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  • Tverin, Malin
    et al.
    Esparza-Salas, Rodrigo
    Swedish Museum of Natural History, Department of Bioinformatics and Genetics.
    Strömberg, Annika
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Tang, Patrik
    Kokkonen, Iiris
    Herrero, Annika
    Kauhala, Kaarina
    Karlsson, Olle
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Tiilikainen, Raisa
    Vetemaa, Markus
    Sinisalo, Tuula
    Käkela, Reijo
    Lundström, Karl
    Complementary methods assessing short and long-term prey of a marine top predator ‒ Application to the grey seal-fishery conflict in the Baltic Sea2019In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 14, no 1, article id e0208694Article in journal (Refereed)
    Abstract [en]

    The growing grey seal (Halichoerus grypus) population in the Baltic Sea has created conflicts with local fisheries, comparable to similar emerging problems worldwide. Adequate information on the foraging habits is a requirement for responsible management of the seal population. We investigated the applicability of available dietary assessment methods by comparing morphological analysis and DNA metabarcoding of gut contents (short-term diet; n = 129/125 seals, respectively), and tissue chemical markers i.e. fatty acid (FA) profiles of blubber and stable isotopes (SIs) of liver and muscle (mid- or long-term diet; n = 108 seals for the FA and SI markers). The methods provided complementary information. Short-term methods indicated prey species and revealed dietary differences between age groups and areas but for limited time period. In the central Baltic, herring was the main prey, while in the Gulf of Finland percid and cyprinid species together comprised the largest part of the diet. Perch was also an important prey in the western Baltic Proper. The DNA analysis provided firm identification of many prey species, which were neglected or identified only at species group level by morphological analysis. Liver SIs distinguished spatial foraging patterns and identified potentially migrated individuals, whereas blubber FAs distinguished individuals frequently utilizing certain types of prey. Tissue chemical markers of adult males suggested specialized feeding to certain areas and prey, which suggest that these individuals are especially prone to cause economic losses for fisheries. We recommend combined analyses of gut contents and tissue chemical markers as dietary monitoring methodology of aquatic top predators to support an optimal ecosystem-based management.

  • Renne, Paul R
    et al.
    Berkeley Geochronology Center, Berkeley, California 94709, USA.
    Arenillas, Ignacio
    Departamento de Ciencias de la Tierra, and Instituto Universitario de Investigación en Ciencias Ambientales de Aragón, Universidad de Zaragoza, E-50009 Zaragoza, Spain.
    Arz, José A.
    Departamento de Ciencias de la Tierra, and Instituto Universitario de Investigación en Ciencias Ambientales de Aragón, Universidad de Zaragoza, E-50009 Zaragoza, Spain.
    Vajda, Vivi
    Swedish Museum of Natural History, Department of Paleobiology. Department of Geology, Lund University, Sweden.
    Gilabert, Vicente
    Departamento de Ciencias de la Tierra, and Instituto Universitario de Investigación en Ciencias Ambientales de Aragón, Universidad de Zaragoza, E-50009 Zaragoza, Spain.
    Bermúdez, Hermann D
    Grupo de Investigación Paleoexplorer, St. George, Vermont 05495, USA.
    Multi-proxy record of the Chicxulub impact at the Cretaceous-Paleogene boundary from Gorgonilla Island, Colombia2018In: Geology, ISSN 0091-7613, E-ISSN 1943-2682, Vol. 46, p. 547-550Article in journal (Refereed)
    Abstract [en]

    A 40 m stratigraphic section at Gorgonilla Island, Colombia, provides a unique deepmarine, low-latitude, Southern Hemisphere record of events related to the end-Cretaceous Chicxulub impact and the global Cretaceous/Paleogene boundary (KPB). The KPB is marked by a 20-mm-thick, densely packed spherule bed as defined by planktic foraminifera, in contrast to complex relationships found in high-energy, impact-proximal sites in the Gulf of Mexico and Caribbean basins. The absence of basal Danian foraminiferal Zone P0 may indicate a possible hiatus of <10 ka immediately above the spherule bed, but is most probably an artifact of deposition below the calcite compensation depth as suggested by the nearly complete absence of calcareous fossils for 20 m below the Zone Pα. A weighted mean 40Ar/39Ar age of 66.051 ± 0.031 Ma for 25 fresh glassy spherules unequivocally establishes both their derivation from Chicxulub, and the association between the impact and the KPB. The spherule bed, and Maastrichtian strata below it, display soft-sediment deformation features consistent with strong seismic motion, suggesting that seismic activity in the immediate aftermath of the Chicxulub impact continued for weeks. We discovered a fern-spike immediately above the spherule bed, representing the first record of this pioneer vegetation from the South American continent, and from a low-latitude (tropical) environment.

  • Peng, Jungang
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Li, Jianguo
    Key Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.
    Slater, Sam M
    Swedish Museum of Natural History, Department of Paleobiology.
    Li, Wenben
    Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.
    Zhu, Huaicheng
    State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.
    Vajda, Vivi
    Swedish Museum of Natural History, Department of Paleobiology. Department of Geology, Lund University, Sweden.
    Triassic palynostratigraphy and palynofloral provinces: evidence from southern Xizang (Tibet), China2018In: Alcheringa, ISSN 0311-5518, E-ISSN 1752-0754, Vol. 42, p. 67-86Article in journal (Refereed)
    Abstract [en]

    Palynological analysis was carried out on Middle to Upper Triassic strata from Tulong, Nyalam County, southern Xizang (Tibet), China. Well-preserved miospore (pollen and spore) assemblages and sparse acritarch occurrences were identified. We recognized four formal and one informal biozones based on stratigraphically important taxa and compositional changes through the succession, in ascending order: the Triplexisporites Interval Zone (Anisian), the Staurosaccites quadrifidus Taxon-range Zone (upper Anisian to lower Norian), the Striatella Interval Zone (lower Norian), the Craterisporites rotundus Taxon-range Zone (middle to upper Norian) and the informal ‘Dictyophyllidites harrisii zone’ (Rhaetian). The zonation was supported by marine fossils (e.g., ammonoids and conodonts), and compositional similarity between the zones was examined using non-metric multidimensional scaling (NMDS). Correlation with other representative palynological sequences across Gondwana was also conducted. The presence of miospore taxa not previously recovered from the Late Triassic North and South China palynofloral provinces (e.g., Ashmoripollis reducta, Craterisporites rotundus, Enzonalasporites vigens, Minutosaccus crenulatus, Samaropollenites speciosus and Staurosaccites quadrifidus) calls for a new province in southwestern China, i.e., the Southern Xizang Province. It is proposed here that the modern expression of the northern boundary runs along the Yarlung Zangbo Suture, the remnant of the Tethys that separated the Indian Plate (southern Xizang) and the Lhasa Block during the Late Triassic. This new palynofloral province comprises typical elements of the Onslow Microflora, indicating the need for an extension of this microflora in southern Xizang, China.

  • Peng, Yungang
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Li, Jianguo
    Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.
    Li, Wenben
    Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.
    Slater, Sam M
    Swedish Museum of Natural History, Department of Paleobiology.
    Zhu, Huaicheng
    State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.
    Vajda, Vivi
    Swedish Museum of Natural History, Department of Paleobiology. Department of Geology, Lund University, Sweden.
    The Triassic to Early Jurassic palynological record of the Tarim Basin, China2018In: Palaeobiodiversity and Palaeoenvironments, ISSN 1867-1594, E-ISSN 1867-1608, Vol. 98, p. 7-28Article in journal (Refereed)
    Abstract [en]

    The Tarim Basin, located in northwestern China, is an important oil-bearing region, and the extensive non-marine Mesozoic successions make this a key location for understanding environmental changes through the Triassic and Jurassic. Palynological analyses on samples from Lunnan-1 and Tazhong-1 drill cores from the northern and central part of the Tarim Basin reveal wellpreserved spore–pollen assemblages. Five palynological assemblages, i.e. Tarim Triassic 1 (TT1)–Tarim Triassic 4 (TT4) and Tarim Jurassic 1 (TJ1), spanning the Early Triassic to Early Jurassic were identified based on compositional changes, which are supported by ordination of samples using non-metric multidimensional scaling (NMDS). The Early Triassic assemblages possess abundant bryophytes and Densoisporites spp.-producers, which potentially represent a recovery succession following the end-Permian event. The Late Triassic spore–pollen assemblages are more similar to those of the North China Palynofloral Province compared to the South China Province. Based on our phytogeographic analysis, we propose that the western section of the boundary between the North and South China palynofloras should be placed at the southern margin of the Tarim Basin.

  • Li, Liqin
    et al.
    State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.
    Wang, Yongdong
    State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.
    Vajda, Vivi
    Swedish Museum of Natural History, Department of Paleobiology. Department of Geology, Lund University, Sweden.
    Liu, Zhaosheng
    State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.
    Late Triassic ecosystem variations inferred by palynological records from Hechuan, southern Sichuan Basin, China2018In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 155, p. 1793-1810Article in journal (Refereed)
    Abstract [en]

    The Late Triassic deposits of the Sichuan Basin, southwestern China are significant for hosting abundant and diverse fossil assemblages including plants (containing spores and pollen), bivalves and insects. However, the Late Triassic palaeoecological variations are still poorly documented in this region. Here we present results from a palynological study from the Upper Triassic Xujiahe Formation in Hechuan of Chongqing, southern Sichuan Basin. The palynological analysis revealed a well-preserved terrestrial palynoflora of high diversity, comprising 184 species in 75 genera of spores and pollen. Three palynological assemblages were recognized, reflecting terrestrial successions throughout the entire interval with significant changes in the vegetation. Cycads/bennettites/ginkgophytes and conifers show an increasing trend into younger deposits, while ferns and lycopsids decrease in relative abundance. The Late Triassic vegetation underwent changes from lowland fern forest to a mixed forest with more canopy trees. We applied the Spore-pollen Morphological Group (SMG) method and Sporomorph EcoGroup (SEG) model to interpret the palaeoclimate features. The results reveal that the lower part of the Xujiahe Formation was deposited under relatively warm and humid conditions with an overall cooling and drying trend from latest Norian to Rhaetian time, accompanied by a general decrease of ferns and simultaneous increase of gymnosperms, and a decline in diversity of miospores. This study presents data on variations within the terrestrial ecosystem prior to the end-Triassic extinction event in the Sichuan Basin, and therefore provides important information for understanding the changes in the vegetation preceding the end-Triassic event.

  • Field, Daniel J
    et al.
    Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK.
    Bercovici, Antoine
    2Department of Paleobiology MRC-121, National Museum of Natural History, Smithsonian Institution, 10th Street and Constitution Avenue, NW, Washington, DC 20560-0121, USA.
    Berv, Jacob S
    Department of Ecology & Evolutionary Biology, Cornell University, 215 Tower Road, Ithaca, NY 14853, USA.
    Dunn, Regan
    Integrated Research Center, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605, USA.
    Fastovsky, David E
    Department of Geosciences, University of Rhode Island, 9 East Alumni Avenue, Kingston, RI 02881, USA.
    Lyson, Tyler R
    6Department of Earth Sciences, Denver Museum of Nature and Science, 2001 Colorado Boulevard, Denver, CO 80205, USA.
    Vajda, Vivi
    Swedish Museum of Natural History, Department of Paleobiology. Department of Geology, Lund University, Sweden.
    Gauthier, Jacques A
    Department of Geology & Geophysics, Yale University 210 Whitney Avenue, New Haven, CT 06511, USA.
    Early Evolution of Modern Birds Structured by Global Forest Collapse at the End-Cretaceous Mass Extinction2018In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 28, p. 1825-1831Article in journal (Refereed)
    Abstract [en]

    The fossil record and recent molecular phylogenies support an extraordinary early-Cenozoic radiation of crown birds (Neornithes) after the Cretaceous-Paleogene (K-Pg) mass extinction [1–3 ]. However, questions remain regarding the mechanisms underlying the survival of the deepest lineages within crown birds across the K-Pg boundary, particularly since this global catastrophe eliminated even the closest stem-group relatives of Neornithes [4 ]. Here, ancestral state reconstructions of neornithine ecology reveal a strong bias toward taxa exhibiting predominantly non-arboreal lifestyles across the K-Pg, with multiple convergent transitions toward predominantly arboreal ecologies later in the Paleocene and Eocene. By contrast, ecomorphological inferences indicate predominantly arboreal lifestyles among enantiornithines, the most diverse and widespread Mesozoic avialans [5–7 ]. Global paleobotanical and palynological data show that the K-Pg Chicxulub impact triggered widespread destruction of forests [8, 9 ]. We suggest that ecological filtering due to the temporary loss of significant plant cover across the K-Pg boundary selected against any flying dinosaurs (Avialae [10 ]) committed to arboreal ecologies, resulting in a predominantly non-arboreal postextinction neornithine avifauna composed of totalclade Palaeognathae, Galloanserae, and terrestrial total-clade Neoaves that rapidly diversified into the broad range of avian ecologies familiar today. The explanation proposed here provides a unifying hypothesis for the K-Pg-associated mass extinction of arboreal stem birds, as well as for the post-K-Pg radiation of arboreal crown birds. It also provides a baseline hypothesis to be further refined pending the discovery of additional neornithine fossils from the Latest Cretaceous and earliest Paleogene.

  • Laurie, John
    et al.
    Geoscience Australia, Canberra, Australia.
    McLoughlin, Stephen
    Swedish Museum of Natural History, Department of Paleobiology.
    Mary Elizabeth White AM:5 January 1926 – 5 August 2018: Obituary2018Other (Other academic)
    Abstract [en]

    Mary White was born in South Africa to an entomologist father and a botanist mother, but spent most of her early years in Southern Rhodesia (now Zimbabwe), where her father was First Director of Agriculture and Professor of Entomology. She attended the University of Cape Town, where she studied botany and zoology. When looking for a subject for her Masters' thesis, Alexander du Toit recommended a paleobotanical subject, as there was no paleobotanist in Africa but it had Gondwanan fossil flora awaiting study. This eventually led to Mary's lifetime interest in Gondwana and the evolution of its biota.

  • Bomfleur, Benjamin
    et al.
    Westfälische Wilhelms-Universität, Münster, Germany.
    Blomenkemper, Patrick
    Westfälische Wilhelms-Universität, Münster, Germany.
    Kerp, Hans
    Westfälische Wilhelms-Universität, Münster, Germany.
    McLoughlin, Stephen
    Swedish Museum of Natural History, Department of Paleobiology.
    Polar regions of the Mesozoic–Paleogene greenhouse world as refugia for relict plant groups2018In: Transformative Paleobotany: Papers to Commemorate the Life and Legacy of Thomas N. Taylor / [ed] Krings, M., Harper, C.J., Cúneo, N.R., Rothwell, G.W., Amsterdam: Elsevier, 2018, p. 593-611Chapter in book (Refereed)
    Abstract [en]

    Throughout Earth history, plants were apparently less dramatically affected by global biotic crises than animals. Here, we present the unexpected occurrence of Dicroidium, the iconic plant fossil of the Gondwanan Triassic, in Jurassic strata of East Antarctica. The material consists of dispersed cuticles of three Dicroidium species, including the type species D. odontopteroides. These youngest occurrences complement a remarkable biogeographic pattern in the distribution of Dicroidium through time: the earliest records are from palaeoequatorial regions, whereas the last records are from polar latitudes. We summarize similar, relictual high-latitude occurrences in other plant groups, including lycopsids, various ‘seed ferns’, Bennettitales, and cheirolepid conifers, to highlight a common phenomenon: during times of global warmth, the ice-free high-latitude regions acted as refugia for relictual plant taxa that have long disappeared elsewhere. Eventually, such last surviving polar populations probably disappeared as they became outcompeted by newly emerging plant groups in the face of environmental change.

  • Edirisooriya, Geetha
    et al.
    Department of Geology, University of Peradeniya, Peradeniya, Sri Lanka.
    Dharmagunawardhane, H.A.
    Department of Geology, University of Peradeniya, Peradeniya, Sri Lanka.
    McLoughlin, Stephen
    Swedish Museum of Natural History, Department of Paleobiology.
    The first record of the Permian Glossopteris flora from Sri Lanka: implications for hydrocarbon source rocks in the Mannar Basin2018In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 155, p. 907-920Article in journal (Refereed)
    Abstract [en]

    Strata exposed near Tabbowa Tank, Tabbowa Basin, western Sri Lanka have yielded the

    first representatives of the distinctive Permian Glossopteris flora from that country. The assemblage

    includes gymnosperm foliage attributable to Glossopteris raniganjensis, roots referable to Vertebraria

    australis, seeds assigned to Samaropsis sp., sphenophyte axes (Paracalamites australis) and

    foliage (Sphenophyllum emarginatum), and fern foliage (Dichotomopteris lindleyi). This small macroflora

    is interpreted to be of probable Lopingian (late Permian) age based on comparisons with the

    fossil floras of Peninsula India. Several Glossopteris leaves in the assemblage bear evidence of terrestrial

    arthropod interactions including hole feeding, margin feeding, possible lamina skeletonization,

    piercing-and-sucking damage and oviposition scarring. The newly identified onshore Permian strata

    necessitate re-evaluation of current models explaining the evolution of the adjacent offshore Mannar

    Basin. Previously considered to have begun subsiding and accumulating sediment during Jurassic

    time, we propose that the Mannar Basin may have initiated as part of a pan-Gondwanan extensional

    phase during late Palaeozoic – Triassic time. We interpret the basal, as yet unsampled, seismically

    reflective strata of this basin to be probable organic-rich continental strata of Lopingian age, equivalent

    to those recorded in the Tabbowa Basin, and similar to the Permian coal-bearing successions

    in the rift basins of eastern India and Antarctica. Such continental fossiliferous strata are particularly

    significant as potential source rocks for recently identified natural gas resources in the Mannar

    Basin.

  • Sadowski, Eva-Maria
    et al.
    Department of Geobiology, University of Göttingen Goldschmidtstraße 3, 37077 Göttingen, Germany.
    Hammel, Jörg U.
    Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Str. 1, 21502 Geesthacht, Germany.
    Denk, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Synchrotron X-rayimaging of a dichasium cupule of Castanopsis from Eocene Baltic amber2018In: American Journal of Botany, ISSN 0002-9122, E-ISSN 1537-2197, Vol. 105, p. 2015-2036Article in journal (Refereed)
    Abstract [en]

    The partial female inflorescence reported here provides an important addition to acorns of Castanopsis described from middle Eocene strata of Europe. Furthermore, the intercontinental distribution of Castanopsis in the Eocene is confirmed. The amber fossil also broadens the picture of the Baltic amber source area, indicating oligotrophic, sandy, bog-like habitats. Finally, this study underscores the great benefit of SRμCT as a powerful tool to investigate plant inclusions from amber in a nondestructive way.

  • McLoughlin, Stephen
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Bomfleur, Benjamin
    Westfälische Wilhelms-Universität, Münster, Germany.
    Drinnan, Andrew N.
    School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia.
    Pachytestopsis tayloriorum gen. et sp. nov., an anatomically preserved glossopterid seed from the Lopingian of Queensland, Australia2018In: Transformative Paleobotany: Papers to Commemorate the Life and Legacy of Thomas N. Taylor / [ed] Krings, M., Harper, C.J., Cúneo, N.R., Rothwell, G.W., Amsterdam: Elsevier, 2018, p. 155-178Chapter in book (Refereed)
    Abstract [en]

    A permineralized seed, Pachytestopsistayloriorum gen. et sp. nov., is described from the Changhsingian (upper Permian) Fort Cooper Coal Measures at the Homevale locality in the northern Bowen Basin, Queensland,Australia. This largest permineralized seed species yet recorded from Permian deposits of Gondwana conforms to a size accommodated by either Rigbyaceae or Lidgettoniaceae (glossopterid) fructifications recorded elsewhere in the Sydney-Bowen basin complex. The seeds are characterized by a thin endotesta of longitudinally orientated cells, thick mesotesta incorporating an inner band of very thick walled sclereids and an outer layer of thin-walled parenchymatous cells, and an exotesta that comprises a well-developed epidermis and several layers of thick-walled hypodermal cells. Vascular supply to the base of the seed passes through the integument and bifurcates into the nucellar pad. Taeniate bisaccate pollen of Protohaploxypinus-type occurs in the pollen chamber of the seed. A comparison of the characters of P. tayloriorum with other permineralized seeds from the Permian of Gondwana indicates that several of the characters used in previous phylogenetic analyses incorporating glossopterids are wrongly scored or ambiguous in their definition.

  • Kusiak, Monika A.
    et al.
    Dunkley, Daniel J.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Wilde, Simon A.
    Sałacińska, Anna
    Konečný, Patrík
    Szopa, Krzysztof
    Gawęda, Aleksandra
    Chew, David
    Peak to post-peak thermal history of the Saglek Block of Labrador: A multiphase and multi-instrumental approach to geochronology2018In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 484, p. 210-223Article in journal (Refereed)
    Abstract [en]

    The Saglek Block of coastal Labrador forms the western margin of the North Atlantic Craton, where Archean gneisses and granulites have been reworked during the Paleoproterozoic. Previous work has established that the block is a composite of Eoarchean to Mesoarchean protoliths metamorphosed to upper amphibolite and granulite facies at around 2.8–2.7Ga. New in-situ microbeam dating of accessory minerals in granoblastic gneisses reveals a complex peak to post-peak thermal history. Zircon growth at ca. 3.7–3.6Ga provides the age of formation of the tonalitic protoliths to the gneisses. Further zircon growth in syn-tectonic granitic gneiss and monazite growth in a variety of orthogneisses confirm peak metamorphic conditions at ca. 2.7Ga, but also reveal high-temperature conditions at ca. 2.6Ga and 2.5Ga. The former is interpreted as the waning stages of the 2.7Ga granulite event, whereas the latter is associated with a younger phase of granitic magmatism. In addition, apatite ages of ca. 2.2Ga may represent either cooling associated with the 2.5Ga event or a previously unrecognized greenschist-facies metamorphism event that predates the Torngat Orogeny.

  • Sałacińska, Anna
    et al.
    Kusiak, Monika A.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Dunkley, Daniel J.
    Wilde, Simon A.
    Kielman, Ross
    Swedish Museum of Natural History, Department of Geology.
    Complexity of the early Archean Uivak Gneiss: Insights from Tigigakyuk Inlet, Saglek Block, Labrador, Canada and possible correlations with south West Greenland2018In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 315, p. 103-119Article in journal (Refereed)
    Abstract [en]

    The Saglek Block of Labrador comprises Eoarchean to Neoarchean lithologies, metamorphosed at high temperature at ca. 2.7 Ga. Here, we investigate the gneisses of Tigigakyuk Inlet, previously identified as the locality exposing the most ancient rocks in the Saglek Block. New geochronological and geochemical results reveal a multistage history. Precise magmatic emplacement ages of 3.75 to 3.71 Ga refine the age of the Uivak Gneiss. Zircon rims and neoblastic grains with low Th/U record metamorphism at ca. 3.6 and 2.8-2.7 Ga. Magmatism between these tectono-metamorphic events is recorded by the presence of meta-mafic dykes in the gneisses, gabbroic enclaves in ca. 2.7 Ga syn-tectonic granitoids, as well as by a ca. 3.56 Ga age for monzonitic gneiss in which metamorphic zircon is present as xenocrysts. Felsic (TTG) magmatism between ca. 3.75 Ga and 3.71 Ga, as well as metamorphism at both ca. 3.6 Ga and 2.8-2.7 Ga, is also recognised in the Itsaq Gneiss Complex of south West Greenland, and is restricted to the Færingehavn Terrane. Our new data enable a more rigorous correlation between these formerly conjugate parts of the North Atlantic Craton.

  • Danielsson, Sara
    et al.
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Benskin, Jonathan
    Department of Environmental Science and Analytical Chemistry, Stockholm University.
    Bignert, Anders
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Bizkarguenaga, Ekhine
    Department of Environmental Science and Analytical Chemistry, Stockholm University..
    de Wit, Cynthia
    Department of Environmental Science and Analytical Chemistry, Stockholm University..
    Egebäck, Anna-Lena
    Department of Environmental Science and Analytical Chemistry, Stockholm University..
    Eriksson, Ulla
    Department of Environmental Science and Analytical Chemistry, Stockholm University..
    Faxneld, Suzanne
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Hjelmquist, Pär
    Department of Environmental Science and Analytical Chemistry, Stockholm University..
    Johansson, Ann-Marie
    Department of Environmental Science and Analytical Chemistry, Stockholm University..
    Jones, Douglas
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Kruså, Martin
    Department of Environmental Science and Analytical Chemistry, Stockholm University..
    Kylberg, Eva
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Mechedal, Jan
    Department of Environmental Science and Analytical Chemistry, Stockholm University..
    Nyberg, Elisabeth
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Sundbom, Marcus
    Department of Environmental Science and Analytical Chemistry, Stockholm University..
    Distribution and conversions of metal- and POP concentrations among various tissues in herring2018Report (Other academic)
  • Kleine, B. I.
    et al.
    Stefánsson, A.
    Halldórsson, S. A.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Jónasson, K.
    Silicon and oxygen isotopes unravel quartz formation processes in the Icelandic crust2018In: Geochemical Perspectives Letters, Vol. 7, p. 5-11Article in journal (Refereed)
    Abstract [en]

    Quartz formation processes in the Icelandic crust were assessed using coupled δ18O and δ30Si systematics of silica deposits formed over a wide temperature range (<150 to >550 °C). Magmatic quartz reveals δ18O (-5.6 to +6.6 ‰) and δ30Si (-0.4 ± 0.2 ‰) values representative of mantle- and crustally-derived melts in Iceland. Hydrothermal quartz and silica polymorphs display a larger range of δ18O (-9.3 to +30.1 ‰) and δ30Si (-4.6 to +0.7 ‰) values. Isotope modelling reveals that such large variations are consistent with variable water sources and equilibrium isotope fractionation between fluids and quartz associated with secondary processes occurring in the crust, including fluid-rock interaction, boiling and cooling. In context of published δ18O and δ30Si data on hydrothermal silica deposits, we demonstrate that large ranges in δ30Si values coupled to insignificant δ18O variations may result from silica precipitation in a hydrothermal fluid conduit associated with near-surface cooling. While equilibrium isotope fractionation between fluids and quartz seems to prevail at high temperatures, kinetic fractionation likely influences isotope systematics at low temperatures.

  • van der Meer, Q H A
    et al.
    Waight, T E
    Tulloch, A J
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Andersen, T
    Magmatic Evolution during the Cretaceous Transition from Subduction to Continental Break-up of the Eastern Gondwana Margin (New Zealand) documented by in-situ Zircon O and €“Hf Isotopes and Bulk-rock Sr and €“Nd Isotopes2018In: Journal of Petrology, Vol. 59, no 5, p. 849-880Article in journal (Refereed)
    Abstract [en]

    Major changes in tectonic style can lead to tapping of highly variable magma sources and potentially result in significant episodes of crustal growth. Here we focus on magmatism associated with a transition from arc magmatism to subsequent over-thickening and eventual orogenic collapse. This transition is associated with cessation of subduction and was followed by continental extension and finally continental break-up as recorded in the Cretaceous magmatic record of Zealandia. Orogenic collapse peaked at 110 Ma and is expressed through core complex formation and the intrusion of I- to evolved I/S-type Rahu Suite plutons that have widely varying chemical compositions but homogeneous whole-rock and zircon isotopic signatures that are intermediate between mantle and local upper crust values. The Rahu Suite is interpreted to be derived from differing degrees of melt extraction from a pre-existing lower crustal source and lacks a demonstrable juvenile component. This lower crustal source was likely formed by magmatic underplating and melt–crust hybridization during preceding arc volcanism (Separation Point and Darran suites), effectively smearing out a pulsed event of crust formation in the zircon record. Therefore, late orogenic I- and I/S-type suites do not have to equate to crustal growth and can be an expression of crustal re-melting. An abrupt change in magma sources in Zealandia occurred after 100 Ma during the onset of progressive crustal extension. A juvenile alkaline component (presumably derived from the lithospheric mantle) is suggested to have been present from >97 Ma. This component became more pronounced with time until the emplacement of granites and trachytes with isotopic signatures overlapping with coeval mafic mantle-derived dikes during bimodal rift-related magmatism. The juvenile alkaline component dictated the composition of the felsic magmas but did not represent a significant crustal growth event due to small total volumes.

  • Drake, Henrik
    et al.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Heim, Christine
    Reiners, Peter W.
    Tillberg, Mikael
    Hogmalm, K. Johan
    Dopson, Mark
    Broman, Curt
    Åström, Mats E.
    Unprecedented 34S-enrichment of pyrite formed following microbial sulfate reduction in fractured crystalline rocks2018In: Geobiology, Vol. 16, no 5, p. 556-574Article in journal (Refereed)
    Abstract [en]

    In the deep biosphere, microbial sulfate reduction (MSR) is exploited for energy. Here, we show that, in fractured continental crystalline bedrock in three areas in Sweden, this process produced sulfide that reacted with iron to form pyrite extremely enriched in 34S relative to 32S. As documented by secondary ion mass spectrometry (SIMS) microanalyses, the δ34Spyrite values are up to +132‰V-CDT and with a total range of 186‰. The lightest δ34Spyrite values (−54‰) suggest very large fractionation during MSR from an initial sulfate with δ34S values (δ34Ssulfate,0) of +14 to +28‰. Fractionation of this magnitude requires a slow MSR rate, a feature we attribute to nutrient and electron donor shortage as well as initial sulfate abundance. The superheavy δ34Spyrite values were produced by Rayleigh fractionation effects in a diminishing sulfate pool. Large volumes of pyrite with superheavy values (+120 ± 15‰) within single fracture intercepts in the boreholes, associated heavy average values up to +75‰ and heavy minimum δ34Spyrite values, suggest isolation of significant amounts of isotopically light sulfide in other parts of the fracture system. Large fracturespecific δ34Spyrite variability and overall average δ34Spyrite values (+11 to +16‰) lower than the anticipated δ34Ssulfate,0 support this hypothesis. The superheavy pyrite found locally in the borehole intercepts thus represents a late stage in a much larger fracture system undergoing Rayleigh fractionation. Microscale Rb–Sr dating and U/Th– He dating of cogenetic minerals reveal that most pyrite formed in the early Paleozoic era, but crystal overgrowths may be significantly younger. The δ13C values in cogenetic calcite suggest that the superheavy δ34Spyrite values are related to organotrophic MSR, in contrast to findings from marine sediments where superheavy pyrite has been proposed to be linked to anaerobic oxidation of methane. The findings provide new insights into MSR-related S-isotope systematics, particularly regarding formation of large fractions of 34S-rich pyrite.

  • Bergkvist, Johanna
    et al.
    Klawonn, Isabell
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Lavik, Gaute
    Brüchert, Volker
    Ploug, Helle
    Turbulence simultaneously stimulates small- and large-scale CO2 sequestration by chain-forming diatoms in the sea2018In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 9, no 1Article in journal (Refereed)
    Abstract [en]

    Chain-forming diatoms are key CO2-fixing organisms in the ocean. Under turbulent conditions they form fast-sinking aggregates that are exported from the upper sunlit ocean to the ocean interior. A decade-old paradigm states that primary production in chain-forming diatoms is stimulated by turbulence. Yet, direct measurements of cell-specific primary production in individual field populations of chain-forming diatoms are poorly documented. Here we measured cell-specific carbon, nitrate and ammonium assimilation in two field populations of chain-forming diatoms (Skeletonema and Chaetoceros) at low-nutrient concentrations under still conditions and turbulent shear using secondary ion mass spectrometry combined with stable isotopic tracers and compared our data with those predicted by mass transfer theory. Turbulent shear significantly increases cell-specific C assimilation compared to still conditions in the cells/chains that also form fast-sinking, aggregates rich in carbon and ammonium. Thus, turbulence simultaneously stimulates small-scale biological CO2 assimilation and large-scale biogeochemical C and N cycles in the ocean.

  • Saji, N. S.
    et al.
    Larsen, K.
    Wielandt, D.
    Schiller, M.
    Costa, M. M.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Rosing, M. T.
    Bizzarro, M.
    Hadean geodynamics inferred from time-varying 142Nd/144Nd in the early Earth rock record2018In: Geochemical Perspectives Letters, Vol. 7, p. 43-48Article in journal (Refereed)
    Abstract [en]

    Tracking the secular evolution of 142Nd/144Nd anomalies is important towards understanding the crust-mantle dynamics in the early Earth. Excessive scatter in the published data, however, precludes identifying the fine structure of 142Nd/144Nd evolution as the expected variability is on the order of few parts per million. We report ultra-high precision 142Nd/144Nd data for Eoarchean and Palaeoarchean rocks from the Isua Supracrustal Belt (SW Greenland) that show a well-resolved 142Nd/144Nd temporal variability suggesting progressive convective homogenisation of the Hadean Isua depleted mantle. This temporally decreasing 142Nd/144Nd signal provides a direct measure of early mantle dynamics, defining a stirring timescale of <250 Myr consistent with vigorous convective stirring in the early mantle. The 142Nd/144Nd evolution suggests protracted crustal residence times of ~1000-2000 Myr, inconsistent with modern-style plate tectonics in the Archean. In contrast, a stagnant-lid regime punctuated by episodes of mantle overturns accounts for the long life-time estimated here for the Hadean proto-crust.

  • Jansson, Lina
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Fåglarna bakom kulisserna2018In: Fåglar i Stockholmstrakten, ISSN 1102-1349, Vol. 47, no 4, p. 40-45Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    På Naturhistoriska riksmuseet finns många vackra och intressanta fåglar som besökarna kan titta på i utställningarna. De allra flesta fåglar som förvaras på museet finns dock i särskilda låsta utrymmen som bara personalen har tillgång till. I detta reportage får vi följa med museets fågelintendent på en vandring bakom kulisserna. Vi får se några av de tiotusentals föremål som finns bevarade här och lära oss om vikten av att ha samlingar.

  • Jansson, Lina
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Ringmärkningscentralen: Ett reportage från hjärtat av svensk ringmärkning2018In: Fåglar i Stockholmstrakten, ISSN 1102-1349, Vol. 47, no 3, p. 56-60Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Varje år ringmärks drygt 300 000 fåglar i Sverige av ringmärkarkåren som finns spridd över nästan hela landet. Syftet med ringmärkningen är att få återfynd av fåglar och information om deras liv och öden. Sedan ringmärkningen påbörjades i Sverige för mer än 100 år sedan har återfynd från större delen av världen rapporterats till Ringmärkningscentralen. Den ansvarar för att hålla koll på alla ringnummer, märkuppgifter och återfynd samt ger service till både ringmärkare och forskare.

  • Jansson, Lina
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Bland hökdun och petmojar: -ett fågelskinn blir till2018In: Fåglar i Stockholmstrakten, ISSN 1102-1349, Vol. 47, no 2, p. 52-57Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Hur går det egentligen till när en död fågel bereds till skinn? Ett skinn som ska hålla för evigt och kunna användas för studier av bland annat morfologi och ruggning. Under en djupdykning i skinnläggning med en av konservatorerna på Naturhistoriska riksmuseet upptäckte Lina Jansson ett äkta hantverk när hon och hennes kollega tog sig an en duvhök.

  • Jansson, Lina
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Konsten att ge ett kadaver evigt liv2018In: Fåglar i Stockholmstrakten, ISSN 1102-1349, Vol. 47, no 1, p. 28-32Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Varje år skickas 500-600 döda fåglar in till Naturhistoriska riksmuseet och lika många däggdjur. Det här reportaget fokuserar så klart på fåglarna och beskriver förvandlingen från kadaver till ett ovärderligt museiföremål som förhoppningsvis ska bevaras i de vetenskapliga samlingarna för evigt. Här kan du som fågelintresserad också lära dig hur du kan bidra till dessa samlingar om du någon gång skulle hitta en död fågel.