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Baddeleyite (monoclinic zirconia; m -ZrO 2) occurs as a late-stage accessory mineral in shergottites and has been used to determine U–Pb igneous crystallization ages via in-situ secondary ion mass spectrometry (SIMS). During shergottite ejection from the surface of Mars, baddeleyite develops a range of microstructures primarily due to a series of shock-induced transformations to high pressure and temperature polymorphs. It remains poorly constrained to what extent U–Pb systematics in baddeleyite are sensitive to shock conditions experienced by shergottites. To investigate this, we examined baddeleyite in the enriched shergottites Jiddat al Harasis (JaH) 479, Northwest Africa (NWA) 10299, and NWA 12919, which bridge the gap in shock conditions represented in previous microstructural studies. Electron backscatter diffraction (EBSD) analysis reveals that although some baddeleyite grains retain magmatic microstructures (i.e. homogenous crystallographic orientations and twinning of igneous origin), there is widespread phase transformation to high-pressure orthogonal polymorphs (o -ZrO 2) followed by reversion. JaH 479 contains more grains with preserved magmatic microstructures than the other two shergottites, suggesting that it experienced lower bulk shock pressures. Nanometer-scale reverted m -ZrO 2 in NWA 10299 and NWA 12919 further points to insufficient post-shock temperatures; this contrasts with JaH 479 where greater variation in local temperature conditions enabled the development of µm-scale domains of reverted m -ZrO 2. Individual grains that are separated into two distinct microstructural domains may reflect controls on shock propagation due to relative density contrast among the surrounding phases. SIMS U–Pb baddeleyite analysis yields igneous crystallization ages of 210 ± 9 Ma (JaH 479), 196 ± 11 Ma (NWA 10299), and 188 ± 11 Ma (NWA 12919). At the SIMS resolution, we find no clear evidence for significant Pb loss in the surveyed baddeleyite grains, suggesting that temperatures during the formation of both nm-scale and µm-scale reverted m -ZrO 2 in the three shergottites were insufficient to cause significant Pb diffusion. Given the robust baddeleyite U–Pb isotope systematics in the majority of shergottites dated by SIMS methods thus far, we argue that shock conditions experienced by the bulk of shergottites were insufficient to introduce significant U–Pb isotopic mobility, which is limited to grains showing microstructural evidence for extensive post-shock heating and recrystallization. Our findings place new constraints on baddeleyite microstructural response to shock conditions of shergottite ejection and demonstrate that microstructural observations are critical when using baddeleyite as a chronometer in shocked planetary materials. [ABSTRACT FROM AUTHOR]

Ancient orogens within the supercontinent like Columbia can remain stable evolution as long as the cratons. What kind of lithospheric mantle was beneath those orogens and how it evolved into a stable state are still enigmatic. The Trans‐North China orogen (TNCO) is one of the typical collisional orogens within the Columbia supercontinent and was formed at ca. 1.85 Ga. Our work reveals that a cluster of kimberlites intruded the orogenic belt at ca. 1.54 Ga. These rocks were originally generated under a thick lithosphere (>200 km). Their entrained olivine cores show a composition of overlapping olivines from refractory mantle peridotites. The results suggest a thick and refractory lithospheric mantle beneath the TNCO at ca. 1.54 Ga. Such craton‐like property may result from large volume melt extraction from the lithospheric mantle, possibly caused by the ca. 1.78 Ga large igneous event, which eventually induces the long‐term stability of the TNCO during the subsequent supercontinent cycle. [ABSTRACT FROM AUTHOR]

The relevance of the research is connected with Russia’s long-term import dependence on zirconium raw materials. Goal of this research: to study the dynamics of commodity flows (production, import, export, consumption) of Russian zirconium raw materials; its prices (world and Russian); the raw material base of zirconium in Russia and the prospects for national production of its extraction and processing. Methods: statistical, graphic, logical. Results: Russia imports the vast majority (3.5–14.9 kt/year or 98–100 % of consumption) of consumed zircon concentrate. At the same time, almost all of the baddeleyite mined in Russia (4.0–9.3 kt/year or (96–100 % of production) is exported. Since 2018 has there been a decrease in its export supplies and an increase in the national consumption (up to 60 % of production). Russia has existing deposits, including a useful zirconium component, but all are connected with a certain economic and technological complexity in their development. In 2022, the national production of selective zircon concentrate began during the development of the Tugan titanium-zirconium deposit. This deposit covers up to 30 % of Russia’s demand for zirconium raw materials up to 2023. Furthermore, the construction of the 2-nd stage of the Tugan mining and processing plant will increase its supply to 15 kt/year. This will completely cover Russian demand for zirconium raw materials. Work is in progress on Zashikhinsky field preparation, where, in the course of enrichment of tantalum-rare-earth ores, up to 8 kt/year of zircon concentrate will be additionally extracted. The emerging trend of reducing Russia’s import dependence on zirconium raw materials, and in the future its complete elimination will allow consumption of zircon and zirconium oxides to be increased in the most demanding area of their use – for dampening the glaze of ceramic tiles. The presence of an independent and sufficient national mining base of zirconium raw materials will allow Russian production of metal zirconium, zirconium refractory and abrasive products, solid fuel energy cells and other zirconiumcontaining applications to be developed.

[Display omitted] • U-Pb in situ SIMS baddeleyite suggests a crystallization age of 650 Ma for the Mangabal Complex. • Modeling suggests all the rocks from the Complex could have formed from a single parental magma. • Mangabal Complex could be formed by rollback subduction and/or mantle plume, or both. The Mangabal Complex lies within the Brasília Belt, a long-lived Neoproterozoic orogen formed during the amalgamation of the São Francisco/Congo, Amazonian, and Paranapanema Cratons in western Gondwana. The complex comprises two sequences of mafic and ultramafic cumulates, separated by less than 3 km. Despite having undergone variable degrees of deformation and metamorphism, the two sequences exhibit locally preserved pristine relict igneous minerals and textures. The origin and parental magma for the complex remain poorly constrained. We present petrography, whole-rock lithogeochemistry, mineral chemistry and U-Pb in-situ SIMS data from micro-baddeleyite and zircon from Mangabal Complex rocks collected from drill holes. We show that a simple thermodynamic model of batch crystallization using a tholeiitic basalt as parental magma in the upper crust closely matches the studied rocks and agrees with a broadly comagmatic origin for the two sequences. Baddeleyite inferred to represent a primary igneous phase of the complex gives a minimum age of 653 ± 31 Ma, suggesting that the Mangabal Complex, hosted in the Arenópolis-Arc segment, could be coeval with the Damolândia and Taquaral intrusions, hosted in the high-grade Anápolis-Itauçu Complex. Considering the temporal and spatial correlations, we propose that decompression melting of upwelling asthenosphere triggered by rollback subduction and/or the influence of a mantle plume is required to explain the petrogenesis of the mafic–ultramafic intrusions in the eastern Arenópolis Arc and westernmost Anápolis-Itauçu Complex. [ABSTRACT FROM AUTHOR]

The Jizerka Quaternary alluvial placer in the Czech Republic has been a well-known source of gemstones since the 16th century, and the only one in Europe that has yielded a significant amount of jewel-quality sapphire. Besides Mg-rich ilmenite ("iserine"), which is the most common heavy mineral at the locality, some other minerals have been mined for jewellery purposes. These are corundum (sapphire and ruby varieties), zircon ("hyacinth" gemstone variety) and spinel. Here, we present a detailed petrological and geochronological investigation of the enigmatic relationship between the sapphires and their supposed host rocks, supporting their xenogenetic link. Our hypothesis is based on thermal resetting of the U–Pb isotopic age of the zircon inclusion found inside Jizerka blue sapphire to the estimated time of the anticipated host alkaline basalt intrusion. The host rocks of the gemstones (sapphire and zircon) and Mg-rich ilmenite are not yet known, but could be related to the Cenozoic volcanism located near the Jizerka gem placer (Bukovec diatreme volcano, Pytlácká jáma Pit diatreme and Hruškovy skály basalt pipe). The transport of sapphire, zircon and Mg-rich ilmenite to the surface was connected with serial volcanic events, likely the fast ascent of alkali basalts and formation of multi-explosive diatreme maar structures with later deposition of volcanoclastic material in eluvial and alluvial sediments in nearby areas. All mineral xenocrysts usually show traces of magmatic corrosion textures, indicating disequilibrium with the transporting alkali basalt magma. In order to constrain the provenance and age of the Jizerka placer heavy mineral assemblage, zircon inclusion and associated phases (niobian rutile, baddeleyite and silicate melts) in the blue sapphire have been studied using LA–ICP–MS (laser ablation–inductively coupled plasma–mass spectrometry) geochemistry and U–Pb in situ dating. Modification of the zircon inclusion into baddeleyite by exposure to temperature above 1400 °C in a basaltic melt is accompanied by zircon U–Pb age resetting. A zircon inclusion in a Jizerka sapphire was dated at 31.2 ± 0.4 Ma, and its baddeleyite rim at 31 ± 16 Ma. The composition of the melt inclusions in sapphire and incorporated niobian rutile suggests that the parental rock of the sapphire was alkali syenite. The Eocene to late Miocene (Messinian) ages of Jizerka zircon are new findings within the Eger Graben structure, as well as among the other sapphire–zircon occurrences within the European Variscides. Jizerka blue sapphire mineral inclusions indicate a provenience of this gemstone mineral assemblage from different parental rocks of unknown age and unknown levels of the upper crust or lithospheric mantle. [ABSTRACT FROM AUTHOR]

Alumina-toughened calcia-stabilized tetragonal zirconia ceramics are produced using baddeleyite as raw material. A 3 wt.% CaO-ZrO2/Al2O3 ceramic containing 15 wt.% Al2O3 is characterized by sufficiently high mechanical properties: a hardness of 12.6 GPa, Young's modulus of 248 GPa and fracture toughness of 10.3 MPa⋅m0.5. The hardness and Young's modulus of this ceramic exceed those of alumina-free 3 wt.% CaO-ZrO2 ceramic by about 8.6% and 9.3%, respectively. However, fracture toughness of the prepared composite ceramic is lower than that of 3 wt.% CaO-ZrO2 ceramic by about 13.7%. It is revealed that in the fabricated 3 wt.% CaO-ZrO2/Al2O3 ceramic in the range of used Al2O3 concentrations transformation toughening prevails over residual stress toughening and crack deflection toughening. [ABSTRACT FROM AUTHOR]

There are rich deposits of rare earth elements (REE) in the Murmansk region, Russia (approximately 14 194 kt of REE2O3). At the moment only one of REE deposits are being extracted and processed, the Lovozero Loparite deposit. The main purpose of this article is to estimate the expected value of existing REE resources in the Murmansk region and to make an overview on actual technologies for the extraction and processing of REE from ore minerals. Based on these data, the authors propose a direction for the development of REE industry in the region, namely extraction of REE from minerals already mined (apatite of the Khibiny deposits and baddeleyite of the Kovdor deposit); optimisation or development of mineral processing technologies of eudialyte (the Lovozero Eudialyte deposit) and perovskite (the Afrikanda deposit); carrying out exploration works at the Keivy Zr-REE ore occurrences and developing processing and technologies for these ores. [ABSTRACT FROM AUTHOR]

Several mafic-ultramafic layered intrusions were emplaced in the NE Fennoscandian Shield during a magmatic episode at 2.44 Ga. The Paleoproterozoic Näränkävaara layered intrusion, northern Finland, is one of the largest ultramafic bodies in the Fennoscandian Shield, with a surface area of 25 km x 5 km and a magmatic stratigraphic thickness of ~3 km. The intrusion comprises a 1.3 km-thick peridotitic–dioritic layered series (2436 ± 5 Ma) with two peridotitic reversals, and a 1.5–2 km thick basal dunite series mainly composed of olivine adcumulates (dated here). The intrusion has been studied since the 1960’s, but several questions regarding its structure and petrogenesis remain. The basal dunite shows several lithological features typical of komatiitic rather than intrusive olivine cumulates; namely, >1 km-thick “extreme” olivine adcumulates, some showing textures with bimodal grain sizes, oscillating variations in Mg# with stratigraphic height, and poikilitic chromite. With Archean greenstone belts nearby, it was previously hypothesized that the basal dunite series could represent an Archean komatiitic wall rock to the Paleoproterozoic layered series. However, our new U-Pb ID-TIMS baddeleyite age of 2441.7 ± 0.9 Ma for the basal dunite series shows that the basal dunite and layered series of the Näränkävaara intrusion are co-genetic. New whole-rock Sm-Nd isotope data from key stratigraphic units (initial εNd at 2440 Ma of -3.5 to -1.7) indicate that the intrusion was constructed from repeated emplacement of LREE-enriched high-MgO basaltic magmas that were mantle-derived and contaminated by crust, similarly to other Fennoscandian 2.44 Ga intrusions. The parental magmas show similar compositions regardless of stratigraphic position, suggesting that most wall rock contamination and homogenization had occurred before emplacement, with in situ contamination being a relatively minor process. The open-system features of the basal dunite suggest that it may have formed (at least partly) as a feeder channel cumulate, possibly related to the ~100 km long Koillismaa-Näränkävaara Layered Igneous Complex. The Näränkävaara parental magmas show variably depleted metal ratios and could have potential for orthomagmatic mineral deposits, given the availability of S-rich wall rocks.

Small intercalations of clinohumite-forsterite marble with spinel occurs in Moldanubian sillimanite-biotite migmatites near Volary (Šumava Mountains, Southern Bohemia). Along with clinohumite and forsterite, the marble contains purple and gray-green spinel, chlorite (clinochlore) and phlogopite as minor minerals. The accessory minerals are represented by fluorapatite and sulfides (pyrite, pyrrhotite, sphalerite and galena) and less abundant Zr-bearing phases (baddeleyite, zircon). The high-temperature mineral baddeleyite is a product of regional HT-LP metamorphism (> ~700 °C) and was typically overgrown with younger zircon. Sporadically baddeleyite occurs as intergrows with unidentified Th-U oxides. The whole mineral assemblage of the clinohumite-forsterite marble at Volary corresponds to marbles from migmatites at the Prachatice region. The spatial relationship to the adjacent granulite and melasyenite (durbachites) bodies is similar to marble occurrences in the Písek region, and in the contact aureole of the Třebíč durbachite pluton in Western Moravia. [ABSTRACT FROM AUTHOR]

We performed density functional theory (DFT) calculations on binary and ternary oxo/fluoro crystals of the geochemical twin pair zirconium and hafnium to evaluate and compare their stabilities. This is the first DFT study on bulk ZrF4 or HfF4, as well as on a hypothetical ZrOF2 or HfOF2 bulk crystal. For α-MO2, β-MF4 and MOF2, we have found significantly higher cohesive energies for the respective hafnium species. This suggests a considerable gap in affinity toward fluorine and oxygen between the twin pair in the solid state. In agreement with experimental findings, this gap is slightly more pronounced for fluorine. This study is also the first to evaluate the theoretical, endothermic mono-hydroxylation of the respective fluorides or oxyfluorides to model the difference in affinity toward fluoride versus hydroxide. For these, we could also find a slight energetic preference for the hafnium compound. [ABSTRACT FROM AUTHOR]

The results of geochronological and petrological studies of the largest mafic dyke in the northern part of the Fennoscandian Shield, called the Great Dyke of the Kola Peninsula (GDK), are presented. According to U-Pb D-TIMS baddeleyite dating, the GDK crystallization age is 2680 ± 6 Ma. The age of host granites is 2.75–2.72 Ga (U-Pb, zircon, SHRIMP-II). The dyke has a simple internal structure with no signs of multistage melt injection. It comprises equigranular and plagioclase-porphyritic dolerites and gabbro that are amphibolitized to varying degrees. All rocks are low-Mg (Mg# less than 0.37) with low concentrations of Cr and Ni, and were derived through differentiation of more primitive melts. The analysis of geochemical and Sr-Nd isotopic data suggests that GDK melts could be formed by mixing of two types of mantle melts: depleted asthenospheric melt and enriched melt formed via melting of a lithospheric mantle. The weakly fractionated HREE patterns indicate that primary GDK melts originated at shallow (<60 km) depths outside the garnet stability field. The generation and injection of melts of the Neoarchean GDK occurred immediately after large-scale granitic magmatism and main crustal growth event in the Murmansk Craton and marked the cratonization of the continental lithosphere in the northeastern part of the Fennoscandian Shield. [ABSTRACT FROM AUTHOR]

Meteorite impact processes are ubiquitous on the surfaces of rocky and icy bodies in the Solar System, including the Moon. One of the most common accessory minerals, zircon, when shocked, produces specific micro-structures that may become indicative of the age and shock conditions of these impact processes. To better understand the shock mechanisms in zircon from Apollo 15 and 16 impact breccias, we applied transmission electron microscopy (TEM) and studied nano-structures in eight lunar zircons displaying four different morphologies from breccias 15455, 67915, and 67955. Our observations revealed a range of shock-related features in zircon: (1) planar and non-planar fractures, (2) "columnar" zircon rims around baddeleyite cores, (3) granular textured zircon, in most cases with sub-µm-size inclusions of monoclinic ZrO2 (baddeleyite) and cubic ZrO2 (zirconia), (4) silica-rich glass and metal inclusions of FeS and FeNi present at triple junctions in granular zircon and in baddeleyite, (5) inclusions of rutile in shocked baddeleyite, (6) amorphous domains, (7) recrystallized domains. In many grain aggregates, shock-related micro-structures overprint each other, indicating either different stages of a single impact process or multiple impact events. During shock, some zircons were transformed to diaplectic glass (6), and others (7) were completely decomposed into SiO2 and Zr-oxide, evident from the observed round shapes of cubic zirconia and silica-rich glass filling triple junctions of zircon granules. Despite the highly variable effect on textures and Zr phases, shock-related features show no correlation with relatively homogeneous U–Pb or 207Pb/206Pb ages of zircons. Either the shock events occurred very soon after the solidification or recrystallization of the different Zr phases, or the shock events were too brief to result in noticeable Pb loss during shock metamorphism. [ABSTRACT FROM AUTHOR]

The Varena Iron Ore deposit in the SW East European Craton is a significant ore body that occurs within metamorphosed and hydrothermally reworked Paleoproterozoic dolostones. We have performed microstructural investigations supplemented with mineral chemistry and geochronological investigations (LA-ICP-MS) to obtain age constraints on the ore-forming event(s) and improve the understanding of the conditions during mineralization process. Mineral chemistry and textures suggest a drop in pressure after the event of peak metamorphic skarn formation. Influx of oxidized, iron-rich H 2 O fluids resulted in (1) Mg mobility that caused secondary dolomitization of calcite, (2) dissolution of metamorphic magnetite and formation of a new, inclusion-rich (Mag-1) and inclusion-poor (Mag-2) magnetite, and (3) replacement of the peak skarn assemblages. During these fluid-related processes, accessory phases of monazite, baddeleyite, and zircon were formed. Their U Pb dating yield individually robust ages of 1721 ± 9 Ma (monazite, 23 spots), 1703 ± 10 Ma (baddeleyite, 18 spots) and 1706 ± 54 Ma (zircon, 14 spots), respectively. The weighted mean age of 1713 ± 7 Ma (2σ internal) is considered to represent the best age estimate of the iron-ore mineralization in the Varena Iron Ore deposit, and possibly also dates influx of P, REEs etc. into the system. This mineralization event is contemporaneous with ca. 1.73–1.70 Ga metamorphic reworking of the host rocks in the region and may be linked to regional continental-margin type Transscandinavian Igneous Belt (TIB) magmatism in south-central Sweden. [Display omitted] • Varena iron ore deposit in the SW East European Craton is hosted by Ca Mg skarns. • Magnetite precipitated from a water fluid together with secondary alterations. • Accessory monazite, baddeleyite and zircon grew simultaneously with magnetite. • Laser ablation inductively coupled plasma mass spectrometry allowed to date a major ore mineralization phase at 1.71 Ga. [ABSTRACT FROM AUTHOR]

• Baddeleyite-zircon pairs well developed in hydrothermal superimposed Ni-Cu ores. • Baddeleyite cores and zircon rims yielded ages of ∼ 2.2 Ga and ∼ 1.9 Ga, respectively. • Baddeleyite-zircon pairs reveal both magmatic and hydrotheraml mineralization. Ni-Cu-(PGE) sulfide deposits associated with mafic–ultramafic rocks are the most important sources of Ni and platinum-group elements (PGE) in the world. These deposits also contain significant amounts of Cu. Such deposits are generally considered to have formed by multiple stages of primary magmatic concentration and secondary hydrothermal remobilization. However, constraining the ages of Ni-Cu-(PGE) sulfide deposits has proven challenging, particularly those that have experienced post-magmatic hydrothermal overprinting and remobilization. The lack of robust geochronology data has hindered understanding of the geological controls on this important type of mineralization. The Chibaisong Ni-Cu-(PGE) sulfide deposit in the North China Craton is characterized by disseminated and net-textured ores formed by magmatic processes and overprinted by hydrothermal Cu-rich vein stockwork. The Cu-rich vein stockwork is fracture-controlled, and contains a mineral assemblage of Ni-Cu sulfides (chalcopyrite, pyrrhotite, pentlandite), amphibole and quartz. Chalcopyrite in the hydrothermal stockwork is relatively depleted in Ni but enriched in Ag and Cd compared with disseminated magmatic chalcopyrite, typical of hydrothermal superimposed ores as documented elsewhere. We identified baddeleyite-zircon pairs associated with Ni-Cu sulfides in hydrothermal superimposed ores of the Chibaisong deposit, in which the baddeleyite is unequivocally of primary igneous origin whereas the zircon represents the replacement product of baddeleyite during hydrothermal alteration. In situ SIMS U-Pb dating of baddeleyite and zircon yielded weighted mean 207Pb/206Pb ages of 2181 ± 21 Ma and 1892 ± 33 Ma, respectively, interpreted as the timing of magmatic mineralization and subsequent hydrothermal remobilization of the Ni-Cu-(PGE) deposit. Our results explain the large discrepancies in sulfide Re-Os ages previously obtained from this deposit. This study demonstrates that on the basis of detailed BSE imaging, in situ SIMS U-Pb dating of baddeleyite-zircon pairs can provide robust age constraints for both magmatic mineralization and hydrothermal remobilization of Ni-Cu-(PGE) sulfide deposits hosted in mafic–ultramafic intrusions, although further studies are needed to test whether the formation of such deposits commonly entails multiple stages of hydrothermal remobilization. Since baddeleyite or baddeleyite-zircon pairs are common accessory minerals in Ni-Cu-(PGE)-bearing mafic–ultramafic rocks, the dating approach employed in this study may be applicable to similar deposits elsewhere. [ABSTRACT FROM AUTHOR]

The majority of Turkish bituminous coal resources are located in the Zonguldak Basin. The Carboniferous coal seams in the Alacaağzı, Kozlu, and Karadon formations have received interest. However, the detailed mineralogical compositions of clayey sedimentary rocks in coal-bearing sequences in the basin have been limited. This study aims to investigate vertical variations of mineralogical compositions of Carboniferous and Early Cretaceous clayey sedimentary rocks cored in the two-deep exploration wells (K20/K and K20/H) from the Kozlu coalfield using XRD and SEM-EDX analyses data. In addition, a special interest is also given to tonstein layers identified within the Kozlu and Karadon formations. The XRD analyses revealed that the quartz and clay minerals are the main components, and the latter is generally the dominant phase in all studied formations. Besides, clay fraction minerals (chlorite, illite/mica, and kaolinite) are common, while illite/smectite mixed-layer clay mineral is only identified in the two samples. The tonstein samples display similar mineralogical compositions to other samples, while several accessory minerals (e.g., apatite, baddeleyite, monazite, and zircon) are also present. Furthermore, calcite, dolomite, and hematite are mainly observed from the Early Cretaceous samples of the Zonguldak Formation. The vertical distributions of quartz and clay fraction minerals are variable throughout the studied two exploration wells. The vertical variations of clay fraction mineral illite/mica could be mainly related to changes in clastic influx from the basement, while kaolinite seems to be controlled by synchronous volcanic inputs during the Carboniferous. This could also be evident by the predominance of kaolinite and associated volcanogenic mineral grains in tonstein samples. The common presence of carbonate minerals in the Zonguldak Formation is clearly related to shallow marine depositional conditions, while hematite in the reddish mudstone and claystone samples of this formation could be related to short-term terrestrization during the Cretaceous or afterwards. [ABSTRACT FROM AUTHOR]

Kimberlites are deep and relatively rare mantle‐derived igneous rocks, which provide key insights into the lithospheric mantle composition beneath continents (i.e., from the entrained mantle materials) at the time of magma emplacement. In addition, the temporal distribution of kimberlites throughout Earth's history may reveal secular changes in global geodynamics. However, alteration and abundant exotic material (i.e., xenoliths and xenocrysts) of different ages, both typical of kimberlites, often hinder reliable dating of these rocks. In this study, we investigated zircon xenocrysts and their replacement by desilicification reaction rims (DSRs), which consist mainly of baddeleyite, in the metamorphosed Kimozero kimberlites from the Karelian Craton, Russia. Similar DSRs have been identified previously on mantle‐derived zircons in numerous kimberlites, but the precise timing and location of formation of these rims remain unclear. U–Pb isotope dating of mantle zircon xenocrysts in the Kimozero kimberlites indicates that these rocks were emplaced at ca. 1.97 Ga. DSRs with similar textures and baddeleyite chemistry occur on both the 1.97 Ga mantle and 2.70–2.38 Ga crustal zircon xenocrysts in these kimberlites. Pb–Pb isotope dating of the DSRs yields the same age (i.e., ca. 1.97 Ga) as the mantle zircons. The data constrain the formation of DSRs to crustal levels and, more importantly, indicate that these rims record the timing of kimberlite emplacement. Therefore, we suggest that such baddeleyite reaction rims are a new and promising material for kimberlite geochronology. Plain Language Summary: Kimberlites are magmatic rocks produced by magma that ascended from mantle depths. It is important to obtain accurate kimberlite ages mainly because: (a) mantle rocks and minerals, carried by these magmas, allow assessment of the composition of the lithospheric mantle beneath continents at the time of kimberlite emplacement; and (b) the worldwide distribution of kimberlite ages may record secular changes in global geodynamics. However, kimberlites are readily altered and commonly contain exotic material of different ages and origins, which both hinder reliable kimberlite dating. Here, we investigated xenocrystic zircons and their reaction rims, which consist mainly of baddeleyite, in the strongly altered Kimozero kimberlites. Similar rims have been identified on mantle‐derived zircons in numerous kimberlites, but the timing and location of rim formation is poorly constrained. We found that the rims have replaced zircon xenocrysts of different ages and with both mantle and crustal origins, implying the rims formed at crustal levels. The results of Pb–Pb dating for these rims compared with those obtained from zircon U–Pb dating indicate that the rims record the timing of Kimozero kimberlite emplacement at ca. 1.97 Ga. Therefore, such baddeleyite rims are suggested as a promising material for obtaining reliable kimberlite ages. Key Points: Desilicification (i.e., baddeleyite) rims replace kimberlite‐hosted zircon xenocrysts of mantle and crustal originsThese rims represent a promising material for kimberlite geochronology, as they form at the time of kimberlite emplacementThe Kimozero kimberlites intruded the Karelian Craton at ca. 1.97 Ga [ABSTRACT FROM AUTHOR]

The Burpala massif located in the Northern Baikal region contains ore-bearing pegmatites, carbonatites and apatite-fluorite rocks with Zr-Nb-REE-rare-metal mineralization. Considering their petrological, geochemical, geological and thermobarochemical features, it was established that apatite-fluorite rocks were formed from a residual fluid melt containing minor CO2, increased P2O5 and F. Apatite-fluorite rocks of the Burpala massif are similar to the foscorite formations of most carbonatite complexes distinguished by the presence of fluorite.The mineral composition of these rocks was for the first time studied in details. In addition to apatite and fluorite, the following minerals are present: zircon, baddeleyite, barite-celeistine, barite, thorianite, ilmenite, magnetite, hematite, biotite, potassium feldspar, pyroxene, as well as rare minerals with high Ta, Nb and Pb content.

The Jizerka Quaternary alluvial placer in the Czech Republic has been a well-known source of gemstones since the 16th century, and the only one in Europe that has yielded a significant amount of jewel-quality sapphire. Besides Mg-rich ilmenite (“iserine”), which is the most common heavy mineral at the locality, some other minerals have been mined for jewellery purposes. These are corundum (sapphire and ruby varieties), zircon (“hyacinth” gemstone variety) and spinel. Here, we present a detailed petrological and geochronological investigation of the enigmatic relationship between the sapphires and their supposed host rocks, supporting their xenogenetic link. Our hypothesis is based on thermal resetting of the U–Pb isotopic age of the zircon inclusion found inside Jizerka blue sapphire to the estimated time of the anticipated host alkaline basalt intrusion. The host rocks of the gemstones (sapphire and zircon) and Mg-rich ilmenite are not yet known, but could be related to the Cenozoic volcanism located near the Jizerka gem placer (Bukovec diatreme volcano, Pytlácká jáma Pit diatreme and Hruškovy skály basalt pipe). The transport of sapphire, zircon and Mg-rich ilmenite to the surface was connected with serial volcanic events, likely the fast ascent of alkali basalts and formation of multi-explosive diatreme maar structures with later deposition of volcanoclastic material in eluvial and alluvial sediments in nearby areas. All mineral xenocrysts usually show traces of magmatic corrosion textures, indicating disequilibrium with the transporting alkali basalt magma. In order to constrain the provenance and age of the Jizerka placer heavy mineral assemblage, zircon inclusion and associated phases (niobian rutile, baddeleyite and silicate melts) in the blue sapphire have been studied using LA–ICP–MS (laser ablation–inductively coupled plasma–mass spectrometry) geochemistry and U–Pb in situ dating. Modification of the zircon inclusion into baddeleyite by exposure to temperature above 1400 °C in a basaltic melt is accompanied by zircon U–Pb age resetting. A zircon inclusion in a Jizerka sapphire was dated at 31.2 ± 0.4 Ma, and its baddeleyite rim at 31 ± 16 Ma. The composition of the melt inclusions in sapphire and incorporated niobian rutile suggests that the parental rock of the sapphire was alkali syenite. The Eocene to late Miocene (Messinian) ages of Jizerka zircon are new findings within the Eger Graben structure, as well as among the other sapphire–zircon occurrences within the European Variscides. Jizerka blue sapphire mineral inclusions indicate a provenience of this gemstone mineral assemblage from different parental rocks of unknown age and unknown levels of the upper crust or lithospheric mantle.

Zr-Th-U minerals, namely baddeleyite, zircon and U-Th-oxide, were found in high-Mg diorite from the Late Devonian – Early Carboniferous synplutonic dyke in granodiorites of the Chelyabinsk massif, South Urals. Micron-sized minerals were investigated by electron microscopy and cathodoluminescence spectroscopy. Their chemical compositions were determined by electron probe microanalysis that was optimized to ensure more precise measurements of the composition of minerals. Baddeleyite grains are found as inclusions in amphibole crystals and reside in intergranular areas. The former retain their composition and show no traces of corrosion or substitution. In the intergranular areas, baddeleyite grains were replaced by polycrystalline zircon due to the reaction with an acid melt, and the U-Th-oxide precipitated inside baddeleyite simultaneously, which suggests the restite origin of baddeleyite. The main features of the baddeleyite composition are extremely high concentrations of ThO2 and UO2 (to 0.03 wt. % and 1.0 wt. %, respectively), which may be due to the metasomatic interaction between the mantle peridotite and the crustal or carbonatite fluid or melt.

The paper is devoted to developing a model of baddeleyite recovery from dump products of an apatite-baddeleyite processing plant using centrifugal concentrators. The relevance of the work arises from the acquisition of new knowledge on the optimization of technological parameters of centrifugal concentrators using Knelson CVD (continuous variable discharge) technology – in particular, setting the frequency of valve opening and the duration of valves remaining open. The purpose of the research was to assess the applicability of CVD technology in the treatment of various dump products of the processing plant and to build a model of dependencies between the concentrate and tailings yields and the adjustable parameters, which will allow to perform preliminary calculations of the efficiency of implementing this technology at processing plants. The research objects are middling and main separation tailings of the coarse-grained stream and combined product of main and recleaner separation tailings of the fine-grained stream. The study uses general methods of mathematical statistics: methods of regression analysis, aimed at building statistically significant models, describing dependence of a particular variable on a set of regressors; group method of data handling, the main idea of which is to build a set of models of a given class and choose the optimal one among them. Authors proposed an algorithm for processing experiment results based on classical regression analysis and formulated an original criterion for model selection. Models of dependencies between the concentrate and tailings yields and the adjustable parameters were built, which allowed to establish a relationship between the concentrate yield and the valve opening time, as well as a relationship between the tailings yield and the G-force of the installation.

• Baddeleyite U-Pb age of the Banbiyan diabase dyke in the Shennongjia area is ∼ 1670 Ma. • The main magma source of the Banbiyan diabase is E-MORB. • They should respond to the rifting of Columbia Supercontinent. The Shennongjia Group in the northern margin of the Yangtze Craton consists mainly of thick carbonate rocks interlayered with some intervals of volcanic and terrigenous clastic rocks. With the geochronological achievements in recent years, the depositional age of this group can be constrained into the time span of 1400–1000 Ma at present, belonging to the Mesoproterozoic Ectasian period. It is also a potential candidate interval for the "Undefined System/Period" in the Regional Chronostratigraphic Chart of China. According to the 1:200,000-scale conventional regional geological survey in the '1960–1970 s', at the northwest side of the dominant peak of the Mt. Shennongding, it shows a ring-shaped gabbro-diabase dyke intruded in these Ectasian formations. However, due to the lack of comprehensive studies, there are lots of controversy both about the intrusion time and the tectonic setting of the mafic dyke. In this study, by means of the LA-ICP-MS and SHRIMP method successfully, the baddeleyite from the Banbiyan gabbro-diabase dyke yielded gained the weighted average 207Pb/206Pb age 1668.3 ± 5 Ma (MSWD = 1, N = 53) and 1667.8 ± 7 Ma (MSWD = 0.7, N = 23), respectively. It represents an unambiguous late Paleoproterozoic Statherian Period magmatic event in northern Yangtze Craton. Further, for the first time, it indicates the existence of the geological records prior to ∼ 1.67 Ga in the Shennongjia area. In addition, Banbiyan gabbro-diabase samples have relatively concentrated SiO 2 (48.33 % to 49.65 %) and high whole iron content (10.25 % to 12.78 %). They show Na 2 O + K 2 O ranging from 2.9 % to 4.64 % and TiO 2 from 1.36 % to 1.62 %. All samples are enriched in LILE, e.g., Rb, K, and Ba. The REE pattern shows a moderately right-inclined curve between E-MORB and OIB. These geochemiacal characteristics are agreed with contemporaneous magmatic event in the southwestern Yangtze Craton, indicating a within-plate rifting background and should correspond to the rifting of the Columbia Supercontinent. [ABSTRACT FROM AUTHOR]

Zircon is a common accessory mineral in various rocks, especially in the crustal ones. It is the best mineral for U-Pb dating. Meanwhile, trace elements and isotopes of the mineral can also provide much information concerning the formation and evolution of rocks. There are a growing number of reports of zircon existing in mantle peridotite. However, it is generally considered that zircon is unlikely crystallized in ultrabasic rocks due to SiO2-unsaturation. In this paper, the SiO2 activity and zircon/baddeleyite transition curve at different conditions were calculated through thermodynamic phase equilibrium modeling, to reveal the main factors affecting the SiO2 activity and the stability of zircon/baddeleyite in ultrabasic and basic rocks, especially in mantle peridotite. These results provide a thermodynamic basis for interpreting the genesis and significance of zircon in mantle rocks. That is, the SiO2 activity is mainly controlled by stable mineral assemblages and temperature-pressure conditions. The orthopyroxene+olivine assemblage in peridotite as an effective buffer restricts the SiO2 activity in a relatively high range with a small variation. The upper temperature limit of zircon can reach more than 1500°C with this mineral assemblage. During the low-temperature serpentinization of peridotite, the replacement of olivine and pyroxene by serpentine can result in a significant decrease of SiO2 activity, and baddeleyite can be stabilized at <530°C and < 2.7 GPa. When peridotite is strongly metasomatized by the SiO2-bearing fluid, the addition of SiO2 can increase its activity and make zircon stable at low temperatures. The SiO2 activity in ultrabasic-basic rocks is not only positively correlated with the SiO2 content but also negatively correlated with the Ca and Na contents of rocks. This is because Ca and Na preferentially combine with Si and Al to form Si-rich minerals, such as clinopyroxene and feldspar. This process will consume excessive SiO2, decreasing the SiO2 activity. This may be the reason why zircon can be found in ultrabasic rocks, while baddeleyite can exist in some basic and alkaline rocks. The thermodynamic modeling can also reasonably explain the mutual transformation between zircon and baddeleyite in ultrabasic-basic rocks. Our results indicate that zircon can exist stably in mantle peridotite in a wide range of temperature-pressure conditions and its formation is related to melt/fluid metasomatism. That is, the presence of zircon in mantle peridotite is an important information carrier of crust-mantle interaction for deep material cycling. [ABSTRACT FROM AUTHOR]

Several mafic-ultramafic layered intrusions were emplaced in the NE Fennoscandian Shield during a magmatic episode at 2.44 Ga. The Paleoproterozoic Näränkävaara layered intrusion, northern Finland, is one of the largest ultramafic bodies in the Fennoscandian Shield, with a surface area of 25 km x 5 km and a magmatic stratigraphic thickness of ~3 km. The intrusion comprises a 1.3 km-thick peridotitic-dioritic layered series (2436 ± 5 Ma) with two peridotitic reversals, and a 1.5-2 km thick basal dunite series mainly composed of olivine adcumulates (dated here). The intrusion has been studied since the 1960's, but several questions regarding its structure and petrogenesis remain. The basal dunite shows several lithological features typical of komatiitic rather than intrusive olivine cumulates; namely, >1 km-thick ôextremeö olivine adcumulates, some showing textures with bimodal grain sizes, oscillating variations in Mg# with stratigraphic height, and poikilitic chromite. With Archean greenstone belts nearby, it was previously hypothesized that the basal dunite series could represent an Archean komatiitic wall rock to the Paleoproterozoic layered series. However, our new U-Pb ID-TIMS baddeleyite age of 2441.7 ± 0.9 Ma for the basal dunite series shows that the basal dunite and layered series of the Näränkävaara intrusion are co-genetic. New whole-rock Sm-Nd isotope data from key stratigraphic units (initial εNd at 2440 Ma of -3.5 to -1.7) indicate that the intrusion was constructed from repeated emplacement of LREE-enriched high-MgO basaltic magmas that were mantle-derived and contaminated by crust, similarly to other Fennoscandian 2.44 Ga intrusions. The parental magmas show similar compositions regardless of stratigraphic position, suggesting that most wall rock contamination and homogenization had occurred before emplacement, with in situ contamination being a relatively minor process. The open-system features of the basal dunite suggest that it may have formed (at least partly) as a feeder channel cumulate, possibly related to the ~100 km long Koillismaa-Näränkävaara Layered Igneous Complex. The Näränkävaara parental magmas show variably depleted metal ratios and could have potential for orthomagmatic mineral deposits, given the availability of S-rich wall rocks. [ABSTRACT FROM AUTHOR]

• Combined microstructural and U-Pb chronology of baddeleyite within shergottites. • Widespread reversion from orthorhombic zirconia polymorphs revealed by microstructures. • No link between microstructure and U-Pb chronology; ages date crystallization. • Insufficient heating during shock metamorphism to induce Pb mobility. • New ages of NWA 7257 and NWA 8679 of 195 ± 15 Ma and 220 ± 23 Ma, respectively. Baddeleyite (monoclinic; m -ZrO 2) is a widespread accessory phase within shergottites. However, the effects of shock loading on baddeleyite U-Pb isotopic systematics, and therefore its reliability as a geochronometer within highly shocked lithologies, are less well constrained. To investigate the effects of shock metamorphism on baddeleyite U-Pb chronology, we have conducted high-resolution microstructural analysis and in-situ U-Pb isotopic measurements for baddeleyite within enriched basaltic shergottites Northwest Africa (NWA) 7257, NWA 8679 and Zagami. Electron backscatter diffraction (EBSD) analyses of baddeleyite reveal significant microstructural heterogeneity within individual thin sections, recording widespread partial to complete reversion from high-pressure (≥3.3 GPa) orthorhombic zirconia polymorphs. We define a continuum of baddeleyite microstructures into four groupings on the basis of microstructural characteristics, including rare grains that retain magmatic twin relationships. Uncorrected U-Pb isotopic measurements form Tera-Wasserburg discordia, yielding new 238U-206Pb discordia ages of 195 ± 15 Ma (n = 17) for NWA 7257 and 220 ± 23 Ma (n = 10) for NWA 8679. Critically, there is no resolvable link between baddeleyite microstructure and U-Pb isotope systematics, indicating negligible open-system behaviour of U-Pb during zirconia phase transformations. Instead, we confirm that high post-shock temperatures exert the greatest control on Pb mobility within shocked baddeleyite; in the absence of high post-shock temperatures, baddeleyite yield robust U-Pb isotope systematics and date the age of magmatic crystallization. Low bulk post-shock temperatures recorded within Zagami (≤220 °C), and suggested within NWA 7257 and NWA 8679 by baddeleyite microstructure and other petrological constraints, confirm that the previously derived baddeleyite age of Zagami records magmatic crystallization, and provide greater age diversity to 225 Ma to 160 Ma enriched shergottites. While our data yield no resolvable link between microstructure and U-Pb isotopic composition, we strongly recommend that microstructural analyses should represent an essential step of baddeleyite U-Pb chronology within planetary (e.g., martian, lunar, asteroidal) and shocked terrestrial samples, allowing full contextualisation prior to destructive isotopic techniques. Microstructurally constrained in-situ U-Pb analyses of baddeleyite thus define new opportunities for the absolute chronology of martian meteorites and, more broadly, shocked planetary materials. [ABSTRACT FROM AUTHOR]

Samples of ore and gravity concentrate from the Algama zirconium occurrence were studied. Concentrations of rare-earth elements (REE), and rare and noble metals were determined. The REE content is 200–300 g/t in the ore and reaches 400 g/t in the gravity concentrate. REE distribution patterns show a clear negative Ce anomaly and MREE and Y predominance. The ore and the concentrate have elevated Hf, W, U, Ta, Au, and Pt contents. Their source is the ancient weathering crust developed after ultra-alkaline rocks of the Ingili massif. The presence of a buried weathering crust enriched in valuable components is inferred in the studied area. [ABSTRACT FROM AUTHOR]

ABSTRACT: A suite of ultramafic and mafic rocks developed in the Chigu Tso area, eastern Tethyan Himalaya. Baddeleyite and zircon U-Pb ages acquired by SIMS and LA-ICP-MS from olivine pyroxenite rocks in the Chigu Tso area are 138.9±3.0 Ma and 139.0±1.9 Ma, respectively. These two Early Cretaceous ages are similar with the ages of the more abundant mafic rocks in the eastern Tethyan Himalaya, indicating that this suite of ultramafic and mafic rocks in the Chigu Tso area should be included in the outcrop area of the Comei Large Igneous Province (LIP). These ultramafic rocks provide significant evidence that the involvement of mantle plume/hot spot activities in the formation of the Comei LIP. Baddeleyite U-Pb dating by SIMS is one reliable and convenient method to constrain the formation time of ultramafic rocks. The dating results of baddeleyite and zircon from the olivine pyroxenite samples in this paper are consistent with each other within analytical uncertainties, suggesting that baddeleyite and zircon were both formed during the same magmatic process. The consistency of baddeleyite U-Pb ages in the Chigu Tso area with zircon U-Pb ages for a large number of Early Cretaceous mafic rocks in the eastern Tethyan Himalaya further support that zircon grains from such mafic rocks yielding Early Cretaceous ages are also magmatic in origin.

The determination of ancient ages of zircons in dunites from the orogenic regions and central-type platform massifs raised a number of issues: 1) the equilibrium of zircon with dunite material and, as a result, the possibility of determining the age of dunite using zircon; 2) polychronic zircons in dunites and the mechanism for the formation of zoned zircon crystals; 3) the origin of the oldest dunite material dated at more than 2500 Ma; 4) mechanism for the formation of zoned zircon crystals in dunite. The article presents results of studying phase equilibrium in the system MgO–SiO2–ZrO2, which confirmed the possibility of zircon crystallisation in equilibrium with olivine and pyroxene. It was found that zircon is stable in dunite up to 1450°C, whereas at higher temperatures zircon is replaced by baddeleyite. It is shown that zoned zircon crystals can be formed in dunite as a result of the gradual transformation of zircon into baddeleyite and vice versa. Drawing on the experimental data, the authors proposed a mechanism for the accumulation of dunite material in the form of restite, which forms during the partial melting of mantle peridotite, as well as the possible way for dunite resitite to raise to the surface in the form of diapir. The difference between the Ural alpine-type ultrabasites and the ultrabasites of the Platiniferous Belt is discussed. It is proposed that the alpine-type ultrabasite occur сloser to the surface where they actively interact with water.

We performed density functional theory (DFT) calculations on binary and ternary oxo/fluoro crystals of the geochemical twin pair zirconium and hafnium to evaluate and compare their stabilities. This is the first DFT study on bulk ZrF4 or HfF4, as well as on a hypothetical ZrOF2 or HfOF2 bulk crystal. For α-MO2, β-MF4 and MOF2, we have found significantly higher cohesive energies for the respective hafnium species. This suggests a considerable gap in affinity toward fluorine and oxygen between the twin pair in the solid state. In agreement with experimental findings, this gap is slightly more pronounced for fluorine. This study is also the first to evaluate the theoretical, endothermic mono-hydroxylation of the respective fluorides or oxyfluorides to model the difference in affinity toward fluoride versus hydroxide. For these, we could also find a slight energetic preference for the hafnium compound.

A review of zirconium dioxide or zirconia ZrO2 is presented. The finding of zirconium compounds in nature, the physical and chemical properties of ZrO2 are given, the polymorphism of zirconium oxide, and the phase diagrams of systems with its participation are considered. The areas of application of zirconia compounds are highlighted: automotive industry, electronics industry, energy and industrial ecology, equipment manufacturing and mechanical engineering the production of zirconium-based refractories, ceramics, enamels, glass, superhard materials, applications in medicine, nuclear energetics, and many others areas of human activity. Cubic modification of zirconium dioxide, stabilized by oxides of rare earth elements, is a jewelry stone (fianite). Partially stabilized zirconium dioxide is a versatile structural material with very high resistance to crack propagation. Solid solutions of REE oxides, especially scandium, have a high oxygen conductivity, which is used in sensors for measuring the partial pressure of oxygen and in fuel cells. Attention is paid to heat-resistant oxide ceramic materials with low thermal conductivity used in the quality of heat-resistant coatings. Considerable attention was paid to the second most important mineral of zirconia - baddeleyite (ZrO2). Baddeleyite is widely used in the production of refractory materials. It is mined for the production of metallic zirconium. The achievements of Soviet and Russian scientists in the development of technologies for the production of fianite and artificial baddeleyite are presented.

The Ottfjället Dyke Swarm (ODS) is a prominent component of the Ediacaran mafic magmatism associated with opening of the Iapetus ocean, and hosted in the Särv Nappe, Middle Allochthon of the Scandinavian Caledonides. A U-Pb baddeleyite age of 596.3 ± 1.5 Ma for a thick, well preserved, plagioclase-phyric dolerite dyke in Härjedalen, Sweden, dates emplacement of the swarm. The age represents a robust, inheritance-free reference age for variably deformed and metamorphosed tholeiitic dykes in sandstone-dominated sequences of the lower part of the Middle Allochthon, representing the proximal, rifted Baltoscandian margin preceding the opening of Iapetus. The new age is within the narrow time span between 610 and 595 Ma defined by the most reliable age estimates for mafic dykes in structurally higher nappes (upper part of Middle Allochthon), representing the distal margin during the opening of Iapetus. The Ottfjället Dyke Swarm cuts the Tossåsfjället Group succession, which includes sabkha-related carbonate platform and diamictite couples, one of several correlated Neoproterozoic glaciogenic successions in Scandinavia. The intrusion age of ca. 596 Ma therefore sets a minimum age for the glaciogenic successions. It implies that Neoproterozoic glaciations in Scandinavia predate the ca. 580 Ma Gaskiers glaciation event and are probably part of the ca. 635 Ma Marinoan "Snowball-Earth"-type glaciation. [ABSTRACT FROM AUTHOR]

Data are provided for preparing fuzed and fuzed stabilized zirconia from baddeleyite and synthetic zirconia in induction, plasma, and electric arc furnaces. Results are discussed and prospects for carbothermal preparation of zirconium dioxide from zircon in an electric arc furnace are demonstrated. A favorable effect of oxidation melting in an electric arc furnace on quality and the process of fuzed product preparation is demonstrated. Data are provided for preparing fuzed zirconia from zircon in plasma furnaces. [ABSTRACT FROM AUTHOR]

The Mesoproterozoic Roper Group of the McArthur Basin has excellent petroleum potential, but exploration has been hampered by poor constraints on its post-depositional history that has compromised understanding of the tectonostratigraphic evolution of the basin. The Derim Derim Dolerite occupies an important position in the event chronology of the McArthur Basin, having intruded the Roper Group prior to post-Roper basin inversion, and it is also a major component of Mesoproterozoic intraplate mafic magmatism in northern Australia. Since 1997, the Derim Derim Dolerite has been assigned a magmatic crystallisation age of 1324 ± 4 Ma (all uncertainties are 95% confidence), based on unpublished sensitive high-resolution ion micro probe (SHRIMP) U–Pb analyses on baddeleyite attributed to a dolerite sample from Bureau of Mineral Resources drill-hole Urapunga 5. Herein, we establish that the SHRIMP sample originated from the type locality of the Derim Derim Dolerite in outcrop 90 km northwest of Urapunga 5 and document the 207Pb/206Pb date interpreted from the 1997 dataset. New U–Pb SHRIMP reanalysis of the same grain-mounts yielded a mean 207Pb/206Pb date of 1320.1 ± 5.3 Ma, confirming the 1997 result, and isotope dilution-thermal ionisation mass spectrometry (ID-TIMS) analysis of baddeleyites plucked from the mounts yielded a precise mean 207Pb/206Pb date of 1327.5 ± 0.6 Ma. This date is significantly older than a baddeleyite U–Pb ID-TIMS date of ca 1313 Ma recently reported elsewhere from dolerite in the Beetaloo Sub-basin 200 km to the south, indicating that magmatism attributed to the Derim Derim Dolerite spanned at least 10–15 Ma. Previously documented geochemical variation in Mesoproterozoic intraplate mafic rocks across the Northern Territory (such as the 1325 ± 36 Ma Galiwinku Dolerite in the McArthur Basin, 1316 ± 40 Ma phonolites in the Nimbuwah Domain of the eastern Pine Creek Orogen, and 1295 ± 14 Ma gabbro in the Tomkinson Province) may reflect episodic pulses of magmatism hitherto obscured by the low precision of the available isotopic dates. The timing and geochemistry of Derim Derim-Galiwinku mafic igneous activity is strikingly similar to that of the Yanliao Large Igneous Province (LIP) in the northern North China Craton, and the global paucity of 1330–1300 Ma LIPs suggests that the North Australian Craton and the North China Craton were in relatively close proximity at that time. We document a previously unpublished U–Pb baddeleyite date of 1324 ± 4 Ma for the Derim Derim Dolerite in the McArthur Basin, obtained via sensitive high-resolution ion micro probe (SHRIMP), and substantiate it with an isotope dilution-thermal ionisation mass spectrometry (ID-TIMS) date of 1327.5 ± 0.6 Ma from the same sample. Our dates are significantly older than a U–Pb baddeleyite ID-TIMS date of ca 1313 Ma from dolerite in the Beetaloo Sub-basin 200 km to the south, indicating that magmatism attributed to the Derim Derim Dolerite spanned at least 10–15 Ma. Contemporaneous intraplate mafic magmatism extended hundreds of kilometres across the Northern Territory, spanning the Tomkinson Province, the McArthur Basin, and the Nimbuwah Domain of the eastern Pine Creek Orogen. The timing and geochemistry of Derim Derim Dolerite magmatism strongly resembles the Yanliao Large Igneous Province (LIP) in the northern North China Craton, which suggests that the North Australian Craton and the North China Craton were in close proximity during the Mesoproterozoic. [ABSTRACT FROM AUTHOR]

Fluid infiltration into metacarbonates is a key mechanism to induce orogenic decarbonation, which influences the global carbon cycle and long‐term climate evolution. Little is known regarding the fluid pathways during episodic infiltration events and how flow patterns control time‐integrated CO2 outflux. We investigate the "vein‐like" polycrystalline mineral reaction zones (PMRZs) in dolomite marbles (Mogok metamorphic belt, Myanmar), which are formed by metasomatism via the infiltration of Si–Al–K–Ti–Zr‐bearing fluids. The petrographic textures and mineral U–Pb chronology reveal three episodes of fluid influx in a single PMRZ: (1) the initial episode (Stage‐I) transformed most dolomite into Mg‐rich silicates/oxides and calcite at ∼35–36 Ma indicated by baddeleyite cores; (2) baddeleyite rims gave ages of ∼23–24 Ma, representing a subsequent infiltration episode (Stage‐II) that modified Stage‐I minerals via a dissolution–precipitation mechanism; (3) the final episode (Stage‐III) is recorded by zircon replacing baddeleyite, which yielded ages of ∼17 Ma. Stage‐III fluid has a higher SiO2 activity and XCO2 [CO2/(CO2 + H2O)] than Stage‐I/Stage‐II fluids. Thermodynamic and mass‐balance analyses indicate that Stage‐I infiltration causes >62–67% loss of CO2 by both dolomite‐consuming reactions and calcite dissolution, whereas the latter two infiltration episodes induce <12–18% loss of CO2 via calcite dissolution. Our results provide compelling evidence that repeated episodes of infiltration (each separated in time by 7–13 Ma) occurred along a single channel in marbles. The initial infiltration episode may create high‐permeability regions, offering favorable channels for later‐stage fluids that transfer obviously less CO2 than the initial metasomatism. This considerably complicates a quantitative assessment of CO2 liberation from metacarbonates during orogenesis. Key Points: Gem‐bearing reaction zones in Mogok marbles record three episodes of fluid infiltration each separated in time by 7–13 MaInitial fluid infiltration drives dolomite‐consuming reactions and produces high‐permeability zones that channelize later fluid transportEffect of multiple fluid infiltration episodes on metamorphic CO2 release from marbles in orogenic belts is assessed [ABSTRACT FROM AUTHOR]

Mineralogical features of the minerals of Gradiştea de Munte, demonstrate its long multistage crystallization. The multi-staged mineralizing process is supported by textural relationships of all rare minerals constituents of ore, where replacement of earlier minerals by later ones is common. The textural relations between -Nb, -REE(Y), -Th, -U an -Zr minerals, and between the zircon and minerals of the host rock, show that zircon/cyrtolite shows many generations: the old zircon occurs as discrete grains in phlogopite and magnetite, is good crystallized, transparent, similar to igneous zircon; the zircon/cyrtolite have a texture consisting of a mixture of two microdomains, metamict and crystalline. The new zircon generations overgrown as small clean crystals, as a fringe on cyrtolite, baddeleyite, thorite, etc could be considered as resulting from hydrothermal processes. Their geochemical zoning indicates a different origin of each part of the crystal. Representative microprobe analysis of Gradiştea de Munte zircon/cyrtolite show high contents of Th, Y, Yb, Ce, Hf; U and less La, Nd, Sm, Dy and Nb. The heavy rare earth elements (HREE), specially Y, beside Th and sometimes Hf; are the predominant trace elements in OM zircon/cyrtolite, because of their similarity in ionic radius to Zr4+. The baddeleyite occurrence as one of the oldest mineral, indicates that the first vein mineralizing solutions were subsaturated in silica. The absence of silica has stabilized baddeleyite and its presence has stabilized the zircon/cyrtolite. [ABSTRACT FROM AUTHOR]

Initial excess protactinium (231Pa) is a frequently suspected source of discordance in baddeleyite (ZrO2) geochronology, which limits accurate U/Pb dating, but such excesses have never been directly demonstrated. In this study, Pa incorporation in late Holocene baddeleyite from Somma-Vesuvius (Campanian Volcanic Province, central Italy) and Laacher See (East Eifel Volcanic Field, western Germany) was quantified by U-Th-Pa measurements using a large-geometry ion microprobe. Bad-deleyite crystals isolated from subvolcanic syenites have average U concentrations of ~200 ppm and are largely stoichiometric with minor abundances of Nb, Hf, Ti, and Fe up to a few weight percent. Measured (231Pa)/(235U) activity ratios are significantly above the secular equilibrium value of unity and range from 3.4(8) to 14.9(2.6) in Vesuvius baddeleyite and from 3.6(9) to 8.9(1.4) in Laacher See baddeleyite (values within parentheses represent uncertainties in the last significant figures reported as 1σ throughout the text). Crystallization ages of 5.12(56) ka (Vesuvius; MSWD = 0.96, n = 12) and 15.6(2.0) ka (Laacher See; MSWD = 0.91, n = 10) were obtained from (230Th)/(238U) disequilibria for the same crystals, which are close to the respective eruption ages. Applying a corresponding age correction indicates average initial (231Pa)/(235U)0 of 8.8(1.0) (Vesuvius) and 7.9(5) (Laacher See). For reasonable melt activities, model baddeleyite-melt distribution coefficients of DPa/DU = 5.8(2) and 4.1(2) are obtained for Vesuvius and Laacher See, respectively. Speciation-dependent (Pa4+ vs. Pa5+) partitioning coefficients (D values) from crystal lattice strain models for tetra- and pentavalent proxy ions significantly exceed DPa/DU inferred from direct analysis of 231Pa for Pa5+. This is consistent with predominantly reduced Pa4+ in the melt, for which D values similar to U4+ are expected. Contrary to common assumptions, baddeleyite-crystallizing melts from Vesuvius and Laacher See appear to be dominated by Pa4+ rather than Pa5+. An initial disequilibrium correction for baddeleyite geochronology using DPa/DU = 5 ± 1 is recommended for oxidized phonolitic melt compositions. [ABSTRACT FROM AUTHOR]

Baddeleyite (ZrO2) is used to infer shock pressures and understand the impact history of planetary bodies. Although the high‐pressure phase transition behavior of baddeleyite has been intensively investigated under hydrostatic conditions, there is little information on the dynamic response of phase transitions under shock‐loading conditions. We performed in situ X‐ray diffraction measurements on shock‐loaded baddeleyite using a synchrotron X‐ray pulse at beamline NW14A of the Photon Factory Advanced Ring, High Energy Accelerator Research Organization (KEK), Japan. A phase transition from monoclinic to orthorhombic‐I ZrO2 occurs at 3.3 GPa during shock compression and immediately returns to the monoclinic phase during subsequent release. Orthorhombic‐II ZrO2 is not observed up to 15 GPa. This study refines the phase transition behavior of baddeleyite under shock conditions up to 15 GPa, and the phase transition boundary is determined from direct observations. These findings improve the understanding of the shock history of planetary bodies. Plain Language Summary: Understanding the amount of pressure generated by an impact event between astronomical objects is essential for studying solar system evolution. Baddeleyite (ZrO2) is a widespread mineral found in the Earth, Moon, Mars, and meteorites and can be applied as a shock‐pressure barometer and geochronometer. Impact events induce instantaneous high‐pressure conditions (on the order of giga [1012] pascals [GPa]), which is referred to as shock compression. The crystal structure of baddeleyite is known to change under such high‐pressure conditions; however, this transformation has not been directly observed under shock compression due to experimental difficulties. In this study, we directly observed the baddeleyite phase transformation in shock experiments performed at a synchrotron facility (Photon Factory Advanced Ring, High Energy Accelerator Research Organization (KEK), Japan). A high‐power laser was used to generate the shock wave, and the crystal structural response during the shock compression was detected using a synchrotron X‐ray pulse. The time‐resolved X‐ray diffraction measurements show that baddeleyite's crystal structure transforms to the high‐pressure phase during shock compression at 3.3 GPa but immediately returns back to the low‐pressure phase upon decompression. Our results can be used to estimate the size of past planetary impact events and better understand mineral behavior under shock conditions. Key Points: A phase transition in baddeleyite is directly observed under shock wave loading by in situ time‐resolved X‐ray diffractionA phase transition occurs from baddeleyite to orthorhombic‐I ZrO2 at 3.3 GPa, but immediately returns to baddeleyite upon decompressionThe baddeleyite‐orthorhombic‐I ZrO2 phase transition during shock compression is similar to that during static compression [ABSTRACT FROM AUTHOR]

U–Pb ID-TIMS dating of igneous baddeleyite from metamorphosed coronitic gabbronorites in the сentral part of the Belomorian mobile belt, Fennoscandian shield was performed for the first time. The obtained age of 2404 ± 11 Ma indicates that studied gabbronorites belong to the ca. 2400 Ma large igneous province and thereby allows to extend its area on the Fennoscandian Shield. A short duration of large mafic igneous events in the Paleoproterozoic. [ABSTRACT FROM AUTHOR]

Strongly carbonatized alkaline rocks and a carbonatite s. s. (xenolith) were discovered in the R-2 drillcore in the Roztoky Intrusive Complex (Figs 1, 2, 7; Rapprich et al. 2017). Both carbonate-rich rock types contain minerals of critical elements reported for the first time in the alkaline volcanic rocks of the České středohoří Mts. These include (Ca)-REE fluorocarbonates, minerals of Zr (zircon, baddeleyite; Fig. 3) and columbite. Chemical composition of these minerals was determined using SEM and EMP and the crystalchemical formulae were calculated. Columbite was classified as columbite-(Mn) (Tab. 3). (Ca)-REE fluorocarbonates were detected in two different samples and rock types. Ca-poor bastnäsite-(Ce) represents the only REE mineral present in carbonatized trachyte at the depth of 156.5 m. Synchysite-(Ce), bastnäsite-(Ce) and parisite-(Ce) were found in dolomite carbonatite at 286.5 m. These minerals form epitactic intergrowths up to 30 µm in size (Fig. 5, 8), which is, according to Armbrustmacher (1979), typical for primary (magmatic) REE minerals. (Ca)-REE fluorocarbonates are Ce-dominant (0.5 apfu), containing significant amounts of La (0.3 apfu) and Nd (0.2 apfu) (Tab. 1). The REE minerals show a typical Y3+?REE3+ substitution, which is especially significant in Ce-poor phases represented by analyses e3 and e4, where Ce is substituted by Y (0.1 apfu) and minor Sm, Eu, Gd and Th (Tab. 1). [ABSTRACT FROM AUTHOR]

New data on the age of dolerite dikes in the NE part of the Kola province of the Fennoscandinavian shield and the picrodolerite sills that cut the dikes are presented. The results of U–Pb ID-TIMS baddeleyite dating indicate that dolerites were formed between 2508 ± 6 and 2513 ± 16 Ma ago, simultaneously with the intrusions of the Monchegorsk group. A comparison of the composition of the dolerites studied with dykes of the same age found in other Archean cratons shows their significant similarity and suggests their formation at the same large magmatic province. The age of baddeleyite from the picrodolerites sills at 2403 ± 12 Ma ago indicates an event of basic magmatism that was not previously established in this part of the Fennoscandinavian shield. It is possible that, along with dolerite dykes with an age of 2405 Ma and komatiites of the Vetreny belt of the Karelian craton, sills of the Kola province are a component of a unified large magmatic event. [ABSTRACT FROM AUTHOR]

Northwest Africa (NWA) 6950 is an olivine-gabbro lunar meteorite that has a distinctly different petrographic texture from other lunar basalts. In this contribution, we report the petrography, mineralogy, and U-Pb geochronology of baddeleyite and phosphate in this lunar meteorite and make a comparison with other NWA 773 paired meteorites. NWA 6950 consists mainly of coarse-grained olivine, pyroxene, and plagioclase, with minor ilmenite, chromite, troilite, baddeleyite, taenite, and apatite. The abundant rounded to euhedral olivine has a limited Fo ranging from 68 to 69. Pyroxenes include both augite and pigeonite, with a narrow range of Mg#=71–80, and composition, respectively, En46–52Fs12–16Wo32–41 and En58–68Fs19–28Wo7–20. Plagioclase is mainly anhedral, conforming to the crystal margins of olivine and pyroxene. The plagioclase grains are elongated and several hundreds of microns in length. Raman spectra shows that plagioclase has been transformed into maskelynite, which is very calcic (An87–95) with low sodium and very low potassium (Ab4–9Or0.6–3.7). The weighted mean 207Pb/206Pb ages of baddeleyite and phosphate measured using a sensitive high resolution ion micro probe (SHRIMP II) are 3119 ± 16 Ma (n = 9, MSWD = 2.5) (mean squared weighted deviates, MSWD) and 3119 ± 18 Ma (n = 15, MSWD = 2.1), respectively, giving the crystallization age of the meteorite. NWA 6950 has similar mineral compositions, geochemical characteristics, and an almost identical age of crystallization to the magnesian gabbro of the NWA 773 clan. We conclude that NWA 6950 and NWA 773 are paired meteorites, which crystallize at ca. 3119 Ma, and represent magmatic activities in the KREEP (potassium (K), rare earth elements (REE) and phosphorus (P) rich lunar material) region of the Moon. [ABSTRACT FROM AUTHOR]

Wet high-energy milling and uniaxial pressing are used to fabricate CaO-stabilized tetragonal zirconia polycrystalline ceramic (Ca-TZP) with decent mechanical characteristics, i.e., a hardness of 11.5 GPa, Young’s modulus of 230 GPa, and fracture toughness of 13 MPa·m0.5. The effect of CaO concentration and the sintering temperature on phase composition and mechanical characteristics of CaO-stabilized zirconia ceramic made of baddeleyite is investigated.

This study reports a novel preparation method of zirconia micro-nanoflakes with high (001) facets that is generated through a hydrolysis reaction of the fluozirconic acid (H2ZrF6). Zirconia micro-nanoflakes synthesized at varied conditions were analyzed by the SEM, EDS, μ-XRD, and Raman spectroscopy to characterize the morphology and probe into the crystal growth mechanism. The synthesized zirconia crystals in the form of elliptical micro-nanoflakes or irregular nanoflakes generally display the highly exposed (001) facets with a thickness of 1–100 nm and a length of 0.1–2.0 μm. As the temperature and initial solution concentration increased, the particle sizes of the synthesized zirconia micro-nanoflakes became more uniform and the thicknesses of the (001) facets became larger, suggesting that the synthesized zirconia crystals grow along the (001) facets and mostly along the c-axis direction. This is confirmed by the data from the μ-XRD patterns. The results also demonstrate that an oriented attachment-based growth occurring in a fluorine-rich solution environment was involved in the aggregation and coarsening of zirconia micro-nanoflakes. Meanwhile, synthesized zirconia micro-nanoflakes also evolved from a mixture of monoclinic and tetragonal systems to a pure monoclinic system (i.e., baddeleyite) with the temperature increasing, suggesting a key role of temperature regarding zirconia’s growth.

Granulitic lunar meteorites offer rare insights into the timing and nature of igneous, metamorphic and impact processes in the lunar crust. Accurately dating the different events recorded by these materials is very challenging, however, due to low trace element abundances (e.g. Sm, Nd, Lu, Hf), rare micrometer-scale U-Th-bearing accessory minerals, and disturbed Ar-Ar systematics following a multi-stage history of shock and thermal metamorphism. Here we report on micro-baddeleyite grains in granulitic mafic breccia NWA 3163 for the first time and show that targeted microstructural analysis (electron backscatter diffraction) and nanoscale geochronology (atom probe tomography) can overcome these barriers to lunar chronology. A twinned (∼90°/<401>) baddeleyite domain yields a 232Th/208Pb age of 4328 ± 309 Ma, which overlaps with a robust secondary ion mass spectrometry (SIMS) 207Pb/206Pb age of 4308 ± 18.6 Ma and is interpreted here as the crystallization age for the igneous protolith of NWA 3163. A second microstructural domain, < 2 μm in width, contains patchy overprinting baddeleyite and yields a Th-Pb age of 2175 ± 143 Ma, interpreted as dating the last substantial impact event to affect the sample. This finding demonstrates the potential of combining microstructural characterization with nanoscale geochronology when resolving complex P-T-t histories in planetary materials, here yielding the oldest measured crystallization age for components of lunar granulite NWA 3163 and placing further constraints on the formation and evolution of lunar crust. Image 1 • Lunar meteorite NWA 3163 contains structurally complex baddeleyite (<5 μm) grains. • Targeted dating by atom probe tomography generates accurate Th-Pb ages. • Allows for new temporal constraints on the formation and evolution of the Moon. • Dates previously 'hidden' protolith age (c. 4.3 Ga) of a piece of lunar crust. [ABSTRACT FROM AUTHOR]

We present ten new ID-TIMS U-Pb baddeleyite ages for late Neoarchean to Paleoproterozoic dyke swarms cutting Archean gneisses of the Hopedale block (North Atlantic craton, NAC). An age of 2505 ± 4 Ma for a NNE-trending pyroxenite dyke represents the first date for extension-related mafic magmatism of this antiquity in the Labrador portion of the NAC. Four samples of N-S to NNE-trending Kikkertavak dykes yield ages between 2238 ± 6 Ma and 2216 ± 2 Ma, defining a minimum age range and distribution for this extensive swarm. A single NNE-trending dyke is dated at 2169 ± 13 Ma, representing a new magmatic event at this age in Nain Province, but is equivalent in timing to the well-known Biscotasing dykes in the southern Superior craton. Three NW-trending dykes (termed Ellen Island dykes) yield ages of 2051 ± 6 Ma, 2051 ± 1 Ma and 2050 ± 2 Ma, and represent part of a newly-recognized but important swarm in southern Nain craton. The 2.05 Ga dykes better define a vast radiating fan of dykes that include Kangâmiut and MD3 dykes of southern West and South-West Greenland, respectively. A U-Pb baddeleyite age of 1800 ± 4 Ma has been obtained for a fourth, NW-trending ("Ussiranniak Lake") dyke, which also represents a newly-revealed mafic magmatic event, both in the Labrador and Greenland portions of the NAC. The results presented here are unique for Labrador, but invite comparison with other Neoarchean and Paleoproterozoic mafic dykes elsewhere in the North Atlantic craton and other Archean cratons (e.g., Superior, Kola-Karelia, Zimbabwe). Multiple precise age matches, dyke geochemistry, and dyke geometries for several swarms allow a preliminary level testing of possible reconstructions involving the North Atlantic and eastern Superior cratons. [ABSTRACT FROM AUTHOR]