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  • 251.
    Langhof, Jörgen
    Swedish Museum of Natural History, Department of Geology.
    Mineralfynd vid Nordmarksberg - en historisk överblick2015In: Historien om Nordmarksbergs gruvor / [ed] Jan Kruse, Mjölby: Atremi AB , 2015, 750, p. 174-176Chapter in book (Other (popular science, discussion, etc.))
  • 252.
    Langhof, Jörgen
    Swedish Museum of Natural History, Department of Geology.
    Nils Sundius2014In: Svenskt Biografiskt Lexikon, Vol. 34, no 167, p. 274-279Article in journal (Other academic)
  • 253.
    Langhof, Jörgen
    Swedish Museum of Natural History, Department of Geology.
    Personporträtt - Erik Ygberg2014In: Långbansnytt, ISSN 1650-4968, Vol. 20, no 2, p. 4-6Article in journal (Other (popular science, discussion, etc.))
  • 254.
    Langhof, Jörgen
    Swedish Museum of Natural History, Department of Geology.
    Schwedisches Naturhistorisches Reichsmuseum: Schätze aus der Mineralien-sammlung Hjalmar Sjögren2016In: The Munich Show - Mineralientage München: Die Verborgenen Schätze der Museen, Wachholtz Verlag - Murmann Publishers , 2016, p. 68-71Chapter in book (Other (popular science, discussion, etc.))
  • 255.
    Langhof, Jörgen
    Swedish Museum of Natural History, Department of Geology.
    Sveriges största granater? Del II2018In: Geologsikt Forum, ISSN 1104-4721, no 100, p. 31-31Article in journal (Other (popular science, discussion, etc.))
  • 256.
    Langhof, Jörgen
    Swedish Museum of Natural History, Department of Geology.
    Swedish Museum of Natural History: Treasures from the Hjalmar Sjögren mineral collection2016In: The Munich Show - Mineralientage München: Hidden treasures of the museums, Kiel/Hamburg: Wachholtz Verlag - Murmann Publishers , 2016, p. 68-71Chapter in book (Other (popular science, discussion, etc.))
  • 257.
    Langhof, Jörgen
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Bahfenne, Silmarilly
    Queensland University of Technology.
    Rintoul, Llew
    Queensland University of Technology.
    Frost, Ray L
    Queensland University of Technology.
    Single-crystal Raman spectroscopy of natural finnemanite and comparison with its synthesised analogue2011In: Journal of Raman Spectroscopy, ISSN 0377-0486, E-ISSN 1097-4555, p. 1-7Article in journal (Refereed)
  • 258.
    Langhof, Jörgen
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Bahfenne, Silmarilly
    Queensland University of Technology.
    Rintoul, Llew
    Queensland University of Technology.
    Frost, Ray L
    Queensland University of Technology.
    Singlecrystal Raman spectroscopy of natural paulmooreite Pb2As2O5 in comparison with the synthesized analog2012In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 97, p. 143-149Article in journal (Refereed)
  • 259.
    Langhof, Jörgen
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Vanadinit - ett nytt mineral för Jakobsberg2014In: Långbansnytt, ISSN 1650-4968, Vol. 20, no 2, p. 11-12Article in journal (Other (popular science, discussion, etc.))
  • 260.
    Langhof, Jörgen
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Jonsson, Erik
    Upptäckten av litium fyller 200 år!2018In: Geologiskt forum, ISSN 1104-4721, no 97, p. 8-11Article in journal (Other (popular science, discussion, etc.))
  • 261.
    Langhof, Jörgen
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Jonsson, Erik
    Gustafsson, Lars
    Sekundära Be-mineral i svenska granitpegmatiter - en översikt2016In: Norsk mineralsymposium 2016 / [ed] Alf Olav Larsen och Torfinn Kjaernet, Stathelle, 2016, p. 43-52Conference paper (Other academic)
  • 262.
    Langhof, Jörgen
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Larsen, Alf Olav
    Nordrum, Fred Steinar
    Berylliummineraler fra Langöy, Kargerö2017In: Norsk mineralsymposium 2017 / [ed] Alf Olav Larsen & Torfinn Kjaernet, Stathelle, 2017, p. 5-15Conference paper (Other academic)
  • 263.
    Langhof, Jörgen
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Secher, Karsten
    Stockmann, Gabrielle
    Sturkell, Erik
    Grönländsk kryolit - 130 år med gruvdrift2017In: Geologiskt Forum, ISSN 1104-4721, no 96, p. 12-17Article in journal (Other (popular science, discussion, etc.))
  • 264.
    Langhof, Jörgen
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Skoda, Radek
    Plasil, Jakub
    Jonsson, Erik
    Copjakova, Renata
    Vasinova Galiova, Michaela
    Redefinition of thalenite-(Y) and descreditation of fluorthalenite-(Y): A re-investigation of type material from the Österby pegmatite, Dalarna, Sweden, and from additional localities2015In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 79, no 4, p. 965-983Article in journal (Refereed)
  • 265.
    Langhof, Jörgen
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Strand, Urban
    Swedish Museum of Natural History, Department of Geology.
    Celebert besök i Långban2015In: Långbansnytt, ISSN 1650-4968, Vol. 21, no 1, p. 4-8Article in journal (Other (popular science, discussion, etc.))
  • 266.
    Langhof, Jörgen
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Strand, Urban
    Swedish Museum of Natural History, Department of Geology.
    Molybdofyllitens ursprung spårat2015In: Långbansnytt, ISSN 1650-4968, Vol. 21, no 1, p. 9-13Article in journal (Other (popular science, discussion, etc.))
  • 267. Laurent, Antonin T.
    et al.
    Bingen, Bernard
    Duchene, Stephanie
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Seydoux-Guillaume, Anne-magali
    Bosse, Valerie
    Decoding a protracted zircon geochronological record in ultrahigh temperature granulite, and persistence of partial melting in the crust, Rogaland, Norway2018In: Contributions to Mineralogy and Petrology, ISSN 0010-7999, E-ISSN 1432-0967, Vol. 173, no 4Article in journal (Refereed)
    Abstract [en]

    This contribution evaluates the relation between protracted zircon geochronological signal and protracted crustal melting in the course of polyphase high to ultrahigh temperature (UHT; T > 900 °C) granulite facies metamorphism. New U–Pb, oxygen isotope, trace element, ion imaging and cathodoluminescence (CL) imaging data in zircon are reported from five samples from Rogaland, South Norway. The data reveal that the spread of apparent age captured by zircon, between 1040 and 930 Ma, results both from open-system growth and closed-system post-crystallization disturbance. Post-crystallization disturbance is evidenced by inverse age zoning induced by solid-state recrystallization of metamict cores that received an alpha dose above 35 × 1017 α  g−1. Zircon neocrystallization is documented by CL-dark domains displaying O isotope open-system behaviour. In UHT samples, O isotopic ratios are homogenous (δ18O = 8.91 ± 0.08‰), pointing to high-temperature diffusion. Scanning ion imaging of these CL-dark domains did not reveal unsupported radiogenic Pb. The continuous geochronological signal retrieved from the CL-dark zircon in UHT samples is similar to that of monazite for the two recognized metamorphic phases (M1: 1040–990 Ma; M2: 940–930 Ma). A specific zircon-forming event is identified in the orthopyroxene and UHT zone with a probability peak at ca. 975 Ma, lasting until ca. 955 Ma. Coupling U–Pb geochronology and Ti-in-zircon thermometry provides firm evidence of protracted melting lasting up to 110 My (1040–930 Ma) in the UHT zone, 85 My (ca. 1040–955 Ma) in the orthopyroxene zone and some 40 My (ca. 1040–1000 Ma) in the regional basement. These results demonstrate the persistence of melt over long timescales in the crust, punctuated by two UHT incursions.

  • 268. Leat, Philip T.
    et al.
    Jordan, Tom A.
    Flowerdew, Michael J.
    Riley, Teal R.
    Ferraccioli, Fausto
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Jurassic high heat production granites associated with the Weddell Sea rift system, Antarctica2018In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 722, p. 249-264Article in journal (Refereed)
    Abstract [en]

    The distribution of heat flow in Antarctic continental crust is critical to understanding continental tectonics, ice sheet growth and subglacial hydrology. We identify a group of High Heat Production granites, intruded into upper crustal Palaeozoic metasedimentary sequences, which may contribute to locally high heat flow beneath the West Antarctic Ice Sheet. Four of the granite plutons are exposed above ice sheet level at Pagano Nunatak, Pirrit Hills, Nash Hills and Whitmore Mountains. A new UPb zircon age from Pirrit Hills of 178.0±3.5Ma confirms earlier RbSr and UPb dating and that the granites were emplaced approximately coincident with the first stage of Gondwana break-up and the developing Weddell rift, and ~5m.y. after eruption of the Karoo-Ferrar large igneous province. Aerogeophysical data indicate that the plutons are distributed unevenly over 40,000km2 with one intruded into the transtensional Pagano Shear Zone, while the others were emplaced within the more stable Ellsworth-Whitmore mountains continental block. The granites are weakly peraluminous A-types and have Th and U abundances up to 60.7 and 28.6ppm respectively. Measured heat production of the granite samples is 2.96–9.06μW/m3 (mean 5.35W/m3), significantly higher than average upper continental crust and contemporaneous silicic rocks in the Antarctic Peninsula. Heat flow associated with the granite intrusions is predicted to be in the range 70–95mW/m2 depending on the thickness of the high heat production granite layer and the regional heat flow value. Analysis of detrital zircon compositions and ages indicates that the high Th and U abundances are related to enrichment of the lower-mid crust that dates back to 200–299Ma at the time of the formation of the Gondwanide fold belt and its post-orogenic collapse and extension.

  • 269.
    Lelis, Martynas
    et al.
    Lithuanian Energy Institute, Kaunas.
    Milcius, Darius
    Lithuanian Energy Institute, Kaunas.
    Wirth, Emmanuel
    Lithuanian Energy Institute, Kaunas.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Eriksson, Lars
    Stockholms universitet.
    Jansson, Kjell
    Stockholms universitet.
    Kadir, Karim
    Stockholms universitet.
    Ruan, Juanfang
    Stockholms universitet.
    Sato, Toyoto
    Tokohu University.
    Yokosawa, Tadahiro
    National Institute of Material Sciences, Tsukuba.
    Noréus, Dag
    Stockholms universitet.
    A mechanically switchable metal–insulator transition in Mg2NiH4 discovers a strain sensitive, nanoscale modulated resistivity connected to a stacking fault2010In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 496, p. 81-86Article in journal (Refereed)
  • 270.
    Lenaz, Davide
    et al.
    University of Trieste.
    Henrik, Skogby
    Swedish Museum of Natural History, Department of Geology.
    Structural changes in the FeAl2O4- FeCr2O4 solid solution series and their consequences on natural Cr-bearing spinels.2013In: Physics and chemistry of minerals, ISSN 0342-1791, E-ISSN 1432-2021, Vol. 40, p. 587-595Article in journal (Refereed)
  • 271.
    Lenaz, Davide
    et al.
    Università degli Studi di Trieste.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Princivalle, Francesco
    Università degli Studi di Trieste.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    The MgCr2O4-MgFe2O4 solid solution series: Effects of octahedrally coordinated Fe3+ on T-O bond lengths2006In: Physics and chemistry of minerals, ISSN 0342-1791, E-ISSN 1432-2021, Vol. 33, p. 465-474Article in journal (Refereed)
  • 272.
    Lenaz, Davide
    et al.
    University of Trieste.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Rigonat, Nicola
    University of Trieste.
    Berger, Julien
    University of Toulouse.
    Following the Amphibolite to Greenschist Metamorphic Path through the Structural Parameters of Spinels from Amsaga (Mauritania)2018In: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 8, no 1, article id 27Article in journal (Refereed)
  • 273.
    Lenaz, Davide
    et al.
    University of Trieste, Italy.
    Velicogna, Matteo
    University of Trieste.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    O'Driscoll, Brian
    University of Manchester, United Kingdom.
    Structural parameters of Cr-bearing spinels and pleonaste from the Cuillin Igneous Complex (Isle of Skye, Scotland): Implications for metamorphic and cooling history2016In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 80, no 5, p. 749-764Article in journal (Refereed)
    Abstract [en]

    The Outer Layered Suite of the Cuillin Igneous Complex (Isle of Skye, NW Scotland) comprises a Peridotite Series and a younger Allivalite Series (the latter comprising troctolites, eucrites and gabbros). Close to the junction between the Peridotite and the Allivalite Series (but wholly contained within the latter), an ultramafic breccia unit containing abundant peridotite xenoliths crops out. In the Peridotite Series, reddish-brown Cr-bearing spinels are present as disseminated crystals in the peridotite and also as chromitite seams, while in the peridotite xenoliths of the breccia unit, green pleonaste occurs in both of these modes of textural occurrence. Optical absorption spectroscopy reveals that the colour difference between the two spinel phases is related mainly to variable Al, Cr and Fe contents, while crystal structural analysis shows that the cooling rate calculated utilizing the oxygen positional parameter is comparable for all samples. The intracrystalline closure temperature for the Cr-spinel in the Peridotite Series is different for the disseminated and seam textural occurrences of the spinels, while the temperatures yielded by pleonaste in the peridotite xenoliths are the same for both textural occurrences. Our dataset suggests that the pleonaste in the peridotite xenoliths has been heated and equilibrated under subsolidus conditions, probably during breccia formation. During this heating, homogenization of the closure temperatures of pleonaste spinels occurred.

  • 274.
    Ling, Johan
    et al.
    University of Gothenburg.
    Stos-Gale, Zophia
    Grandin, Lena
    Billström, Kjell
    Swedish Museum of Natural History, Department of Geology.
    Hjärthner-Holdar, Eva
    Persson, Per-Olof
    Moving metals II: Provenancing Scandinavian Bronze Age artefacts by lead isotope and elemental analyses2014In: Journal of Archaeological Science, ISSN 0305-4403, Vol. 41, p. 106-132Article in journal (Refereed)
    Abstract [en]

    The first part of this research published previously proved without doubt that the metals dated to the Nordic Bronze Age found in Sweden were not smelted from the local copper ores. In this second part we present a detailed interpretation of these analytical data with the aim to identify the ore sources from which these metals originated. The interpretation of lead isotope and chemical data of 71 Swedish Bronze Age metals is based on the direct comparisons between the lead isotope data and geochemistry of ore deposits that are known to have produced copper in the Bronze Age. The presented interpretations of chemical and lead isotope analyses of Swedish metals dated to the Nordic Bronze Age are surprising and bring some information not known from previous work. Apart from a steady supply of copper from the Alpine ores in the North Tyrol, the main sources of copper seem to be ores from the Iberian Peninsula and Sardinia. Thus from the results presented here a new complex picture emerges of possible connectivities and flows in the Bronze Age between Scandinavia and Europe.

  • 275.
    Lynch, Edward
    et al.
    Sveriges geologiska undersökning.
    Bauer, Tobias
    Luleå University of Technology.
    Jörnberger, Johan
    Sveriges geologiska undersökning.
    Smarlus, Zmar
    Luleå University of Technology.
    Morris, George
    Sveriges geologiska undersökning.
    Persson, Per-Olof
    Swedish Museum of Natural History, Department of Geology.
    Petrological and structural character of c. 1.88 Ga meta-volcanosedimentary rocks hosting iron oxide-copper-gold and related mineralisation in the Nautanen–Aitik area, northern Sweden2018In: SGU Rapporter och meddelanden, ISSN 0349-2176, Vol. 141, p. 107-150Article in journal (Refereed)
    Abstract [en]

    The petrological and deformation characteristics of a Palaeoproterozoic meta-volcanosedimentary sequence in the Nautanen–Aitik area (near Gällivare, northern Sweden) are presented. The investigated sequence (part of the Muorjevaara group) predominantly comprises metavolcaniclastic rocks displaying variable grain size, textural and syn-depositional features (e.g. grading, cross-laminae, compositional banding). Locally, poorly sorted agglomerate-like horizons with coarser clasts (lapilli-to block-size) occur. Interbedded sections of mainly fine-grained, volcanogenic (epiclastic) metasedimentary rocks contain syn-depositional features that suggest a sub-aqueous, relatively shallow depositional environment. Locally preserved cross-laminae in this unit provide evidence of way-up and paleocurrent directions. Intercalations of pelite, mica schist and amphibolitic schist also occur throughout the sequence. In general, least altered samples indicate a predominantly intermediate (basaltic andesitic to andesitic), calc-alkaline composition for the sequence.

    U-Pb SIMS zircon dating of a meta-andesite horizon, intercalated within the sequence, has yielded a precise U-Pb concordia age of 1 878 ± 7 Ma (2σ, n = 12). This date constrains the timing of intermediate volcanism and the deposition of syn-volcanic epiclastic material. By inference, it also provides an estimate for the age of Muorjevaara group rocks hosting the Nautanen Cu-Au and Aitik Cu-Au-Ag deposits. When combined with lithogeochemical signatures, the new age also confirms a genetic link between the metavolcaniclastic package and gabbroic to dioritic intrusions in the area (e.g. the c. 1.88 Ga Aitik stock). Additionally, several zircon cores record 207Pb/206Pb apparent ages between c. 1.90 and 1.89 Ga, suggesting inheritance of marginally older volcanic ± plutonic material not exposed at the present erosion level.

    The Nautanen–Aitik area contains the roughly north-northwest-trending Nautanen deformation zone (NDZ), a major composite brittle-ductile structure hosting hydrothermal iron oxide-Cu-Au (IOCG)-style mineralisation (e.g. the Nautanen deposit). Here, the bedrock is relatively intensely altered and sheared, and has been transposed into a sub-parallel high-strain zone predominantly consisting of a composite planar penetrative fabric. Outside the high-strain zone, relatively large-scale approximately north-northwest-aligned folds and discordant brittle structures occur. Magnetic susceptibility and VLF-resistivity modelling of the NDZ confirm that composite planar structures mainly dip steeply to the west-southwest and continue at depth.

  • 276.
    Lynch, Edward
    et al.
    Sveriges geologiska undersökning.
    Hellström, Fredrik
    Sveriges geologiska undersökning.
    Huhma, Hannu
    Geological survey of Finland.
    Jörnberger, Johan
    Sveriges geologiska undersökning.
    Persson, Per-Olof
    Swedish Museum of Natural History, Department of Geology.
    Morris, George
    Sveriges geologiska undersökning.
    Geology, lithostratigraphy and petrogenesis of c. 2.14 Ga greenstones in the Nunasvaara and Masugnsbyn areas, northernmost Sweden2018In: SGU Rapporter och meddelanden, ISSN 0349-2176, Vol. 141, p. 19-77Article in journal (Refereed)
    Abstract [en]

    Two Palaeoproterozoic greenstone successions in the Nunasvaara and Masugnsbyn areas of north-central Norrbotten (northernmost Sweden) have been investigated to (1) characterise their primary depositional features; (2) establish lithostratigraphic correlations between both areas; and (3) gain insights into the petrogenesis of greenstone-type volcano-sedimentary successions in this sector of the Fennoscandian Shield.

    In the Nunasvaara area (Vittangi greenstone group), a partly conformable, polydeformed, approxi­mately 2.4 km thick greenstone sequence mainly consists of basaltic (tholeiitic) metavolcanic and metavolcaniclastic rocks (amygdaloidal lava, laminated tuff). Intercalated metasedimentary units include graphite-bearing black schist, and pelite. The uppermost part consists of amphibolitic pelite with intercalated metacarbonate layers and rare meta-ironstone, metachert and meta-ultrabasic horizons. Numerous metadoleritic sills occur throughout the package.

    In the Masugnsbyn area (Veikkavaara greenstone group) a relatively conformable approximately 3.4 km thick greenstone sequence displays lithological, geochemical and geophysical characteristics similar to that at Nunasvaara. This succession consists of a dominant basaltic metatuff sequence over­lain by metasedimentary units towards the top (e.g. meta-ironstone, metachert, amphibolitic schist, calcitic and dolomitic marbles). Minor metadolerite sills occur in the metatuffs. Near the base of the metatuff package, a graphitic black schist horizon occupies a similar stratigraphic position to a prom­inent black schist layer at Nunasvaara (here named the Nunasvaara member). This unit is a key mark­er horizon providing lateral correlation between both successions and also acts as a useful strain marker for reconstructing deformational events.

    Both greenstone successions record the effects of overprinting syn-to late-orogenic (Svecokarelian) tectonothermal events. These include complex, polyphase ductile deformation (D1 to D3 events at Nunasvaara, forming the Nunasvaara dome), peak amphibolite facies metamorphism, metasomatic-hydrothermal alteration and late-stage retrogression and brittle faulting (composite D4 at Nunasvaara). Locally, these overprinting processes formed metamorphic graphite, skarn-related Fe ± Cu and hydro­thermal Cu ± Pb ± Mo mineralisation.

    U-Pb SIMS zircon dating of a metadolerite dyke from Nunasvaara and a metadolerite sill from Masugnsbyn have yielded mean weighted 207Pb/206Pb ages of 2 144 ±5 Ma (2σ, n = 10) and 2 139 ±4 Ma (2σ, n = 5) Ma, respectively. These precise dates constrain the timing of hypabyssal mafic magmatism, provide a minimum age for the deposition of the volcanic and sedimentary rocks, and identify a new approximetly 2.14 Ga episode of tholeiitic magmatism in this sector of the Fennoscandian Shield. Whole-rock initial εNd values for greenstone meta-igneous units range from +0.4 to +4.0 at Nunasvaara (n = 11) and +0.4 to +3.7 at Masugnsbyn (n = 7). These data indicate a juvenile depleted to partly enriched mantle (asthenospheric or lithospheric) as a major source of the tholeiitic melts. Corresponding trace element systematics have enriched mid-ocean ridge (E-MORB)-type signatures, and indicate minor assimilation of Archaean continental crust (i.e. Norrbotten craton) during magma ascent and storage. Overall, the combined geological, geochemical and isotopic characteristics of the greenstones are consistent with protolith formation within an incipient oceanic basin (epieric Norrbotten Seaway) during approximetly 2.14 Ga rifting and sagging of the Norrbotten craton.

  • 277. Majka, Jarosław
    et al.
    Mazur, Stanisław
    Młynarska, Maria
    Klonowska, Iwona
    Tual, Lorraine
    Swedish Museum of Natural History, Department of Geology.
    Kośmińska, Karolina
    Tarasiuk, Jacek
    Wroński, Sebastian
    Integrating X‐ray mapping and microtomography of garnet with thermobarometry to define the P–T evolution of the (near) UHP Międzygórze eclogite, Sudetes, SW Poland2018In: Journal of Metamorphic Geology, ISSN 0263-4929, E-ISSN 1525-1314Article in journal (Refereed)
  • 278.
    Martinsson, Olof
    et al.
    Luleå University of Technology.
    Bergman, Stefan
    Sveriges geologiska undersökning.
    Persson, Per-Olof
    Swedish Museum of Natural History, Department of Geology.
    Hellström, Fredrik
    Sveriges geologiska undersökning.
    Age and character of late-Svecokarelian monzonitic intrusions in northeastern Norrbotten, northern Sweden2018In: SGU Rapporter och meddelanden, ISSN 0349-2176, Vol. 141, p. 381-400Article in journal (Refereed)
    Abstract [en]

    Palaeoproterozoic magmatism in northern Norrbotten shows a complex evolution, with several different plutonic suites ranging in age 1.93–1.70 Ga. Here we present data for three monzonitic intrusions from different parts of the area. They are petrographically and chemically similar, consisting mainly of perthite, augite and orthopyroxene, with megacrysts of poikilitic biotite as a characteristic minor component, and with high Sr and Ba. The intrusions have been dated at 1.80 Ga and may be part of a more extensive magmatic event in northern Sweden, including other chemically similar monzonitic and gabbroic intrusions, which often occur as ring dykes at the Merasjärvi gravity high (MGH) in northeastern Norrbotten. The monzonitic intrusions have A-type signatures and chemical characteristics overlapping those of rocks in arc and within-plate settings. These intrusions may thus have formed in either a back arc setting related to eastward subduction associated with the Transscandinavian Igneous Belt further west (TIB 1), or through a separate igneous event caused by a mantle plume.

  • 279.
    Martinsson, Olof
    et al.
    Luleå Tekniska Universitet.
    Bergman, Stefan
    SGU.
    Persson, Per-Olof
    Swedish Museum of Natural History, Department of Geology.
    Schöberg, Hans
    Swedish Museum of Natural History, Department of Geology.
    Billström, Kjell
    Swedish Museum of Natural History, Department of Geology.
    Shumlyanskyy, Leonid
    Stratigraphy and ages of Palaeoproterozoic metavolcanic and metasedimentary rocks at Käymäjärvi, northern Sweden2018In: Swedish Geological Survey, Rapporter och meddelanden, Vol. 141, p. 79-106Article in journal (Refereed)
  • 280.
    Martinsson, Olof
    et al.
    Luleå Tekniska Universitet.
    Billström, Kjell
    Swedish Museum of Natural History, Department of Geology.
    Broman, Curt
    Stockholms Universitet.
    Weihed, Pär
    Luleå Tekniska Universitet.
    Wanhainen, Christina
    Luleå Tekniska Universitet.
    Metallogeny of the Northern Norrbotten Ore Province, northern Fennoscandian Shield with emphasis on IOCG and apatite-iron ore deposits2016In: Ore Geology Reviews, ISSN 0169-1368, E-ISSN 1872-7360, article id doi: 10.1016/j.oregeorev.2016.02.011Article in journal (Refereed)
    Abstract [en]

    The Northern Norrbotten Ore Province in northernmost Sweden includes the type localities for Kiruna-type apatite iron deposits and has been the focus for intense exploration and research related to Fe oxide-Cu-Aumineralisation during the last decades. Several different types of Fe-oxide and Cu-Au±Fe oxide mineralisationoccur in the region and include: stratiform Cu±Zn±Pb±Fe oxide type, iron formations (including BIF´s), Kiruna-type apatite iron ore, and epigenetic Cu±Au±Fe oxide type which may be further subdivided into different styles of mineralisation, some of them with typical IOCG (Iron Oxide-Copper-Gold) characteristics. Generally, the formation of Fe oxide±Cu±Au mineralisation is directly or indirectly dated between ~2.1 and 1.75 Ga, thus spanning about 350 m.y. of geological evolution.The current paper will present in more detail the characteristics of certain key deposits, and aims to put the global concepts of Fe-oxide Cu-Au mineralisations into a regional context. The focus will be on iron deposits and various types of deposits containing Fe-oxides and Cu-sulphides in different proportions which generally have some characteristics in common with the IOCG style. In particular, ore fluid characteristics (magmatic versus non-magmatic) and new geochronological data are used to link the ore-forming processes with the overall crustal evolution to generate a metallogenetic model. Rift bounded shallow marine basins developed at ~2.1-2.0 Ga following a long period of extensional tectonics within the Greenstone-dominated, 2.5-2.0 Ga Karelian craton. The ~1.9-1.8 Ga Svecofennian Orogen is characterised by subduction and accretion from the southwest. An initial emplacement of calc-alkaline magmas into ~1.9 Ga continental arcs led to the formation of the Haparanda Suite and the Porphyrite Group volcanic rocks. Following this early stage of magmatic activity, and separated from it by the earliest deformation and metamorphism, more alkali-rich magmas of the Perthite Monzonite Suite and the Kiirunavaara Group volcanic rocks were formed at ~1.88 Ga. Subsequently, partial melting of the middle crust produced large volumes of~1.85 and 1.8 Ga S-type granites in conjunction with subduction related A-/I-type magmatism and associated deformation and metamorphism.

    In our metallogenetic model the ore formation is considered to relate to the geological evolution as follows. Iron formations and a few stratiform sulphide deposits were deposited in relation to exhalative processes in rift bounded marine basins. The iron formations may be sub-divided into BIF- (banded iron formations) and Mg-rich types, and at several locations these types grade into each other. There is no direct age evidence to constrain the deposition of iron formations, but stable isotope data and stratigraphic correlations suggest a formation within the 2.1-2.0 Ga age range. The major Kiruna-type ores formed from an iron-rich  magma (generally with a hydrothermal over-print) and are restricted to areas occupied by volcanic rocks of the Kiirunavaara Group. It is suggested here that 1.89-1.88 Ga tholeiitic magmas underwent magma liquid immiscibility reactions during fractionation and interaction with crustal rocks, including metaevaporites, generating more felsic magmatic rocks and Kiruna-type iron deposits. A second generation of this ore type, with a minor economic importance, appears to have been formed about 100 Ma later. The epigenetic Cu-Au±Fe oxide mineralisation formed during two stages of the Svecofennian evolution in association with magmatic and metamorphic events and crustal-scale shear zones. During the first stage of mineralisation, from 1.89-1.88 Ga, intrusion-related (porphyry-style) mineralisation and Cu-Au deposits of IOCG affinity formed from magmatichydrothermal systems, whereas vein-style and shear zone deposits largely formed at c. 1.78 Ga. The large range of different Fe oxide and Cu-Au±Fe oxide deposits in Northern Norrbotten is associated with various alteration systems, involving e.g. scapolite, albite, K feldspar, biotite, carbonates, tourmaline and sericite. However, among the apatite iron ores and the epigenetic Cu-Au±Fe oxide deposits the character of mineralization, type of ore- and alteration minerals and metal associations are partly controlled by stratigraphic position (i.e. depth of emplacement). Highly saline, NaCl+CaCl2 dominated fluids, commonly also including a CO2-rich population, appear to be a common characteristic feature irrespective of type and age of deposits. Thus, fluids with similar characteristics appear to have been active during quite different stages of the geological evolution. Ore fluids related to epigenetic Cu-Au±Fe oxides display a trend with decreasing salinity, which probably was caused by mixing with meteoric water. Tentatively, this can be linked to different Cu-Au ore paragenesis, including an initial (magnetite)-pyrite-chalcopyrite stage, a main chalcopyrite stage, and a late bornite stage. Based on the anion composition and the Br/Cl ratio of ore related fluids bittern brines and metaevaporites (including scapolite) seem to be important sources to the high salinity hydrothermal systems generating most of the deposits in Norrbotten. Depending on local conditions and position in the crust these fluids generated a variety of Cu-Au deposits. These include typical IOCG-deposits (Fe-oxides and Cu-Au are part of the same process), IOCG of iron stone type (pre-existing Fe-oxide deposit with later addition of Cu-Au), IOCG of reduced type (lacking Fe-oxides due to local reducing conditions) and vein-style Cu-Au deposits. From a strict genetic point of view, IOCG deposits that formed from fluids of a mainly magmatic origin should be considered to be a different type than those deposits associated with mainly non-magmatic fluids. The former tend to overlap with porphyry systems, whereas those of a mainly non-magmatic origin overlap with sediment hosted Cu-deposits with respect to their origin and character of the ore fluids.

  • 281. McAteer, Claire A.
    et al.
    Daly, J. Stephen
    Flowerdew, Michael J.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Monaghan, Niamh M.
    Sedimentary provenance, age and possible correlation of the Iona Group, SW Scotland2014In: Scottish Journal of Geology, ISSN 0036-9276, E-ISSN 2041-4951, Vol. 50, no 2, p. 143-158Article in journal (Refereed)
  • 282. McKay, C.L.
    et al.
    Groenevold, J.
    Filipsson, H.L.
    Gallego-Torres, D.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Toyofuku, T.
    Romero, O.E.
    A comparison of benthic foraminiferal Mn/Ca and sedimentary Mn/Al as proxies of relative bottom-water oxygenation in the low-latitude NE Atlantic upwelling system.2015In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 12, p. 5415-5428Article in journal (Refereed)
    Abstract [en]

    Trace element incorporation into foraminiferal shells (tests) is governed by physical and chemical conditions of the surrounding marine environment, and therefore foraminiferal geochemistry provides a means of palaeo-oceanographic reconstructions. With the availability of high-spatial-resolution instrumentation with high precision, foraminiferal geochemistry has become a major research topic over recent years. However, reconstructions of past bottom-water oxygenation using foraminiferal tests remain in their infancy. In this study we explore the potential of using Mn / Ca determined by secondary ion mass spectrometry (SIMS) as well as by flow-through inductively coupled plasma optical emission spectroscopy (FT-ICP-OES) in the benthic foraminiferal species Eubuliminella exilis as a proxy for recording changes in bottom-water oxygen conditions in the low-latitude NE Atlantic upwelling system. Furthermore, we compare the SIMS and FT-ICP-OES results with published Mn sediment bulk measurements from the same sediment core. This is the first time that benthic foraminiferal Mn / Ca is directly compared with Mn bulk measurements, which largely agree on the former oxygen conditions. Samples were selected to include different productivity regimes related to Marine Isotope Stage 3 (35–28 ka), the Last Glacial Maximum (28–19 ka), Heinrich Event 1 (18–15.5 ka), Bølling Allerød (15.5–13.5 ka) and the Younger Dryas (13.5–11.5 ka). Foraminiferal Mn / Ca determined by SIMS and FT-ICP-OES is comparable. Mn / Ca was higher during periods with high primary productivity, such as during the Younger Dryas, which indicates low-oxygen conditions. This is further supported by the benthic foraminiferal faunal composition. Our results highlight the proxy potential of Mn / Ca in benthic foraminifera from upwelling systems for reconstructing past variations in oxygen conditions of the sea floor environment as well as the need to use it in combination with other proxy records such as faunal assemblage data.

  • 283. Melheim, Lene
    et al.
    Grandin, Lena
    Persson, Per-Olof
    Swedish Museum of Natural History, Department of Geology.
    Billström, Kjell
    Swedish Museum of Natural History, Department of Geology.
    Stoz-Gale, Zofia
    Williams, A.
    Angelini, I.
    Canovaro, C.
    Hjärthner-Holdar, Eva
    Kristiansen, K.
    Possible origins for copper in Bronze Age Denmark based on lead isotopes and geochemistry2018In: Journal of Archaeological Science, ISSN 0305-4403, E-ISSN 1095-9238, Vol. 96, p. 85-105Article in journal (Refereed)
  • 284. Menneken, M.
    et al.
    Geisler, T.
    Nemchin, A.A.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Wilde, S.A.
    Gasharova, B.
    Pidgeon, R.T.
    CO2 fluid inclusions in Jack Hills zircons.2017In: Contributions to Mineralogy and Petrology, ISSN 0010-7999, E-ISSN 1432-0967, Vol. 172, article id 66Article in journal (Refereed)
    Abstract [en]

    The discovery of Hadean to Paleoarchean zircons in a metaconglomerate from Jack Hills, Western Australia, has catalyzed intensive study of these zircons and their mineral inclusions, as they represent unique geochemical archives that can be used to unravel the geological evolution of early Earth. Here, we report the occurrence and physical properties of previously undetected CO2 inclusions that were identified in 3.36–3.47 Ga and 3.80–4.13 Ga zircon grains by confocal micro-Raman spectroscopy. Minimum P–T conditions of zircon formation were determined from the highest density of the inclusions, determined from the density-dependence of the Fermi diad splitting in the Raman spectrum and Ti-in-zircon thermometry. For both age periods, the CO2 densities and Ti-in-zircon temperatures correspond to high-grade metamorphic conditions (≥5 to ≥7 kbar/~670 to 770 °C) that are typical of mid-crustal regional metamorphism throughout Earth’s history. In addition, fully enclosed, highly disordered graphitic carbon inclusions were identified in two zircon grains from the older population that also contained CO2 inclusions. Transmission electron microscopy on one of these inclusions revealed that carbon forms a thin amorphous film on the inclusion wall, whereas the rest of the volume was probably occupied by CO2 prior to analysis. This indicates a close relationship between CO2 and the reduced carbon inclusions and, in particular that the carbon precipitated from a CO2-rich fluid, which is inconsistent with the recently proposed biogenic origin of carbon inclusions found in Hadean zircons from Jack Hills.

  • 285.
    Merle, Renaud
    et al.
    Curtin University.
    Nemchin, Alexander
    Curtin University.
    Whitehouse, Martin
    Swedish Museum of Natural History, Department of Geology.
    Pidgeon, Robert
    Curtin University.
    Grange, Marion
    Curtin University.
    Snape, Joshua
    Swedish Museum of Natural History, Department of Geology.
    Thiessen, Fiona
    Swedish Museum of Natural History, Department of Geology.
    Origin and transportation history of lunar breccia 143112017In: Meteoritics and Planetary Science, ISSN 1086-9379, E-ISSN 1945-5100, Vol. 52, no 5, p. 842-858Article in journal (Refereed)
    Abstract [en]

    In this paper, we compare the U-Pb zircon age distribution pattern of sample 14311 from the Apollo 14 landing site with those from other breccias collected at the same landing site. Zircons in breccia 14311 show major age peaks at 4340 and 4240 Ma and small peaks at 4110, 4030, and 3960 Ma. The zircon age patterns of breccia 14311 and other Apollo 14 breccias are statistically different suggesting a separate provenance and transportation history for these breccias. This interpretation is supported by different U-Pb Ca-phosphate and exposure ages for breccia 14311 (Ca-phosphate age: 3938 ± 4 Ma, exposure age: ~550–660 Ma) from the other Apollo 14 breccias (Ca-phosphate age: 3927 ± 2 Ma, compatible with the Imbrium impact, exposure age: ~25–30 Ma). Based on these observations, we consider two hypotheses for the origin and transportation history of sample 14311. (1) Breccia 14311 was formed in the Procellarum KREEP terrane by a 3938 Ma-old impact and deposited near the future site of the Imbrium basin. The breccia was integrated into the Fra Mauro Formation during the deposition of the Imbrium impact ejecta at 3927 Ma. The zircons were annealed by mare basalt flooding at 3400 Ma at Apollo 14 landing site. Eventually, at approximately 660 Ma, a small and local impact event excavated this sample and it has been at the surface of the Moon since this time. (2) Breccia 14311 was formed by a 3938 Ma-old impact. The location of the sample is not known at that time but at 3400 Ma, it was located nearby or buried by hot basaltic flows. It was transported from where it was deposited to the Apollo 14 landing site by an impact at approximately 660 Ma, possibly related to the formation of the Copernicus crater and has remained at the surface of the Moon since this event. This latter hypothesis is the simplest scenario for the formation and transportation history of the 14311 breccia.

  • 286.
    Miyawaki, Ritsuro
    et al.
    National Museum of Nature and Science, Tokyo, Japan.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Hatert, Frédéric
    Université de Liège, Belgium.
    Pasero, Marco
    Università di Pisa, Italy.
    Mills, Stuart J.
    Museum Victoria, Melbourne, Australia.
    IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) Newsletter 472019In: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 31, no 1, p. 197-202Article in journal (Other academic)
  • 287. Molnár, F.
    et al.
    Mänttäri, I.
    O'Brien, H.
    Lahaye, Y.
    Pakkanen, L.
    Johanson, B.
    Käpyaho, A.
    Sorjonen-Ward, P.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Sakellaris, G.
    Boron, sulphur and copper isotope systematics in the orogenic gold deposits of the Archaean Hattu schist belt, eastern Finland2016In: Ore Geology Reviews, ISSN 0169-1368, E-ISSN 1872-7360, Vol. 77, p. 133-162Article in journal (Refereed)
    Abstract [en]

    The Hattu schist belt is located in the western part of the Archaean Karelian domain of the Fennoscandian Shield. The orogenic gold deposits with Au–Bi–Te geochemical signatures are hosted by NE–SW, N–S and NW–SE oriented shear zones that deform 2.76–2.73 Ga volcanic and sedimentary sequences, as well as 2.75–2.72 Ga tonalite–granodiorite intrusions and diverse felsic porphyry dykes. Mo–W mineralization is also present in some tonalite intrusions, both separate from, and associated with Au mineralization. Somewhat younger, unmineralized leucogranite intrusions (2.70 Ga) also intrude the belt. Lower amphibolite facies peak metamorphism at 3–5 kbar pressures and at 500–600 °C temperatures affected the belt at around 2.70 Ga and post-date hydrothermal alteration and ore formation. In this study, we investigated the potential influence of magmatic-hydrothermal processes on the formation of orogenic gold deposits on the basis of multiple stable isotope (B, S, Cu) studies of tourmaline and sulphide minerals by application of in situ SIMS and LA ICP MS analytical techniques.

    Crystal chemistry of tourmaline from a Mo–W mineralization hosted by a tonalite intrusion in the Hattu schist belt is characterized by Fe3 +–Al3 +-substitution indicating relatively oxidizing conditions of hydrothermal processes. The range of δ11B data for this kind of tourmaline is from − 17.2‰ to − 12.2‰. The hydrothermal tourmaline from felsic porphyry dyke swith gold mineralization has similar crystal chemistry (e.g. dravite–povondraite compositional trend with Fe3 +–Al3 + substitution) and δ11B values between − 19.0‰ and − 9.6‰. The uvite–foitite compositional trend and δ11B ‰ values between − 24.1% and − 13.6% characterize metasomatic–hydrothermal tourmaline from the metasediment-hosted gold deposits. Composition of hydrothermal vein-filling and disseminated tourmaline from the gold-bearing shear zones in metavolcanic rocks is transitional between the felsic intrusion and metasedimentary rock hosted hydrothermal tourmaline but the range of average boron isotope data is essentially identical with that of the metasediment-hosted tourmaline. Rock-forming (magmatic) tourmaline from leucogranite has δ11B values between − 14.5‰ and − 10.8‰ and the major element composition is similar to that of the metasediment-hosted tourmaline.

    The range of δ34SVCDT values measured in pyrite, chalcopyrite and pyrrhotite is from − 9.1 to + 8.5‰, which falls within the typical range of sulphur isotope data for Archaean orogenic gold deposits. In the Hattu schist belt, positive δ34SVCDT values characterize metasediment-hosted gold ores with sulphide parageneses dominated by pyrrhotite and arsenopyrite. The δ34SVCDT values are both positive and negative in ore mineral parageneses within felsic intrusive rocks in which variable amounts of pyrrhotite are associated with pyrite. Purely negative values were only recorded from the pyrite-dominated gold mineralization within metavolcanic units. Therefore the shift of δ34SVCDT values to the negative values reflects precipitation of sulphide minerals from relatively oxidizing fluids. The range of measured δ65CuNBS978 values from chalcopyrite is from − 1.11 to 1.19‰. Positive values are common for mineralization in felsic intrusive rocks and negative values are more typical for deposits confined to metasedimentary rocks. Positive and negative δ65CuNBS978 values occur in the ores hosted by metavolcanic rocks. There is no correlation between sulphur and copper isotope data obtained in the same chalcopyrite grains.

    Evaluation of sulphur and boron isotope data together and comparisons with other Archaean orogenic gold provinces supports the hypothesis that the metasedimentary rocks were the major sources of sulphur and boron in the orogenic gold deposits in the Hattu schist belt. Variations in major element and boron isotope compositions in tourmaline, as well as in the δ34SVCDT values in sulphide minerals are attributed to localized involvement of magmatic fluids in the hydrothermal processes. The results of copper isotope studies indicate that local sources of copper in orogenic gold deposits may potentially be recognized if the original, distinct signatures of the sources have not been homogenized by widespread interaction of fluids with a large variety of rocks and provided that local chemical variations have been too small to trigger changes in the oxidation state of copper during hydrothermal processes.

  • 288. Mosimane, Keotshephile
    et al.
    Struyf, Eric
    Gondwe, Mangaliso
    Frings, Patrick J
    Swedish Museum of Natural History, Department of Geology.
    van Pelt, Dimitri
    Wolski, Piotr
    Schoelynck, Jonas
    Schaller, Jörg
    Conley, Daniel
    Murray-Hudson, Mike
    Variability in chemistry of surface and soil waters of an evapotranspiration-dominated flood-pulsed wetland: solute processing in the Okavango Delta, Botswana2017In: Water SA, ISSN 0378-4738, Vol. 43, no 1, p. 104-115Article in journal (Refereed)
    Abstract [en]

    Water chemistry is important for the maintenance of wetland structure and function. Interpreting ecological patterns in a wetland system therefore requires an in-depth understanding of the water chemistry of that system. We investigated the spatial distribution of chemical solutes both in soil pore water and surface water, along island-floodplain-channel hydrological gradients in seasonally and permanently inundated habitats between major regions in the Okavango Delta, Botswana. Our results show that major cations (Ca, Na, Mg, and K), dissolved silica (DSi), dissolved boron (B), dissolved organic matter (DOC) and electrical conductivity increased significantly, at  < 0.05, from the inlet of the Delta (the Panhandle) to the distal downstream reaches, suggesting the influence of evapoconcentration. Concentrations of dissolved Fe, Al, Zn, Cu, and Mn significantly decreased, at < 0.05, from the inflow of the Delta to the distal reaches. Only Na, Mn, Fe, Al, and DOC showed significant differences, at < 0.05, along the local floodplain-channel hydrological gradients, with higher solute concentrations in the floodplains than the channels. Solute concentrations in soil water exhibited similar distribution patterns to those in surface water, but concentrations were higher in soil water. Based on the results, we hypothesise that floodplain emergent vegetation and the channel-fringing vegetation in the Panhandle (a fault-bounded entry trough to the Delta) and the permanently inundated eco-region together influence the cycling of solutes that enter the Delta through uptake.

  • 289.
    Murphy, Melissa
    et al.
    University of Oxford.
    Porcelli, Don
    University of Oxford.
    Pogge von Strandmann, Philip
    University College London.
    Hirst, Catherine
    Swedish Museum of Natural History, Department of Geology.
    Kutscher, Liselott
    Swedish Museum of Natural History, Department of Geology.
    Katchinoff, Joachim
    Yale University.
    Mörth, Carl-Magnus
    Stockholm University.
    Maximov, Trofim
    Institute for Biological Problems in the Cryolitic Zone, Yakutsk.
    Andersson, Per
    Swedish Museum of Natural History, Research Division.
    Tracingsilicate weathering processes in the permafrost-dominated Lena River watershedusing lithium isotopes2019In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 245, p. 154-171Article in journal (Refereed)
    Abstract [en]

    Increasing global temperatures are causing widespread changes in the Arctic, including permafrost thawing and altered freshwater inputs and trace metal and carbon fluxes into the ocean and atmosphere. Changes in the permafrost active layer thickness can affect subsurface water flow paths and water-rock interaction times, and hence weathering processes. Riverine lithium isotope ratios (reported as δ7Li) are tracers of silicate weathering that are unaffected by biological uptake, redox, carbonate weathering and primary lithology. Here we use Li isotopes to examine silicate weathering processes in one of the largest Russian Arctic rivers: the Lena River in eastern Siberia. The Lena River watershed is a large multi-lithological catchment, underlain by continuous permafrost. An extensive dataset of dissolved Li isotopic compositions of waters from the Lena River main channel, two main tributaries (the Aldan and Viliui Rivers) and a range of smaller sub tributaries are presented from the post-spring flood/early-summer period at the onset of active layer development and enhanced water-rock interactions. The Lena River main channel (average δ7Lidiss ~19‰) has a slightly lower isotopic composition than the mean global average of 23‰ (Huh

    et al., 1998a). The greatest range of [Li] and δ7Lidiss are observed in catchments draining the south facing slopes of the Verkhoyansk Mountain Range. South-facing slopes in high-latitude, permafrost dominated regions are typically characterised by increased summer insolation and higher daytime temperatures relative to other slope aspects. The increased solar radiation on south-facing catchments promotes repeated freeze-thaw cycles, and contributes to more rapid melting of snow cover, warmer soils, and increased active layer thaw depths. The greater variability in δ7Li and [Li] in the south-facing rivers likely reflect the greater infiltration of melt water and enhanced water rock interactions within the active layer. A similar magnitude of isotopic fractionation is observed between the low-lying regions of the Central Siberian Plateau (and catchments draining into the Viliui River), and catchments draining the Verkhoyansk Mountain Range into the Aldan River. This is in contrast to global rivers in non permafrost terrains that drain high elevations or areas of rapid uplift, where high degrees of physical erosion promote dissolution of freshly exposed primary rock typically yielding low δ7Lidiss, and low lying regions exhibit high riverine δ7Li values resulting from greater water-rock interaction and formation of secondary mineral that fractionates Li isotopes. Overall, the range of Li concentrations and δ7Lidiss observed within the Lena River catchment are comparable to global rivers located in temperate and tropical regions. This suggests that cryogenic weathering features specific to permafrost regions (such as the continual exposure of fresh primary minerals due to seasonal freeze-thaw cycles, frost shattering and salt weathering), and climate (temperature and runoff), are not a dominant control on δ7Li variations. Despite vastly different climatic and weathering regimes, the same range of riverine δ7Li values globally suggests that the same processes govern Li geochemistry – that is, the balance between primary silicate mineral dissolution and the formation (or exchange with) secondary minerals. This has implications for the use of δ7Li as a palaeo weathering tracer for interpreting changes in past weathering regimes.

  • 290.
    Nazzareni, Sabrina
    et al.
    Perugia University.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Crystal chemistry of Sc-bearing synthetic diopsides2013In: Physics and chemistry of minerals, ISSN 0342-1791, E-ISSN 1432-2021, Vol. 40, p. 789-798Article in journal (Refereed)
  • 291.
    Nemchin, A.A.
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Humayun, M.
    Whitehouse, Martin
    Swedish Museum of Natural History, Department of Geology.
    Hewins, R.H.
    Lorand, J.-P.
    Kennedy, A.
    Grange, M.
    Zanda, B.
    Fieni, C.
    Deldicque, D.
    Record of the ancient martian hydrosphere and atmosphere preserved in zircon from a martian meteorite2014In: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 7, p. 638-642Article in journal (Refereed)
    Abstract [en]

    Mars exhibits ample evidence for an ancient surfacehydrosphere. The oxygen isotope compositions of carbonateminerals and alteration products in martian meteoritessuggest that this ancient hydrosphere was not in isotopicequilibrium with the martian lithosphere1–4. Martian meteoriteNWA 7533 is composed of regolith breccia from the heavilycratered terrains of ancient Mars and contains zircon grainsfor which U–Pb ages have been reported5. Here we reportvariations between the oxygen isotopic compositions offour zircon grains from NWA 7533. We propose that thesevariations can be explained if the mantle melts from whichthe zircon crystallized approximately 4.43Gyr ago hadassimiliated 17O-enriched regolith materials, and that someof the zircon grains, while in a metamict state, were lateraltered by low-temperature fluids near the surface less than1.7Gyr ago. Enrichment of the martian regolith in 17O beforethe zircon crystallized, presumably through exchange withthe 17O-enriched atmosphere or hydrosphere during surfacealteration, suggests that the thick primary atmosphere ofMars was lost within the first 120Myr after accretion. Weconclude that the observed variation of 17O anomalies in zirconfrom NWA 7533 points to prolonged interaction between themartian regolith, atmosphere and hydrosphere.

  • 292.
    Nemchin, Alexander
    et al.
    Curtin University.
    Jeon, Heejin
    University of Western Australia.
    Bellucci, Jeremy
    Swedish Museum of Natural History, Department of Geology.
    Timms, Nick
    Curtin University.
    Snape, Joshua
    Swedish Museum of Natural History, Department of Geology.
    Kilburn, Matthew
    University of Western Australia.
    Whitehouse, Martin
    Swedish Museum of Natural History, Department of Geology.
    Pb-Pb ages of feldspathic clasts in two Apollo 14 breccia samples2017In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 217, p. 441-461Article in journal (Refereed)
    Abstract [en]

    Pb-Pb isochron ages of ca. 3.92 Ga for three K-feldspar-rich clasts from Apollo 14 breccias 14303 and 14083 were determinedusing Secondary Ion Mass Spectrometry (SIMS). These ages are interpreted to represent the resetting of the U-Pb systemin the clasts as a result of brecciation during the Imbrium impact. One of the clasts contains zircon grains that record asignificantly older crystallization age (ca. 4.33–4.35 Ga) for the rock represented by that clast. Initial Pb compositions determinedfor the clasts, combined with the previously measured Pb isotopic compositions of K-feldspar grains from severalApollo 14 breccia samples, constrain a range of initial Pb compositions in the ca. 3.9 Ga Fra Mauro formation at the Apollo14 landing site. This range in initial Pb compositions indicates that the rocks represented by these clasts, or the sources ofthose rocks, evolved with a high 238U/204Pb (µ-value) for substantial periods of time, although the precise crystallization agesof the rocks represented by at least two of the clasts investigated here are unknown.

  • 293. Neumann, E.-R.
    et al.
    Abu El-Rus, M.A:
    Tiepolo, M.
    Ottolini, L.
    Vannucci, R.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Serpentinization and deserpentinization reactions in the upper mantle beneath Fuerteventura revealed by peridotite xenoliths with fibrous orthopyroxene and mottled olivine.2015In: Journal of Petrology, ISSN 0022-3530, E-ISSN 1460-2415, Vol. 56, p. 3-31Article in journal (Refereed)
    Abstract [en]

    Mantle xenoliths collected from Fuerteventura, one of the easternmost Canary Islands, exhibit a complex evolutionary history comprising events of depletion, serpentinization, dehydration and melt metasomatism. Each of these events left imprints on both the texture and chemistry of the xenoliths. Extensive partial melting is shown by complete lack of primary clinopyroxene, the ultra-refractory trace element composition of orthopyroxene porphyroclasts, and low heavy rare earth element contents as compared with abyssal peridotites sampled along mid-ocean ridges and oceanic fracture zones, in the xenoliths least affected by later metasomatism. In many xenoliths the original orthopyroxene porphyroclasts and some olivines are replaced by fibrous aggregates of orthopyroxene and/or large, deformed olivine porphyroclasts with mottled rims with stringy glass and fluid inclusions. Such features are very rare in ocean island xenoliths. Unusually high H2O and Cl concentrations, together with very high H2O/Ce and Cl/K ratios in interstitial glasses, suggest that the fibrous orthopyroxene formed by local serpentinization by hot seawater. The volume increase accompanying the serpentinization caused extensive fracturing of adjacent olivine porphyroclasts. The most likely scenario for local mantle invasion by hydrous fluids is along deep faults and fractures caused by tectonic movements along the continent–ocean transition during the early phases of the opening of the Atlantic Ocean. The peridotites were later (probably during the Canary Islands magmatism) dehydrated, causing the serpentine minerals to be replaced by porous domains of fibrous orthopyroxene. Hydrous fluids released by the deserpentinization escaped into neighbouring and overlying rocks leaving trails of fluid inclusions along fractures and grain boundaries causing mottled rims and zones in olivine porphyroclasts. During the Canary Islands magmatism the upper mantle beneath Fuerteventura was also infiltrated by enriched silicate magmas that caused different degrees of Fe–Ti-metasomatism. A higher degree of melt metasomatism in rocks with fibrous orthopyroxene and mottled olivine than in the massive harzburgites strongly suggests that the sublithospheric Canarian magmas reused serpentinized extensional faults during their rise to the surface. The strongest degree of melt metasomatism appears to have resulted in the formation of lherzolites, wehrlites, and dunites.                  

  • 294. Ng, S.W.-P.
    et al.
    Chung, S.-L.
    Robb, L.J.
    Searle, M.P.
    Ghani, A.A.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Oliver, G.J.H.
    Sone, M.
    Gardiner, N.J.
    Roselee, M.H.
    Petrogenesis of Malaysian granitoids in the Southeast Asian Tin Belt: Part 1. Geochemical and Sr-Nd isotopic characteristics.2015In: Geological Society of America Bulletin, ISSN 0016-7606, E-ISSN 1943-2674, Vol. 127, p. 1209-1237Article in journal (Refereed)
    Abstract [en]

    The Malaysian granitoids of the Southeast Asian tin belt have been traditionally divided into a Permian to Late Triassic “I-type”–dominated arc-related Eastern province (Indochina terrane) and a Late Triassic “S-type”–dominated collision-related Main Range province (Sibumasu terrane), separated by the Bentong-Raub Paleo-Tethyan suture that closed in the Late Triassic. The present study, however, shows that this model is oversimplified and that the direct application of Chappell and White’s (1974) I- and S-type classification cannot account for many of the characteristics shared by Malaysian granitoids. Despite being commonly hornblende bearing, as is typical for I-type granites, the roof zones of the Eastern province granites are hornblende free. In addition, the Main Range province granitoids contain insignificant primary muscovite, and are dominated by biotite granites, mineralogically similar to many of the plutons of the Eastern province. In general, the Malaysian granitoids from both provinces are more enriched in high field strength elements than typical Cordilleran I- and S-type granitoids. The mineralogy and geochemistry of the Eastern province granitoids, and their relationship with contemporaneous volcanics, confirm their I-type nature. The bulk liquid lines of descent of both granitic provinces largely overlap with one another. Sr-Nd isotopic data further demonstrate that the Malaysian granitoids, especially those of the Main Range, were hybridized melts derived from two “end-member” source regions, one of which is isotopically similar to the Kontum orthoamphibolites and the other akin to the Kontum paragneisses of the Indochina block. However, there are differences in the source rocks for the two provinces, and it is suggested in this paper that these are related to differing proportions of igneous and sedimentary protoliths. The incorporation of sedimentary-sourced melts in the Eastern province is insignificant, which allowed the granites in this belt to maintain their I-type nature. The presence of minor primary tin mineralization in the Eastern province compared to the much more significant tin endowment in the Main Range is considered to reflect the incorporation of a smaller proportion of sedimentary protolith in the melt products of the former.                  

  • 295. Ng, S.W.P.
    et al.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Roselee, M.H.
    Teschner, C.
    Murtadha, S.
    Oliver, G.J.
    Ghani, A.A.
    Chang, S.C.
    Late Triassic granites from Bangka, Indonesia: a continuation of the Main Range granite province of the South-East Asian Tin Belt.2017In: Journal of Asian Earth Sciences, ISSN 1367-9120, E-ISSN 1878-5786, Vol. 138, p. 548-561Article in journal (Refereed)
    Abstract [en]

    The South-East Asian Tin Belt is one of the most tin-productive regions in the world. It comprises three north-south oriented granite provinces, of which the arc-related Eastern granite province and the collision-related Main Range granite province run across Thailand, Singapore, and Indonesia. These tin-producing granite provinces with different mineral assemblages are separated by Paleo-Tethyan sutures exposed in Thailand and Malaysia. The Eastern Province is usually characterised by granites with biotite ± hornblende. Main Range granites are sometimes characterised by the presence of biotite ± muscovite. However, the physical boundary between the two types of granite is not well-defined on the Indonesian Tin Islands, because the Paleo-Tethyan suture is not exposed on land there. Both hornblende-bearing (previously interpreted as I-type) and hornblende-barren (previously interpreted as S-type) granites are apparently randomly distributed on the Indonesian Tin Islands. Granites exposed on Bangka, the largest and southernmost Tin Island, no matter whether they are hornblende-bearing or hornblende-barren, are geochemically similar to Malaysian Main Range granites. The average ɛNd(t) value obtained from the granites from Bangka (average ɛNd(t) = −8.2) falls within the range of the Main Range Province (−9.6 to −5.4). These granites have SIMS zircon U-Pb ages of ca. 225 Ma and ca. 220 Ma, respectively that are both within the period of Main Range magmatism (∼226–201 Ma) in the Peninsular Malaysia. We suggest that the granites exposed on Bangka represent the continuation of the Main Range Province, and that the Paleo-Tethyan suture lies to the east of the island.

  • 296. Ng, S.W.--P.
    et al.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Searle, M.P.
    Robb, L.J.
    Ghani, A.A.
    Chung, S.-L.
    Oliver, G.J.H.
    Sone, M.
    Gardiner, N.J.
    Roselee, M.H.
    Petrogenesis of Malaysian granitoids in the Southeast Asian Tin Belt: Part 2. U-Pb zircon geochronology and tectonic model.2015In: Geological Society of America Bulletin, ISSN 0016-7606, E-ISSN 1943-2674, Vol. 127, p. 1238-1258Article in journal (Refereed)
    Abstract [en]

    In our complementary geochemical study (Part 1), the Malaysian granitoids of the Southeast Asian tin belt were divided into a Middle Permian to Late Triassic I-type–dominated Eastern province (Indochina terrane) and a Triassic to Early Jurassic transitional I/S-type Main Range province (Sibumasu terrane), separated by the Bentong-Raub suture zone which closed in the Late Triassic. Previous geochronology has relied on only a few U-Pb zircon ages together with K-Ar and whole rock Rb-Sr ages that may not accurately record true magmatic ages. We present 39 new high-precision U-Pb zircon ion microprobe ages from granitoids and volcanics across the Malay Peninsula. Our results show that ages from the Eastern province granitoids span 289–220 Ma, with those from the Main Range province granitoids being entirely Late Triassic, spanning 227–201 Ma. A general westerly younging magmatic trend across the Malay Peninsula is considered to reflect steepening and roll-back of the Bentong-Raub subduction zone during progressive closure of Paleo-Tethys. The youngest ages of subduction-related granites in the Eastern province roughly coincide with the youngest ages of marine sedimentary rocks along the Paleo-Tethyan suture zone. Our petrogenetic and U-Pb zircon age data support models that relate the Eastern province granites to pre-collisional Andean-type magmatism and the western Main Range province granites to syn- and post-collisional crustal melting of Sibumasu crust during the Late Triassic. Tin mineralization was mainly associated with the latter phase of magmatism. Two alternative tectonic models are discussed to explain the Triassic evolution of the Malay Peninsula. The first involves a second Late Triassic to Jurassic or Early Cretaceous east-dipping subduction zone west of Sibumasu where subduction-related hornblende and biotite–bearing granites along Sibumasu are paired with Main Range crustal-melt tin-bearing granites, analogous to the Bolivia Cordilleran tin-bearing granite belt. The second model involves westward underthrusting of Indochina beneath the West Malaya Main Range province, resulting in crustal thickening and formation of tin-bearing granites of the Main Ranges. Cretaceous granitoids are also present locally in Singapore (Ubin diorite), on Tioman Island, in the Noring pluton, of the Stong complex (Eastern Province), and along the Sibumasu terrane in southwest Thailand and Burma (Myanmar), reflecting localized crustal melting.                  

  • 297. Ng, S.W.P.
    et al.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Tam, P.Y.
    Jayasingha, P.
    Wong, J.P.-M.
    Denyszyn, S.
    Yiu, J.S.-Y.
    Chang, S.-C.
    Ca. 820-640 Ma SIMS U-Pb age signal in the peripheral Vijayan Complex, Sri Lanka: Identifying magmatic pulses in the assembly of Gondwana.2017In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 294, p. 244-256Article in journal (Refereed)
    Abstract [en]

    Sri Lanka comprises three roughly north-south trending amphibolite- to granulite-facies lithotectonic complexes, from west to east the Highland Complex, the Wanni Complex, and the Vijayan Complex. These terranes were correlated with other East Gondwana continental terranes with similar lithologies forming at similar ages. The Wanni Complex and the Vijayan Complex have been interpreted as volcanic arc terranes brought together by a double-sided subduction. The Highland Complex represents the metamorphosed accretionary prism within the suture when the Wanni and Vijayan Complexes were juxtaposing against each other. In contrast to the Wanni and Highland Complexes, the Vijayan Complex has yielded only a few geochronological data with satisfactory precision. Previous studies suggested that the Vijayan Complex comprises ∼1100–924 Ma granitic gneisses, which were metamorphosed during ∼590–456 Ma. More recently, ∼772–617 Ma mafic intrusions have been identified. This study divides the Vijayan granitic gneisses and the associated melt products geochemically into a low-Nb series and a more primitive high-Nb series. Our SIMS U-Pb zircon data suggested that both series have protolith magmatic ages of ∼1062–935 Ma, and metamorphic ages of ∼580–521 Ma, which is consistent with previous work. However, some of the Vijayan granitic gneisses and granitic anatectic melt products at the Highland-Vijayan tectonic mixed zone preserve an additional Tonian-Cryogenian (∼820–630 Ma) age signal. This age signal suggested that felsic magmatism also occurred when mafic granulites were emplaced along the Highland-Vijayan boundary, which is broadly coeval with to the bimodal magmatism occurring along the Highland-Wanni boundary. This study also suggests that charnockitisation in the Vijayan Complex occurred at 562 ± 6 Ma during the Neoproterozoic regional metamorphism. The Tonian-Cryogenian signal preserved in the Highland-Vijayan tectonic mixed zone can also be found in the alkaline intrusion hosted by the Namuno Terrane and the Lurio Belt in Mozambique. This indicates a relationship between the Vijayan granitic gneisses and the Lurio foreland metagranitic basement, while the Namuno Terrane and the Lurio Belt are correlated with the Highland-Vijayan tectonic mixed zone. The ages and the isotope signatures of these granitic bodies further suggest a genetic relationship of these granitic bodies with various magmatic intrusions in East Antarctica.

  • 298. Nikogosian, I.K.
    et al.
    Ersoy, Ö.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Mason, P.R.D.
    de Hoog, J.C.M.
    Wortel, R.
    van Bergen, M.J.
    Multiple subduction imprints in the mantle below Italy detected in a single lava flow.2016In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 449, p. 12-19Article in journal (Refereed)
    Abstract [en]

    Post-collisional magmatism reflects the regional subduction history prior to collision but the link between the two is complex and often poorly understood. The collision of continents along a convergent plate boundary commonly marks the onset of a variety of transitional geodynamic processes. Typical responses include delamination of subducting lithosphere, crustal thickening in the overriding plate, slab detachment and asthenospheric upwelling, or the complete termination of convergence. A prominent example is the Western–Central Mediterranean, where the ongoing slow convergence of Africa and Europe (Eurasia) has been accommodated by a variety of spreading and subduction systems that dispersed remnants of subducted lithosphere into the mantle, creating a compositionally wide spectrum of magmatism. Using lead isotope compositions of a set of melt inclusions in magmatic olivine crystals we detect exceptional heterogeneity in the mantle domain below Central Italy, which we attribute to the presence of continental material, introduced initially by Alpine and subsequently by Apennine subduction. We show that superimposed subduction imprints of a mantle source can be tapped during a melting episode millions of years later, and are recorded in a single lava flow.

  • 299.
    Nilsson, E.J. Charlotta
    et al.
    Lunds Universitet.
    Kristiansson, Per
    Lunds Universitet.
    Ros, Linus
    Lunds Universitet.
    De La Rosa, Nathaly
    Lunds Universitet.
    Elfman, Mikael
    Lunds Universitet.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Pallon, Jan
    Lunds Universitet.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    A nuclear geochemical analysis system for boron quantification using a focused ion beam2017In: Journal of Radioanalytical and Nuclear Chemistry, ISSN 0236-5731, E-ISSN 1588-2780, Vol. 311, p. 355-364Article in journal (Refereed)
    Abstract [en]

    Ion beam analysis has for decades been used as a tool for geochemical analysis of trace elements using both X-rays (particle induced X-ray emission) and nuclear reaction analysis. With the geoanalytical setup at the Lund Ion Beam Analysis Facility, the boron content in geological samples with a spatial resolution of 1 µm is determined through nuclear reaction analysis. In the newly upgraded setup, a single detector has been replaced by a double sided silicon strip detector with 2048 segments. After optimization, boron content in geological samples as low as 1µg g-1 can be measured.

  • 300.
    Ning, Wenxin
    et al.
    Department of Geology Lund University.
    Andersson, Per S
    Swedish Museum of Natural History, Department of Geology.
    Ghosh, Anupam
    Dept. of Geol. Sciences Jadavpur University India.
    Khan, Mansoor
    Department of Geology Lund University.
    Filipsson, Helena
    Department of Geology Lund University.
    Quantitative salinity reconstructions of the Baltic Sea during the mid-Holocene2017In: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 46, no 1, p. 100-110Article in journal (Refereed)
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