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  • 1. A. Marques, Ana F.
    et al.
    Roerdink, Desiree L.
    Baumberger, Tamara
    de Ronde, Cornel E. J.
    Ditchburn, Robert G.
    Denny, Alden
    Thorseth, Ingunn H.
    Okland, Ingeborg
    Lilley, Marvin D.
    Whitehouse, Martin J.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pedersen, Rolf B.
    The Seven Sisters Hydrothermal System: First Record of Shallow Hybrid Mineralization Hosted in Mafic Volcaniclasts on the Arctic Mid-Ocean Ridge2020Övrigt (Övrigt vetenskapligt)
    Abstract [en]

    We document the discovery of an active, shallow, seafloor hydrothermal system (known as the Seven Sisters Vent Field) hosted in mafic volcaniclasts at a mid-ocean ridge setting. The vent field is located at the southern part of the Arctic mid-ocean ridge where it lies on top of a flat-topped volcano at ~130 m depth. Up to 200 deg C phase-separating fluids vent from summit depressions in the volcano, and from pinnacle-like edifices on top of large hydrothermal mounds. The hydrothermal mineralization at Seven Sisters manifests as a replacement of mafic volcaniclasts, as direct intraclast precipitation from the hydrothermal fluid, and as elemental sulfur deposition within orifices. Barite is ubiquitous, and is sequentially replaced by pyrite, which is the first sulfide to form, followed by Zn-Cu-Pb-Ag bearing sulfides, sulfosalts, and silica. The mineralized rocks at Seven Sisters contain highly anomalous concentrations of ‘epithermal suite’ elements such as Tl, As, Sb and Hg, with secondary alteration assemblages including silica and dickite. Vent fluids have a pH of ~5 and are Ba and metal depleted. Relatively high dissolved Si (~7.6 mmol/L Si) combined with low (0.2–0.4) Fe/Mn suggest high-temperature reactions at ~150 bar. A delta-13C value of -5.4 permil in CO2 dominated fluids denotes magmatic degassing from a relatively undegassed reservoir. Furthermore, low CH4 and H2 (<0.026 mmol/kg and <0.009 mmol/kg, respectively) and 3He/4He of ~8.3 R/Racorr support a MORB-like, sediment-free fluid signature from an upper mantle source. Sulfide and secondary alteration mineralogy, fluid and gas chemistry, as well as delta-34S and 87Sr/86Sr values in barite and pyrite indicate that mineralization at Seven Sisters is sustained by the input of magmatic fluids with minimal seawater contribution. 226Ra/Ba radiometric dating of the barite suggests that this hydrothermal system has been active for at least 4670 +/- 60 yr.

  • 2.
    Allard, Bert
    et al.
    Man-Technology-Environment Research Centre (MTM), Örebro University, SE-701 82 Örebro, Sweden.
    Sjöberg, Susanne
    Department of Geological Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.
    Sjöberg, Viktor
    Man-Technology-Environment Research Centre (MTM), Örebro University, SE-701 82 Örebro, Sweden.
    Skogby, Henrik
    Naturhistoriska riksmuseet, Enheten för geovetenskap. Department of Geosciences, Swedish Museum of Natural History, SE-114 18 Stockholm, Sweden.
    Karlsson, Stefan
    Man-Technology-Environment Research Centre (MTM), Örebro University, SE-701 82 Örebro, Sweden.
    Metal Exchangeability in the REE-Enriched Biogenic Mn Oxide Birnessite from Ytterby, Sweden2023Ingår i: Minerals, E-ISSN 2075-163X, Vol. 13, s. 1-14, artikel-id 1023Artikel i tidskrift (Refereegranskat)
  • 3.
    Altieri, Alessandra
    et al.
    Sapienza University, Rome, Italy.
    Luppi, Riccardo
    Sapienza University, Rome, Italy.
    Skogby, Henrik
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Tempesta, Gioacchino
    Università degli Studi di Bari Aldo Moro, Bari, Italy.
    Pezzotta, Federico
    MUM–Mineralogical Museum “Luigi Celleri”,Campo nell’Elba, Leghorn, Italy.
    Bosi, Ferdinando
    Sapienza University, Rome, Italy.
    Thermal treatment of the tourmaline Fe-rich princivalleite Na(Mn2Al)Al6(Si6O18)(BO3)3(OH)3O2023Ingår i: Physics and chemistry of minerals, ISSN 0342-1791, E-ISSN 1432-2021, Vol. 50, nr 4, s. 1-12, artikel-id 27Artikel i tidskrift (Refereegranskat)
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  • 4. Altieri, Alessandra
    et al.
    Pezzotta, Federico
    Andreozzi, Giovanni B.
    Skogby, Henrik
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Bosi, Ferdinando
    Genetic model for the color anomalies at the termination of pegmatitic gem tourmaline crystals from the island of Elba, Italy2023Ingår i: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 35, nr 5, s. 755-771Artikel i tidskrift (Refereegranskat)
  • 5. Altieri, Alessandra
    et al.
    Pezzotta, Federico
    Skogby, Henrik
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Bosi, Ferdinando
    Dark-coloured Mn-rich overgrowths in an elbaitic tourmaline crystal from the Rosina pegmatite, San Piero in Campo, Elba Island, Italy: witness of late-stage opening of the geochemical system2023Ingår i: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 87, nr 1, s. 130-142Artikel i tidskrift (Refereegranskat)
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  • 6. Alvarez, Belinda
    et al.
    Frings, Patrick J
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Clymans, Wim
    Fontorbe, Guillaume
    Conley, Daniel
    Assessing the Potential of Sponges (Porifera) as Indicators of Ocean Dissolved Si Concentrations2017Ingår i: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 4, nr 373Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We explore the distribution of sponges along dissolved silica (dSi) concentration gradients to test whether sponge assemblages are related to dSi and to assess the validity of fossil sponges as a palaeoecological tool for inferring dSi concentrations of the past oceans. We extracted sponge records from the publically available Global Biodiversity Information Facility (GBIF) database and linked these records with ocean physiochemical data to evaluate if there is any correspondence between dSi concentrations of the waters sponges inhabit and their distribution. Over 320,000 records of Porifera were available, of which 62,360 met strict quality control criteria. Our analyses was limited to the taxonomic levels of family, order and class. Because dSi concentration is correlated with depth in the modern ocean, we also explored sponge taxa distributions as a function of depth. We observe that while some sponge taxa appear to have dSi preferences (e.g., class Hexactinellida occurs mostly at high dSi), the overall distribution of sponge orders and families along dSi gradients is not sufficiently differentiated to unambiguously relate dSi concentrations to sponge taxa assemblages. We also observe that sponge taxa tend to be similarly distributed along a depth gradient. In other words, both dSi and/or another variable that depth is a surrogate for, may play a role in controlling sponge spatial distribution and the challenge is to distinguish between the two. We conclude that inferences about palaeo-dSi concentrations drawn from the abundance of sponges in the stratigraphic records must be treated cautiously as these animals are adapted to a great range of dSi conditions and likely other underlying variables that are related to depth. Our analysis provides a quantification of the dSi ranges of common sponge taxa, expands on previous knowledge related to their bathymetry preferences and suggest that sponge taxa assemblages are not related to particular dSi conditions. 

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  • 7. Anand, Rajagopal
    et al.
    Balakrishnan, Srinivasan
    Kooijman, Ellen
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Mezger, Klaus
    Neoarchean crustal growth by accretionary processes: Evidence from combined zircon–titanite U–Pb isotope studies on granitoid rocks around the Hutti greenstone belt, eastern Dharwar Craton, India2014Ingår i: Journal of Asian Earth Sciences, ISSN 1367-9120, E-ISSN 1878-5786, Vol. 79, s. 72-85Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Neoarchean Hutti greenstone belt hosts mesothermal gold deposits and is surrounded by granitoid rocks on all sides. Combined U–Pb dating of zircon and titanite from the granitoid rocks constrains their emplacement history and subsequent geologic evolution. The Golapalli and Yelagatti granodiorites occurring to the north of the Hutti greenstone belt were emplaced at 2569 ± 17 Ma. The Yelagatti granodiorite yielded a younger titanite age of 2530 ± 6 Ma which indicates that it was affected by a post-crystallization thermal event that exceeded the titanite closure temperature. The western granodiorites from Kardikal have identical titanite and zircon ages of 2557 ± 6 Ma and 2559 ± 19 Ma, respectively. The eastern Kavital granodiorites yielded titanite ages of 2547 ± 6 Ma and 2544 ± 24 Ma which are identical to the published U–Pb zircon SHRIMP ages. These ages imply that the granitoid rocks surrounding the Hutti greenstone belt were formed as discrete batholiths within a short span of ca. 40 Ma between 2570 Ma and 2530 Ma ago. They were juxtaposed by horizontal tectonic forces against the supracrustal rocks that had formed in oceanic settings at the end of the Archean. The first phase of gold mineralization coincided with the last phase of granodiorite intrusion in the Hutti area. A metamorphic overprint occurred at ca. 2300 Ma ago that reset the Rb–Sr isotope system in biotites and possibly caused hydrothermal activity and enrichment of Au in the ore lodes. The eastern Dharwar Craton consists of quartz monzodiorite–granodiorite–granite suites of rocks that are younger than the greenstone belts that are older than ~2650 Ma reported from earlier studies. The granitoid magmatism took place between 2650 and 2510 Ma ago indicating accretionary growth of the eastern Dharwar Craton.

  • 8.
    Anders, Bebhinn
    et al.
    Earth and Ocean Sciences, School of Natural Sciences, NUI Galway, University Road, Galway, Ireland;Sediment Origins Research Team (SORT), NUI Galway, Ireland.
    Tyrrell, S.
    Earth and Ocean Sciences, School of Natural Sciences, NUI Galway, University Road, Galway, Ireland;Sediment Origins Research Team (SORT), NUI Galway, Ireland;Irish Centre for Research in Applied Geosciences (iCRAG), Ireland.
    Chew, D.
    Department of Geology, Trinity College Dublin, College Green, Dublin 2, Ireland;Irish Centre for Research in Applied Geosciences (iCRAG), Ireland.
    Mark, C.
    Naturhistoriska riksmuseet, Enheten för geovetenskap. UCD School of Earth Sciences, University College Dublin, Belfield, Dublin 4, Ireland.
    O'Sullivan, G.
    UCD School of Earth Sciences, University College Dublin, Belfield, Dublin 4, Ireland.
    Murray, J.
    Earth and Ocean Sciences, School of Natural Sciences, NUI Galway, University Road, Galway, Ireland;Irish Centre for Research in Applied Geosciences (iCRAG), Ireland.
    Graham, J.R.
    Department of Geology, Trinity College Dublin, College Green, Dublin 2, Ireland.
    Badenszki, E.
    Irish Centre for Research in Applied Geosciences (iCRAG), Ireland;UCD School of Earth Sciences, University College Dublin, Belfield, Dublin 4, Ireland.
    Spatial variation in provenance signal: identifying complex sand sourcing within a Carboniferous basin using multiproxy provenance analysis2022Ingår i: Journal of the Geological Society, ISSN 0016-7649, E-ISSN 2041-479X, Vol. 179, nr 1, artikel-id jgs2021-045Artikel i tidskrift (Refereegranskat)
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  • 9. Anders, Bébhinn
    et al.
    Tyrrell, Shane
    Chew, David
    O’Sullivan, Gary
    Mark, Chris
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Graham, John
    Badenszki, Eszter
    Murray, John
    Wildfires and Monsoons: Cryptic Drivers for Highly Variable Provenance Signals within a Carboniferous Fluvial System2022Ingår i: Geosciences, E-ISSN 2076-3263, Vol. 12, nr 1, s. 20-20Artikel i tidskrift (Refereegranskat)
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  • 10. Andersson, Stefan S.
    et al.
    Wagner, Thomas
    Jonsson, Erik
    Fusswinkel, Tobias
    Whitehouse, Martin J.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Apatite as a tracer of the source, chemistry and evolution of ore-forming fluids: The case of the Olserum-Djupedal REE-phosphate mineralisation, SE Sweden2019Ingår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 255, s. 163-187Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study explores the suitability of apatite as a tracer of the source(s), chemistry, and evolution of ore-forming hydrothermal fluids. This is tested by analysing the halogen (F, Cl, Br, and I), stable Cl isotopic, and trace element compositions of fluorapatite from the regional-scale Olserum-Djupedal rare earth element (REE) phosphate mineralisation in SE Sweden, which is dominated by monazite-(Ce), xenotime-(Y), and fluorapatite. The primary hydrothermal fluid flow system is recorded in a sequence from proximal granite-hosted to distal metasediment-hosted fluorapatite. Along this sequence, primary fluorapatite shows a gradual increase of Cl and Br concentrations and in (Gd/Yb)N, a decrease of F and I concentrations, a decrease in δ37Cl values, in (La/Sm)N, and partly in (La/Yb)N and (Y/Ho)N. Local compositional differences of halogen and trace element concentrations have developed along rims and in domains adjacent to fractures of fluorapatite due to late-stage partial reaction with fracture fluids. These differences are insignificant compared to the larger deposit-scale zoning. This suggests that apatite can retain the primary record of the original ore-forming fluid despite later overprinting fluid events. The agreement between Br/Cl and I/Cl ratios of apatite and those of co-existing fluid inclusions at lower temperatures indicates that only a minor fractionation of Br from I occurs during apatite precipitation. The halogen ratios of apatite can thus be used as a first-order estimate for the composition of the ore-forming fluid. Taking the small fractionation factors for Cl isotopes between apatite and co-existing fluid at high temperatures into account, we propose that the Cl isotopic composition of apatite and the halogen ratios derived from the apatite composition can be used jointly to trace the source(s) of ore-forming fluids. By contrast, most trace elements incorporated in apatite are affected by the host rock environment and by fluid-mineral partitioning due to growth competition between co-crystallising minerals. Collectively, apatite is sensitive to changing fluid compositions, yet it is also able to record the character of primary ore-forming fluids. Thus, apatite is suitable for tracing the origin, chemistry, and evolution of fluids in hydrothermal ore-forming settings.

  • 11.
    Andreozzi, Giovanni
    et al.
    Sapienza Università di Roma, Italy.
    D'Ippolito, Veronica
    Sapienza Università di Roma, Italy.
    Skogby, Henrik
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Color mechanisms in spinel: a multi-analytical investigation of natural crystals with a wide range of coloration.2019Ingår i: Physics and chemistry of minerals, ISSN 0342-1791, E-ISSN 1432-2021, Vol. 46, nr 4, s. 343-360Artikel i tidskrift (Refereegranskat)
  • 12.
    Ardit, Matteo
    et al.
    University of Ferrara, Italy.
    Cámara, Fernando
    University of Milano, Italy.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Vanadium-induced coloration in grossite (CaAl4O7) and hibonite (CaAl12O19)2021Ingår i: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 106, nr 4, s. 599-608Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High concentrations of vanadium cause very unusual coloration in hibonite (purple) and grossite (light violet) crystals in an exotic mineral assemblage from Sierra de Comechingones (Argentina). In the hibonite (CaAl12O19) structure vanadium ions, in various valence states (divalent, trivalent, and tetravalent), may be distributed over five crystallographic sites with coordinations corresponding to different polyhedra, namely, three unequal octahedra [M1 (D3d), M4 (C3ν), and M5 (Cs)], one M3 tetrahedron (C3ν), and one unusual fivefold-coordinated trigonal bipyramid M2 (D3h). Possible locations of vanadium ions in grossite (CaAl4O7) are limited to two crystallographically distinct sites (T1 and T2, both C1) in tetrahedral coordination.

    The combination of single-crystal X-ray diffraction and absorption spectroscopy techniques aided by chemical analyses has yielded details on the nature of the vanadium-induced color in both hibonite and grossite crystals. In hibonite, both M4 face-sharing octahedral and M2 trigonal bipyramid sites of the R-block are partially occupied by V3+. Strongly polarized bands recorded at relatively low energies in optical absorption spectra indicate that V2+ is located at the M4 octahedral site of the hibonite R-block. Chemical analyses coupled with an accurate determination of the electron densities at structural sites in hibonite suggest that the vanadium ions occupy about 10 and 5% of the M4 and M2 sites, respectively. For grossite, polarized optical absorption spectra reveal no indications of V2+; all observed absorption bands can be assigned to V3+ in tetrahedral coordination. Although not evident by the observed electron densities at the T sites of grossite (due to the low-V content), longer bond distances, and a higher degree of polyhedral distortion suggest that V3+ is located at the T2 site.

  • 13. Augustsson, Carita
    et al.
    Rüsing, Tobias
    Niemeyer, Hans
    Kooijman, Ellen
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Berndt, Jasper
    Bahlburg, Heinrich
    Zimmermann, Udo
    0.3 byr of drainage stability along the Palaeozoic palaeo-Pacific Gondwana margin; a detrital zircon study2015Ingår i: Journal of the Geological Society, ISSN 0016-7649, E-ISSN 2041-479X, Vol. 172, s. 186-200Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The palaeo-Pacific margin of Gondwana in the present-day south–central Andes is marked by tectonic activity related to subduction and terrane accretion. We present detrital zircon U–Pb data encompassing the Palaeozoic era in northern Chile and northwestern Argentina. Cathodoluminescence images reveal dominantly magmatic zircon barely affected by abrasion and displaying only one growth phase. The main age clusters for these zircon grains are Ediacaran to Palaeozoic with an additional peak at 1.3–0.9 Ga and they can be correlated with ‘Grenvillian’ age, and the Brasiliano, Pampean, and Famatinian orogenies. The zircon data reveal main transport from the nearby Ordovician Famatinian arc and related rocks. The Silurian sandstone units are more comparable with Cambrian units, with Brasiliano and Transamazonian ages (2.2–1.9 Ga) being more common, because the Silurian deposits were situated within or east of the (extinct) Famatinian arc. Hence, the arc acted as a transport barrier throughout Palaeozoic time. The complete suite of zircon ages does not record the accretions of exotic terranes or the Palaeozoic glacial periods. We conclude that the transport system along the palaeo-Pacific margin of Gondwana remained stable for c. 0.3 byr and that provenance data do not necessarily reflect the interior of a continent. Hence, inherited geomorphological features must be taken into account when detrital mineral ages are interpreted.

  • 14.
    Babechuk, Michael
    et al.
    Isotope Geochemistry Group, Department of Geosciences, Eberhard Karls University of Tübingen, Tübingen, Germany.
    Weimar, Nadine
    Isotope Geochemistry Group, Department of Geosciences, Eberhard Karls University of Tübingen, Tübingen, Germany.
    Kleinhanns, Ilka
    Isotope Geochemistry Group, Department of Geosciences, Eberhard Karls University of Tübingen, Tübingen, Germany.
    Eroglu, Suemeyya
    Isotope Geochemistry Group, Department of Geosciences, Eberhard Karls University of Tübingen, Tübingen, Germany.
    Swanner, Elizabeth
    Department of Geological & Atmospheric Sciences, Iowa State University, Ames, USA.
    Kenny, Gavin
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Kamber, Balz
    Department of Geology, Trinity College Dublin, Dublin, Ireland.
    Schoenberg, Ronny
    Isotope Geochemistry Group, Department of Geosciences, Eberhard Karls University of Tübingen, Tübingen, Germany.
    Pervasively anoxic surface conditions at the onset of the Great Oxidation Event: New multi-proxy constraints from the Cooper Lake paleosol2019Ingår i: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 323, s. 126-163Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Oceanic element inventories derived from marine sedimentary rocks place important constraints on oxidativecontinental weathering in deep time, but there remains a scarcity in complementary observations directly fromcontinental sedimentary reservoirs. This study focuses on better defining continental weathering conditions nearthe Archean-Proterozoic boundary through the multi-proxy (major and ultra-trace element, Fe and Cr stableisotopes, μ-XRF elemental mapping, and detrital zircon U-Pb geochronology) investigation of the ca. 2.45 billionyear old (giga annum, Ga) Cooper Lake paleosol (saprolith) developed on a sediment-hosted mafic dike withinthe Huronian Supergroup (Ontario, Canada).Throughout the variably altered Cooper Lake saprolith, ratios of immobile elements (Nb, Ta, Zr, Hf, Th, Al, Ti)are constant, indicating a uniform pre-alteration dike composition, lack of extreme pH weathering conditions,and no major influence from ligand-rich fluids during weathering or burial metasomatism/metamorphism. Theloss of Mg, Fe, Na, Sr, and Li, a signature of albite and ferromagnesian silicate weathering, increases towards thetop of the preserved profile (unconformity) and dike margins. Coupled bulk rock behaviour of Fe-Mg-Mn and colocalizationof Fe-Mn in clay minerals (predominantly chlorite) indicates these elements were solubilized primarilyin their divalent state without Fe/Mn-oxide formation. A lack of a Ce anomaly and immobility of Mo, V, and Cr further support pervasively anoxic weathering conditions. Subtle U enrichment, if primary, is the onlygeochemical evidence that could be consistent with oxidative element mobilization. The leaching of ferromagnesiansilicates was accompanied by variable mobility and depletion of transition metals with a relativedepletion order of Fe≈Mg≈Zn > Ni > Co > Cu (Cu being significantly influenced by secondary sulfideformation). Mild enrichment of heavy Fe isotopes (δ56/54Fe from 0.169 to 0.492‰) correlating with Fe depletionin the saprolith indicates open-system loss of isotopically light aqueous Fe(II). Minor REE+Y fractionation withincreasing alteration intensity, including a decreasing Eu anomaly and Y/Ho ratio, is attributed to albitebreakdown and preferential scavenging of HREE > Y by clay minerals, respectively. Younger metasomatismresulted in the addition of several elements (K, Rb, Cs, Be, Tl, Ba, Sn, In, W), partly or wholly obscuring theirearlier paleo-weathering trends.The behavior of Cr at Cooper Lake can help test previous hypotheses of an enhanced, low pH-driven continentalweathering flux of Cr(III) to marine reservoirs between ca. 2.48–2.32 Ga and the utility of the stable Crisotope proxy of Mn-oxide induced Cr(III) oxidation. Synchrotron μ-XRF maps and invariant Cr/Nb ratios revealcomplete immobility of Cr despite its distribution amongst both clay-rich groundmass and Fe-Ti oxides.Assuming a pH-dependent, continental source of Cr(III) to marine basins, the Cr immobility at Cooper Lakeindicates either that signatures of acidic surface waters were localized to uppermost and typically unpreservedregolith horizons or were geographically restricted to acid-generating point sources. However, given detritalpyrite preservation in overlying fluvial sequences, it is probable that the oxidative sulfide corrosion required todrive surface pH < 4 lagged behind in this region relative to other early Proterozoic sequences. The entiresaprolith exhibits a consistently light stable Cr isotope composition (δ53/52Cr: −0.321 ± 0.038‰, 2sd, n=34)that cannot be linked to Cr(III) oxidation and is instead interpreted to have a magmatic origin.

  • 15. Badenszki, Eszter
    et al.
    Daly, J Stephen
    Whitehouse, Martin J.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Kronz, Andreas
    Upton, Brian G J
    Horstwood, Matthew S A
    Age and Origin of Deep Crustal Meta-igneous Xenoliths from the Scottish Midland Valley: Vestiges of an Early Palaeozoic Arc and ‘Newer Granite’ Magmatism2019Ingår i: Journal of Petrology, ISSN 0022-3530, E-ISSN 1460-2415, Vol. 60, nr 8, s. 1543-1574Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Deep crustal felsic xenoliths from classic Scottish Midland Valley localities, carried to the surface by Permo-Carboniferous magmatism, are shown for the first time to include metaigneous varieties with dioritic and tonalitic protoliths. Four hypotheses regarding their origin have been evaluated: (1) Precambrian basement; (2) Permo-Carboniferous underplating; (3) ‘Newer Granite’ magmatism; (4) Ordovician arc magmatism. U–Pb zircon dating results rule out the Precambrian basement and Permo-Carboniferous underplating hypotheses, but establish that the meta-igneous xenoliths represent both ‘Newer Granite’ and Ordovician (to possibly Silurian) arc magmatism. The metadiorite xenoliths are shown to have protolith ages of c. 415 Ma with εHft zircon values ranging from +0·1 to +11·1. These are interpreted to represent unexposed ‘Newer Granite’ plutons, based on age, mineralogical, isotopic and geochemical data. This shows that Devonian ‘Newer Granite’ magmatism had a greater impact on the Midland Valley and Southern Uplands crust than previously realized. Clinopyroxene–plagioclase–quartz barometry on the metadiorites from the east and west of the Midland Valley yielded a similar pressure range of c. 5–10 kbar, and a metadiorite from the east yielded a minimum two-feldspar temperature estimate of c. 793–816°C. These results indicate that the metadiorites once resided in the middle–lower crust. In contrast, two metatonalite xenoliths have a Late Ordovician protolith age (c. 453 Ma), with zircon εHft values of +7·8 to +9·0. These are interpreted as samples of a buried Late Ordovician magmatic arc situated within the Midland Valley. Inherited zircons with similar Late Ordovician ages and εHft=453 values (+1·6 to +10·8) are present in the metadiorites, suggesting that the Devonian ‘Newer Granites’ intruded within or through this Late Ordovician Midland Valley arc. A younger protolith age of c. 430 Ma from one of the metatonalites suggests that arc activity continued until Silurian times. This validates the long-standing ‘arc collision’ hypothesis for the development of the Caledonian Orogen. Based on U–Pb zircon dating, the metatonalite and metadiorite xenoliths have both experienced metamorphism between c. 400 and c. 391 Ma, probably linked to the Acadian Orogeny. An older phase of metamorphism at c. 411 Ma was possibly triggered by the combined effects of heating owing to the emplacement of the ‘Newer Granite’ plutons and the overthrusting of the Southern Uplands terrane onto the southern margin of the Midland Valley terrane.

  • 16.
    Bailey, Lydia R.
    et al.
    Department of Geosciences University of Arizona Tucson AZ USA.
    Drake, Henrik
    Department of Biology and Environmental Science Linnæus University Kalmar Sweden.
    Whitehouse, Martin J.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Reiners, Peter W.
    Department of Geosciences University of Arizona Tucson AZ USA;Faculty of Environment University of Northern British Columbia Prince George BC Canada.
    Characteristics and Consequences of Red Bed Bleaching by Hydrocarbon Migration: A Natural Example From the Entrada Sandstone, Southern Utah2022Ingår i: Geochemistry Geophysics Geosystems, E-ISSN 1525-2027, Vol. 23, nr 8, artikel-id e2022GC010465Artikel i tidskrift (Refereegranskat)
  • 17.
    Baker, Don R.
    et al.
    Department of Earth and Planetary Sciences, McGill University, Montreal, Quebec H3A 0E8, Canada;‡ Special collection papers can be found online at http://www.minsocam.org/MSA/AmMin/special-collections.html..
    Callegaro, Sara
    Centre for Earth Evolution and Dynamics (CEED), University of Oslo, PO Box 1028, Blindern N-0316 Oslo, Norway.
    De Min, Angelo
    Department of Mathematics and Geoscience, University of Trieste, via Weiss 2, 34128 Trieste, Italy.
    Whitehouse, Martin J.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Marzoli, Andrea
    Department of Land, Environment, Agriculture and Forestry, University of Padova, 16-35020 Legnaro, Padova, Italy.
    Fluorine partitioning between quadrilateral clinopyroxenes and melt2022Ingår i: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 107, nr 2, s. 167-177Artikel i tidskrift (Refereegranskat)
  • 18. Baker, Don R.
    et al.
    Callegaro, Sara
    Marzoli, Andrea
    De Min, Angelo
    Geraki, Kalotina
    Whitehouse, Martin J.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Krzesinska, Agata M.
    Fioretti, Anna Maria
    Sulfur and chlorine in nakhlite clinopyroxenes: Source region concentrations and magmatic evolution2023Ingår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 359, s. 1-19Artikel i tidskrift (Refereegranskat)
  • 19. Ballirano, Paolo
    et al.
    Celata, Beatrice
    Skogby, Henrik
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Andreozzi, Giovanni
    Bosi, Ferdinando
    HT breakdown of Mn-bearing elbaite from the Anjanabonoina pegmatite, Madagascar2022Ingår i: Journal of Geosciences, ISSN 1802-6222, E-ISSN 1803-1943, Vol. 67, s. 151-161Artikel i tidskrift (Refereegranskat)
  • 20. Barnes, Christopher J..
    et al.
    Majka, Jarek
    Jeanneret, Pauline
    Ziemniak, Grzegorz
    Kooijman, Ellen
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Kośmińska, Karolina
    Kielman-Schmitt, Melanie
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Schneider, D.A.
    Using Th-U-Pb geochronology to extract crystallization ages of Paleozoic metamorphic monazite contaminated by initial Pb2021Ingår i: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 582, s. 120450-120450, artikel-id 120450Artikel i tidskrift (Refereegranskat)
  • 21.
    Barnes, Christopher
    et al.
    Faculty of Geology, Geophysics and Environmental Protection, AGH University of Science and Technology, Kraków, Poland.
    Jarosław, Majka
    Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
    Schneider, David
    Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, Canada.
    Walczak, Katarzyna
    Faculty of Geology, Geophysics and Environmental Protection, AGH University of Science and Technology, Kraków, Poland.
    Bukała, Michał
    Faculty of Geology, Geophysics and Environmental Protection, AGH University of Science and Technology, Kraków, Poland.
    Kośmińska, Karolina
    Faculty of Geology, Geophysics and Environmental Protection, AGH University of Science and Technology, Kraków, Poland.
    Tokarski, Tomasz
    Academic Center for Materials and NanotechnologyAGH University of Science and TechnologyKrakówPoland.
    Karlsson, Andreas
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    High-spatial resolution dating of monazite and zircon reveals the timing of subduction–exhumation of the Vaimok Lens in the SeveNappe Complex (Scandinavian Caledonides)2019Ingår i: Contributions to Mineralogy and Petrology, ISSN 0010-7999, E-ISSN 1432-0967, Vol. 174, nr 1, artikel-id 5Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In-situ monazite Th–U–total Pb dating and zircon LA–ICP–MS depth-profiling was applied to metasedimentary rocks from the Vaimok Lens in the Seve Nappe Complex (SNC), Scandinavian Caledonides. Results of monazite Th–U–total Pb dating, coupled with major and trace element mapping of monazite, revealed 603 ± 16 Ma Neoproterozoic cores surrounded byrims that formed at 498 ± 10 Ma. Monazite rim formation was facilitated via dissolution–reprecipitation of Neoproterozoic monazite. The monazite rims record garnet growth as they are depleted in Y2O3 with respect to the Neoproterozoic cores. Rims are also characterized by relatively high SrO with respect to the cores. Results of the zircon depth-profiling revealed igneous zircon cores with crystallization ages typical for SNC metasediments. Multiple zircon grains also exhibit rims formedby dissolution–reprecipitation that are defined by enrichment of light rare earth elements, U, Th, P, ± Y, and ± Sr. Rims also have subdued Eu anomalies (Eu/Eu* ≈ 0.6–1.2) with respect to the cores. The age of zircon rim formation was calculated from three metasedimentary rocks: 480 ± 22 Ma; 475 ± 26 Ma; and 479 ± 38 Ma. These results show that both monazite and zircon experienced dissolution–reprecipitation under high-pressure conditions. Caledonian monazite formed coeval with garnet growth during subduction of the Vaimok Lens, whereas zircon rim formation coincided with monazite breakdown to apatite, allanite and clinozoisite during initial exhumation.

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  • 22. Barão, Lúcia
    et al.
    Vandevenne, Floor
    Clymans, Wim
    Frings, Patrick J
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Ragueneau, Olivier
    Meire, Patrick
    Conley, Daniel J.
    Struyf, Eric
    Alkaline-extractable silicon from land to ocean: A challenge for biogenic silicon determination2015Ingår i: Limnology and Oceanography: Methods, E-ISSN 1541-5856, s. n/a-n/aArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    The biogeochemical cycling of silicon (Si) along the land-to-ocean continuum is studied by a variety of research fields and for a variety of scientific reasons. However, there is an increasing need to refine the methodology and the underlying assumptions used to determine biogenic silica (BSi) concentrations. Recent evidence suggests that contributions of nonbiogenic sources of Si dissolving during alkaline extractions, not corrected by standard silicate mineral dissolution correction protocols, can be substantial. The ratio between dissolved Si and aluminum (Al) monitored continuously during the alkaline extraction can be used to infer the origin of the Si fractions present. In this study, we applied both a continuous analysis method (0.5 M NaOH) and a traditional 0.1 M Na2CO3 extraction to a wide array of samples: (1) terrestrial vegetation, (2) soils from forest, cropland and pasture, (3) lake sediments, (4) suspended particulate matter and sediments from rivers, (5) sediments from estuaries and salt marshes and (6) ocean sediments. Our results indicate that the 0.1 M Na2CO3 extraction protocol can overestimate the BSi content, by simultaneously dissolving Si fractions of nonbiogenic origin that may represent up to 100% of the Si traditionally considered as biogenic, hampering interpretation especially in some deeper soil horizons, rivers and coastal oceanic sediments. Moreover, although the term amorphous Si was coined to reflect a growing awareness of nonbiogenic phases we show it is actually inappropriate in samples where silicate minerals may account for a large part of the extracted Si even after linear mineral correction.

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  • 23. Baumgartner, Raphael J
    et al.
    Caruso, Stefano
    Fiorentini, Marco L
    Van Kranendonk, Martin J
    Martin, Laure
    Jeon, Heejin
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pagès, Anais
    Wacey, David
    Sulfidization of 3.48 billion-year-old stromatolites of the Dresser Formation, Pilbara Craton: Constraints from in-situ sulfur isotope analysis of pyrite2020Ingår i: Chemical Geology, Vol. 538Artikel i tidskrift (Refereegranskat)
  • 24. Bellucci, J. J.
    et al.
    Herd, C. D. K.
    Whitehouse, Martin J.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Nemchin, A. A.
    Kenny, G. G.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Merle, Renaud E.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Insights into the chemical diversity of the martian mantle from the Pb isotope systematics of shergottite Northwest Africa 81592020Ingår i: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 545, artikel-id 119638Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Shergottite Northwest Africa (NWA) 8159 is a basaltic rock derived from a mantle source with chemical characteristics that are unique in the martian meteorite suite. To further investigate this source reservoir, the Pb isotope compositions of plagioclase/maskelynite, pyroxene, phosphates, and shock melt-glass in NWA 8159 have been measured in situ by Secondary Ion Mass Spectrometry (SIMS). Due to the limited spread in Pb isotope data, these Pb isotope compositions have been used to calculate an imprecise PbPb isochron age of 3.4 ± 2.1 Ga (2σ), which is broadly consistent with the crystallization age of 2.37 ± 0.25 Ga determined previously by 147Sm143Nd. The lack of radiogenic in-growth within individual minerals since 2.4 Ga means that this sample is depleted in U, which is in agreement with NWA 8159's positive initial ε143Nd. An initial Pb composition was calculated using an x-y weighted average of the least radiogenic Pb isotope population measured in the sample. This initial Pb composition is not consistent with the model for Pb growth in the shergottite mantle at 2.4 Ga. This composition is, however, consistent with the model for the Nakhla-Chassigny mantle. Using the latter model, a source μ (238U/204Pb) of 2.6 ± 0.6 has been calculated. This μ-value is in contrast with the other depleted shergottites (1.4-1.5) and falls significantly off the array of source ε143Nd vs. μ defined by the rest of the martian meteorite suite and thus, necessitates a differentiation history distinct from the other martian meteorites. Sequestering Pb in sulphides during differentiation is the only mechanism to fractionate U from Pb and create a low-μ reservoir. Consequently, the relatively high μ-value of the source of NWA 8159 is in contrast with the positive initial ε143Nd and indicates that its mantle source region likely lacked significant sulphur. This is consistent with the lack of sulphides in the sample itself and could have played a role in its complicated oxidation history.

  • 25. Bellucci, J. J.
    et al.
    Whitehouse, Martin J.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Nemchin, A. A.
    Snape, J. F.
    Kenny, G. G.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Merle, Renaud E.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Bland, P. A.
    Benedix, G. K.
    Tracing martian surface interactions with the triple O isotope compositions of meteoritic phosphates2020Ingår i: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 531, artikel-id 115977Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The triple oxygen isotope compositions of phosphate grains in six martian meteorites have been measured by Secondary Ion Mass Spectrometry (SIMS) and combined together with their chlorine isotope and halogen concentrations have been used to constrain hydrosphere-lithosphere interactions on Mars. These samples include three enriched shergottites (Zagami, Roberts Massif 04262 and Larkman Nunatak 12011), one depleted shergottite (Tissint), an orthopyroxenite (Allan Hills 84001), and a regolith breccia (Northwest Africa 7533). The phosphates measured here have a range in δ18O [(18O/16O)sample/(18O/16O)Standard-1] × 103] from +1.0 to +6.8‰ and could be a result of indigenous mantle values, mixing with martian water, or replacement reactions taking place on the surface of Mars. Three samples have a Δ17O [δ17O-1000(1 + δ18O /1000)0.528-1] in equilibrium with the martian mantle (ALH 84001, Tissint, and Zagami), while three samples (LAR 12011, RBT 04262, and NWA 7533) have an elevated positive Δ17O outside of analytical uncertainty of the martian fractionation line (MFL). The phosphates in the latter group also have positive and negative δ37Cl [(37Cl/35Cl)sample/(37Cl/35Cl)standard – 1] × 103] and enrichments in halogens not seen in the rest of the sample suite. Perchlorate formation on Earth fractionates Cl in both positive and negative directions and generates a correlated positive Δ17O. Further, perchlorate has been detected in wt% amounts on the martian surface. Thus, these results strongly suggest the presence of multiple Cl isotope reservoirs on the martian surface that have interacted with the samples studied here over the last ca. 2 Ga of geologic time. The weighted average of Δ17O measurements from phosphate grains (n = 13) in NWA 7533, which are the explicit result of exchange reactions on the martian surface, yields a statistically robust mean value of 1.39 ± 0.19‰ (2σ, MSWD = 1.5, p = 0.13). This value likely represents an accurate estimate for an oxidized surface reservoir on Mars.

  • 26.
    Bellucci, Jeremy
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pb Isotopic Composition of Panamanian Colonial Majolica by LA-ICP-MS2016Ingår i: Recent Advances in Laser Ablation ICP-MS for Archaeology / [ed] L. Dussubieux, Springer Berlin/Heidelberg, 2016Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Panama ́ Viejo, founded in 1519 by the Spanish explorer Pedrarias Da ́vila, was the first permanent European settlement on the Pacific Ocean, and became a city, by royal decree, in 1521. Shortly after its creation, the city became an important base for trade with Spain. In 1671, the English pirate Henry Morgan waged an attack on Panama ́ Viejo, which resulted in a fire that destroyed the entire city. A new settlement built a few miles west, called Casco Antiguo or San Felipe, is now the historic district of modern Panama City. The Pb isotopic compositions of the glazes on the surface of sixteenth to seventeenth century majolica pottery sherds from Panama Viejo and Casco Antiguo (both in Panama), and Lima (Peru) were determined via non-destructive laser ablation multi-collector ICP-MS (LA-MC-ICP-MS). The contrast in Pb isotopic compositions in the glazes on ceramics recovered in different locations demonstrate that early majolica pottery production during this period used Pb obtained from the Andes. However, the Pb used in later majolica production in Panama is of Spanish origin. After Panama ́ Viejo was burned to the ground, Panamanian majolica production ended.

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  • 27.
    Bellucci, Jeremy
    et al.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Nemchin, Alexander
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Whitehouse, Martin
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Ross, Kielman
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Snape, Joshua
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pidgeon, Robert
    Geochronology of Hadean zircon grains from the Jack Hills, Western Australia constrained by quantitative scanning ion imaging2018Ingår i: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 476, s. 469-480Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Five Hadean (> 4 Ga) aged zircon grains from the Jack Hills metasedimentary belt have been investigated by a secondary ion mass spectrometry scanning ion image technique. This technique has the ability to obtain accurate and precise full U-Pb systematics on a scale < 5 μm, as well as document the spatial distribution of U, Th and Pb. All five of the grains investigated here have complex cathodoluminescence patterns that correlate to different U, Th, and Pb concentration domains. The age determinations for these different chemical zones indicate multiple reworking events that are preserved in each grain and have affected the primary crystalized zircon on the scale of < 10 μm, smaller than conventional ion microprobe spot analyses. In comparison to the spot analyses performed on these grains, these new scanning ion images and age determinations indicate that almost half of the spot analyses have intersected several age and chemical domains in both fractured and unfractured parts of the individual crystals. Some of these unfractured, mixed domain spot analyses have concordant ages that are inaccurate. Thus, if the frequency of spot analyses intersecting mixed domains here is even close to representative of all other studies of the Jack Hills zircon population, it makes the interpretation of any trace element, Hf, or O isotopic data present in the literature tenuous. Lastly, all of the grains analysed here preserve at least two distinguishable 207Pb/206Pb ages. These ages are preserved in core-rim and/or complex internal textural relationships in unfractured domains. These secondary events took place at ca. 4.3, 4.2, 4.1, 4.0, 3.7, and 2.9 Ga, which are coincident with previously determined statistically robust age peaks present in this zircon population.

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  • 28.
    Bellucci, Jeremy
    et al.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Nemchin, Alexander
    Whitehouse, Martin
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Snape, Joshua
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Bland, Phil
    Benedix, Gretchen
    Roszjar, Julia
    Pb evolution in the Martian mantle2018Ingår i: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 485, s. 79-87Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The initial Pb compositions of one enriched shergottite, one intermediate shergottite, two depleted shergottites, and Nakhla have been measured by Secondary Ion Mass Spectrometry (SIMS). These values, in addition to data from previous studies using an identical analytical method performed on three enriched shergottites, ALH 84001, and Chassigny, are used to construct a unified and internally consistent model for the differentiation history of the Martian mantle and crystallization ages for Martian meteorites. The differentiation history of the shergottites and Nakhla/Chassigny are fundamentally different, which is in agreement with short-lived radiogenic isotope systematics. The initial Pb compositions of Nakhla/Chassigny are best explained by the late addition of a Pb-enriched component with a primitive, non-radiogenic composition. In contrast, the Pb isotopic compositions of the shergottite group indicate a relatively simple evolutionary history of the Martian mantle that can be modeled based on recent results from the Sm–Nd system. The shergottites have been linked to a single mantle differentiation event at 4504 Ma. Thus, the shergottite Pb isotopic model here reflects a two-stage history 1) pre-silicate differentiation (4504 Ma) and 2) post-silicate differentiation to the age of eruption (as determined by concordant radiogenic isochron ages). The μ-values (238U/204Pb) obtained for these two different stages of Pb growth are μ1 of 1.8 and a range of μ2 from 1.4–4.7, respectively. The μ1-value of 1.8 is in broad agreement with enstatite and ordinary chondrites and that proposed for proto Earth, suggesting this is the initial μ-value for inner Solar System bodies. When plotted against other source radiogenic isotopic variables (Sri, γ187Os, ε143Nd, and ε176Hf), the second stage mantle evolution range in observed mantle μ-values display excellent linear correlations (r2 > 0.85) and represent a spectrum of Martian mantle mixing-end members (depleted, intermediate, enriched).

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  • 29.
    Bellucci, Jeremy
    et al.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Whitehouse, Martin
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Snape, Joshua
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Halogen and Cl isotopic systematics in Martian phosphates: Implications for the Cl cycle and surface halogen reservoirs on Mars2017Ingår i: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 458, s. 192-202Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Cl isotopic compositions and halogen (Cl, F, Br, and I) abundances in phosphates from eight Martian meteorites, spanning most rock types and ages currently available, have been measured in situ by Secondary Ion Mass Spectrometry (SIMS). Likewise, the distribution of halogens has been documented by x-ray mapping. Halogen concentrations range over several orders of magnitude up to some of the largest concentrations yet measured in Martian samples or on the Martian surface, and the inter-element ratios are highly variable. Similarly, Cl isotope compositions exhibit a larger range than all pristine terrestrial igneous rocks. Phosphates in ancient (>4 Ga) meteorites (orthopyroxenite ALH 84001 and breccia NWA 7533) have positive d37Cl anomalies (+1.1 to +2.5 ‰).  These samples also exhibit explicit whole rock and grain scale evidence for hydrothermal or aqueous activity. In contrast, the phosphates in the younger basaltic Shergottite meteorites (<600 Ma) have negative d37Cl anomalies (-0.2 to -5.6 ‰).  Phosphates with the largest negative d37Cl anomalies display zonation where the rims of the grains are enriched in all halogens and have significantly more negative d37Cl anomalies indicating interaction with the surface of Mars during the latest stages of basalt crystallization. The phosphates with no textural, major element, or halogen enrichment evidence for mixing with this surface reservoir have an average d37Cl of -0.6 ‰, which suggests a similar Cl isotope composition between Mars, the Earth, and the Moon. The only process known to fractionate Cl isotopes, both positively and negatively, is formation of perchlorate, which has been detected in weight percent concentrations on the Martian surface. The age range and obvious mixing history of the phosphates studied here suggest perchlorate formation and halogen cycling via brines, which have also been observed on the Martian surface, has been active throughout Martian history. 

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  • 30.
    Biagion, Cristian
    et al.
    Università di Pisa, Italy.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pasero, Marco
    Università di Pisa, Italy.
    The crystal structure of turneaureite, Ca5(AsO4)3Cl, the arsenate analog of chlorapatite and its relationships with the arsenate apatites johnbaumite and svabite2017Ingår i: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 102, s. 1981-1986Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The crystal structure of turneaureite, ideally Ca5(AsO4)3Cl, was studied using a specimen from the Brattfors mine, Nordmark, Värmland, Sweden, by means of single-crystal X-ray diffraction data. The structure was refinedto R1 = 0.017 on the basis of 716 unique reflectios with Fo > 4σ(Fo) in the P63/m space group, with unit-cell parameters a = 9.9218(3), c = 6.8638(2) Å, V = 585.16(4) Å3. The chemical composition of the sample, determined by electron-microprobe analysis, is (in wt%; average of 10 spot analyses): SO3 0.22, P2O5 0.20, V2O5 0.01, As2O5 51.76, SiO2 0.06, CaO 41.39, MnO 1.89, SrO 0.12, BaO 0.52, PbO 0.10, Na2O 0.02, F 0.32, Cl 2.56, H2Ocalc 0.58, O(≡F+Cl) –0.71, total 99.04. On the basis of 13 anions per formula unit, the empirical formula corresponds to (Ca4.82Mn0.17Ba0.02Sr0.01)∑5.02 (As2.94P0.02S0.02Si0.01)∑2.99O12[Cl0.47(OH)0.42F0.11]∑1.00.Turneaureite is topologically similar to the other members of the apatite supergroup: columns of face-sharing M1 polyhedra running along c are connected through TO4 tetrahedra with channels hosting M2 cations and X anions. Owing to its particular chemical composition, the studied turneaureite can be considered as a ternary calcium arsenate apatite; consequently it has several partially filledanion sites within the anion columns. Polarized single-crystal FTIR spectra of the studied sample indicate stronger hydrogen bonding and less diverse short-range atom arrangements around (OH) groups in turneaureite as compared to the related minerals johnbaumite and svabite. An accurate knowledge of the atomic arrangement of this apatite-remediation mineral represents an improvement in our understanding of minerals able to sequester and stabilize heavy metals such as arsenic in polluted areas.

  • 31.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy.
    Bindi, Luca
    Università di Firenze, Italy.
    Mauro, Daniela
    Università di Pisa.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Crystal chemistry of sulfates from the Apuan Alps (Tuscany, Italy). V. Scordariite, K8(Fe3+0.67ο0.33)[Fe3+3O(SO4)6(H2O)3)]2(H2O)11 , a new metavoltine-related mineral2019Ingår i: Minerals, E-ISSN 2075-163X, Vol. 9, nr 11, s. 1-14, artikel-id 0702Artikel i tidskrift (Refereegranskat)
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  • 32.
    Biagioni, Cristian
    et al.
    Università di Pisa, Pisa, Italy.
    Bonaccorsi, Elena
    Università di Pisa, Pisa, Italy.
    Perchiazzi, Natale
    Università di Pisa, Pisa, Italy.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Zaccarini, Federica
    Univeristy of Leoben, Leoben, Austria.
    Derbylite and graeserite from the Monte Arsiccio mine, Apuan Alps,Tuscany, Italy: occurrence and crystal-chemistry2020Ingår i: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 84, nr 5, s. 766-777Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New occurrences of derbylite, Fex2+Fe3+4–2xTi4+3+xSb3+O13(OH), and graeserite, Fex2+Fe3+4–2xTi4+3+xAs3+O13(OH), have been identified in the Monte Arsiccio mine, Apuan Alps, Tuscany, Italy. Derbylite occurs as prismatic to acicular black crystals in carbonate veins. Iron and Ti are replaced by V (up to 0.29 atoms per formula unit, apfu) and minor Cr (up to 0.04 apfu). Mössbauer spectroscopy confirmed the occurrence of Fe2+ (up to 0.73 apfu), along with Fe3+. The Sb/(As+Sb) atomic ratio ranges between 0.73 and 0.82. Minor Ba and Pb (up to 0.04 apfu) substitute. Derbylite is monoclinic, space group P21/m, with unit-cell parameters a = 7.1690(3), b = 14.3515(7),c = 4.9867(2) Å, β = 104.820(3)° and V = 495.99(4) Å3. The crystal structure was refined to R1 = 0.0352 for 1955 reflections with Fo > 4σ(Fo). Graeserite occurs as prismatic to tabular black crystals, usually twinned, in carbonate veins or as porphyroblasts in schist. Graeserite in the first kind of assemblage is V rich (up to 0.66 apfu), and V poor in the second kind (0.03 apfu). Along with minor Cr (up to 0.06 apfu), this element replaces Fe and Ti. The occurrence of Fe2+ (up to 0.68 apfu) is confirmed by Mössbauer spectroscopy. Arsenic is dominant over Sb and detectable amounts of Ba and Pb have been measured (up to 0.27 apfu). Graeserite is monoclinic, space group C2/m, with unit-cell parameters for two samples: a = 5.0225(7), b = 14.3114(18), c = 7.1743(9) Å,β = 104.878(3)°, V = 498.39(11) Å3; and a = 5.0275(4), b = 14.2668(11), c = 7.1663(5) Å, β = 105.123(4)° and V = 496.21(7) Å3. The crystal structures were refined to R1 = 0.0399 and 0.0237 for 428 and 1081 reflections with Fo > 4σ(Fo), respectively. Derbylite and graeserite are homeotypic. They share the same tunnel structure, characterised by an octahedral framework and cuboctahedral cavities, hosting (As/Sb)O3 groups and (Ba/Pb) atoms.

  • 33.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pasero, Marco
    Università di Pisa, Italy.
    The crystal structure of svabite, Ca5(AsO4)3F, an arsenate member of the apatite supergroup2016Ingår i: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 101, s. 1750-1755Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The crystal structure of svabite, ideally Ca5(AsO4)3F, was studied using a specimen from the Jakobsberg mine, Värmland, Sweden, by means of single-crystal X‑ray diffraction data. The structure was refined to R1 = 0.032 on the basis of 928 unique reflections with Fo > 4s(Fo) in the P63/m space group, with unit-cell parameters a = 9.7268(5), c = 6.9820(4) Å, V = 572.07(5) Å3. The chemical composition of the sample, determined by electron-microprobe analysis, is (in wt%, average of 10 spot analyses): SO3 0.49, P2O5 0.21, V2O5 0.04, As2O5 51.21, SiO2 0.19, CaO 39.31, MnO 0.48, SrO 0.03, PbO 5.19, Na2O 0.13, F 2.12, Cl 0.08, H2Ocalc 0.33, O (≡ F+Cl) –0.91, total 98.90. On the basis of 13 anions per formula unit, the empirical formula corresponds to (Ca4.66Pb0.16Mn0.04Na0.03)Σ4.89(As2.96S0.04Si0.02P0.02)Σ3.04O12[F0.74(OH)0.24Cl0.01]. Svabite is topologically similar to the other members of the apatite supergroup: columns of face-sharing M1 polyhedra running along c are connected through TO4 tetrahedra with channels hosting M2 cations and X anions. The crystal structure of synthetic Ca5(AsO4)3F was previously reported as triclinic. On the contrary, the present refinement of the crystal structure of svabite shows no deviations from the hexagonal symmetry. An accurate knowledge of the atomic arrangement of this apatite-remediation mineral represents an improvement in our understanding of minerals able to sequester and stabilize heavy metals such as arsenic in polluted areas.

  • 34. Biagioni, Cristian
    et al.
    Bosi, Ferdinando
    Mauro, Daniela
    Skogby, Henrik
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Dini, Andrea
    Zaccarini, Federica
    Dutrowite, Na(Fe2+2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3O, a new mineral from the Apuan Alps (Tuscany, Italy): the first member of the tourmaline supergroup with Ti as a species-forming chemical constituent2023Ingår i: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 35, nr 1, s. 81-94Artikel i tidskrift (Refereegranskat)
  • 35.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy..
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Miyawaki, Ritsuro
    National Museum of Nature and Science, Tsukuba, Japan.
    Pasero, Marco
    Università di Pisa, Italy..
    Nuove specie mineralogiche Italiane2019Ingår i: Rivista Mineralogica Italiana, Vol. 43, nr 4, s. 256-262Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
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  • 36.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy..
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pasero, Marco
    Università di Pisa, Italy..
    Nuovi minerali Italiana - La approvazioni 20172018Ingår i: Revista Mineralogica Italiana, ISSN 0391-9641, Vol. 42, nr 3, s. 190-197Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
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  • 37.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy..
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pasero, Marco
    Università di Pisa, Italy..
    Karlsson, Andreas
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Hydroxylhedyphane, Ca2Pb3(AsO4)3(OH), a new member of the apatite supergroup from Långban, Sweden2019Ingår i: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 31, nr 5-6, s. 1007-1014Artikel i tidskrift (Refereegranskat)
  • 38.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy..
    Pasero, Marco
    Università di Pisa, Italy..
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Bianchiniite, Ba2(Ti4+V3+)(As2O5)2OF, a new diarsenite mineral fromthe Monte Arsiccio mine, Apuan Alps, Tuscany, Italy2021Ingår i: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 3, s. 354-363Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The new mineral bianchiniite, Ba2(Ti4+V3+)(As2O5)2OF, has been discovered in the Monte Arsiccio mine, Apuan Alps, Tuscany, Italy. It occurs as brown {001} tabular crystals, up to 1 mm across, with a vitreous lustre. It is brittle, with a perfect {001} cleavage. Streak is brownish. In reflected light, bianchiniite is grey, with orange–yellow internal reflections. It is weakly bireflectant, with a very weak anisotropy in shades of grey. Minimum and maximum reflectance data for COM wavelengths [Rmin/Rmax (%), (λ, nm)] are: 5.0/5.8 (470),5.7/6.5 (546), 5.7/7.0 (589) and 5.2/6.3 (650). Electron microprobe analyses gave (wt.% – average of 10 spot analyses): TiO2 10.34, V2O33.77, Fe2O3 3.76,As2O3 44.36, Sb2O3 0.22, SrO 0.45, BaO 34.79, PbO 0.28, F 1.77, sum 99.74, –O=F–0.75, total 98.99. On the basis of 12 anions per formula unit, the empirical formula of bianchiniite is (Ba2.00Sr0.04Pb0.02)Σ2.06(Ti4+1.14V3+0.44Fe3+0.42)Σ2.00[(As3.96Sb0.02)Σ3.98O10](O1.18F0.82)Σ2.00. Bianchiniite is tetragonal, space group I4/mcm, with unit-cell parameters a = 8.7266(4), c = 15.6777(7) Å, V = 1193.91(12) Å3 and Z = 8. Its crystal structure was refined from single-crystal X-ray diffraction data to R1 = 0.0134 on the basis of 555 unique reflections with Fo > 4σ(Fo)and 34 refined parameters. The crystal structure shows columns of corner-sharing [Ti/(V,Fe)]-centred octahedra running along c, connected along a and b through (As2O5) dimers. A {001} layer of Ba-centred [10+2]-coordinated polyhedra is intercalated between (As2O5) dimers. Bianchiniite has structural relations with fresnoite- and melilite-group minerals. The name honours the two mineral collectors Andrea Bianchini (b. 1959) and Mario Bianchini (b. 1962) for their contribution to the knowledge of the mineralogy of pyrite ± baryte ± iron-oxide ore deposits from the Apuan Alps.

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  • 39. Bolhar, R.
    et al.
    Hofmann, A.
    Kemp, A.I.S.
    Whitehouse, Martin J.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Wind, S.
    Kamber, B.S.
    Juvenile crust formation in the Zimbabwe Craton deduced from the O-Hf isotopic record of 3.8-3.0 Ga detrital zircons2017Ingår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 215, s. 432-446Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hafnium and oxygen isotopic compositions measured in-situ on U-Pb dated zircon from Archaean sedimentary successions belonging to the 2.9–2.8 Ga Belingwean/Bulawayan groups and previously undated Sebakwian Group are used to characterize the crustal evolution of the Zimbabwe Craton prior to 3.0 Ga. Microstructural and compositional criteria were used to minimize effects arising from Pb loss due to metamorphic overprinting and interaction with low-temperature fluids. 207Pb/206Pb age spectra (concordance >90%) reveal prominent peaks at 3.8, 3.6, 3.5, and 3.35 Ga, corresponding to documented geological events, both globally and within the Zimbabwe Craton. Zircon δ18O values from +4 to +10‰ point to both derivation from magmas in equilibrium with mantle oxygen and the incorporation of material that had previously interacted with water in near-surface environments. In εHf-time space, 3.8–3.6 Ga grains define an array consistent with reworking of a mafic reservoir (176Lu/177Hf ∼0.015) that separated from chondritic mantle at ∼3.9 Ga. Crustal domains formed after 3.6 Ga depict a more complex evolution, involving contribution from chondritic mantle sources and, to a lesser extent, reworking of pre-existing crust. Protracted remelting was not accompanied by significant mantle depletion prior to 3.35 Ga. This implies that early crust production in the Zimbabwe Craton did not cause complementary enriched and depleted reservoirs that were tapped by later magmas, possibly because the volume of crust extracted and stabilised was too small to influence (asthenospheric) mantle isotopic evolution. Growth of continental crust through pulsed emplacement of juvenile (chondritic mantle-derived) melts, into and onto the existing cratonic nucleus, however, involved formation of complementary depleted subcontinental lithospheric mantle since the early Archaean, indicative of strongly coupled evolutionary histories of both reservoirs, with limited evidence for recycling and lateral accretion of arc-related crustal blocks until 3.35 Ga.

  • 40. Bolhar, Robert
    et al.
    Whitehouse, Martin J.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Milani, Lorenzo
    Magalhães, Nivea
    Golding, Suzanne D.
    Bybee, Grant
    LeBras, Loic
    Bekker, Andrey
    Atmospheric S and lithospheric Pb in sulphides from the 2.06 Ga Phalaborwa phoscorite-carbonatite Complex, South Africa2020Ingår i: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 530, artikel-id 115939Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lead and multiple sulphur isotope compositions were measured in-situ by SIMS on sulphide minerals from phoscorites and carbonatites of the ca. 2.06 Ga Phalaborwa Complex in South Africa. Additionally, sulphide mineral separates and bulk-rock samples were analyzed with IRMS methods to confirm SIMS data. Lead isotope ratios define a trend stretching from unradiogenic to highly radiogenic ratios corresponding to a Pb–Pb regression date of 2054 ± 99 Ma. This apparent date is consistent with the timing of emplacement and thus provides an age estimate for the sulphide mineralization. The least radiogenic Pb isotope compositions overlap, and the regression line intersects, a hypothetical mixing line between MORB mantle and an upper crustal reservoir at ca. 2.1 Ga, suggesting that either a significant quantity of crustal Pb contributed to sulphide mineralization, or that sulphidic xenomelts were derived from an isotopically enriched mantle source. Sulphur isotope ratios of individual sulphide minerals obtained by SIMS are highly variable (δ34S: −15 to +15‰ V-CDT) and, importantly, reveal the contribution of pre-Great Oxidation Event (GOE) atmospheric sulphur with mass-independent isotope fractionation (Δ33S = δ33S–[(1+δ34S)0.515-1]×1000 ≠0.0‰). Mass-independent sulphur isotope fractionation is also revealed by sulphur isotope ratios measured on sulphide mineral separates (Δ33S: 0.2 to 0.7‰) and bulk rock samples (Δ33S: 0.2 to 0.4‰). Generally, the range of sulphur isotope ratios obtained with SIMS is much larger than that observed in non-SIMS data, possibly reflecting isotopic variability at the μm scale, resolvable only with microbeam measurements. Various sources and mechanisms by which supracrustal material may have been incorporated into mantle-derived carbonatite-phoscorite magmas are assessed, taking into account that geological evidence for the presence of sedimentary material available for assimilation during shallow-level magma emplacement is lacking. Given the variability in S and Pb isotopic compositions, it is inferred that pre-GOE surficial Pb and S were not derived from asthenospheric mantle contaminated with supracrustal materials. Instead, whole rock trace element compositions, in concert with published geochemical and petrological evidence, are consistent with interaction of asthenospheric, plume-derived melt with compositionally heterogeneous lithospheric mantle that was metasomatically modified by fluids and melts released from a subducting slab. Despite geochemical and geochronological similarities with the 2055 Ma Busvheld Complex, lead and sulphur isotope data for both complexes are resolvably different, pointing to distinct lithospheric mantle sources involved in sulphide mineralization.

  • 41. Bollard, J.
    et al.
    Connelly, J.N.
    Whitehouse, Martin J.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pringle, E.A.
    Bonal, E.A.
    Jørgensen, J.K.
    Nordlund, Å.
    Moynier, F.
    Bizzarro, M.
    Early formation of planetary building blocks inferred from Pb isotopic ages of chondrules.2017Ingår i: Science Advances, E-ISSN 2375-2548, Vol. 3, artikel-id e1700407Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The most abundant components of primitive meteorites (chondrites) are millimeter-sized glassy spherical chondrules formed by transient melting events in the solar protoplanetary disk. Using Pb-Pb dates of 22 individual chondrules, we show that primary production of chondrules in the early solar system was restricted to the first million years after the formation of the Sun and that these existing chondrules were recycled for the remaining lifetime of the protoplanetary disk. This finding is consistent with a primary chondrule formation episode during the early high-mass accretion phase of the protoplanetary disk that transitions into a longer period of chondrule reworking. An abundance of chondrules at early times provides the precursor material required to drive the efficient and rapid formation of planetary objects via chondrule accretion.

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  • 42. Bose, Swayoma
    et al.
    Anand, R.
    D'Souza, Joseph
    Hartnady, Michael
    Kirkland, Chris
    Kooijman, Ellen
    Naturhistoriska riksmuseet, Enheten för geovetenskap. Department of Geosciences, Swedish Museum of Natural History, Stockholm, Sweden.
    Zircon U Pb and Hf isotope insights into the Mesoproterozoic breakup of supercontinent Columbia from the Sausar Belt, Central Indian Tectonic Zone2023Ingår i: Chemie der Erde, ISSN 0009-2819, E-ISSN 1611-5864, s. 126054-126054, artikel-id 126054Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Credible records of rifting and associated sedimentation and granitoid magmatism coinciding with the Columbia breakup event are not common in the Precambrian Indian continent. We report a 1322 ± 3 Ma concordia age for magmatic zircons from the granitoid rocks of the Sausar mobile belt, Central Indian Tectonic Zone (CITZ). The rocks exhibit geochemical characteristics of A-type granitoid rocks and were generated by the dehydration melting of shallow crust in an extensional tectonic setting. The predominantly negative εHf(t) values and partial melting modelling imply their origin by the reworking of pre-existing granitoid crust. TDM2 (Hf) model ages for these rocks range from 2856 Ma to 1885 Ma suggesting a prolonged period of crustal evolution and reworking of Archean to Paleoproterozoic basement rocks. The temperature for magma generation, determined from the calculated zircon saturation temperature of 874.2 °C is suggestive of melting of a thinned crust that was heated by the upwelling asthenosphere in an extensional tectonic setting. The obtained ages provide evidence for the existence of an extensional event during mid-Mesoproterozoic coinciding with the Columbia breakup event. The extension could also be argued as a local event related to far-field stresses generated due to the ca. 1.6 to 1.5 Ga subduction-collision event at the plate margin farther to the north of the studied region of the CITZ. The recrystallized margins of zircon grains yield 207Pb/206Pb ages between 0.95 Ga and 1.0 Ga implying their alteration during a metamorphic event that can be identified with the final amalgamation and stabilization of the northern and southern Indian blocks along the CITZ, coinciding with the Rodinia assembly, during which the regional structural fabric developed.

  • 43.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma.
    Andreozzi, Giovanni B.
    Sapienza Università di Roma.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Zn-O tetrahedral bond length variations in normal spinel oxides2011Ingår i: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 96, s. 594-598Artikel i tidskrift (Refereegranskat)
  • 44.
    Bosi, Ferdinando
    et al.
    Università di Roma, Italien.
    Andreozzi, Giovanni
    Università di Roma, Italien.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Skogby, Henrik
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Experimental evidence for partial Fe2+ disorder at the Y and Z sites of tourmaline: a combined EMP, SREF, MS, IR and OAS study of schorl2015Ingår i: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 79, nr 3, s. 515-528Artikel i tidskrift (Refereegranskat)
  • 45.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Biagioni, Cristian
    Università di Pisa, Italy.
    Pezzotta, Federico
    Natural History Museum, Milan, Italy.
    Skogby, Henrik
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Cempírek, Jan
    Masaryk University, Brno, Czech Republic.
    Hawthorne, Frank C.
    University of Manitoba, Canada.
    Lussier, Aaron J.
    Univeristy of Manitoba, Canada.
    Abdu, Yassir A.
    University of Manitoba, Canada.
    Day, Maxwell C.
    University of Manitoba, Canada.
    Fayek, Mostafa
    University of Manitoba, Canada.
    Clark, Christine M.
    Eastern Michigan University, USA.
    Grice, Joel D.
    Canadian Museum of Nature, Ottawa, Canada.
    Henry, Darrell J.
    Lousiana State University, USA.
    Uvite, CaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH), a new, but long-anticipated mineral species of the tourmaline supergroup from San Piero in Campo, Elba Island, Italy2022Ingår i: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 86, nr 5, s. 767-776Artikel i tidskrift (Refereegranskat)
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  • 46.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Celata, Beatrice
    Sapienza Università di Roma, Italy.
    Skogby, Henrik
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Tempesta, Gioacchino
    University of Bari "Aldo Moro", Italy.
    Ciriotti, Marco
    University of Turin, Italy.
    Bittarello, Erica
    Univerity of Turin, Italy.
    Marengo, Alessandra
    Univerity of Turin, Italy.
    Mn-bearing purplish-red tourmaline from the Anjanabonoina pegmatite, Madagascar2021Ingår i: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 85, nr 2, s. 242-253Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A gem-quality purplish-red tourmaline sample of alleged liddicoatitic composition from the Anjanabonoina pegmatite, Madagascar, hasbeen fully characterised using a multi-analytical approach to define its crystal-chemical identity. Single-crystal X-ray diffraction, chem-ical and spectroscopic analysis resulted in the formula: X(Na0.410.35Ca0.24)Σ1.00Y(Al1.81Li1.00

    Fe3+0.04Mn3+0.02Mn2+0.12Ti0.004)Σ3.00

    ZAl6[T(Si5.60B0.406.00O18]

    (BO3)3(OH)3W[(OH)0.50F0.13O0.37]Σ1.00, which corresponds to the tourmaline species elbaite having the typical space group R3m and relatively small unit-cell dimensions, a= 15.7935(4) Å, c= 7.0860(2) Å and V= 7.0860(2) Å3.Optical absorption spectroscopy showed that the purplish-red colour is caused by minor amounts of Mn3+(Mn2O3= 0.20 wt.%).Thermal treatment in air up to 750°C strongly intensified the colour of the sample due to the oxidation of all Mn2+ to Mn3+ (Mn2O3 up to 1.21 wt.%). Based on infrared and Raman data, a crystal-chemical model regarding the electrostatic interaction betweenthe X cation and W anion, and involving the Y cations as well, is proposed to explain the absence or rarity of the mineral species ‘liddicoatite’.

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  • 47.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Christy, Andrew
    Australian National University, Canberra, Australia.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Crystal-chemical aspects of the roméite group, A2Sb2O6Y, of the pyrochlore supergroup2017Ingår i: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 81, nr 6, s. 1287-1302Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Four specimens of the roméite-group minerals oxyplumboroméite and fluorcalcioroméite from the Långban Mn-Fe deposit in Central Sweden were structurally and chemically characterized by single-crystal X-ray diffraction, electron microprobe analysis and infrared spectroscopy. The data obtained and those on additional roméite samples from literature show that the main structural variations within the roméite group are related to variations in the content of Pb2+, which is incorporated into the roméite structure via the substitution Pb2+ → A2+ where A2+ = Ca, Mn and Sr. Additionally, the cation occupancy at the six-fold coordinated B site, which is associated with the heterovalent substitution BFe3+ + Y□ → BSb5+ + YO2–, can strongly affect structural parameters.

    Chemical formulae of the roméite minerals group are discussed. According to crystal-chemical information, the species associated with the name ‘kenoplumboroméite’, hydroxycalcioroméite and fluorcalcioroméite most closely approximate end-member compositions Pb2(SbFe3+)O6□, Ca2(Sb5+Ti)O6(OH) and (CaNa)Sb2O6F, respectively. However, in accord with pyrochlore nomenclature rules, their names correspond to multiple end-members and are best described by the general formulae: (Pb,#)2(Sb,#)2O6□, (Ca,#)2(Sb,#)2O6(OH) and (Ca,#)Sb2(O,#)6F, where ‘#’ indicates an unspecified charge-balancing chemical substituent, including vacancies.

  • 48.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Cámara, Fernando
    Università di Torino, Italy.
    Ciriotti, Marco
    Associazione Micromineralogica Italiana, Torino, Italy.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Reznitskii, Leonid
    Russian Academy of Science, Irkutsk, Russia.
    Stagno, Vincenzo
    Sapienza Università di Roma, Italy.
    Crystal-chemical relations and classification problems in tourmalines belonging to the oxy-schorl—oxy-dravite—bosiite—povondraite series2017Ingår i: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 29, nr 3, s. 445-455Artikel i tidskrift (Refereegranskat)
  • 49.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Hatert, Frédéric
    Université de Liège, Belgium..
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pasero, Marco
    Università di Pisa, Italy..
    Miyawaki, Ritsuro
    National Museum of Nature and Science, Tsukuba, Japan.
    Mills, Stuart J.
    Museum Victoria, Melbourne, Australia..
    On the application of the IMA-CNMNC dominant-valency rule to complex mineral compositions2019Ingår i: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 83, nr 5, s. 627-632Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mineral species should be identified by an end-member formula and by using the dominant-valency rule as recommended by the IMA–CNMNC. However, the dominant-end-member approach has also been used in the literature. These two approaches generally converge, but for some intermediate compositions, significant differences between the dominant-valency rule and the dominant end-member approach can be observed. As demonstrated for garnet-supergroup minerals, for example, the end-member approach is ambiguous, as end-member proportions strongly depend on the calculation sequence. For this reason, the IMA–CNMNC strongly recommends the use of the dominant-valency rule for mineral nomenclature, because it alone may lead to unambiguous mineral identification. Although the simple application of the dominant-valency rule is successful for the identification of many mineral compositions, sometimes it leads to unbalanced end-member formulae, due to the occurrence of a coupled heterovalent substitution at two sites along with a heterovalent substitution at a single site. In these cases, it may be useful to use the site-total-charge approach to identify the dominant root-charge arrangement on which to apply the dominant-constituent rule. The dominant-valency rule and the site-totalcharge approach may be considered two procedures complementary to each other for mineral identification. Their critical point is to find the most appropriate root-charge and atomic arrangements consistent with the overriding condition dictated by the end-member formula. These procedures were approved by the IMA−CNMNC in May 2019.

  • 50.
    Bosi, Ferdinando
    et al.
    Sapienza University, Rome, Italy.
    Hatert, Frédéric
    Université de Liège, Belgium..
    Pasero, Marco
    Università di Pisa, Italy..
    Mills, Stuart J.
    Museum Victoria, Melbourne, Australia..
    Miyawaki, Ritsuro
    National Museum of Nature and Science, Tsukuba, Japan.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    A brief comment on Hawthorne (2023): “On the definition of distinct mineral species: A critique of current IMA-CNMNC procedures”2023Ingår i: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 87, nr 3, s. 505-507Artikel i tidskrift (Refereegranskat)
    Ladda ner fulltext (pdf)
    fulltext
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