/177Hf for the crustal source region, and (iii) analytical uncertainties. Two types of model ages are calculated based on constant crustal 176Lu/177Hf (T AM C), and on variable 176Lu/177Hf (T AM V), the latter being constrained by zircon δ18O values. Histograms of the calculated T AM C and T AM V model ages both show major juvenile extraction events between the late Paleo- and Mesoproterozoic. Although the principal periods in the European crustal growth contrast with those identified in the African, Russian and Mississippi river basins, the overall growth curves for the four continents show comparable results: (i) the formation of little or no continental crust before 4.0 Ga, and (ii) the formation of 50 % of the present crustal volume by ca. 2.0–1.6 Ga. [ABSTRACT FROM AUTHOR]

The Jiamusi Block is a crucial geological unit joining multiple tectonic regimes, including the Late Palaeozoic Palaeo‐Asian Ocean and the superposition of the Early Mesozoic Palaeo‐Pacific tectonic domain. However, the duration of the Palaeo‐Pacific Plate subduction beneath the Jiamusi Block has long been controversial. In this paper, we focus on clastic rocks from the Nanshuangyashan and Yunshan formations on the east margin of the Jiamusi Block and use the modal analysis of sandstones and detrital zircon U–Pb dating to trace the subduction history of the Palaeo‐Pacific Plate. Our analysis results suggest that the two groups of samples are characterized by a high content of monocrystalline quartz and a low content of lithic and feldspar, indicating that the sedimentary provenances were stable continental blocks and magmatic arcs. The detrital zircon ages of the Nanshuangyashan Formation have a major peak at ca. 245 Ma and two secondary peaks at ca. 470 and 228 Ma, respectively. The Yunshan Formation has a major peak at ca. 494 Ma and a secondary peak at ca. 265 Ma. The provenances of the Nanshuangyashan Formation were attributed to the Jiamusi Block, Khanka Block, and a Late Triassic magmatic arc. Similarly, the provenances of the Yunshan Formation were attributed to the Jiamusi and Khanka blocks. Detrital zircon analysis results show that the eastern margin of the Jiamusi Block was in the same back‐arc basin settings in the Late Triassic and the Late Jurassic. Thus, we propose that the eastern margin of the Jiamusi Block had been affected by the Palaeo‐Pacific Plate subduction in the Late Triassic and had continued to the Late Jurassic. [ABSTRACT FROM AUTHOR]

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 Jabal Hadb Ad Dayheen granitic complex in central Saudi Arabia is an alkaline granitic ring complex associated with a collapsed caldera. It mainly consists of monzogranite in the center, biotite-hornblende porphyritic granite, and biotite-aegirine-riebeckite granite, intruded by some felsic and mafic dikes. The petrological and geochemical characteristics show that the granitic suites consist of metalminous-peralkaline A-type granites. The secondary ion mass spectrometry (SIMS) zircon U-Pb analysis yielded 206Pb/238U ages of 613.3 ± 8.1–603.8 ± 3.8, 602.4 ± 3.8, 596 ± 5.6 Ma for biotitehornblende porphyritic granite, microgranite, and biotite-aegirine-riebeckite granite, respectively. The trace element characteristics and positive εHf(t) values (3.2–12.2) indicate that the granitic rocks of the Dayheen Ring Complex are mainly derived from the juvenile crust with the involvement of mantle-derived materials. Combined with the regional tectonic evolution, the formation of the Dayheen Ring Complex mainly covered four periods: (1) subduction initiation and formation of arc terranes (870–620 Ma)—volcanic craters formed during this period provided the channel for alkaline complex intrusion; (2) collision between East and West Gondwana continents and formation of the north East African Orogen (640−613 Ma)—monzogranite stock at the center of the ring complex emplaced during this period; (3) post-collision extension and collapse (613−602 Ma)—red metaluminous biotite-hornblende porphyritic granite and microgranite sheets in the rim of the Dayheen Ring Complex emplaced during this period; (4) within-plate extension (602 − 545 Ma)—white peralkaline biotite-aegirine-riebeckite granite and plenty of felsic and mafic dikes in the rim mainly formed during this period. The granitic rocks of the Dayheen Ring Complex mainly formed during the transitional stage of post-collison to within-plate extension after the collision between East and West Gondwana continents, and part of them formed during the early stage of the within-plate extension. U, Th, Zr, Nb, and rare earth element mineralization mainly formed during the early stage of the last period, having a close relationship with the intrusion of white peralkaline biotite-aegirine-riebeckite granite. [ABSTRACT FROM AUTHOR]

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The Early Cretaceous Yellow Cat Member of the terrestrial Cedar Mountain Formation in Utah, USA. has been interpreted as a "time-rich" unit because of its dinosaur fossils, prominent paleosols, and the results of preliminary chemostratigraphic and geochronologic studies. Herein, we refine prior interpretations with: (1) a new composite C-isotope chemostratigraphic profile from the well-known Utahraptor Ridge dinosaur site, which exhibits δ13C features tentatively interpreted as the Valanginian double-peak carbon isotope excursion (the so-called "Weissert Event") and some unnamed Berriasian features; and (2) a new cryptotephra zircon eruption age of 135.10 ± 0.30/0.31/0.34 Ma (2σ) derived from the CA-ID-TIMS U-Pb analyses of zircons from a paleosol cryptotephra. Our interpretations of δ13C features on our chemostratigraphic profile, in the context of our new radiometric age, are compatible with at least one prior age model for the "Weissert Event" and the most recent revision of the Cretaceous time scale. Our results also support the interpretation that the Yellow Cat Member records a significant part of Early Cretaceous time. [ABSTRACT FROM AUTHOR]

The Jinzhuping and Changkeng granites are related to the Helong W–Sn ore field in southern Jiangxi Province, China. Three different phases can be found in the Jinzhuping pluton, and their LA-ICP-MS zircon U–Pb ages are 155.2 ± 0.68 Ma, 154.0 ± 0.56 Ma, and 153.4 ± 0.99 Ma, respectively, indicating two types of granitic rocks. All granites in the Helong ore field have similar geochemical characteristics, they have high contents of SiO2 (73.99 wt.%–77.68 wt.%), and total alkali (7.56 wt.%–8.76 wt.%) and are weakly to strongly peraluminous. They are slightly enriched in HREE and depleted in Eu, Ba, Sr, P, and Ti. Zircon εHf(t) values of the Jinzhuping three granites are from −14.4 to −10.4, from −15.3 to −11.4, and from −18.1 to −10.5, and the Hf TDM model ages range from 1.83 to 2.06 Ga, from 1.89 to 2.14 Ga, and from 1.83 to 2.31 Ga, respectively. Whole-rock geochemistry and Hf isotope analysis indicate that the Helong granites experienced a high degree of differentiation and evolution derived by partial melting of the Late Paleoproterozoic crustal materials, and they formed in a backarc caused by low-angle subduction of the Paleopacific plate. [ABSTRACT FROM AUTHOR]

Reconstructing the tectonic architecture of the southern Altaids is of great importance to piece together the continental growth history of the Central Asian continent. In this paper, we address the subduction‐accretion process of the Paleo‐Tianshan Ocean, one branch of the South Tianshan Ocean, in the southern Altaids, through a detailed geological and geochemical investigation of the Wulanmoren Accretionary Complex (WAC). The WAC is composed of ophiolitic mélanges, ocean plate stratigraphy mélanges, and turbiditic coherent units. In this study, we present key geological, petrological, and geochemical evidence indicating back‐arc and ocean island affinity of the igneous rocks of the WAC. Zircon U‐Pb dates of these rocks ages range between 380.2 ± 1.3 and 302.0 ± 5.3 Ma. The sedimentary matrix units of the mélanges were deposited in the Early Devonian (∼405 Ma) to the Late Triassic (∼222 Ma), rather than Silurian strata as previously thought. However, the ages of some detrital zircons in the sedimentary matrix are Precambrian, pointing to a complex evolution involving multiple ocean island terrains and island arcs of different ages that accreted from the mid‐Paleozoic to the Early Mesozoic. Plain Language Summary: Well‐exposed rock outcrops of the Wulanmoren Accretionary Complex (WAC) offer an ideal opportunity to solve the enigma of the evolutionary history of the Paleo‐Tianshan Ocean (PTO) of Central Asia. We report field observations, geochemistry, and geochronology of the WAC in the southern Altaids, pointing to multiple tectonic settings of ages spanning from the Early Devonian (∼405 Ma) to the Late Triassic (∼222 Ma). These reconstructions suggest closure time of the PTO occurred post‐Triassic. Based on detrital zircons provenance analysis, we propose a multi‐island ocean model to explain the tectonic evolution of the PTO in the time period studied. Key Points: The Wulanmoren Accretionary Complex was composed of ophiolitic mélanges, ocean plate stratigraphy mélanges, and coherent unitsThe Late Paleozoic MORB‐like and OIB‐type basalts, and ∼222 Ma coherent units indicate closure of the Paleo‐Tianshan Ocean occurred post‐TriassicThe southern Paleo‐Asian Ocean was an archipelago with several subduction systems which is similar to the modern southwest Pacific [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]

Estimations of the reproducibility of U–Pb ages from SHRIMP (Sensitive High-Resolution Ion MicroProbe) instruments are based on data from studies that are nearly 2 decades old. Since that time, refinement of analytical procedures and operational improvements have reduced the historically identified uncertainties of SHRIMP U–Pb analysis. This paper investigates 36 SHRIMP thermal ionisation mass spectrometry (TIMS) double-dated "real-world" geologic samples from a variety of igneous rock types to better understand both geological and analytical sources of disagreement between the two dating methods. Geoscience Australia's (GA) use of high-precision chemical abrasion thermal ionisation mass spectrometry (CA-TIMS) for chronostratigraphy in Australian sedimentary basins has produced a substantial selection of precisely dated zircons, which we can use to cross-correlate the SHRIMP and CA-TIMS ages throughout the Phanerozoic. A total of 33 of the 36 ages were reported with external SHRIMP uncertainties less than 1 % (95 % confidence). Six of eight cases where the CA-TIMS age was outside the SHRIMP uncertainty envelope were in samples where the 95 % confidence interval of the reported SHRIMP age was below 0.66 % uncertainty, suggesting that SHRIMP analyses of untreated zircon with smaller uncertainties are probably overoptimistic. The mean age offset between SHRIMP and TIMS ages is 0.095 %, but the distribution appears bimodal. Geological explanations for age discrepancies between SHRIMP and CA-TIMS are suggested by considering intrusive and extrusive age results separately. All but one sample where the SHRIMP age is more than 0.25 % older are volcanic. This offset could be explained by the better single-grain age resolution of TIMS, allowing identification and exclusion of antecrysts from the eruptive population, while SHRIMP does not have a sufficient single-grain precision to deconvolve these populations – leading to an apparent older SHRIMP age. In contrast, SHRIMP ages from plutonic rocks – particularly plutonic rocks from the early Paleozoic – are typically younger than the CA-TIMS ages from the same samples, most likely reflecting Pb loss from non-chemically abraded SHRIMP zircons, while chemical abrasion of zircons prior to TIMS analysis destroyed or corrected these areas of Pb loss. [ABSTRACT FROM AUTHOR]

Significant changes in tectonic style and climate occurred from the late Archaean to early Proterozoic when continental growth and emergence provided opportunities for photosynthetic life to proliferate by the initiation of the Great Oxidation Event (GOE). In this study, we report a Neoarchaean passive-margin-type sequence (2560–2500 million years ago) from the Precambrian basement of China that formed in an accretionary orogen. Tectonostratigraphic and detrital zircon analysis reveal that thermal subsidence on the backside of a recently amalgamated oceanic archipelago created a quiet, shallow water environment, marked by deposition of carbonates, shales, and shallow water sediments, likely hosts to early photosynthetic microbes. Distinct from the traditional understanding of passive margins generated by continental rifting, post-collisional subsidence of archipelago margins represents a novel stable niche, signalling initial continental maturity and foreshadowing great changes at the Archaean-Proterozoic boundary. This research reports a 2.5-billion year-old passive margin formed in accreting archipelagos, highlighting the contribution of early continent formation and the relationship between continental stabilization and early atmospheric oxygen rise. [ABSTRACT FROM AUTHOR]

Location of the southwestern suture zone between Yangtze and Cathaysia blocks remains a controversial issue in South China tectonic research. This paper presents new LA-ICP-MS U–Pb geochronological and Hf isotopic data of detrital zircons obtained from the Nanhua System in Yingyangguan region of northeastern Guangxi and discusses their provenance and sedimentary tectonic setting of the Nanhua System. By comparison with the recently published detrital zircon geochronological and Hf isotopic data of the coeval Nanhua System in Longsheng region of northern Guangxi along the southeastern margin of the Yangtze Block and of the Neoproterozoic strata in Cathaysia block, this study attempts to constrain the southwestern suture zone or the boundary between Yangtze and Cathaysia blocks. The Nanhua System in Yingyangguan region includes Tianzidi and Zhengyuanling formations. The U–Pb ages of 107 grains from Tianzidi Formation are peaked at 0.65–0.72 Ga, 0.72–0.80 Ga, 0.90–1.30 Ga, 1.40–2.25 Ga, and 2.35–2.94 Ga. The U–Pb ages of 106 grains from the Zhengyuanling Formation are peaked at 0.65–0.72 Ga, 0.72–0.90 Ga, 0.90–1.30 Ga, 1.40–2.10 Ga, and 2.40–2.92 Ga. Most of the U–Pb ages of detrital zircon grains cluster at 0.90–1.30 Ga, demonstrating a remarkable difference from the coeval Nanhua System in Longsheng region, and suggesting the Cathaysia Block as a major source of sediments for the Nanhua System in the Yingyangguan region. The εHf(t) values of the detrital zircon grains from the Nanhua System of the Yingyangguan region are mostly positive (0–10); they are different from those of the Longsheng region of northern Guangxi where they are mainly negative (− 10 to − 2), but similar to the Cathaysia Block (− 3 to 5). Based on the new detrital zircon U–Pb ages and Hf isotopic data, it is suggested that the southwestern suture zone or the boundary between Cathaysia and Yangtze blocks is located in the area between Yingyangguan and Longsheng area of Guangxi. [ABSTRACT FROM AUTHOR]

The middle Cretaceous Blackleaf Formation records the first major transgression-regression of the Western Interior Seaway into the southwestern Montana retroforeland basin. Although Blackleaf sedimentology is well documented, sediment provenance and potential linkages with regional tectonics are not. Recent characterization of hinterland tectonics, fold-thrust belt detrital zircon signatures, and advances in high-n detrital zircon analysis allow for significant provenance refinement. We present new detrital zircon ages (n = 5468) from ten samples from the upper Blackleaf Formation (Intervals C and D) in southwestern Montana. Based on maximum depositional ages, sedimentation spanned from 106 to 92 Ma. Jurassic and Cretaceous grains were primarily derived from the older portion of the Cordilleran magmatic arc in western Idaho. Triassic and older grains were recycled from older central Idaho sedimentary strata inboard of the arc. Three depositional stages are identified based on statistical modeling of detrital age distributions. Stage 1 (106–104 Ma) records sourcing from lower Paleozoic strata in central Idaho. Stage 2 (105–101 Ma) records initial unroofing of upper Paleozoic–Triassic strata via propagation of the fold-thrust belt into eastern Idaho, accommodating shortening of Mississippian and younger rocks above the Lemhi Arch. Stage 3 (102–100 Ma) records continued unroofing in central Idaho down to Cambrian stratigraphic levels and distal mixing of sources in the eastern part of the basin. Exhumation in the fold-thrust belt beginning at ca. 105 Ma is coincident with margin-wide fault slip-rate increases. We infer that increased sedimentation rates and low-magnitude flexural loading from shallow thrusting in eastern Idaho drove clastic wedge progradation across the basin. [ABSTRACT FROM AUTHOR]

The Cenozoic development of the Scotia Sea and opening of Drake Passage evolved in a complex tectonic setting with sea‐floor spreading accompanied by the dispersal of continental fragments and the creation of rifted oceanic basins. The post‐Eocene tectonic setting of the Scotia Sea is relatively well established, but Late Mesozoic palaeo‐locations of many continental fragments prior to dispersal are largely unknown, with almost no geological control on the submerged banks. Detrital zircon analysis of dredged metasedimentary rocks of Bruce Bank from the South Scotia Ridge demonstrates a geological continuity with the South Orkney microcontinent (SOM) and also a clear geological affinity with the Trinity Peninsula Group metasedimentary rocks of the Antarctic Peninsula and components of the Cordillera Darwin Metamorphic Complex of Tierra del Fuego. Kinematic modelling indicates an Antarctic Plate origin for Bruce Bank and the SOM is the most plausible setting, prior to translation to the Scotia Plate during Scotia Sea opening. [ABSTRACT FROM AUTHOR]

The chemical compositions of zircons have been used as magma fertility indicators for porphyry copper mineralization potential. Here, we trained and tested two machine learning (ML) models: support vector machines and random forest to classify the metallogenic fertility (fertile vs. unfertile) based on igneous zircon chemistry. Both models achieved good classification accuracy (~ 93%) against the testing dataset, suggesting the feasibility and effectiveness of using the ML methods to discriminate whether zircons are from fertile or unfertile magmas. The feature importance analysis of the RF classifiers identified that the most important parameters of fertile magma are Eu, Ce, and Dy, further validating previous studies of the genesis of porphyry copper deposit-related magma. As a case study, we predicted the metallogenic fertility of the detrital zircons in the eastern Gangdese belt in southern Tibet by applying the ML models trained by igneous zircon labeled data. Our ML models suggest that the magmas that formed after 50 Ma, especially from 30 to 10 Ma, have higher fertile percentages. Taking this together with the local singularity analysis of detrital zircon U–Pb ages, we suggest that magmatic flare-ups with high FP and singularity index values are more favorable for porphyry copper formation. Our ML models and defined FP may help reveal temporal variation of the favorability for porphyry copper formation. [ABSTRACT FROM AUTHOR]

Trace elements in magmatic zircon exhibit characteristic trends during magma compositional evolution. Zircon geochemistry presents the advantage over whole rock geochemistry of showing progressive 'snapshots' of accompanying melt chemistry during magma crystallization, and in situ methods such as LA-ICPMS and SIMS can provide multiple analyses in zoned zircons for higher resolution of magmatic processes. However, one limitation is that zircon is typically a late-crystallizing phase, leaving much of the magmatic history unrecorded. Using the CAMECA ims1290 ion microprobe with Hyperion-II ion source, we explore whether micro-zircon (ca. 5–40 µm) captured by relatively early-crystallizing magmatic accessory minerals can meaningfully enhance the interpretations of zircon trace element records of magmatic evolution in two granites from Southern California: the La Posta 2-mica granite and the granite of Butler Peak (Big Bear Lake Intrusive Suite). We find that contamination of the inclusion measurement by major structural constituents of the host phase is a problem for most measurements, but that species which are not structural components of the host phases follow typical magmatic zircon trace element evolution trends. Compared to free grains from a mineral separate, zircon inclusions in ilmenite and apatite from the La Posta 2-mica granite are on average lower in Hf, recording plausible extensions of these magmatic evolution trends to earlier periods in magma evolution. Free zircons from the granite of Butler Peak's mineral separate form a more complex story, recording both mixing between Cretaceous magmas derived from different depths (based on their U/Yb and Eu/Eu* behavior) and inheritance of older Mesozoic to Proterozoic zircon. Most zircon inclusions in Butler Peak magnetite and ilmenite are chemically like the apparently shallow magma-derived Cretaceous zircons in the free matrix, while a small proportion of the included zircon resemble more closely the apparently deeper magma or the inherited grains. [ABSTRACT FROM AUTHOR]

Two episodes of late Neoarchean-early Paleoproterozoic and late Paleoproterozoic garnet-bearing leucogranite, named the Baotou and Jining–Liangcheng garnet-bearing leucogranite are recognized from the Khondalite Belt in the North China Craton. Geochemical studies show that garnet-bearing leucogranite has high Al2O3 content and FeOT/MgO ratio, with a large variation in the CaO content and K2O/Na2O ratio. Additionally, the garnet-bearing leucogranite is enriched in light rare earth elements and large ion lithophile elements and depleted in Nb, Ta, P, and Ti. However, there are some variations in Eu anomalies, as indicated by the Eu-enriched and Eu-depleted patterns. The sensitive high-resolution ion microprobe (SHRIMP) zircon U-Pb dating of the Baotou garnet-bearing leucogranite and Jining–Liangcheng garnet-bearing leucogranite show that their anatectic ages were 2.35–2.43 Ga and 1.90–1.92 Ga, respectively, with zircon εHf (t) values of −0.01–3.93 and −4.36–1.99, and two-stage model ages (TDM2) of 2.76–3.02 Ga and 2.57–2.83 Ga, respectively. U-Th-Pb SHRIMP analyses on zircon reveal ages of ca. 2.35–2.47 Ga for the Baotou metapelite gneiss and ca. 1.90–1.91 Ga for the Jining–Liangcheng metapelite gneiss, which represent the ages of tectonic metamorphic events related to the anatexis. Our results, combined with geological and petrographical observations, geochemistry, and geochronology, suggest that (1) Garnet-bearing leucogranites formed as a result of anatexis of metapelite gneisses; (2) They are mixtures of leucosomes, residual minerals and mantle-derived materials; (3) Two episodes of garnet-bearing leucogranites have been identified; (4) Both two episodes of garnet-bearing leucogranites corresponded to late Neoarchean-early Paleoproterozoic and late Palaeoproterozoic tectonothermal events, respectively. [ABSTRACT FROM AUTHOR]

The Baishi W-Cu deposit is located in the Nanling metallogenic belt, which is famous for its numerous W deposits and reserves. The formation age of this deposit remains unclear. In order to further infer the formation age of the deposit, this study conducted detailed LA-ICP-MS U-Pb isotopic analyses of zircon and monazite selected from ore-related Baishi granite. The LA-ICP-MS zircon U-Pb weighted average ages of Baishi granite were determined to be 223 ± 2 Ma and 226 ± 1 Ma, and the LA-ICP-MS U-Pb weighted average ages of monazite were determined to be 224 ± 2 Ma and 223 ± 1 Ma. The BSE image of monazite was homogeneous, and the pattern of rare earth elements had an obvious negative Eu anomaly, indicating that monazite was of magmatic origin. Combining the ages of zircon and monazite, this study inferred that Baishi granite and the Baishi W-Cu deposit formed in the Triassic. The determination of the ore-forming event of the Baishi W-Cu deposit provides new data regarding the important Indosinian (Triassic) mineralization events in the Nanling metallogenic belt and suggests that geologists should strengthen the prospecting work of Indosinian tungsten deposits in the Nanling area. In terms of tectonic setting, it was inferred that the Triassic Baishi W-Cu deposit was formed in the extensional environment after intracontinental orogeny. [ABSTRACT FROM AUTHOR]

The Saar–Nahe Basin is one of the largest intra-continental basins of the European Variscides. It is filled with up to 6500 m thick volcano-sedimentary rocks representing up to 40 million years of late- and post-orogenic basin evolution from the early Pennsylvanian to the late Early Permian. Radioisotopic dating of magmatites as well as intra- and extra-basinal pyroclastic rocks from the study area was carried out mainly during the end of the last century. Here, we present the first high-precision U–Pb CA-ID-TIMS age of 298.7 ± 0.4 Ma for a hitherto undated ash tuff layer of the Altenglan Formation near the middle part of the Pennsylvanian-Permian succession of the Saar–Nahe Basin. Comparative analyses of zircons from the same tuff layer and a closely associated tuff by U–Pb LA-ICP-MS yielded an age of 299.5 ± 2.6 Ma supporting the CA-ID-TIMS result. Based on the new data, the Pennsylvanian-Permian boundary in the study area is close to or even within the Altenglan Formation and overlying Rotliegend formations have to be considered of clearly Permian in age. A recently discovered and globally important fossil tetrapod lagerstaette of the Remigiusberg Formation lying immediately below the Altenglan Formation at the base of the Saar–Nahe Rotliegend is suggested to be of earliest Asselian minimum age. [ABSTRACT FROM AUTHOR]

The Cenozoic geological hallmark of Western Yunnan is the characteristic voluminous Late Cretaceous‐Eocene granites; however, their geological background and petrogenesis have not been well constrained and elucidated. In this study, we present new zircon U‐Pb dating, along with geochemical and Sr‐Nd‐Hf isotopic data for granites from the Tengchong–Lianghe granitoid belt (as abbreviated to Tengliang belt) and West Yingjiang batholiths from the Tengchong block. The mineralogical and geochemical features of the Tengliang granites and the West Yingjiang batholiths are ascribed to aluminous S‐type granites and weak peraluminous I‐type, respectively. Zircon U‐Pb analyses yielded consistent ages ranging from 67.5 Ma, 68.4 Ma and 66.2 Ma from the Tengliang granitoid belt and 50.4 Ma to 60.8 Ma for three samples from the west Yingjiang batholiths. The Tengliang granites were emplaced during the Late Cretaceous (68–66 Ma) and demonstrate negative εHf(t) values (–24 to –4) and initial 87Sr/86Sr ratios of 0.7101–0.7139 and significant negative εNd(t) values from –8.91 to –13.2, indicating a Proterozoic sedimentary source or enriched components. The hornblende‐bearing I‐type granites from West Yingjiang are characterized by lower initial 87Sr/86Sr ratios of 0.7076–0.7106, compared to Tengliang granite and negative whole‐rock εNd(t) values from –4.0 to –11.9. The early Eocene west Yingjiang gneissic granites show wide ranges of εHf(t) values from +7.4 to –8.5 and T2DM of 1.30–0.65 Ga, indicating partial melting of ancient crust with contributions of depleted mantle materials. In combination with the regional background and previous studies, we propose that such a spatio‐temporal distribution of the Tengchong granitoid belt might be related to the rollback or angle‐switching of the Neo‐Tethyan subducting slab. This study sheds new light on the evolutionary history of the Tengchong block. [ABSTRACT FROM AUTHOR]

Zircon-melt partitioning of Ce is sensitive to the redox conditions of magmas as zircon crystallizes, because Ce4+ is far more compatible than Ce3+ in zircon. This makes Ce in zircon an effective tool to constrain magma oxygen fugacity (f O 2). However, trivalent light rare earth element (LREE) concentrations in zircon analyses are easily inflated by inclusions and alteration, which makes estimation of the concentration of Ce3+ within the zircon structure very difficult. We propose new treatments of measured Ce concentrations in zircon and of zircon/melt Ce partitioning to improve estimates of Ce4+ and Ce3+ in zircon and the melt from which it grew. To minimize the LREE contamination effect that plagues zircon analysis, we propose a revised method to quantify Ce3+ and Ce4+ in zircon that extrapolates using a logarithmic function of ionic radius of the middle to heavy rare earth elements. We then present improved Ti-dependent zircon/melt partition coefficients for both Ce3+ and Ce4+ based on the lattice strain model to estimate Ce3+ and Ce4+ in the coexisting melt. Derived estimates of Ce4+ in both zircon and melt are robust; estimates of Ce3+ are less so. We then calculate Ce4+/Ce3+ of the melt using both Ce3+ melt obtained from our new partition coefficients and typical Ce total concentrations in melts based on the relatively narrow global measured range. The f O 2 values calculated using these estimated Ce4+/Ce3+ ratios and the model of Smythe and Brenan (2016) for analyzed zircons from a range of tectonic settings fall within plausible ranges. We suggest that our new approaches, particularly with respect to estimating Ce4+ concentrations, may be broadly useful for constraining magma oxidation state, especially for studies of detrital zircon whose provenance is unknown. • An alternative method of determining Ce3+ and Ce4+ in zircon and melt. • Improved zircon/melt partition coefficients for Ce3+ and Ce4+. • Contaminated zircon analyses can be screened out by La concentrations. • Modeled melt Ce4+/Ce3+ is capable of constraining magma oxidation states. [ABSTRACT FROM AUTHOR]

The Neoproterozoic Panium Sandstone Formation of the Kurnool Group (India) offers a unique scope for understanding regressive depositional history in a Neoproterozoic clastic shoreline. It is divided into two 'Systems Tracts' namely forced regression and lowstand. Process-based facies and paleo-environmental analysis identified twelve different facies types; grouped under four facies associations (FA I–IV) belonging to both continental and shallow-marine domains viz. distal braided fluvial, swash bar-foreshore runnel, upper shoreface bar-trough, and lower shoreface bar-interbar. Whereas the fluvial deposit (FA I), sharply and erosionally overlying the argillaceous shelf succession of the Owk shelf shale, represents the product of forced regression, the wave-dominated shallow marine deposits (FA II, III and IV) record the depositional history of lowstand in the coastline. A basin ward transition from unconformity (base of FA I) to correlative conformity (base of shallow marine deposits FA II, III, and IV) is documented. The shoreline had a north-northwest to south-southeast alignment and the north-eastward flowing fluvial system met the shoreline at a high angle. Detrital zircon geochronology from the Panium fluvial sandstone allowed documentation of Paleoproterozoic (~2050 Ma–1800 Ma) and Mesoproterozoic (~1500 Ma to ~1200 Ma) age clusters, in addition to earlier documented age clusters from the Banganapalle alluvial sandstone present at the basal part of Kurnool succession. The new age data suggest an addition of new provenances and in turn, tectonic intervention behind the regression in the Kurnool coastline that triggered Panium deposition. Further, the Paleoproterozoic age cluster, obtained from the Panium fluvial deposit, helped in the justification of solitary zircon grain occurrences within the Owk Shale, as described in earlier studies. [Display omitted] • Neoproterozoic Panium sandstone bears a regressive depositional history. • Panium sandstone was deposited during forced regression and lowstand system tracts. • U Pb age data suggest the addition of new provenance in course of Panium deposition. • The provenance was shifted from NNW to SSW during Panium deposition. • Tectonic perturbances reversed local basin slope and introduced addition of new provenance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Subduction slab break-off occurred at ∼835 Ma in the southwestern JNO. • Final assembly of the Yangtze and Cathaysia blocks is before ∼810 Ma. • Southwestern JNO occupied a deep-water area of the Nanhua Rift Basin. • The SCB was located at the periphery of Rodinia in the Neoproterozoic. The Neoproterozoic Jiangnan Orogen (JNO) marks the consolidation of the South China Block, sparking ongoing debates on its early to mid-Neoproterozoic tectonic evolution. In this study, we have gathered detrital zircon data from the southwestern JNO, presenting new detrital zircon U-Pb ages alongside trace element data from the mid-Neoproterozoic Banxi Group and Sinian System within this region. Our objective is to illuminate the early to mid-Neoproterozoic tectonic evolution within the southwestern JNO through a comprehensive detrital zircon analysis. The obtained dating results derived from detrital zircons reveal maximum depositional ages of ∼733 Ma and ∼713 Ma for Mobin Formation (Banxi Group) and Jiangkou Formation (Sinian System) sedimentary rocks, suggesting a proximal source, possibly originating from magmatic rocks within the southwestern JNO. Within the paleo-geographic context, it is plausible that these samples were deposited within the deep-water expanse of the Nanhua Rift Basin. Trace element analysis of detrital zircons within the southwestern JNO highlights distinctive fluctuations, delineating three crucial time points (∼885 Ma, ∼835 Ma, and ∼810 Ma): the beginning of early Neoproterozoic subduction of the South China Ocean towards the Yangtze Block beneath the southwestern JNO, the subduction slab rollback, and the Nanhua rifting initiation. The discernible shifts in detrital zircon age distributions within these sedimentary rocks serve as robust validation for the proposed model and crustal reworking. We then propose that the southwestern JNO was in a lull of magmatism before ∼885 Ma, then transitioned to a convergent setting around 885–835 Ma, subsequently subduction slab rollback after ∼835 Ma. The time of final assembly of the Yangtze and Cathaysia blocks in the southwestern JNO is no later than ∼810 Ma. This transformative period (∼810–720 Ma) witnessed the development of a rift basin concurrently with the accumulation of deep-water deposits within the southwestern JNO. [ABSTRACT FROM AUTHOR]

• The alkaline pluton of Balda, located at the boundary of the geological domains of Northwestern Cameroon and Mayo-Kébbi, underwent tectonic deformation subsequent to its emplacement. • The pluton was emplaced at 732.7 ± 7.5 Ma in a syn -orogenic extensional context of a back-arc basin. • The deformation is related to the continental collision of the NW Cameroon and Mayo-Kébbi domains and resulted from a sinistral simple shear-dominated transpressive tectonic regime, dated to around 680 Ma. Located on the border between the NW Cameroon and Mayo-Kebbi domains in northern Cameroon, the Balda pluton is a deformed alkaline granite. Due to its unique location and geological features, it holds crucial information for understanding the evolution of the Central African Orogenic Belt (CAOB), which remains poorly understood. This multidisciplinary study combines field data, microscopic observations, Anisotropy of Magnetic Susceptibility (AMS), and U-Pb zircon dating to constrain the geodynamic evolution of the CAOB. The Balda pluton is a NNE-SSW elongated pluton consists mainly of aegirine-riebeckite granite and leucogranite. It displays diverse magnetic susceptibility values (Km) spanning from 0.19 x 10-3 to 21.98 x 10-3. Notably, 93 % of the Km values exceed 5 × 10-4SI, indicating a prevalence of mixed paramagnetic and ferromagnetic mineralogy (such as magnetite-rich). This observation is supported by microscopic examinations and K-T curves. An analysis of AMS unveils high P% values (2.8 to 58.7 %, with a mean of 15 %) and prevalent oblate magnetic fabrics (68 %). The magnetic foliation generally aligns with the field foliation and has steep dips ranging from NNE to NE or from SSW to SW and magnetic lineations exhibit shallow plunges (<35°) from SSW to SW. Microscopic analysis reveals high-temperature, solid-state deformation microstructures, indicating post-emplacement deformation processes and the presence of kinematic markers consistent with sinistral shear. Zircon grain analysis reveals two distinct types: "bright" and "dark." These types differ in both their appearance under cathodoluminescence and their chemical composition. Bright zircons yield a U-Pb age of 732.7 ± 7.5 Ma, interpreted as the pluton emplacement age. Dark zircons are younger (ca. 680 Ma), suggesting a later tectono-metamorphic or alteration event. The integration of these results in a larger geodynamic context suggests that the Balda pluton formed within a syn -orogenic extensional back-arc basin. This emplacement was followed by significant post-emplacement deformation characterized by sinistral simple shear-dominated transpression likely related to the continental collision (ca. 680 Ma) of the NW Cameroon and Mayo-Kébbi domains. [ABSTRACT FROM AUTHOR]

• Two distinct LREE-rich mineralizing events in the Central Grenville province (Quebec) • LREE-rich pegmatite derived from anatectic melting of metaigneous rocks. • Source of anatectic melts is not critical for the genesis of LREE-rich pegmatites. The source of the melt forming rare-metal granitic pegmatites in high-grade metamorphic orogenic belts is debated and is interpreted to be either (i) the product of magmatic differentiation of a large volume of granitic melt or (ii) the anatectic product of local crustal rocks. The Haut-Saint-Maurice region of the Grenville Province, Canada is of special interest to this controversy as it hosts alkaline plutonic rocks and granitic pegmatite dykes associated with significant light rare earth element (LREE) mineralization. This study focuses on the richest known LREE-bearing granitic pegmatite dyke (up to 2.7 wt% REE) of the region, named Blanchette-1. Zircon U-Pb analysis on the LREE-rich Blanchette-1 granitic pegmatite, and on nearby intrusive rock belonging to the LREE-rich Toad alkaline intrusive suite, returned ages of 1061 ± 7 Ma and 982 ± 5 Ma, respectively. The 80 Myr gap between these dates suggests no genetic link between the two LREE mineralization types. Zircon Lu-Hf and trace element analyses are integrated with micro-XRF and electron microprobe analysis of amphibole and biotite from the LREE-rich Blanchette-1 granitic pegmatite, two genetically related granitoid dykes, and from the Toad alkaline intrusive suite to investigate their potential sources and the processes controlling the LREE content of these rocks. Zircon in the three dykes record a high proportion of inheritance from ∼ 1100 Ma to ∼ 1450 Ma, a linear increase of the εHf (t) from ∼+3 to ∼+13 through time, and Hf model ages from ∼ 1300 to ∼ 1500 Ma, strongly supporting a pre-Grenvillian, crustal, metaigneous origin of the melt that formed the granitic dykes. This inferred metaigneous source for the LREE-rich pegmatites in the Haut-Saint-Maurice region contrasts with the metasedimentary source proposed for the LREE-rich pegmatite dykes located in the Lac Okaopéo region suggesting that the nature of the protolith (metaigneous vs metasedimentary) is not a critical factor for the genesis of either suite of LREE-rich pegmatite dykes. Finally, the recorded LREE, Th, and Zr enrichments in the Blanchette-1 granitic pegmatite resulted from the differentiation of the Cl- and F-rich anatectic melt during ascent through the crust and subsequent disequilibrium crystallization of allanite, zircon, and thorite crystals in discrete zones of the pegmatite dyke. [ABSTRACT FROM AUTHOR]

• Zircon ages reveal that the Helanshan shear zones developed at ca. 1904–1826 Ma. • Orogen-parallel shear zones in the Khondalite Belt occurred at ca. 1.90–1.82 Ga. • The Khondalite Belt suffered polyphase deformation (D 1 -D 3) at ca. 1.97–1.82 Ga. • The Khondalite Belt recorded a protracted (>100 Myr) orogeny in the Orosirian. The Khondalite Belt has been regarded as a Paleoproterozoic collisional orogen in the northwestern North China Craton, but the geochronological framework of polyphase deformation in the Khondalite Belt still remains unclear, particularly the timing of orogen-parallel ductile shearing. In this study, we conducted field-based structural analysis and LA-ICP-MS zircon U-Pb geochronology on the Helanshan ductile shear zones (HDSZ) in the Khondalite Belt. The results show that three pre-kinematic leucocratic dykes have been reworked by the shear zones and yielded magmatic zircon ages of 1934 ± 13 Ma, 1924 ± 5 Ma and 1920 ± 24 Ma. Two syn -kinematic leucocratic dykes appeared along the mylonitic foliations and were dated at 1887 ± 21 Ma and 1871 ± 28 Ma. A post-kinematic leucocratic dyke cut the mylonitic foliations and gave a crystallization age of 1816 ± 28 Ma. These emplacement ages of shear zone-related dykes constrain the development of the HDSZ at some time between ∼ 1920 Ma and ∼ 1816 Ma. Meanwhile, zircon overgrowth rims from three intrusions that suffered the shear deformation exhibited metamorphic ages of 1904 ± 11 Ma, 1840 ± 13 Ma and 1826 ± 31 Ma. Similar metamorphic ages of 1901 ± 7 Ma, 1888 ± 8 Ma and 1849 ± 29 Ma were also obtained from high-temperature felsic, pelitic and calcitic mylonites. These results further unravel that the HDSZ most likely developed at ca. 1904–1826 Ma. Additionally, we have summarized available deformation-related geochronological data in the Khondalite Belt, and proposed that this belt underwent three major phases of deformation (D 1 -D 3) in the Orosirian. D 1 mainly produced overturned to recumbent isoclinal folds F 1 , penetrative transposition foliations S 1 and mineral lineations L 1 at ca. 1.97–1.93 Ga. Subsequently, D 2 dominantly resulted in tight to open upright folds F 2 at ca. 1.93–1.90 Ga. Later, D 3 generated a series of NE- to E-trending orogen-parallel ductile shear zones at ca. 1.90–1.82 Ga. Together with multiple high-grade metamorphism and magmatism, the D 1 -D 3 deformation recorded a complex protracted orogeny (>100 Myr) in response to the collision between the Yinshan and Ordos blocks. [ABSTRACT FROM AUTHOR]

• Three units make up the Piedra Alta Terrane: arc-related igneous basement, intra-arc basins and late intrusive granites. • U-Pb ages in zircon restrict the formation of the three units that make up the PAT to the Rhyacian. • Largely predominant positive εHf (T) values attest to the juvenile nature of PAT's crustal segment. • The development of the PAT is related to the evolution of an intraoceanic magmatic arc. This work delves into the intricate Paleoproterozoic geological setting of Uruguay, focusing on the Rio de la Plata Craton (RPC) and its prominent constituent Piedra Alta Terrane (PAT). The PAT constitutes the core of the RPC, characterized as a complex geological entity that encompasses a granite-migmatite basement, metamorphic belts, granite intrusions, and Proterozoic magmatism. To the west, it interfaces with the Transbrasiliano-Kandi tectonic corridor, bounded by the Late-Neoproterozoic Pampia Terrane. The PAT s southeastern boundary extends to Sierra de Tandil and perhaps to Sierra de La Ventana, demarcating its limits with Phanerozoic rocks of the North Patagonian Massif. The Sarandí del Yí shear zone defines the eastern limit of the PAT. Despite varied interpretations of the Piedra Alta Terrane's significance, it is important to note that consensus prevails regarding its four major associations: a granite-gneiss-migmatitic basement complex, three volcanosedimentary belts of low to medium metamorphic grade, diverse late igneous intrusions, and extensional Statherian magmatism (1.79 Ga), represented by tholeiitic gabbroic dikes. In this study, a novel tectonic model for the PAT evolution emerges, supported by an extensive zircon dataset comprising new U-Pb ages, Hf isotopes, and trace element geochemistry. The analytical core involves U-Pb analyses on zircon for dating igneous rocks and establishing the provenance and maximum age of deposition of metavolcanosedimentary sequences. Lu-Hf isotopic analyses on the same zircon crystals provide petrogenetic insights, revealing episodes of crustal growth and minor recycling. Trace element geochemistry and zircon εHf(t) data further accentuate these findings, hinting at mantle source enrichment due to subduction within an intraoceanic magmatic-arc arc setting. [ABSTRACT FROM AUTHOR]

The activities of the three large strike-slip fault systems—the Karakoram, the Karakax, and the Longmu Co-Guozha Co faults—located in the western Tibetan Plateau have induced the intense exhumation of the Karakoram and the southern Western Kunlun ranges. However, the histories of these faults remain debated or loosely constrained, partly due to the restricted access to bedrock samples and associated comprehensive analyses. The application of detrital provenance analysis and detrital thermochronology to sediments can provide valuable information on the locations, crystallization timing, and exhumation of the source terranes of the sediments, thereby shedding light on tectonic histories. This study utilizes modern fluvial sand to obtain exhumation information on the Karakoram and the southern Western Kunlun ranges and to reconstruct the history of the major faults. We achieve this through provenance analysis (heavy-mineral analysis and detrital zircon U Pb dating) and detrital apatite fission-track dating. Our results reveal widespread Paleogene rock exhumation across the western Tibetan Plateau and focused mid-Miocene (ca. 15–12 Ma) exhumation along the Karakoram and the southern Western Kunlun ranges. Moreover, the Karakoram Range experienced renewed exhumation at ca. 7 Ma. Through an integration of our results and regional geological evidence, we suggest that the focused mid-Miocene exhumation reflects the initiation of the Karakoram and the Karakax faults; the subsequent ca. 7 Ma exhumation episode of the Karakoram Range indicates a regional kinematic reorganization due to the initiation of the Longmu Co-Guozha Co Fault. We propose that the middle and late Miocene strike-slip faulting in the western Tibetan Plateau was driven by the oblique underthrusting of the Indian lithosphere. • The Karakoram Fault and the Karakax Fault initiated synchronously at ca. 15 Ma. • The Longmu Co-Guozha Co Fault likely initiated at ca. 8–7 Ma. • Oblique underthrusting of Indian slab triggers Miocene strike-slip in western Tibet. [ABSTRACT FROM AUTHOR]

[Display omitted] • Detrital Zircons in the Shifang phosphorite show three main age peaks. • Zircons in the Shifang phosphorite may directly originate from the underlying strata. • Cambrian phosphorite may provide an important phosphorus source. Phosphorites (P 2 O 5 content > 18 wt%) are widespread in the world; however, high-quality phosphorite (P 2 O 5 content > 30 wt%) is exceptionally rare. In South China, the Devonian Shifang phosphorite deposit represents not only a high-quality phosphorus ore resource but also hosts abundant rare earth elements (up to 3677.6 ppm). Despite its significance, the provenance of this unique phosphorite deposit has remained unclear. In this study, we conducted U-Pb dating, Hf isotope, and trace element concentrations analysis of detrital zircon from the phosphorite in the Shifang phosphorite deposit to well constrain the specific provenance and potential material source of the phosphorite. Cathodoluminescence (CL) images and trace elements analysis of zircons suggested that the majority of zircons have a magmatic origin. The U-Pb dating age of these zircons revealed three main age peaks at ∼ 560–520 Ma, ∼850–750 Ma and ∼ 1050–950 Ma. A comparison of the εHf values of zircons for the same age group worldwide revealed the following: (1) The 1050 ∼ 950 Ma detrital zircon in the Shifang phosphorite deposit could be derived from North India; (2) The 850–750 Ma zircons originated from Tonian granites in the western South China Block; (3) The 560–520 Ma zircons had two sources, one could be the Kuungan orogeny in the east-Gondwana, and another could be the Arabian-Nubian Shield in the northern-west-Gondwana. In addition, our new age histograms of detrital zircon U-Pb ages are well consistent with underlying strata, such as Silurian and early-middle Devonian. Combining these findings with the geological activities in the study area, we conclude that zircons in the Shifang phosphorite deposit may directly originate from the underlying strata in the study area and the Cambrian Qingping phosphorite deposit may have served as an essential phosphorus source for the Shifang phosphorite deposit. [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]

Downstream sediment transport in river systems is impacted by anthropogenic modifications, such as dams or levees. This study used detrital zircon U-Pb geochronology and sediment mixture modeling to investigate the effects of dams on provenance signatures and sediment transport along the upper Missouri and Yellowstone Rivers. The Yellowstone River is the longest dam-free river in North America, while the upper Missouri River has several major reservoir-forming dams. We present 4777 new individual detrital zircon U-Pb ages from 32 sand samples collected from sand bars of the Missouri and Yellowstone Rivers and their major tributaries. These new data along the Missouri River track downstream modification of detrital zircon U-Pb age signatures due to sediment sequestration in reservoirs, bank erosion, and mixing at stream confluences. In contrast, detrital zircon U-Pb age data evolve more progressively downstream along the Yellowstone River, which displays less anthropogenic influence and muted tributary mixing and dilution. U-Pb age component proportions along the extensively dammed Missouri River vary up to 27% downstream, with amplified changes occurring at river confluences downstream from dams. These dramatic changes are attributed to storage of sediment and preferential capture of heavy minerals (including zircon) in reservoirs, resulting in a reduced sediment load in the river downstream from dams. Consequently, detrital zircon mixture models show a disproportionate provenance contribution from tributaries compared to the trunk river downstream from the dams. Dams not only reduce the sediment flux from a river but also change the locations where sediment is generated by initiating erosion in a river downstream from a dam. [ABSTRACT FROM AUTHOR]

During the Tertiary evolution of the Western Mediterranean subduction system, a migrating foreland basin system developed between the Maghrebian orogenic belt and the adjacent African Craton. However, a comprehensive reconstruction of the foreland basin systems of the Rif Chain is still missing. By integrating field observations with quantitative biostratigraphic data from calcareous nannofossil assemblages, sandstone composition, and detrital zircon U-Pb geochronology from selected stratigraphic successions, we reconstruct the foreland basin system that developed in the early Miocene in front of the growing Rif orogen. The successions analyzed are representative of (1) the classical "Numidian Facies" from the Intrarifian Tanger Unit and (2) the Numidian-like deposits (mixed successions) of the "Mérinides Facies" from the "Maghrebian Flysch Basin" and the "Beliounis Facies" from the Predorsalian Unit. Our petrographic analyses and detrital zircon U-Pb ages show that the quartzarenites of the "Numidian Facies" originated from the African Craton, whereas the sublitharenites and feldspathic litharenites from the Mérinides and Beliounis Facies originated from a cratonic area and the exhuming Rif Chain. Our biostratigraphic analyses suggest a simultaneous arrival of the quartz grains in the Numidian, Mérinides, and Beliounis deposits, which indicates that their deposition occurred at ~1 m.y. (ca. 20-19 Ma, early Burdigalian) and allows us to delineate the early Burdigalian foreland basin system of the Rif Chain. The foreland depozone received the "Numidian Facies," the foredeep-hosted ~2000 m of the "Mérinides Facies" and the Beni Ider Flysch, whereas the wedge-top depozone was characterized by deposition of the "Beliounis Facies." The Numidian Sandstones and the Numidian-like deposits analyzed in Morocco show the same age as similar deposits from Algeria, Tunisia, and Sicily, which suggests a comparable early Burdigalian tectono-sedimentary evolution along the southern branch of the Western Mediterranean subductionrelated orogen. [ABSTRACT FROM AUTHOR]

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The usual main purpose of the zircon investigation is to determine the precise age of particular rocks, applying the U-Pb isotope method. In this study we attempt to reveal the vast potential of zircons in understanding the magmatic and modification processes, as well as the structure of the deeper Earth's interior, using the analysis of the zircon population of the major volcanic variety in the Ruen tectono-magmatic zone, Kyustendil area, SW Bulgaria. The ascending magmas crosscut different rock types and units along their path to the Earth's surface. Using the zircon crystal analysis, we may make consideration about the age and chemical characteristics of these units. The trace and rare earth element (REE) content of the zircons brings insights for the rock formation time and discloses characteristics of the deeper parts of the Earth's crust. [ABSTRACT FROM AUTHOR]

The Geo‐chronology of the Mesozoic sequences from the northern Ordos Basin provides an excellent window for understanding the source‐to‐sink analysis and tectonic settings. In this study, nine groups of detrital zircon U–Pb ages from the Middle Triassic to Lower Cretaceous strata of the northern Ordos Basin are presented. Three dominant age groups are revealed through the kernal density estimation: ca. 2,300 ~ 2,500 Ma (Siderian), ca. 2,050 ~ 1,800 Ma (Orosirian), and ca. 358.9 ~ 298.9 Ma (Carboniferous). Significant differences are distinguished according to multidimensional scaling analysis and cumulative distribution function. The Middle Triassic sample is the closest to the Yin Mts and the upper Triassic and lower Jurassic samples have significant similarities with the Jining area. The samples YA‐1 and ZL‐1 from the Middle Jurassic sequences are the closest to the Daqing Mts (DQS) and Wula Mts (WLS), respectively. The sample ZL‐1 is the second closest to the DQS. The sample YJ‐1 from the Lower Cretaceous sequences has apparent affinities with multiple resources, including the DQS, WLS and samples EM‐1 and AD‐1, while the sample LH‐1 only resembles the sample YA‐1. Overall, the northern Ordos Basin experienced three stages of transformations in the source areas: (a) Southward migration during the Middle Triassic and the Early Jurassic; (b) Westward migration during the Early Jurassic and latest Middle Jurassic; (c) Southward migration during the latest Middle Jurassic, and multiple resources and recycled sediments for the Cretaceous sequences. The transition to the North China Craton's (NCC) extensional tectonic setting was closely related to the transformation from the Palaeo‐Asian Ocean's closure to the Palaeo‐Pacific Plate's subduction during the Early Jurassic. The multiple resources and recycled resources for the Lower Cretaceous sequences were related to the destruction of the NCC. [ABSTRACT FROM AUTHOR]

We utilized the Neoma™, a recently released MC-ICP-MS platform offered by ThermoFisher Scientific, to assess the behavior of the Lu-Yb-Hf system during laser ablation analyses of various zircon standards as well as solution-based analyses of the JMC-475 Hf standard doped with varying quantities of Yb and Lu. The primary goal of this work was to characterize the behavior of the Yb interference correction on the Neoma™ platform since this is one of the biggest issues in the Hf isotope analysis community and because the Neoma™ platform will supplant the Neptune™ series instrument. During laser ablation analysis, we found that the overall data quality scales proportionally with the total Hf signal intensity, with higher signal analyses producing extremely accurate (within 1 εHf unit) and precise (sub εHf unit within-run standard errors) data. At low Yb signals (<0.1 V 173Yb), we were not able to produce an accurate internal Yb mass bias factor. However, utilizing an empirical approach allows for the application of session-specific relationships between the Yb and Hf mass bias factors, determined by analysis of standards of varying Yb content, to produce accurate εHf values from zircons with higher Yb/Hf ratios even where the total Hf signal intensity is relatively low. Similar behavior was observed in the solution analyses. Lastly, while the behavior of the Yb interference correction on the Neoma™ platform appears comparable to the Neptune™ series MC-ICP-MS, further work will help refine the understanding of the controls on mass bias behavior, oxide formation, session-to-session stability, etc. [ABSTRACT FROM AUTHOR]