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  • 1. Abu El-Enen, M.M.
    et al.
    Abu-Alam, T.S.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Ali, K.A.
    Okrusch, M.
    P–T path and timing of crustal thickening during amalgamation of East and West Gondwana: A case study from the Hafafit Metamorphic Complex, Eastern Desert of Egypt.2016In: Lithos, ISSN 0024-4937, E-ISSN 1872-6143, Vol. 263, p. 213-238Article in journal (Refereed)
    Abstract [en]

    The southeastern sector of the Hafafit Metamorphic Complex, southern Eastern Desert of Egypt comprises infrastructural orthogneisses of tonalite and syenogranite parentage, amphibolites, and a volcano-sedimentary association. These are overthrust by an obducted suprastructural ophiolite nappes via the Nugrus thrust. The protolith of the biotite–hornblende-gneisses was formed during island-arc accretion, while that of the garnet–biotite gneisses were formed in a within-plate regime, consistent with a transition to a post-collisional setting. The volcano-sedimentary association comprises interbedded and intercalated highly foliated metapelitic schists, metabasites, and leucocratic gneisses, deposited in a back-arc basin. The metapelites and the leucocratic gneisses originated from immature Fe-shales and arkoses derived from intermediate-mafic and acidic igneous rocks, respectively, via weak chemical weathering in a tectonically active island arc terrane. The intercalated amphibolites were derived from tholeiitic basalts generated in a back-arc setting.

    The volcano-sedimentary association was metamorphosed under upper-amphibolite facies conditions with pressures of 9–13 kbar and temperatures of 570–675 °C, as derived from conventional geothermobarometry and pseudosection calculation. A steep, tight clockwise P–T path is constrained and a geothermal gradient around 20 °C/km is estimated for the peak metamorphism. We assume that deformation and metamorphism are due to crustal thickening during the collision of East and West Gondwana, where peak metamorphism took place in the middle to lower crust at 33 km average crustal depth. This was followed by a subsequent quasi-isothermal decompression due to rapid exhumation during wrench tectonics. Sinistral transcurrent shearing with extensional denudation resulted in vertical ductile thinning that was accompanied by heat input from magmatism, as indicated by a higher geothermal gradient during retrograde metamorphism and exhumation of the complex.

    U–Pb data from magmatic zircons yields protolith ages of 731 ± 3 Ma for the biotite–hornblende gneisses and 646 ± 12 Ma for the garnet–biotite gneisses. Conforming to field evidence, our geochronology data point to a depositional age of the volcano-sedimentary cover at around 650 Ma. The age of metamorphism is constrained by a low Th/U ratio of a zircon grain crystallized at an age of 597 ± 6 Ma.

  • 2.
    Alexander, Louise
    et al.
    Birkbeck College, University of London, United Kingdom.
    Snape, Joshua
    Swedish Museum of Natural History, Department of Geology.
    Joy, Katherine
    University of Manchester, United Kingdom.
    Downes, Hilary
    Birkbeck College, University of London, United Kingdom.
    Crawford, Ian
    Birkbeck College, University of London, United Kingdom.
    An analysis of Apollo lunar soil samples 12070,889, 12030,187, and 12070,891: Basaltic diversity at the Apollo 12 landing site and implications for classification of small-sized lunar samples2016In: Meteoritics and Planetary Science, ISSN 1086-9379, E-ISSN 1945-5100, Vol. 51, p. 1654-1677Article in journal (Refereed)
    Abstract [en]

    Lunar mare basalts provide insights into the compositional diversity of the Moon's interior. Basalt fragments from the lunar regolith can potentially sample lava flows from regions of the Moon not previously visited, thus, increasing our understanding of lunar geological evolution. As part of a study of basaltic diversity at the Apollo 12 landing site, detailed petrological and geochemical data are provided here for 13 basaltic chips. In addition to bulk chemistry, we have analyzed the major, minor, and trace element chemistry of mineral phases which highlight differences between basalt groups. Where samples contain olivine, the equilibrium parent melt magnesium number (Mg#; atomic Mg/[Mg + Fe]) can be calculated to estimate parent melt composition. Ilmenite and plagioclase chemistry can also determine differences between basalt groups. We conclude that samples of approximately 1–2 mm in size can be categorized provided that appropriate mineral phases (olivine, plagioclase, and ilmenite) are present. Where samples are fine-grained (grain size <0.3 mm), a “paired samples t-test” can provide a statistical comparison between a particular sample and known lunar basalts. Of the fragments analyzed here, three are found to belong to each of the previously identified olivine and ilmenite basalt suites, four to the pigeonite basalt suite, one is an olivine cumulate, and two could not be categorized because of their coarse grain sizes and lack of appropriate mineral phases. Our approach introduces methods that can be used to investigate small sample sizes (i.e., fines) from future sample return missions to investigate lava flow diversity and petrological significance.

  • 3. Ali, K.A.
    et al.
    Surour, A.A:
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Andresen, A.
    Single zircon Hf-O isotope constraints on the origin of A-type granites from the Jabal Al-Hassir ring complex, Saudi Arabia.2015In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 256, p. 131-147Article in journal (Refereed)
    Abstract [en]

    The Jabal Al-Hassir ring complex in the southern Arabian Shield is an alkaline granite complex comprising an inner core of biotite granite that outwardly becomes a porphyritic sodic-calcic amphibole (ferrobarroisite–katophorite) granite. A combined study of mineral chemistry and single zircon Hf–O zircon isotope analyses was carried out to infer the magma sources of the Neoproterozoic post-collisional A-type granitoids in Saudi Arabia. The granitic rocks show high positive initial ɛHf(t) values of +7.0 to +10.3 and δ18O values of +5.8‰ to +7.4‰ that are consistent with melting of a juvenile crustal protolith that was formed during the Neoproterozoic assembly of the Arabian-Nubian Shield (ANS). Crustal-model ages (Hf-tNC) of 0.71–0.94 Ga indicate minor contribution from an older continental crust in the formation of the Jabal Al-Hassir granitic rocks (crystallization age = 620 ±3 Ma), but any such component is likely to be Neoproterozoic in age. Temperature and oxygen fugacity (ƒO2) estimates suggested that the Jabal Al-Hassir A-type granite magma was generated at high temperature (820–1050 °C) and low ƒO2. Geochemical characteristics (e.g., low ƒO2), geochronological data, and Hf and O isotope compositions, indicate that the magmas of the Neoproterozoic A-type granites of the Jabal Al-Hassir ring complex were likely generated by crustal partial melting of a juvenile Neoproterozoic lower crustal tholeiitic rocks, following collision between East and West Gondwana in the final stages of the evolution of the Arabian Shield.

  • 4. Alroy, John
    et al.
    Bernor, R. L.
    Fortelius, Mikael
    Werdelin, Lars
    Swedish Museum of Natural History, Department of Paleobiology.
    The MN System: regional or continental?1998In: Mitteilungen der Bayerischen Staatssammlung für Paläontologie und historische Geologie, Vol. 38, p. 243-258Article in journal (Refereed)
  • 5. Anand, Rajagopal
    et al.
    Balakrishnan, Srinivasan
    Kooijman, Ellen
    Swedish Museum of Natural History, Department of Geology.
    Mezger, Klaus
    Neoarchean crustal growth by accretionary processes: Evidence from combined zircon–titanite U–Pb isotope studies on granitoid rocks around the Hutti greenstone belt, eastern Dharwar Craton, India2014In: Journal of Asian Earth Sciences, ISSN 1367-9120, E-ISSN 1878-5786, Vol. 79, p. 72-85Article in journal (Refereed)
    Abstract [en]

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

  • 6. Armands, Gösta
    et al.
    Claesson, Stefan
    Swedish Museum of Natural History, Department of Geology.
    Johansson, Åke
    Swedish Museum of Natural History, Department of Geology.
    Lundqvist, Thomas
    En pionjär inom svensk isotopgeologi. In memoriam, Eric Welin, 1923-20142015In: Geologiskt forum, Vol. 22, no 85, p. 26-27Article in journal (Other (popular science, discussion, etc.))
  • 7. Augustsson, Carita
    et al.
    Rüsing, Tobias
    Niemeyer, Hans
    Kooijman, Ellen
    Swedish Museum of Natural History, Department of Geology.
    Berndt, Jasper
    Bahlburg, Heinrich
    Zimmermann, Udo
    0.3 byr of drainage stability along the Palaeozoic palaeo-Pacific Gondwana margin; a detrital zircon study2015In: Journal of the Geological Society, ISSN 0016-7649, E-ISSN 2041-479X, Vol. 172, p. 186-200Article in journal (Refereed)
    Abstract [en]

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

  • 8. BADAWY, AHMED SALAH
    et al.
    Mehlqvist, Kristina
    Vajda, Vivi
    Swedish Museum of Natural History, Department of Paleobiology.
    Ahlberg, Per
    Calner, Mikael
    Late Ordovician (Katian) spores in Sweden: oldest land plant remains from Baltica2014In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 136, no 1, p. 16-21Article in journal (Refereed)
    Abstract [en]

    A palynological study of the Ordovician–Silurian boundary (Katian–Rhuddanian) succession in the Röstaånga-1 drillcore, southern Sweden, has been performed. The lithology is dominated by mudstone and graptolitic shale, with subordinate limestone, formed in the deeper marine halo of southernBaltica. The palynological assemblages are dominated by marine microfossils, mainly chitinozoans and acritarchs. Sparse but well-preserved cryptospores, including Tetrahedraletes medinensis, Tetrahedraletes grayii and Pseudodyadospora sp., were encountered in the Lindegård Formation (late Katian–early Hirnantian), with the oldest record just above the first appearance of the graptolite species Dicellograptus complanatus. This represents the earliest record of early land plant spores from Sweden and possibly also from Baltica and implies that land plants had migrated to the palaeocontinent Baltica by at least the Late Ordovician.

  • 9.
    Bellucci, Jeremy
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Nemchin, Alexander
    Pidgeon, Robert
    Grange, Marion
    Reddy, Steven
    Timms, Nick
    A scanning ion imaging investigation into the micron-scale U-Pb systematics in a complex lunar zircon2016In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 438, p. 112-122Article in journal (Refereed)
    Abstract [en]

    The full U-Pb isotopic systematics in a complex lunar zircon ‘Pomegranate’ from lunar impact breccia 73235 have been investigated by the development of a novel Secondary Ion Mass Spectrometry (SIMS) scanning ion imaging (SII) technique. This technique offers at least a four-fold increase in analytical spatial resolution over traditional SIMS analyses in zircon. Results from this study confirm the hypothesis that the Pomegranate zircon crystallized at 4.302 ± 0.013 Ga and experienced an impact that formed, U-enriched zircon around primary zircon cores at 4.184 ± 0.007 Ga (2σ, all uncertainties). The increase in spatial resolution offered by this technique has facilitated targeting of primary zircon that was previously inaccessible to conventional spot analyses. This approach has yielded results indicating that individual grains with a diffusive distance of less than ~4 μm have been reset to the young impact age, while individual grains with a diffusive distance larger than ~6 μm have retained the old crystallization age. Assuming a broad range in cooling rate of 0.5–50 °C/year, which has been observed in a suite of similar lunar breccias, a maximum localized temperature generated by the impact that reset small prima- ry zircon and created new, high-U zircon is estimated to be between 1100 and 1280 °C.

  • 10.
    Bellucci, Jeremy
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Whitehouse, Martin
    Swedish Museum of Natural History, Department of Geology.
    Snape, Joshua
    Swedish Museum of Natural History, Department of Geology.
    Nemchin, Alexander
    A Pb isotopic resolution to the Martian meteorite age paradox2016In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 433, p. 241-248Article in journal (Refereed)
  • 11.
    Bellucci, Jeremy
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Whitehouse, Martin
    Swedish Museum of Natural History, Department of Geology.
    Snape, Joshua
    Swedish Museum of Natural History, Department of Geology.
    Nemchin, Alexander
    The Pb isotopic evolution of the Martian mantle constrained by initial Pb in Martian meteorites2015In: Journal of Geophysical Research - Planets, ISSN 2169-9097, E-ISSN 2169-9100, Vol. 120, p. 2224-2240Article in journal (Refereed)
  • 12.
    Bengtson, Stefan
    Swedish Museum of Natural History, Department of Paleobiology.
    Presentation of the 2010 Charles Schuchert Award of the Paleontological Society to Philip C. J. Donoghue.2011In: Journal of Paleontology, ISSN 0022-3360, E-ISSN 1937-2337, Journal of Paleontology, Vol. 85, no 5, p. 1015-Article in journal (Refereed)
    Abstract [en]

    LADIES AND gentlemen, friends and colleagues, the winner of the 2010 Charles Schuchert Award is Professor Philip Donoghue of the University of Bristol. In the natural progression of our personal lives, the transition from young snot to old fart is so gradual that one tends not to recognize it, least of all in oneself. Most of us— those further along in their careers— have passed through the stage of young, promising paleontologist to become middleaged promising paleontologists. Not so Phil Donoghue. I first met him when he was a graduate student at the University of Leicester. We got into a discussion about the nature of conodonts and certain pet ideas of mine that I had published. Phil did not agree with me so he went down in my book as a young snot. Soon thereafter, he published a ground-breaking, paradigm-changing paper, together with Peter Forey and Dick Aldridge, on the phylogenetic position of conodonts. Now, I realized that it was I who was the old fart. Phil had demonstrated that he had skipped the young-and-promising stage. He was, and is, young and delivering. Most people who start working on conodonts tend to remain with them. There is something about that mouth apparatus and the way in which it grabs hold of you. But Phil quickly tore himself loose from its grip. He quickly demonstrated an unquenchable zeal in attacking central issues in evolutionary paleontology, such as the origin of microstructures in teeth, the origin of teeth in jaws, the origin of jaws in vertebrates, the origin of vertebrates among animals, the origin of animals in the biosphere, and so on. I fear he will not stop until he has solved the question of the origin of life, the universe, and everything else. The breadth of questions he has already addressed is one aspect of Phil’s work. The diversity of tools he brings to bear on them is another. There is a lot of grinding powder under his fingernails, and lots of devo in his evo. After a sabbatical at the University of Bath, where he seems to have broken every rule of the Sabbath, he came out as a full-fledged molecular biologist, with RNA libraries at his fingertips. He is at the forefront in marrying data from living organisms with that from fossil taxa in phylogenetic analyses. Recently, he came out in defense of the paraphyletic stem group with arguments such that I have high hopes for his post-Schuchert development. Yes, paraphyletic groups are much more interesting than the monophyletic dead-ends called clades, although Phil of course refuses to call them groups. When Phil and some colleagues published a paper in Nature on the Cambrian fossil embryo Markuelia (again showing me wrong on a central issue), it caught the eye of Marco Stampanoni, a physicist who works at the Swiss Light Source (SLS) synchrotron near Zu¨ rich, in Switzerland. Marco had been developing methods of X-ray microtomography, using SLS beamlines. He contacted Phil with a proposal to collaborate, and Phil contacted me. Now, our collaboration based on this revolutionary technique, with Phil at the forefront, has opened our eyes to a huge amount of information to which we did not have access only a few years ago. Taphonomy is like the weather, people speak about it, but few do anything about it. But if you neglect it, you are in deep peril. Phil is much more concerned about taphonomy than most colleagues I know, and he does something about it. He started a project with embryologist Rudy Raff to determine how bacteria go about decomposing embryos in ways such that they are upgraded to exquisite fossils. He is engaging many colleagues, post-docs and students in the investigation of these processes and their end results. As a result, we are gaining insight into how bacteria can invade, devour and faithfully replicate intracellular features, and how different populations of bacteria play different roles in the process. An intriguing observation has emerged from Phil’s taphonomic work with Mark Purnell. Taphonomic degradation tends to bring about a stemward slippage of taxa in their apparent phylogenetic relationships, on account of sequential disappearance of preserved apomorphies. The general significance of this observation has still to be tested, but its potential importance for the phylogenetic analysis of fossils is obvious. Phil is leading an amazingly diverse and successful program in paleontology at the University of Bristol, permeated by his holistic approach and addressing everything from organismbased paleontology to molecular biology. Molecular, organismic, orgiastic paleontology—that’s the realm of Phil Donoghue. Mr. President, please hand the Schuchert Award for 2010 over to Phil. He thoroughly deserves it.

  • 13.
    Bengtson, Stefan
    Swedish Museum of Natural History, Department of Paleobiology.
    Presentation of the 2010 Paleontological Society Medal to Bruce Runnegar.2011In: Journal of Paleontology, ISSN 0022-3360, E-ISSN 1937-2337, Journal of Paleontology, Vol. 85, no 5, p. 1012-Article in journal (Refereed)
    Abstract [en]

    Ladies and gentlemen, friends and colleagues, the 2010 Paleontological Society Medal is awarded to Professor Bruce Runnegar of the University of California at Los Angeles. Preparing for this presentation, I got hold of a list of Bruce’s invited lectures, given during the past ten years. There are 86 titles on almost as many subjects. I will mention what these presentations were about, so you can get an impression of this Renaissance mind: Carbon isotopes and ocean evolution; Precambrian–Cambrian stratigraphy; Molecular evolution and the fossil record; Ediacaran organisms; Life on Mars; Oxygen and metazoan evolution; Orbital dynamics of the Earth–Moon system; Snowball Earth; Multiplated mollusks; Mass-independent fractionation of sulfur; Biomineralization; The Cambrian Explosion; Geobiology in the Archean; Cross-calibration of geological and astronomical time scales; Origins of biological complexity; Astrobiology of the Earth; Astrobiology of everything else; The Acraman impact of the Ediacaran; Biosignatures in ancient rocks; Microbial metabolism in the Early Archean. Now, most people can waffle about almost anything. A good teacher can read up on such topics and deliver useful lectures on them to students. But, as you will know if you are the least bit familiar with Bruce’s work, these are nearly all topics in fields where he has made startlingly innovative and pioneering contributions. Some would say that his most important contributions are missing from this list, such as molecular paleobiology, for example, or—if you prefer more tangible fossils—the systematics and evolution of Cambrian and Permian mollusks. But what is represented on the list is sufficient to document several brilliant careers in science: Bruce broke new ground in understanding the biomineralization processes of early mollusks by working with natural phosphatic replicas of the now vanished crystals of various species of calcium carbonate. He published a seminal set of papers on the evolution of the earliest mollusks, together with his longtime friend John Pojeta. And, as a leader of the astrobiology movement, Bruce has not only inspired everyone to start looking at life in a universal context, he has also brought his visions to life as Director of NASA’s Astrobiology Institute. It was in this context that Bruce was formally transformed from a U.S.-based Aussie to a full-fledged Australian– American (which is, I think, the politically correct term). In reference to molecular paleontology, I have some personal recollections. Bruce and I both have backgrounds as editors of paleontological journals. Bruce founded and for several years edited the successful Australasian journal Alcheringa, which is still going strong. Some of my first interactions with Bruce occurred in the 1970s, when he submitted manuscripts to Lethaia, of which I was an editor. One of my early forays was to question the number of authors of one of these manuscripts. I knew that no less than five authors of a single paper was excessive and confronted Bruce with this. It may have been the first time I really annoyed him, as he politely told me not to forget to turn my brain on, next time I wrote to him. Well, recently I saw an article in Nature with 230 authors, at which point it finally became clear to me that Bruce was ahead of his time. But back in those times I was a wee bit miffed, so when Bruce sent me a manuscript in which he estimated geological ages of major animal lineages using molecular clock techniques, I knew I could get my revenge. I sent the paper out for review by the sharpest molecular biologists of the day, smugly expecting to receive patronizing comments about paleontologists who should stick to their snail shells rather than pretending to be real scientists. No such luck. The reviews that came in were extravagant in their praise of the paper. Published in 1982, it predated by almost 15 years the avalanche of contributions that later came out on this topic. As usual, Bruce was ahead of the pack, but when others reached the spot where he had stood 15 years earlier, he wasn’t there anymore. Discrepancies between molecular and fossil data for a while seemed insurmountable, not to mention the discrepancies between different sets of molecular data and different sorts of analyses. But Bruce had inspired a bright set of younger biologists and paleontologists to refine their calculations. When the dust settled, one of those with whom Bruce had shared his spark, Kevin Peterson, was able to show that there is no significant conflict between the dates provided by fossils and by molecules. But I mentioned molecular paleontology. In 1986, Bruce published a seminal paper with just that title. In it he expressed his credo, thus: ‘‘palaeontologists should use all available sources of information to understand the evolution of life and its effect on the planet.’’ These are not empty words; they present a formidable challenge. Like all splendid visions, they stake out a direction rather than a goal. That it is possible to pursue this vision we see from the example set by this year’s Schuchert Award winner, Phil Donoghue, who together with Kevin Peterson and Roger Summons wrote a stimulating twenty-first century follow-up to Bruce’s earlier paper. But the foremost example is Bruce Runnegar himself. Here is a taste of the way in which his productive mind works. In 1982, Bruce used the anatomy and hypothesized physiology of the Ediacaran fossil Dickinsonia to estimate constraints for ambient oxygen levels in the Ediacaran atmosphere. This paper is much cited, and geochemists are only now catching up with him, developing geochemical proxies to test the hypothesis that a rising oxygen level was a trigger for the Cambrian Explosion, or, as Bruce so aptly put it, that one ‘‘ingredient, as in most explosives, may well have been a strong oxidising agent.’’ Finally, consider another example. In 1998, Bruce published a cladistic analysis of glaciogenic sediments, testing and corroborating the hypothesis that there were only two major Neoproterozoic glaciations, a result that still seems to stand. Who but Bruce would have thought of such a preposterous idea, using cladistics to resolve a stratigraphical conundrum? Bruce Runnegar has, over the years, formed collegial bonds with many scientists. The many younger people inspired by him include Phil Donoghue, now standing on Bruce’s shoulders. Bruce himself has stood on the shoulders of other giants, as he is quick to acknowledge. But, like Sir Isaac Newton, he has no reason to be bashful about his success, and I don’t think he is. The Paleontological Society Medal was really made for Bruce Runnegar, so please, Mr. President, give it to him!

  • 14.
    Bengtson, Stefan
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Collins, Desmond
    Chancelloriids of the Cambrian Burgess Shale2015In: Palaeontologia Electronica, ISSN 1935-3952, E-ISSN 1094-8074, Vol. 18, no 1, p. 1-67Article in journal (Refereed)
    Abstract [en]

    The cactus-like chancelloriids from the Middle Cambrian Burgess Shale are revised on the basis of Walcott’s (1920) original collections and new material containing several hundred specimens collected by Royal Ontario Museum field expeditions from 1975 to 2000. Walcott’s interpretation of chancelloriids as sponges was based on a misinterpretation of the dermal coelosclerites as embedded sponge-type spicules, an interpretation that further led to the lumping of three distinct taxa into one species, Chancelloria eros Walcott, 1920. The other two taxa are herein separated from C. eros and described as Allonnia tintinopsis n.sp. and Archiasterella coriacea n.sp., all belonging to the Family Chancelloriidae Walcott, 1920. Chancelloriids were sedentary animals, anchored to shells or lumps of debris in the muddy bottom, or to sponges, or to other chancelloriids. They had a radially symmetrical body and an apical orifice surrounded by a palisade of modified sclerites. Well-preserved integuments in Al. tintinopsis and Ar. coriacea do not show any ostium-like openings. Neither is there any evidence for internal organs, such as a gut. Partly narrowed specimens suggest that the body periodically contracted from the attached end to expel waste material from the body cavity. Chancelloriids were close in organization to cnidarians but shared the character of coelosclerites with the bilaterian halkieriids and siphogonuchitids. The taxon Coeloscleritophora is most likely paraphyletic.

  • 15.
    Bengtson, Stefan
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Cunningham, John A.
    Yin, Chongyu
    Donoghue, Philip C.J.
    University of Bristol.
    A merciful death for the “earliest bilaterian,” Vernanimalcula.2012In: Evolution and Development, ISSN 1520-541x, Vol. 14, no 5, p. 421-427Article in journal (Refereed)
    Abstract [en]

    Fossils described as Vernanimalcula guizhouena, from the nearly 600 million-year-old Doushantuo Formation in South China, have been interpreted as the remains of bilaterian animals. As such they would represent the oldest putative record of bilaterian animals in Earth history, and they have been invoked in debate over this formative episode of early animal evolution. However, this interpretation is fallacious. We review the evidential basis of the biological interpretation of Vernanimalcula, concluding that the structures key to animal identity are effects of mineralization that do not represent biological tissues, and, furthermore, that it is not possible to derive its anatomical reconstruction on the basis of the available evidence. There is no evidential basis for interpreting Vernanimalcula as an animal, let alone a bilaterian. The conclusions of evolutionary studies that have relied upon the bilaterian interpretation of Vernanimalcula must be called into question.

  • 16.
    Bengtson, Stefan
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Ivarsson, Magnus
    Swedish Museum of Natural History, Department of Paleobiology.
    Astolfo, Alberto
    Paul Scherrer Institute.
    Belivanova, Veneta
    Swedish Museum of Natural History, Department of Paleobiology.
    Broman, Curt
    Stockholm University.
    Marone, Federica
    Paul Scherrer Institute.
    Stampanoni, Marco
    ETH Zürich.
    Deep-biosphere consortium of fungi and prokaryotes in Eocene sub-seafloor basalts.2014In: Geobiology, ISSN 1472-4677, E-ISSN 1472-4669, Vol. 12, no 6, p. 489-496Article in journal (Refereed)
    Abstract [en]

    The deep biosphere of the subseafloor crust is believed to contain a significant part of Earth’s biomass, but because of the difficulties of directly observing the living organisms, its composition and ecology are poorly known. We report here a consortium of fossilized prokaryotic and eukaryotic microorganisms, occupying cavities in deep-drilled vesicular basalt from the Emperor Seamounts, Pacific Ocean, 67.5 meters below seafloor (mbsf). Fungal hyphae provide the framework on which prokaryote-like organisms are suspended like cobwebs and iron-oxidizing bacteria form microstromatolites (Frutexites). The spatial interrelationships show that the organisms were living at the same time in an integrated fashion, suggesting symbiotic interdependence. The community is contemporaneous with secondary mineralizations of calcite partly filling the cavities. The fungal hyphae frequently extend into the calcite, indicating that they were able to bore into the substrate through mineral dissolution. A symbiotic relationship with chemoautotrophs, as inferred for the observed consortium, may be a prerequisite for the eukaryotic colonization of crustal rocks. Fossils thus open a window to the extant as well as the ancient deep biosphere.

  • 17.
    Bengtson, Stefan
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Rasmussen, Birger
    Curtin University.
    Ivarsson, Magnus
    Swedish Museum of Natural History, Department of Paleobiology.
    Muhling, Janet
    Curtin University.
    Broman, Curt
    Stockholm University.
    Marone, Federica
    Stampanoni, Marco
    Bekker, Andrey
    University of California Riverside.
    Fungus-like mycelial fossils in 2.4-billion-year-old vesicular basalt.2017In: Nature Ecology & Evolution, ISSN 2397-334X, Vol. 1, no 6, p. 1-6, article id 0141Article in journal (Refereed)
    Abstract [en]

    Fungi have recently been found to comprise a significant part of the deep biosphere in oceanic sediments and crustal rocks. Fossils occupying fractures and pores in Phanerozoic volcanics indicate that this habitat is at least 400 million years old, but its origin may be considerably older. A 2.4-billion-year-old basalt from the Palaeoproterozoic Ongeluk Formation in South Africa contains filamentous fossils in vesicles and fractures. The filaments form mycelium-like structures growing from a basal film attached to the internal rock surfaces. Filaments branch and anastomose, touch and entangle each other. They are indistinguishable from mycelial fossils found in similar deep-biosphere habitats in the Phanerozoic, where they are attributed to fungi on the basis of chemical and morphological similarities to living fungi. The Ongeluk fossils, however, are two to three times older than current age estimates of the fungal clade. Unless they represent an unknown branch of fungus-like organisms, the fossils imply that the fungal clade is considerably older than previously thought, and that fungal origin and early evolution may lie in the oceanic deep biosphere rather than on land. The Ongeluk discovery suggests that life has inhabited submarine volcanics for more than 2.4 billion years.

  • 18.
    Bengtson, Stefan
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Sallstedt, Therese
    Swedish Museum of Natural History, Department of Paleobiology.
    Belivanova, Veneta
    Swedish Museum of Natural History, Department of Paleobiology.
    Whitehouse, Martin
    Swedish Museum of Natural History, Department of Geology.
    Three-dimensional preservation of cellular and subcellular structures suggests 1.6 billion-year-old crown-group red algae2017In: PLoS biology, ISSN 1544-9173, E-ISSN 1545-7885, Vol. 15, no 3, p. 1-38, article id e2000735Article in journal (Refereed)
    Abstract [en]

    The ~1.6 Ga Tirohan Dolomite of the Lower Vindhyan in central India contains phosphatized stromatolitic microbialites. We report from there uniquely well-preserved fossils interpreted as probable crown-group rhodophytes (red algae). The filamentous form Rafatazmia chitrakootensis n. gen, n. sp. has uniserial rows of large cells and grows through diffusely distributed septation. Each cell has a centrally suspended, conspicuous rhomboidal disk interpreted as a pyrenoid. The septa between the cells have central structures that may represent pit connections and pit plugs. Another filamentous form, Denaricion mendax n. gen., n. sp., has coin-like cells reminiscent of those in large sulfur-oxidizing bacteria but much more recalcitrant than the liquid-vacuole-filled cells of the latter. There are also resemblances with oscillatoriacean cyanobacteria, although cell volumes in the latter are much smaller. The wider affinities of Denaricion are uncertain. Ramathallus lobatus n. gen., n. sp. is a lobate sessile alga with pseudoparenchymatous thallus, “cell fountains,” and apical growth, suggesting florideophycean affinity. If these inferences are correct, Rafatazmia and Ramathallus represent crown-group multicellular rhodophytes, antedating the oldest previously accepted red alga in the fossil record by about 400 million years.

  • 19. Bennike, Ole
    et al.
    Hedenäs, Lars
    Swedish Museum of Natural History, Department of Botany.
    High, Kirsty
    Korshöj, Joakim S.
    Lemdahl, Geoffrey
    Penkman, Kirsty
    Preece, Richard C.
    Rosenlund, Knud
    Viehlberg, Finn A.
    New interglacial deposits from Copenhagen, Denmark:marine Isotope Stage 72018In: Boreas, ISSN 0300-9483, E-ISSN 1502-3885Article in journal (Refereed)
  • 20. Betts, Marissa, J.
    et al.
    Paterson, John, R.
    Jacquet, Sarah, M.
    Andrew, Anita S.
    Hall, Philip A.
    Jago, James, B.
    Jagodzinski, Elisabeth A.
    Preiss, Wolfgang V.
    Crowley, James L.
    Brougham, Tom
    Mathewson, Ciaran P.
    Garcia-Bellido, Diego C.
    Topper, Timothy, P.
    Skovsted, Christian
    Swedish Museum of Natural History, Department of Paleobiology.
    Brock, Glenn, A.
    Early Cambrian chronostratigraphy and geochronology of South Australia2018In: Earth-Science Reviews, ISSN 0012-8252, E-ISSN 1872-6828, Vol. 185, p. 498-543Article in journal (Refereed)
    Abstract [en]

    The most successful chronostratigraphic correlation methods enlist multiple proxies such as biostratigraphy and chemostratigraphy to constrain the timing of globally important bio- and geo-events. Here we present the first regional, high-resolution shelly fossil biostratigraphy integrated with δ13C chemostratigraphy (and corresponding δ18O data) from the traditional lower Cambrian (Terreneuvian and provisional Cambrian Series 2) of South Australia. The global ZHUCE, SHICE, positive excursions II and III and the CARE are captured in lower Cambrian successions from the Arrowie and Stansbury basins. The South Australian shelly fossil biostratigraphy has a consistent relationship with the δ13C results, bolstering interpretation, identification and correlation of the excursions. Positive excursion II straddles the boundary between the Kulparina rostrata and Micrina etheridgei zones, and the CARE straddles the boundary between the M. etheridgei and Dailyatia odyssei zones, peaking in the lower parts of the latter zone. New CA-TIMS zircon dates from the upper Hawker Group and Billy Creek Formation provide geochronologic calibration points for the upper D. odyssei Zone and corresponding chemostratigraphic curve, embedding the lower Cambrian successions from South Australia into a global chronostratigraphic context. This multi-proxy investigation demonstrates the power of integrated methods for developing regional biostratigraphic schemes and facilitating robust global correlation of lower Cambrian successions from South Australia (part of East Gondwana) with coeval terranes on other Cambrian palaeocontinents, including South and North China, Siberia, Laurentia, Avalonia and West Gondwana.

  • 21. Betts, Marissa, J.
    et al.
    Paterson, John, R.
    Jago, James, B.
    Jacquet, Sarah, M.
    Skovsted, Christian
    Swedish Museum of Natural History, Department of Paleobiology.
    Topper, Timothy, P.
    Brock, Glenn, A.
    A new lower Cambrian shelly fossil biostratigraphy for South Australia:Reply2017In: Gondwana Research, ISSN 1342-937X, E-ISSN 1878-0571, Vol. 44, p. 262-264Article in journal (Refereed)
  • 22.
    Betts, Marissa, J.
    et al.
    Department of Biological Sciences, Macquarie University, Sydney, 2109, Australia.
    Paterson, John, R.
    Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia.
    Jago, James, B.
    School of Natural and Built Environments, University of South Australia, Mawson Lakes, South Australia 5095, Australia.
    Jacquet, Sarah, M.
    Department of Biological Sciences, Macquarie University, Sydney, 2109, Australia.
    Skovsted, Christian
    Swedish Museum of Natural History, Department of Paleobiology.
    Topper, Timothy, P.
    Palaeoecosystems Group, Department of Earth Sciences, Durham University, Durham, DH1 3LE, UK.
    Brock, Glenn, A.
    Department of Biological Sciences, Macquarie University, Sydney, 2109, Australia.
    Global correlation of the early Cambrian of South Australia: Shelly faunaof the Dailyatia odyssei Zone2017In: Gondwana Research, ISSN 1342-937X, E-ISSN 1878-0571, Vol. 46, p. 240-279Article in journal (Refereed)
    Abstract [en]

    A lack of well resolved biostratigraphic data has prevented robust regional and global correlation of lower Cambriansuccessions from South Australia. A new early Cambrian biostratigraphy, based on data derived from 21measured stratigraphic sections and drill cores (11 described herein) reveals the abundance and diversity ofshelly fauna from the Arrowie Basin, and the value of early Cambrian “small shelly fossils” (SSF) for biostratigraphicstudies. Here we examine shelly fauna associated with the youngest of three recently establishedbiozones, the Dailyatia odyssei Taxon Range Zone (hereafter D. odyssei Zone), and their correlative potential.The D. odyssei Zone features a diverse suite of tommotiids, organophosphatic brachiopods, bradoriid arthropods,molluscs and phosphatic problematica. This fauna permits strong correlation (often at species-level) with othermajor early Cambrian terranes, particularly Antarctica, South China and Laurentia, and suggest a Cambrian Series2, Stages 3–4 age for the D. odyssei Zone. Bradoriids have proven to be useful biostratigraphic tools. Four newspeciesand three new genera are described herein: Acutobalteus sinuosus gen. et sp. nov., Eozhexiella adnyamathanha gen. etsp. nov., Manawarra jonesi gen. et sp. nov. and Mongolitubulus descensus sp. nov. The description of Eohadrotreta sp.cf. zhenbaensis represents the first occurrence of the acrotretoid brachiopod Eohadrotreta from Australia.

  • 23.
    Betts, Marissa J.
    et al.
    Macquarie University, Sydney, Australia.
    Topper, Timothy P.
    Geological Museum, Copenhagen.
    Valentine, James L.
    Macquarie University, Sydney, Australia.
    Skovsted, Christian
    Swedish Museum of Natural History, Department of Paleobiology.
    Brock, Glenn A.
    Macquarie university, Australia.
    A new early Cambrian bradoriid (Arthropoda) assemblage from the northern Flinders Ranges, South Australia2014In: Gondwana Research, ISSN 1342-937X, E-ISSN 1878-0571, Vol. 25, p. 420-437Article in journal (Refereed)
    Abstract [en]

    A new assemblage of early Cambrian bivalved arthropods (Bradoriida) is described from the Arrowie Syncline in the northern Flinders Ranges, South Australia. The well preserved, largely endemic fauna comprises a total of six taxa (including five new species): Jiucunella phaseloa sp. nov., Jixinlingella daimonikoa sp. nov., Mongolitubulus anthelios sp. nov., Neokunmingella moroensis sp. nov., Phasoia cf. spicata ( Öpik, 1968), and Sinskolutella cuspidata sp. nov. This assemblage is derived from a carbonate sedimentary package representing a high energy, shallow water archaeocyath-Renalcis biohermal facies of Terreneuvian, Stage 2 age which transitions up-section to a more restricted, low energy, intra-shelf lagoonal environment that correlates with a Cambrian Series 2, Stage 3 age. The new taxon J. phaseloa sp. nov., has a first appearance datum (FAD) in shallow water biohermal facies of the Hideaway Well Member of the Wilkawillina Limestone at a level 47 m below the FAD of Pelagiella subangulata which is taken to approximate the base of Series 2, Stage 3 in South Australia. Along with Liangshanella circumbolina, this makes J. phaseloa sp. nov. amongst the oldest bivalved arthropods in South Australia and potentially greater Gondwana. The presence of 25 bradoriid taxa from the early Cambrian of South Australia suggests East Gondwana represents a major centre of origin for the Bradoriida.

  • 24. Bezenjani, R. Nasiri
    et al.
    Pease, V.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Shalaby, M. H.
    Kadi, K. A.
    Kozdroj, W.
    Detrital zircon geochronology and provenance of the Neoproterozoic Hammamat Group (Igla Basin), Egypt and the Thalbah Group, NW Saudi Arabia: Implications for regional collision tectonics2014In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 245, p. 225-243Article in journal (Refereed)
  • 25. Bicknell, Russell D.C.
    et al.
    Paterson, John, R.
    Caron, Jean-Bernhard
    Skovsted, Christian
    Swedish Museum of Natural History, Department of Paleobiology.
    The gnathobasic spine microstructure of recent and Silurian chelicerates and the Cambrian artiopodan Sidneyia: Functional and evolutionary implications2018In: Arthropod structure & development, ISSN 1467-8039, E-ISSN 1873-5495, Vol. 47, p. 12-24Article in journal (Refereed)
    Abstract [en]

    Gnathobasic spines are located on the protopodal segments of the appendages of various euarthropod taxa, notably chelicerates. Although they are used to crush shells and masticate soft food items, the microstructure of these spines are relatively poorly known in both extant and extinct forms. Here we compare the gnathobasic spine microstructures of the Silurian eurypterid Eurypterus tetragonophthalmus from Estonia and the Cambrian artiopodan Sidneyia inexpectans from Canada with those of the Recent xiphosuran chelicerate Limulus polyphemus to infer potential variations in functional morphology through time. The thickened fibrous exocuticle in L. polyphemus spine tips enables effective prey mastication and shell crushing, while also reducing pressure on nerve endings that fill the spine cavities. The spine cuticle of E. tetragonophthalmus has a laminate structure and lacks the fibrous layers seen in L. polyphemus spines, suggesting that E. tetragonophthalmus may not have been capable of crushing thick shells, but a durophagous habit cannot be precluded. Conversely, the cuticle of S. inexpectans spines has asimilar fibrous microstructure to L. polyphemus, suggesting that S. inexpectans was a competent shell crusher. This conclusion is consistent with specimens showing preserved gut contents containing various shelly fragments. The shape and arrangement of the gnathobasic spines is similar for both L. polyphemusand S. inexpectans, with stouter spines in the posterior cephalothoracic or trunk appendages, respectively.This differentiation indicates that crushing occurs posteriorly, while the gnathobases on anterior appendages continue mastication and push food towards and into the mouth. The results of recent phylogenetic analyses that considered both modern and fossil euarthropod clades show that xiphosurans and eurypterids are united as crown-group euchelicerates, with S. inexpectans placed within more basalartiopodan clades. These relationships suggest that gnathobases with thickened fibrous exocuticle, if not homoplasious, may be plesiomorphic for chelicerates and deeper relatives within Arachnomorpha. This study shows that the gnathobasic spine microstructure best adapted for durophagy has remained remarkably constant since the Cambrian.

  • 26. Biel, Christina
    et al.
    Subias, Ignacio
    Billström, Kjell
    Swedish Museum of Natural History, Department of Geology.
    Acevedo, Rogelio
    Multi-isotope approach for the identification of metal and fluid sources of the Arroyo Rojo VMS deposit, Tierra del Fuego, Argentina2016In: Ore Geology Reviews, ISSN 0169-1368, E-ISSN 1872-7360Article in journal (Refereed)
  • 27. Bingen, B.
    et al.
    Corfu, F.
    Stein, H.J.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    U-Pb geochronology of the syn-orogenic Knaben molybdenum deposits, Sveconorwegian orogen, Norway2015In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 152, p. 537-556Article in journal (Refereed)
    Abstract [en]

    Paired isotope dilution – thermal ionization mass spectrometry (ID-TIMS) and secondary ion mass spectrometry (SIMS) zircon U–Pb data elucidate geochronological relations in the historically important Knaben molybdenum mining district, Sveconorwegian Orogen, south Norway. This polyphase district provided c. 8.5 Mt of ore with a grade of 0.2%. It consists of mineralized quartz veins, silica-rich gneiss, pegmatites and aplites associated with a heterogeneous, locally sulphide-bearing, amphibolites facies gneiss called Knaben Gneiss, and hosted in a regional-scale monotonous, commonly weakly foliated, granitic gneiss. An augen gneiss at the Knaben I deposit yields a 1257±6 Ma magmatic zircon age, dating the pre-Sveconorwegian protolith of the Knaben Gneiss. Mineralized and non-mineralized granitic gneiss samples at the Knaben II and Kvina deposits contain some 1488–1164 Ma inherited zircon and yield consistent intrusion ages of 1032±4, 1034±6 and 1036±6 Ma. This age links magmatism in the district to the regional 1050–1020 Ma Sirdal I-type granite suite, corresponding to voluminous crustal melting during the Sveconorwegian orogeny. A high-U, low-Th/U zircon rim is present in all samples. It defines several age clusters between 1039±6 and 1009±7 Ma, peaking at c. 1016 Ma and overlapping with a monazite age of 1013±5 Ma. The rim records protracted hydrothermal activity, which started during the main magmatic event and outlasted it. This process was coeval with regional high-grade Sveconorwegian metamorphism. Molybdenum deposition probably started during this event when silica-rich mineralizing fluids or hydrous magmas were released from granite magma batches. An analogy between the Knaben district and shallow, short-lived porphyry Mo deposits is inappropriate.

  • 28. Bingen, B.
    et al.
    Solli, A.
    Viola, G.
    Torgersen, E.
    Sandstad, J.S.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Røhr, T.
    Ganerød, M.
    Nasuti, A.
    Geochronology of the Palaeoproterozoic Kautokeino Greenstone Belt, Finnmark, Norway: Tectonic implications in a Fennoscandia context.2015In: Norwegian Journal of Geology, Vol. 95, p. 365-396Article in journal (Refereed)
    Abstract [en]

    Zircon U–Pb geochronological data in 18 samples from Finnmarksvidda and one sample from the Repparfjord Tectonic Window, northern Norway, constrain the evolution of the Palaeoproterozoic Kautokeino Greenstone Belt and neighbouring units in a Fennoscandia context. The Jergul Complex is an Archaean cratonic block of Karelian affinity, made of variably gneissic, tonalite–trondhjemite–granodiorite–granite plutonic rocks formed between 2975 ± 10 and 2776 ± 6 Ma. It is associated with the Archaean Goldenvárri greenstone–schist formation. At the base of the Kautokeino Greenstone Belt, the Masi Formation is a typical Jatulian quartzite, hosting a Haaskalehto-type, albite–magnetite-rich, mafic sill dated at 2220 ± 7 Ma. The Likčá and Čáskejas formations represent the main event of basaltic magmatism. A synvolcanic metagabbro dates this magmatism at 2137 ± 5 Ma. The geochemical and Nd isotopic signature of the Čáskejas Formation (eNd = +2.2 ± 1.7) is remarkably similar to coeval dykes intruding the Archaean Karelian Craton in Finland and Russia (eNd = +2.5 ± 1.0). The Čáskejas Formation can be correlated with the Kvenvik Formation in the Alta–Kvænangen Tectonic Window. Two large granite plutons yield ages of 1888 ± 7 and 1865 ± 8 Ma, and provide a maximum age for shearing along two prominent NNW–SSE-oriented shear zones recording Svecokarelian transpression. The Bidjovagge Au–Cu deposit formed around 1886 to 1837 Ma and is also related to this NNW–SSE-oriented shear system. The Ráiseatnu Complex is mainly composed of granitic gneisses formed between 1868 ± 13 and 1828 ± 5 Ma, and containing metasediment rafts and zircon xenocrysts ranging from c. 3100 to 2437 Ma. The Kautokeino Greenstone Belt and Ráiseatnu Complex are interpreted as Palaeoproterozoic, pericontinental, lithospheric domains formed during rifting between Archaean cratonic domains. They accommodated oblique convergence between the Karelian and the Norrbotten Archaean cratons during the Svecokarelian orogeny.

  • 29. Blichert-Toft, Janne
    et al.
    Delile, Hugo
    Lee, Cin-Ty
    Stos-Gale, Zofia
    Billström, Kjell
    Swedish Museum of Natural History, Department of Geology.
    Andersen, Tom
    Huhma, Hannu
    Albaréde, Francis
    Large-scale tectonic cycles in Europe revealed by distinct Pb isotope provinces2016In: Geochemistry, Geophysics, Geosystems, ISSN 1525-2027Article in journal (Refereed)
  • 30.
    Bomfleur, Benjamin
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Ferraguti, Marco
    Dipartimento di Bioscienze, Universita` degli Studi di Milano, Milano, Italy.
    Reguero, Marcelo
    Divisio´n Paleontologı´a de Vertebrados, Museo de La Plata, La Plata, Argentina.
    McLoughlin, Stephen
    Swedish Museum of Natural History, Department of Paleobiology.
    Fossilized spermatozoa preserved in a 50-myr-old annelid cocoon from Antarctica2015In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, no 20150431, p. 1-5Article in journal (Refereed)
    Abstract [en]

    The origin and evolution of clitellate annelids—earthworms, leeches and their relatives—is poorly understood, partly because body fossils of these delicate organisms are exceedingly rare. The distinctive egg cases (cocoons) of Clitellata, however, are relatively common in the fossil record, although their potential for phylogenetic studies has remained largely unexplored. Here, we report the remarkable discovery of fossilized spermatozoa preserved within the secreted wall layers of a 50-Myr-old clitellate cocoon from Antarctica, representing the oldest fossil animal sperm yet known. Sperm characters are highly informative for the classification of extant Annelida. The Antarctic fossil spermatozoa have several features that point to affinities with the peculiar, leech-like ‘crayfish worms’ (Branchiobdellida). We anticipate that systematic surveys of cocoon fossils coupled with advances in non-destructive analytical methods may open a new window into the evolution of minute, soft-bodied life forms that are otherwise only rarely observed in the fossil record.

  • 31.
    Bosi, Ferdinando
    University of Rome "La Sapienza".
    Lucchesiite, CaFe2+3 Al6(Si6O18)(BO3)3(OH)3O, a new mineralspecies of the tourmaline supergroup2017In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 81, no 1, p. 1-14Article in journal (Refereed)
  • 32.
    Bosi, Ferdinando
    et al.
    Sapienza Universita di Roma.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Lazor, Peter
    Uppsala Universitet.
    Reznitskii, Leonid
    Russian Academy of Sciences.
    Atomic arrangements around the O3 site in Al- and Cr-rich oxytourmalines: a combined EMP, SREF, FTIR and Raman study2015In: Physics and chemistry of minerals, ISSN 0342-1791, E-ISSN 1432-2021, Vol. 42, p. 441-453Article in journal (Refereed)
  • 33.
    Bouchal, Johannes M.
    Swedish Museum of Natural History, Department of Paleobiology.
    The middle Miocene palynofloras of the Salihpaşalar lignite mine(Yatağan Basin, southwest Anatolia): environmental characterisationand comparison with palynofloras from adjacent basins2018In: Palaeobiodiversity and Palaeoenvironments, ISSN 1867-1594, E-ISSN 1867-1608Article in journal (Other academic)
    Abstract [en]

    As the third part of an ongoing investigation of middle Miocene palynofloras in the Yatağan Basin (YB), southwestern Anatolia, thepalynofloras of the Salihpaşalar lignite mine in the main YB were studied. Seven types of algal spores, aplanospores/zygospores orcysts, six types of lycophyte and fern spores, 12 types of gymnosperm pollen and 90 types of angiosperm pollen were identified. Of atotal of ca. 140 plant taxa described from the YB, over 10% are confined to the Salihpaşalar assemblage. Differences between coevalpalynofloras of the Sekköy Member might reflect changing or prograding depositional environments. A number of rare accessorialtaxa reflect these local differences: Pilularia, Valeriana, Drosera and Persicaria aff. amphibia only occur at Salihpaşalar and aretypical of shallow water or temporary ponds associated with a lake shore. Apart from this, all the palynofloras, originating from thelignite seams and overlying limnic limestones (uppermost Turgut and Sekköy Member), of the YB are strongly indicative of extensivewoody vegetation with a dominance of diverse Fagaceae and Pinaceae. In addition, a list comparing the well-documented YBpalynomorphs to morphologically similar palynomorphs of published late early to middle Miocene plant assemblages of westernAnatolian was compiled. Such a comparison reveals that in many instances different taxon names have been used to denote the sametaxa. Hence, resolving these synonymies is a prerequisite of any meaningful comparison of palynofloras in the region.

  • 34.
    Bouchal, Johannes M.
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Denk, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Grímsson, F.
    Palynostratigraphical correlation of the excavated Miocene lignite seams of the Yatağan basin (Muğla Province, south-western Turkey)2016Conference paper (Other academic)
    Abstract [en]

    The excavated main lignite seams and overlying lacustrine sediments of the opencast mines Eskihisar, Salihpaşalar, and Tınaz, Muğla Province, south-western Turkey were investigated using a high taxonomic resolution palynological approach.

    The Eskihisar section comprises 47m and 56 samples of which 30 were usable for palynological analysis. The Tınaz section comprises 75 m and 29 samples of which 15 were usable for palynological analysis. Finally, the Salihpaşalar section comprises 25 m and 26 samples of which 16 were usable for palynological analysis. The age of the palynological sections is middle to late Miocene based on radiometric dating and vertebrate fossils.

     

    In order to investigate dispersed pollen and spores and their botanical affinities a combined light microscopy and scanning electron microscopy approach was used. The rich palynoflora comprises seven types of algal cysts (Botryococcus, Zygnemataceae), seventeen spore types (Lycopsida, Marsileaceae, Osmundaceae, Pteridaceae, Polypodiaceae), 14 types of gymnosperm pollen (Ephedraceae, Cupressaceae, Pinaceae), five types of monocotyledone pollen (Poaceae, Typhaceae) and ca 90 dicotyledone pollen types (Altingiaceae, Amaranthaceae, Anacardiaceae, Apiaceae, Aquifoliaceae, Asteraceae, Betulaceae, Campanulaceae, Cannabaceae, Caprifoliaceae, Caryophyllaceae, Ericaceae, Eucommiaceae, Euphorbiaceae, Fabaceae, Fagaceae, Geraniaceae, Juglandaceae, Lamiaceae, Linaceae, Lythraceae, Malvaceae, Myricaceae, Oleaceae, Onagraceae, Plumbaginaceae, Polygonaceae, Ranunculaceae, Rosaceae, Salicaceae, Sapindaceae, Sapotaceae, Ulmaceae).

     

    The objectives of this investigation were (1) to evaluate whether the three palynological sections were deposited at the same time, and (2) to show regional vegetation differences within a single sedimentary basin.

     

    We found three general pollen zones corresponding to different sedimentary settings and palaeoenvironments. The first pollen zone was linked to lignite formation (swamp forest, fern spores, Alnus, Decodon). The second pollen zone reflects lacustrine conditions (Typhaceae) and surrounding hinterland vegetation dominated by Fagaceae. The third pollen zone is dominated by herbaceous taxa, whereas woody taxa are less diverse and less abundant.

     

    In general, the three palynological sections are congruent in reflecting distinct pollen zones. However main vegetation types may be represented by different dominating taxa (e. g. Alnus dominace in Eskihisar and Tınaz localities while absent in Salihpaşalar) and rare taxa may differ between localities.

     

    Our results demonstrate that in order to achieve a comprehensive understanding of environmental and vegetation conditions in a sedimentary basin, a single palynological section (locality) may not capture the entirety of environmental conditions and changes.

  • 35.
    Bouchal, Johannes M.
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Denk, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Grímsson, F.
    Zetter, Reinhard
    The middle Miocene palynoflora and palaeoenvironments of Eskihisar (Yatağan Basin, southwestern Anatolia):: a combined LM and SEM investigation2016In: Botanical journal of the Linnean Society, ISSN 0024-4074, E-ISSN 1095-8339, Vol. 182, no 1, p. 14-79Article in journal (Refereed)
    Abstract [en]

    Anatolia was a crossroads for mammal migration during the Miocene due to intermittent land connections between Africa and Anatolia and persisting warm conditions. Here, we investigated a palynological section from middle Miocene sediments of Eskihisar (southwestern Anatolia) in order to establish biogeographic links of the palynoflora and to infer the palaeoenvironment. Four algal palynomorphs, nine spore taxa, eight gymnosperms, three monocots, and 67 dicot pollen types were encountered and investigated using the “single grain method” that combines light microscopy and scanning electron microscopy. Two pollen zones reflect different phases of basin development. Zonal vegetation remained fairly stable across the section and reflects heterogeneous environments including broad-leaved deciduous forest, subtropical forest, and sclerophyllous and semi-evergreen oak forest. Conifers were accessory elements in the broad-leaved deciduous forest communities and replaced these at higher elevations. Some herbaceous taxa (Plumbaginaceae) indicate scattered occurrences of sandy and/or rocky soils. Biogeographic affinities are general Northern Hemispheric, North American, and East Asian as also suggested by the macro fossil record. Only two taxa provide potential biogeographic links with the African flora. This suggests that biome shifts of plant taxa between African subtropical /tropical biomes and Anatolian (western Eurasian) temperate forests and shrublands may have been rare in the middle Miocene.

  • 36. Brengman, L.
    et al.
    Fedo, C.M.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Micro-scale silicon isotope heterogeneity observed in hydrothermal quartz precipitates from the >3.7 Ga Isua Greenstone Belt, SW Greenland.2016In: Terra Nova, ISSN 0954-4879, E-ISSN 1365-3121, Vol. 28, p. 70-75Article in journal (Refereed)
    Abstract [en]

    Pillow basalt and chert form integral lithologies comprising many Archean greenstone belt packages. To investigate details of these lithologies in the >3.7 Ga Isua Greenstone Belt, SW Greenland, we measured silicon isotope compositions of quartz crystals, by secondary ion mass spectrometry, from a quartz-cemented, quartz-amygdaloidal basaltic pillow breccia, recrystallized chert and chert clasts thought to represent silica precipitation under hydrothermal conditions. The recrystallized chert, chert clasts and quartz cement have overlapping δ30Si values, while the δ30Si values of the quartz amygdules span nearly the entire range of previously published values for quartz precipitates of any age, despite amphibolite facies metamorphism. We suggest that the heterogeneity is derived from kinetic isotope fractionation during quartz precipitation under disequilibrium conditions in a hydrothermal setting, consistent with the pillow breccia origin. On the basis of the present data, we conclude that the geological context of each sample must be carefully evaluated when interpreting δ30Si values of quartz.

  • 37. Chi Fru, Ernest
    et al.
    Ivarsson, Magnus
    Swedish Museum of Natural History, Department of Paleobiology.
    Kilias, Stephanos
    Christoffer, Hemmingson
    Broman, Curt
    Bengtson, Stefan
    C, Chatzitheodoridis
    Biogenicity of an early Quaternary iron formation, Milos Island, Greece2015In: Geobiology, ISSN 1472-4677, E-ISSN 1472-4669, Vol. 13, p. 225-244Article in journal (Refereed)
  • 38.
    Claesson, Stefan
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Bibikova, Elena
    Vernadsky Institute of Geochemistry and Analytical Chemistry RAS, Kosygin St 19, 119991 Moscow, Russia.
    Shumlyanskyy, Leonid
    M. P. Semenenko Institute of Geochemistry, Mineralogy and Ore Formation, Palladina Ave. 34, 03142 Kyiv, Ukraine.
    Dhuime, Bruno
    Department of Earth and Environmental Sciences, University of St Andrews, North Streeet, St Andrews KYI6 9AL, UK.
    Hawkesworth, C. H.
    Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8, 1RJ, UK.
    The oldest crust in the Ukrainian Shield - Eoarchaean U-Pb ages and Hf-Nd constraints from enderbites and metasediments2014In: Continent Formation Through Time / [ed] Roberts, N. M. W., van Kranendonk, M., Parman, S., Shirey, S. and Clift, P. D., London: The Geological Society Publishing House, 2014, Vol. 389Chapter in book (Refereed)
    Abstract [en]

    The oldest crust in the Ukrainian Shield occurs in the Podolian and Azov domains which both include Eoarchaeanarchaean components. U-Pb age data for Dniestr-Bug enderbites, Podolian Domain, indicate these are ca. 3.75 Ga old, and Lu-Hf isotope date indicate extraction from chondritic to mildly isotopically depleted sources with εHf up to ca. +2. Nd model ages support their Eoarchaeanarchaean age, while model ages for Dniestr-Bug metasedimentary gneisses indicate that these also include younger crustal material. Most of the Hf-age data for metasedimentary zircon from the Soroki greenstone belt, Azov Domain, reflects Eoarchaeanarchaean primary crustal sources with chondritic to mildly depleted Hf isotope signatures at 3.75 Ga. A minor portion is derived from Mesoarchaeanarchaean crust with a depleted εHf signature of ca. +4 at 3.1 Ga. U-Pb zircon ages from Fedorivka greenstone belt metasediments are consistent with the Soroki age data, but also include a 2.7‒2.9 Ga component. Nd whole rock model ages provide support for a younger crustal component in the latter. Both domains have been subject to Neoarchaeanarchaean, ca. 2.8 Ga, and Palaeoproterozoic, ca. 2.0 Ga metamorphism. The spatial distribution indicates that the Podolian and Azov domains have evolved independently of each other before the amalgamation of the Ukrainian Shield.

  • 39.
    Claesson, Stefan
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Bibikova, Elena V.
    Vernadsky Institute of Geochemistry and Analytical Chemistry, R.A.S., Moscow, Russia.
    Shumlyanskyy, Leonid
    M.P Semenenko Institute of Geochemistry, Mineralogy and Ore Formation, Palladina Ave. 34, 03680 Kyiv, Ukraine.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Billström, Kjell
    Swedish Museum of Natural History, Department of Geology.
    Can oxygen isotopes in magmatic zircon be modified by metamorphism? A case study from the Eoarchean Dniester-Bug Series, Ukrainian Shield2016In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 273, p. 1-11Article in journal (Refereed)
  • 40.
    Cornacchia, Irene
    et al.
    Dipartimento di Scienze della Terra, Sapienza Universita di Roma.
    Andersson, Per
    Swedish Museum of Natural History, Department of Geology.
    Agostine, Samuele
    Instituto di Geosciencze e Georisorse, CNR, Pisa.
    Brandanao, Marco
    Dipartimento di Scienze della Terra, Sapienza Universita di Roma.
    Strontium stratigraphy of the upper Miocene Lithothamnion Limestone in the Majella Mountain, central Italy, and its palaeoenvironmental implications2017In: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 50, no 4, p. 561-575Article in journal (Refereed)
    Abstract [en]

    The87Sr/86Sr isotope ratio has been widely used as aphysical tool to date and correlate carbonate successions due to the long Srresidence time in comparison with the ocean mixing time. If this method workson oceanic successions, marginal basins may show different Sr isotope recordsin comparison with the coeval ocean one due to sea-level variations,continental run-off and restricted water exchanges. In this work, we present the87Sr/86Sr isotope record of the upper Miocene carbonateramp of the Lithothamnion Limestone(Majella Mountain, central Apennines), as an example of the onset of restrictedwater exchanges between a marginal basin and the ocean water masses. The overalllatemost Tortonian–earlyMessinian Sr isotope record of the Lithothamnion Limestonefits below the global reference line. This deviation has been interpreted as dueto the strong control that freshwater input and enhanced continental run-off,linked to the migration of the Apennine accretionary wedge and foredeep system,have had on the central Adriatic water chemistry. These results imply that anaccurate oceanographic and geodynamic framework along with diagenetic overprintinvestigation has to be taken into consideration prior to apply SIS oncarbonate successions on marginal basins, even when facies analyses indicatefully marine conditions. This seems to be the case for the upper MioceneCentral Mediterranean carbonate successions, but may have more general validityand be extended to other recent or past marginal basins.

  • 41. Crémière, A.
    et al.
    Lepland, A.
    Chand, S.
    Sahy, D.
    Kirsimäe, K.
    Bau, M.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Noble, S.R.
    Martma, T.
    Thorsnes, T.
    Brunstad, H.
    Fluid source and methane-related diagenetic processes recorded in cold seep carbonates from the Alvheim channel, central North Sea2016In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 432, p. 16-33Article in journal (Refereed)
    Abstract [en]

    Integrated petrography, mineralogy, geochronology and geochemistry of cold seep carbonate crusts and free gas from the Alvheim channel elucidate diagenetic carbonate precipitation and related seepage histories in the central North Sea. Free gas isotope characteristics coupled with carbonate δ13C values as low as − 66‰ VPDB, indicate a predominantly microbial methane source with minor thermogenic contribution. We estimate that ~ 70% of the carbon sequestered into carbonate precipitates was derived from local oxidation of methane. The early stage of crust growth is represented by microcrystalline aragonite and Mg-calcite (10 to 40% mol MgCO3) cementing seafloor sediments consisting of clays, quartz, feldspar, and minor detrital low Mg-calcite and dolomite. Typical association of aragonite cement with coarse-grained detritus may reflect elevated fluid flow and flushing of fine particles prior to cementation close to the seafloor. Middle rare earth element enrichment in early generation microcrystalline cements containing framboidal pyrite indicates diagenetic precipitation within the zone of anaerobic methane oxidation contiguous to iron reduction. The later generation diagenetic phase corresponds to less abundant radial fibrous and botryoidal aragonite which lines cavities developed within the crusts. In contrast to early generation cements, late generation cavity infills have rare earth elements and Y patterns with small negative Ce anomalies similar to seawater, consistent with carbonate precipitation in a more open, seawater dominated system. Aragonite U–Th ages indicate carbonate precipitation between 6.09 and 3.46 kyr BP in the northern part of the channel, whereas in the southern part precipitation occurred between 1.94 and 0.81 kyr BP reflecting regional changes in fluid conduit position.

  • 42. Cunningham, J. A.
    et al.
    Thomas, C.-W.
    Bengtson, Stefan
    Swedish Museum of Natural History, Department of Paleobiology.
    Marone, Federica
    Paul Scherrer Institute.
    Stampanoni, Marco
    ETH Zürich.
    Turner, F. R.
    Bailey, J. V.
    Raff, R. A.
    Raff, E. C.
    Donoghue, Philip C.J.
    University of Bristol.
    Experimental taphonomy of giant sulphur bacteria: implications for the interpretation of the embryo-like Ediacaran Doushantuo fossils.2012In: Proceedings of the Royal Society of London. B. Biological Sciences, ISSN 0962-8452, Vol. 279, no 1734, p. 1857-1864Article in journal (Refereed)
    Abstract [en]

    The Ediacaran Doushantuo biota has yielded fossils interpreted as eukaryotic organisms, either animal embryos or eukaryotes basal or distantly related to Metazoa. However, the fossils have been interpreted alternatively as giant sulphur bacteria similar to the extant Thiomargarita. To test this hypothesis, living and decayed Thiomargarita were compared with Doushantuo fossils and experimental taphonomic pathways were compared with modern embryos. In the fossils, as in eukaryotic cells, subcellular structures are distributed throughout cell volume; in Thiomargarita, a central vacuole encompasses approximately 98 per cent cell volume. Key features of the fossils, including putative lipid vesicles and nuclei, complex envelope ornament, and ornate outer vesicles are incompatible with living and decay morphologies observed in Thiomargarita. Microbial taphonomy of Thiomargarita also differed from that of embryos. Embryo tissues can be consumed and replaced by bacteria, forming a replica composed of a threedimensional biofilm, a stable fabric for potential fossilization. Vacuolated Thiomargarita cells collapse easily and do not provide an internal substrate for bacteria. The findings do not support the hypothesis that giant sulphur bacteria are an appropriate interpretative model for the embryo-like Doushantuo fossils. However, sulphur bacteria may have mediated fossil mineralization and may provide a potential bacterial analogue for other macroscopic Precambrian remains.

  • 43. Cunningham, J.A.
    et al.
    Thomas, C.-W.
    Bengtson, Stefan
    Swedish Museum of Natural History, Department of Paleobiology.
    Kearns, S.L.
    Xiao, S.
    Marone, Federica
    Paul Scherrer Institute.
    Stampanoni, Marco
    ETH Zürich.
    Donoghue, Philip C.J.
    University of Bristol.
    Distinguishing geology from biology in the Ediacaran Doushantuo biota relaxes constraints on the timing of the origin of bilaterians.2012In: Proceedings of the Royal Society. B. Biological Sciences, ISSN 0962-8452, Vol. 279, no 1737, p. 2369-2376Article in journal (Refereed)
    Abstract [en]

    The Ediacaran Doushantuo biota has yielded fossils that include the oldest widely accepted record of the animal evolutionary lineage, as well as specimens with alleged bilaterian affinity. However, these systematic interpretations are contingent on the presence of key biological structures that have been reinterpreted by some workers as artefacts of diagenetic mineralization. On the basis of chemistry and crystallographic fabric, we characterize and discriminate phases of mineralization that reflect: (i) replication of original biological structure, and (ii) void-filling diagenetic mineralization. The results indicate that all fossils from the Doushantuo assemblage preserve a complex me´lange of mineral phases, even where subcellular anatomy appears to be preserved. The findings allow these phases to be distinguished in more controversial fossils, facilitating a critical re-evaluation of the Doushantuo fossil assemblage and its implications as an archive of Ediacaran animal diversity. We find that putative subcellular structures exhibit fabrics consistent with preservation of original morphology. Cells in later developmental stages are not in original configuration and are therefore uninformative concerning gastrulation. Key structures used to identify Doushantuo bilaterians can be dismissed as late diagenetic artefacts. Therefore, when diagenetic mineralization is considered, there is no convincing evidence for bilaterians in the Doushantuo assemblage.

  • 44.
    Cunningham, John A.
    et al.
    Swedish Museum of Natural History, Department of Paleobiology. University of Bristol.
    Liu, Alexander G.
    University of Cambridge.
    Bengtson, Stefan
    Swedish Museum of Natural History, Department of Paleobiology.
    Donoghue, Philip C.J.
    University of Bristol.
    The origin of animals: Can molecular clocks and the fossil record be reconciled?2016In: Bioessays, ISSN 0265-9247, E-ISSN 1521-1878, Vol. 38, p. 1-12Article in journal (Refereed)
    Abstract [en]

    The evolutionary emergence of animals is one of the most significant episodes in the history of life, but its timing remains poorly constrained. Molecular clocks estimate that animals originated and began diversifying over 100 million years before the first definitive metazoan fossil evidence in the Cambrian. However, closer inspection reveals that clock estimates and the fossil record are less divergent than is often claimed. Modern clock analyses do not predict the presence of the crown-representatives of most animal phyla in the Neoproterozoic. Furthermore, despite challenges provided by incomplete preservation, a paucity of phylogenetically informative characters, and uncertain expectations of the anatomy of early animals, a number of Neoproterozoic fossils can reasonably be interpreted as metazoans. A considerable discrepancy remains, but much of this can be explained by the limited preservation potential of early metazoans and the difficulties associated with their identificationin the fossil record. Critical assessment of both recordsmay permitbetter resolutionof the tempo and mode of early animal evolution.

  • 45.
    Cunningham, John A.
    et al.
    Swedish Museum of Natural History, Department of Paleobiology. University of Bristol.
    Vargas, Kelly
    School of Earth Sciences, University of Bristol, Bristol.
    Yin, Zongjun
    State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing.
    Bengtson, Stefan
    Swedish Museum of Natural History, Department of Paleobiology.
    Donoghue, Philip C.J.
    University of Bristol.
    The Weng’an Biota (Doushantuo Formation): an Ediacaran window on soft bodied and multicellular microorganisms.2017In: journal of the geological society, ISSN 2041-479X, Vol. 174, no 5, p. 793-802Article in journal (Refereed)
    Abstract [en]

    The Weng’an Biota is a fossil Konservat-Lagerstätte in South China that is approximately 570-600 million years old and provides an unparalleled snapshot of marine life during the interval in which molecular clocks estimate that animal clades were diversifying. It yields specimens that are three-dimensionally preserved in calcium phosphate with cellular and sometimes subcellular fidelity. The biota includes candidates for the oldest animals in the fossil record, including embryonic, larval and adult forms. We argue that, while the Weng’an Biota includes forms that could be animals, none can currently be assigned to this group with confidence. Nonetheless, the biota offers a rare and valuable window on the evolution of multicellular and soft-bodied organisms in the prelude to the Cambrian radiation.

  • 46.
    Cunningham, John
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Donoghue, Philip C.J.
    University of Bristol.
    Bengtson, Stefan
    Swedish Museum of Natural History, Department of Paleobiology.
    Distinguishing biology from geology in soft-tissue preservation.2014In: Reading and Writing of the Fossil Record: Preservational Pathways to Exceptional Fossilization / [ed] Marc Laflamme, James D. Schiffbauer, Simon A. F. Darroch, The Paleontological Society , 2014, p. 275-287Chapter in book (Refereed)
    Abstract [en]

    Knowledge of evolutionary history is based extensively on relatively rare fossils that preserve soft tissues. These fossils record a much greater proportion of anatomy than would be known solely from mineralized remains and provide key data for testing evolutionary hypotheses in deep time. Ironically, however, exceptionally preserved fossils are often among the most contentious because they are difficult to interpret. This is because their morphology has invariably been affected by the processes of decay and diagenesis, meaning that it is often difficult to distinguish preserved biology from artifacts introduced by these processes. Here we describe how a range of analytical techniques can be used to tease apart mineralization that preserves biological structures from unrelated geological mineralization phases. This approach involves using a series of X-ray, ion, electron and laser beam techniques to characterize the texture and chemistry of the different phases so that they can be differentiated in material that is difficult to interpret. This approach is demonstrated using a case study of its application to the study of fossils from the Ediacaran Doushantuo Biota.

  • 47.
    Cunningham, John
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Vargas, Kelly
    Liu, Pengju
    Belivanova, Veneta
    Swedish Museum of Natural History, Department of Paleobiology.
    Marone, Federica
    Martínez-Pérez, Carlos
    Guizar-Sicairos, Manuel
    Holler, Mirko
    Bengtson, Stefan
    Swedish Museum of Natural History, Department of Paleobiology.
    Donoghue, Philip C.J.
    Critical appraisal of tubular putative eumetazoans from the Ediacaran Weng’an Doushantuo biota2015In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, p. 1-9, article id 2151169Article in journal (Refereed)
    Abstract [en]

    Molecular clock analyses estimate that crown-group animals began diversifying hundreds of millions of years before the start of the Cambrian period. However, the fossil record has not yielded unequivocal evidence for animals during this interval. Some of the most promising candidates for Precambrian animals occur in theWeng’an biota of South China, including a suite of tubular fossils assigned to Sinocyclocyclicus, Ramitubus, Crassitubus and Quadratitubus, that have been interpreted as soft-bodied eumetazoans comparable to tabulate corals. Here, we present new insights into the anatomy, original composition and phylogenetic affinities of these taxa based on data from synchrotron radiation X-ray tomographic microscopy, ptychographic nanotomography, scanning electron microscopy and electron probe microanalysis. The patterns of deformation observed suggest that the cross walls of Sinocyclocyclicus and Quadratitubus were more rigid than those of Ramitubus and Crassitubus. Ramitubus and Crassitubus specimens preserve enigmatic cellular clusters at terminal positions in the tubes. Specimens of Sinocyclocyclicus and Ramitubus have biological features that might be cellular tissue or subcellular structures filling the spaces between the crosswalls. These observations are incompatible with a cnidarian interpretation, in which the spaces between cross walls are abandoned parts of the former living positions of the polyp. The affinity of the Weng’an tubular fossils may lie within the algae.

  • 48.
    Dahlin, Peter
    et al.
    Uppsala Universitet.
    Johansson, Åke
    Swedish Museum of Natural History, Department of Geology.
    Andersson, Ulf Bertil
    LKAB.
    Source character, mixing, fractionation and alkali metasomatism in Palaeoproterozoic greenstone dykes, Dannemora area, NE Bergslagen region, Sweden2014In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 151, no 4, p. 573-590Article in journal (Refereed)
    Abstract [en]

    The geochemical and isotopic characteristics of metamorphosed Svecofennian mafic dykes from the Dannemora area in the NE part of the Bergslagen region in central Sweden were investigated and compared to mafic intrusive rocks in their vicinity. The dykes, with an inferred age of c. 1860–1870 Ma, are calc-alkaline, sub-alkaline and basaltic in composition and have a mixed subduction and within-plate geochemical affinity. They are the result of mixing of at least three mantle source components with similar basaltic major element composition, but different concentrations of incompatible trace elements. Magma M1 is strongly enriched both in Rare Earth Elements (REE) and High-Field-Strength Elements (HFSE); magma M2 is highly enriched in Large-Ion Lithophile Elements (LILE, except Sr) with only moderate enrichment in HFSE and REE (particularly low in Heavy Rare Earth Elements); and magma M3 is enriched in Sr and has a flat REE profile. Magma M3 also has a somewhat more positive (depleted) initial εNd value of +1.8, compared to +0.4 to +0.5 for magmas M1 and M2. The magma evolution was controlled by a mixture of fractionation (mainly affecting the compatible elements) and mixing, best seen in the incompatible element concentrations and the Nd isotope data. The basaltic overall composition indicates little or no wholesale contamination by upper continental crust, but the dykes have undergone later metasomatic changes mainly affecting the alkali elements.

  • 49.
    Dekov, Vesselin
    et al.
    University of Sofia.
    Boycheva, Tanya
    University of Sofia.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Billström, Kjell
    Swedish Museum of Natural History, Department of Geology.
    Kamenov, George D.
    University of Florida.
    Shanks, Wayne C.
    U.S. Geological Survey, Denver.
    Stummeyer, Jens
    Bundesanstalt für Geowissenschaften, Hannover.
    Mineralogical and geochemical evidence for recent hydrothermal activity at the west wall of 12°50´N core complex (Mid-Atlantic Ridge): a new ultramafic-hosted seafloor hydrothermal deposit?2011In: Marine Geology, ISSN 0025-3227, E-ISSN 1872-6151, Vol. 288, p. 90-102Article in journal (Refereed)
  • 50.
    Dekov, Vesselin
    et al.
    University of Sofia.
    Boycheva, Tanya
    University of Sofia.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Petersen, Sven
    Leibiz-Institut für Meeresforschung, IFM-GEOMAR.
    Billström, Kjell
    Swedish Museum of Natural History, Department of Geology.
    Stummeyer, Jens
    Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover.
    Kamenov, George
    University of Florida.
    Shanks, Wayne
    U.S. Geological Survey, Denver.
    Atacamite and paratacamite from the ultramafic-hosted Logatchev seafloor vent field (14°45´ N, Mid-Atlantic Ridge)2011In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 286, p. 169-184Article in journal (Refereed)
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