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  • 1. BADAWY, AHMED SALAH
    et al.
    Mehlqvist, Kristina
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Ahlberg, Per
    Calner, Mikael
    Late Ordovician (Katian) spores in Sweden: oldest land plant remains from Baltica2014Ingår i: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 136, nr 1, s. 16-21Artikel i tidskrift (Refereegranskat)
    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.

  • 2.
    Bercovici, Antoine
    et al.
    Department of Geology, Lund University, Sölvegatan 12, SE-223 62 Lund, Sweden.
    Cui, Ying
    Department of Geosciences, 512 Deike Building, The Pennsylvania State University, University Park, PA 16802, USA.
    Forel, Marie-Béatrice
    State Key Laboratory of Biogeology and Environmental Geology of Ministry of Education, China University of Geosciences, Wuhan 430074, People’s Republic of China.
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Department of Geology, Lund University, Sweden.
    Terrestrial paleoenvironment characterization across the Permian–Triassic boundary in South China2015Ingår i: Journal of Asian Earth Sciences, ISSN 1367-9120, Vol. 98, s. 225-246Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Well-preserved marine fossils in carbonate rocks permit detailed studies of the end-Permian extinction event in the marine realm. However, the rarity of fossils in terrestrial depositional environments makes it more challenging to attain a satisfactory degree of resolution to describe the biotic turnover on land. Here we present new sedimentological, paleontological and geochemical (X-ray fluorescence) analysis from the study of four terrestrial sections (Chahe, Zhejue, Mide and Jiucaichong) in Western Guizhou and Eastern Yunnan (Yangtze Platform, South China) to evaluate paleoenvironmental changes through the Permian–Triassic transition.

    Our results show major differences in the depositional environments between the Permian Xuanwei and the Triassic Kayitou formations with a change from fluvial–lacustrine to coastal marine settings. This change is associated with a drastic modification of the preservation mode of the fossil plants, from large compressions to small comminuted debris. Plant fossils spanning the Permian–Triassic boundary show the existence of two distinct assemblages: In the Xuanwei Formation, a Late Permian (Changhsingian) assemblage with characteristic Cathaysian wetland plants (mainly Gigantopteris dictyophylloides, Gigantonoclea guizhouensis, G. nicotianaefolia, G. plumosa, G. hallei, Lobatannularia heinanensis, L. cathaysiana, L. multifolia, Annularia pingloensis, A. shirakii, Paracalamites stenocostatus, Cordaites sp.) is identified. In the lowermost Kayitou Formation, an Early Triassic (Induan)Annalepis–Peltaspermum assemblage is shown, associated with very rare, relictual gigantopterids. Palynological samples are poor, and low yield samples show assemblages almost exclusively represented by spores. A 1 m thick zone enriched in putative fungal spores was identified near the top of the Xuanwei Formation, including diverse multicellular forms, such as Reduviasporonites sp. This interval likely corresponds to the PTB ‘‘fungal spike’’ conventionally associated with land denudation and ecosystem collapse. While the floral turnover is evident, further studies based on plant diversity would be required in order to assess contribution linked to the end-Permian mass extinction versus local paleoenvironmental changes associated with the transition between the Xuanwei and Kayitou formations.

  • 3.
    Bomfleur, Benjamin
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    McLoughlin, Stephen
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Vajda, Vivi
    Lund University.
    Fossilized nuclei and chromosomes reveal 180 millionyears of genomic stasis in Royal Ferns2014Ingår i: Science, ISSN ISSN 0036-8075, Vol. 343, s. 1376-1377Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Rapidly permineralized fossils can provide exceptional insights into the evolution of life over geological time. Here, we present an exquisitely preserved, calcified stem of a royal fern (Osmundaceae) from Early Jurassic lahar deposits of Sweden in which authigenic mineral precipitation from hydrothermal brines occurred so rapidly that it preserved cytoplasm, cytosol granules, nuclei, and even chromosomes in various stages of cell division. Morphometric parameters of interphase nuclei match those of extant Osmundaceae, indicating that the genome size of these reputed “living fossils” has remained unchanged over at least 180 million years—a paramount example of evolutionary stasis.

  • 4. Cui, Ying
    et al.
    Bercovici, Antoine
    Yu, Yianxin
    Kump, Lee
    Freeman, Katherine
    Su, Shangguo
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Carbon cycle perturbation expressed in terrestrial Permian–Triassic boundary sections in South China2015Ingår i: Global and Planetary Change, ISSN 0921-8181, E-ISSN 1872-6364Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Stable isotopes of inorganic and organic carbon are commonly used in chemostratigraphy to correlate marine and terrestrial sedimentary sequences based on the assumption that the carbon isotopic signature of the exogenic carbon pool dominates other sources of variability. Here, sediment samples from four Permian–Triassic boundary (PTB) sections of western Guizhou and eastern Yunnan provinces in South China, representing a terrestrial to marine transitional setting, were analyzed for δ13C of organic matter (δ13Corg). These values were subsequently compared to published δ13C values of carbonates (δ13Ccarb) from the Global Stratotype Section and Point at Meishan and many other marine and terrestrial sections. A similar isotopic trend evident through all four sections is characterized by a negative shift of 2–3‰ at the top of the Xuanwei Formation, where we tentatively place the PTB. This negative shift also corresponds to a turnover in the vegetation and the occurrence of fungal spores, which is generally interpreted as a proliferation of decomposers and collapse of complex ecosystems during the end-Permian mass extinction event. Moreover, the absolute values of δ13Corg are more extreme in the more distal (marine) deposits. The δ13Corg values for the studied sediments are more variable compared to coeval δ13Ccarb records from marine records especially in the interval below the extinction horizon. We contend that the depositional environment influenced the δ13Corg values, but that the persisting geographic δ13Corg pattern through the extinction event across the four independent sections is an indication that the atmospheric δ13C signal left an indelible imprint on the geologic record related to the profound ecosystem change during the end-Permian extinction event.

  • 5.
    Einarsson, Elisabeth
    Department of Geology, Lund University.
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Department of Geology, Lund University, Sweden.
    First evidence of the Cretaceous decapod crustacean Protocallianassa from Sweden2016Ingår i: Geological Society, London, Special Publications, ISSN ISSN 0305-8719, Vol. 434, s. 241-250Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An assemblage of the burrowing ghost shrimp, Protocallianassa faujasi, is described, providing the first evidence of this decapod species from Sweden. The fossils occur in successions of the informal earliest late Campanian Belemnellocamax balsvikensis Zone at Åsen and the latest early Campanian B. mammillatus zone at Ivö Klack, both in the Kristianstad Basin of NE Skåne. Numerous, heavily calcified chelipeds were found within a restricted bed at Åsen that was rich in carbonate-cemented nodules. Based on the burrowing lifestyle of modern mud shrimps, we interpret these nodules as infilled burrow chambers. The low abundance of molluscs within the Protocallianassa beds is also consistent with analogous extant communities, indicating that a similar ecologically exclusive relationship ruled within the Late Cretaceous shallow marine ecosystems.

  • 6.
    Halamski, Adam
    Institute of Paleobiology, Polish Academy of Sciences.
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Department of Geology, Lund University, Sweden.
    Late Cretaceous (Campanian) leaf and palynoflora from southern Sweden2016Ingår i: Geological Society of London Special Publications, ISSN 0305-8719, Vol. 434, s. 207-230Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A Late Cretaceous (Campanian) leaf megaflora from the Vomb Trough in southern Skåne, Sweden, has been investigated on the basis of collections held at the Swedish Museum of Natural History. The main plant-bearing locality is Köpinge, but single specimens originate from Högestad, Ingelstorp, Rödmölla, Svenstorps mölla and Tosterup. The fossil flora is dominated by the angiosperm (eudicot) Debeya (Dewalquea) haldemiana (Debey ex de Saporta & Marion) Halamski. Other dicots are cf. Dryophyllum sp., Ettingshausenia sp., Rarytkinia? sp., Dicotylophyllum friesii (Nilsson) comb. nov. and Salicites wahlbergii (Nilsson) Hisinger. Conifers are represented by cf. Aachenia sp. (cone scales), Pagiophyllum sp. and Cyparissidium sp. (leaves). Single poorly preserved specimens of ferns and monocots have also been identified. The terrestrial palynomorphs (the focus herein) clearly link to the megaflora, although with different relative abundances. The fern spore Cyathidites dominates along with the conifer pollen Perinopollenites elatoides and Classopollis. Angiosperm pollen comprise up to 15% of the assemblage, represented by monocolpate, tricolpate and periporate pollen and the extinct Normapolles group. The spores in the kerogen residue show a thermal alteration index (TAI) of 2+. The flora probably represents mainly a coastal lowland Debeya/conifer forest, and is similar to approximately coeval assemblages from analogous palaeo-communities described from eastern Poland, western Ukraine and Westphalia.

  • 7.
    Kear, Benjamin
    et al.
    Museum of Evolution, Uppsala University.
    Lindgren, Johan
    Department of Geology, Lund University.
    Jörn Hurum, Jörn
    Natural History Museum, University of Oslo.
    Milan, Jesper
    Geomuseum Faxe/Østsjællands Museum.
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Department of Geology, Lund University, Sweden.
    An introduction to the Mesozoic biotas of Scandinavia and its Arctic territories2016Ingår i: Geological Society, London, Special Publications, ISSN ISSN 0305-8719, Vol. 434, s. 1-14Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Mesozoic biotas of Scandinavia have been studied for nearly two centuries. However, the last 15 years have witnessed an explosive advance in research, most notably on the richly fossiliferous Triassic (Olenekian–Carnian) and Jurassic (Tithonian) Lagersta¨tten of the Norwegian Arctic Svalbard archipelago, Late Cretaceous (Campanian) Kristianstad Basin and Vomb Trough of Skåne in southern Sweden, and the UNESCO heritage site at Stevns Klint in Denmark – the latter constituting one of the most complete Cretaceous–Palaeogene (Maastrichtian–Danian) boundary sections known globally. Other internationally significant deposits include earliest (Induan) and latest Triassic (Norian–Rhaetian) strata from the Danish autonomous territory of Greenland, and the Early Jurassic (Sinemurian–Pliensbachian) to Early Cretaceous (Berriasian) rocks of southern Sweden and the Danish Baltic island of Bornholm, respectively. Marine palaeocommunities are especially well documented, and comprise prolific benthic macroinvertebrates, together with pelagic cephalopods, chondrichthyans, actinopterygians and aquatic amniotes (ichthyopterygians, sauropterygians and mosasauroids). Terrestrial plant remains (lycophytes, sphenophytes, ferns, pteridosperms, cycadophytes, bennettitaleans and ginkgoes), including exceptionally well-preserved carbonized flowers, are also world famous, and are occasionally associated with faunal traces such as temnospondyl amphibian bones and dinosaurian footprints. While this collective documented record is substantial, much still awaits discovery. Thus, Scandinavia and its Arctic territories represent some of the most exciting prospects for future insights into the spectacular history of Mesozoic life and environments.

  • 8.
    McLoughlin, Stephen
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Bomfleur, Benjamin
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Vajda, Vivi
    Lund University.
    A phenomenal fossil fern, forgotten for forty years2014Ingår i: Deposits Magazine, ISSN 17749588, Vol. 40, s. 16-21Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    On some occasions, it is the hard sweat and toil of palaeontologists labouring in the field at carefully planned excavation sites that yields the prize specimen on which careers are built. On other occasions, it is the chance discovery by an amateur collector that may yield that special fossil. We present an account of one such remarkable fossil discovery by an eccentric farmer in southern Sweden. However, more remarkable is that this exceptional fossil remained unstudied and largely unnoticed in a major museum for almost 40 years, before its true significance was realised.

  • 9.
    McLoughlin, Stephen
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Jansson, Ida-Maria
    Lund University.
    Vajda, Vivi
    Lund University.
    Megaspore and microfossil assemblages reveal diverse herbaceous lycophytes in the Australian Early Jurassic flora2014Ingår i: Grana, ISSN 0017-3134, Vol. 53, s. 22-53Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Here, we describe and illustrate by transmitted light and scanning electron microscopy the first Australian Jurassic megaspore assemblages. The megaspores and other mesofossils were isolated from terrestrial deposits of the Marburg Subgroup (late Pliensbachian) at Inverleigh Quarry, Clarence-Moreton Basin, eastern Australia. Nine megaspore taxa are identified including one new species: Paxillitriletes rainei. Miospore assemblages recovered from the same samples at Inverleigh reveal a slightly higher diversity of lycophyte microspores. The collective megaspore suite from Inverleigh shares several genera with mid-Mesozoic assemblages from widely distributed parts of the world, but most of the Inverleigh species have subtle morphological differences from congeneric forms elsewhere. The megaspores accumulated in fluvial floodplain facies and are associated with mostly dissociated isoetalean leaf debris. Other mesofossils in the sampled interval include annelid egg cases, dispersed seeds and charcoal. Invertebrate burrows and possible vertebrate tracks also occur in this succession. Lycophyte macrofossils are otherwise known from only two other Australian Jurassic deposits. The richness of the megaspore and microspore suites attest to a significant diversity of lycophytes in the Australian Jurassic floras not hitherto appreciated from described macrofloras

  • 10. Mehlqvist, Kristina
    et al.
    Larsson, Kent
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Linking upper Silurian terrestrial and marine successions—Palynologicalstudy from Skåne, Sweden2014Ingår i: Review of Palaeobotany and Palynology, ISSN 0034-6667, E-ISSN 1879-0615, Vol. 202, s. 1-14Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have performed a palynostratigraphic study on miospore assemblages from near-shore marine Silurian sed-imentary rocks of Skåne, southern Sweden. The material includes both drillcore (from Klintaborrningen 1 and Bjärsjölagårdborrningen 2) and outcrop samples from various localities in Skåne. Well- preserved spore assemblages were identified. Long ranging species with a global distribution dominate the spore assemblages, including Ambitisporites sp., Dyadospora sp., Laevolancis sp., and Tetrahedraletes sp. and complemented with key taxa including Emphanisporites neglectus, Hispanaediscus lamontii, Hispanaediscus verrucatus, Scylaspora scripta, Synorisporites libycus and Synorisporites tripapillatus. Based on biostratigraphical schemes for early land plant spores, the studied sedimentary rocks of the cores Klintaborrningen 1 and Bjärsjölagårdborrningen 2 are interpreted as late Silurian in age, spanning Ludlow to Přídolí. The spore assemblages are compared and correlated to marine fossil schemes including those of conodonts, chitinozoans, graptolites and tentaculitids. Additionally, relative abundance data of specific spore taxa have been used for correlation between the drillcores and the outcrops.

  • 11.
    Mehlqvist, Kristina
    et al.
    Department of Geology, Lund University, Sölvegatan 12, SE-223 62 Lund, Sweden.
    Steemans, Philippe
    Palaeogeobiology–Palaeobotany–Palaeopalynology, University of Liège, Allée du 6 Août, Bât. B-18, parking 40, B-4000 Liège 1, Belgium.
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Department of Geology, Lund University, Sweden.
    First evidence of Devonian strata in Sweden — A palynological investigation of Övedskloster drillcores 1 and 2, Skåne, Sweden2015Ingår i: Review of Palaeobotany and Palynology, ISSN 0034-6667, E-ISSN 1879-0615, Vol. 221, s. 144-159Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Palynological analyses were carried out on 50 samples from the Övedskloster 1 (Ö1) and 2 drillcores (Ö2), southern Sweden. The study revealed well-preserved palynological assemblages including 77 spore species in 28 genera, and some additional forms retained under open nomenclature. The spore assemblages are collectively dominated by trilete spores in terms of abundance and diversity and have been ascribed to two informal palynozones (Assemblage A and Assemblage B), based on the representation of spore taxa. The presence of the spore species Acinosporites salopiensis, Chelinohilates erraticus, Cymbohilates allenii, Cymbohilates allenii var. magnus, and Retusotriletes maccullockii indicates that the stratigraphic succession spans the Silurian–Devonian boundary (Přídolí–Lochkovian), and thus constitutes the first robust evidence of Devonian strata on the Swedish mainland. These results have implications for the age of fossil faunas (e.g. fish) from the samedeposits, previously dated as late Silurian. Palynofacies analyses reveal a shallowing-upward succession with nearshore marine marls at the base of the investigated core, grading into sandstones in conjunction with a decrease in the relative abundance of marine palynomorphs. The uppermost 70 m are mainly represented by red sandstones that are devoid of recognizable palynomorphs and host only phytodebris. We interpret this interval to represent predominantly paralic to fluvial deposits equivalent to facies represented in the Old Red Sandstone of Britain.

  • 12. Mehlqvist, Kristina
    et al.
    Wigforss-Lange, Jane
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    A palynological study from Sweden reveals stable terrestrial environments during Late Silurian extreme marine conditions2015Ingår i: Earth and environmental science transactions of the Royal Society of Edinburgh, ISSN 1755-6910, E-ISSN 1755-6929, Vol. 105, s. 149-158Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A palynological study of the upper Silurian Öved–Ramsåsa Group in Skåne, Sweden yields a well preserved spore assemblage with low relative abundances of marine microfossils. In total, 26 spore taxa represented by 15 genera were identified. The spore assemblage is dominated by long-ranging cryptospore taxa, and the trilete spore Ambitisporites avitus-dilutus. However, key-species identified include Artemopyra radiata, Hispanaediscus lamontii, H. major, H. verrucatus, Scylaspora scripta and Synorisporites cf. libycus. Importantly, Scylaspora klintaensis was identified, allowing correlation with the Klinta 1 drillcore (Skåne). A Ludlow age is inferred for the exposed succession, which agrees well with previous conodont stratigraphy. The organic residue is dominated by phytodebris and spores, but with high relative abundances of acritarchs at two levels, possibly related to flooding surfaces. Based on the palynofacies analysis, a near-shore marine environment is proposed. The close proximity to land is inferred by the high proportions of spores, and the dispersed assemblage most likely represents the local flora growing on delta plains. The palynological signal also infers a stable terrestrial environment and vegetation, in contrast to unstable conditions in the marine environment characterised by ooid formation in an evaporitic environment. Comparisons with coeval spore assemblages from Gotland, Avalonia and Laurentia show relatively close similarities in taxonomic composition at the generic level.

  • 13.
    Peterffy, Olof
    et al.
    Department of Geology, Lund University.
    Calner, Michael
    Department of Geology, Lund University.
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Department of Geology, Lund University, Sweden.
    Early Jurassic microbial mats—A potential response to reduced biotic activity in the aftermath of the end-Triassic mass extinction event2016Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 464, s. 76-85Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Wrinkle structures are microbially induced sedimentary structures (MISS) formed by cyanobacteria and are common in pre-Cambrian and Cambrian siltstones and sandstones but are otherwise rare in the Phanerozoic geological record. This paper reports the first discovery of Mesozoic wrinkle structures from Sweden. These are preserved in fine-grained and organic-rich heterolithic strata of the Lower Jurassic (Hettangian) Höganäs Formation in Skåne, southern Sweden. The strata formed in a low-energy, shallowsubtidal setting in themarginal parts of the Danish rift-basin. Palynological analyses of fine-grained sandstones hosting the wrinkle structures show that the local terrestrial environment probably consisted of a wetland hosting ferns, cypress and the extinct conifer family Cheirolepidaceae. Palynostratigraphy indicates a Hettangian age, stillwithin the floral recovery phase following the end-Triassic mass extinction event. The finding of wrinkle structures is significant as the presence of microbial mats in the shallow subtidal zone, (in a deeper setting compared to where modern epibenthic microbial mats grow) suggests decreased benthic biodiversity and suppressed grazing in shallow marine environments in the early aftermath of the end-Triassic mass extinction event.

  • 14.
    Qu, Yuangao
    et al.
    Department of Earth Science and Centre for Geobiology, University of Bergen, Norway.
    Engdahl, Anders
    MAX IV Laboratory, Lund University, Sweden.
    Zhu, Shixing
    Tianjin Institute of Geology and Mineral Resources, CGS, China.
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Department of Geology, Lund University, Sweden.
    McLoughlin, Nicola
    Department of Geology, Lund University, Sweden.
    Ultrastructural heterogeneity of carbonaceous material in ancient cherts: investigating biosignature origin and preservation2015Ingår i: Astrobiology, ISSN 1531-1074, E-ISSN 1557-8070, Vol. 15, nr 10, s. 825-842Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Opaline silica deposits on Mars may be good target sites where organic biosignatures could be preserved. Potential analogues on Earth are provided by ancient cherts containing carbonaceous material (CM) permineralized by silica. In this study, we investigated the ultrastructure and chemical characteristics of CM in the Rhynie chert (c. 410 Ma, UK), Bitter Springs Formation (c. 820 Ma, Australia), and Wumishan Formation (c. 1485 Ma, China). Raman spectroscopy indicates that the CM has experienced advanced diagenesis or lowgrade metamorphism at peak metamorphic temperatures of 150–350C. Raman mapping and micro-Fourier transform infrared (micro-FTIR) spectroscopy were used to document subcellular-scale variation in the CM of fossilized plants, fungi, prokaryotes, and carbonaceous stromatolites.

    In the Rhynie chert, ultrastructural variation in the CM was found within individual fossils, while in coccoidal and filamentous microfossils of the Bitter Springs and formless CM of the Wumishan stromatolites ultrastructural variation was found between, not within, different microfossils. This heterogeneity cannot be explained by secondary geological processes but supports diverse carbonaceous precursors that experienced differential graphitization. Micro-FTIR analysis found that CM with lower structural order contains more straight carbon chains (has a lower R3/2 branching index) and that the structural order of eukaryotic CM is more heterogeneous than prokaryotic CM.

    This study demonstrates how Raman spectroscopy combined with micro-FTIR can be used to investigate the origin and preservation of silica-permineralized organics. This approach has good capability for furthering our understanding of CM preserved in Precambrian cherts, and potential biosignatures in siliceous deposits on Mars. Key

  • 15.
    Sha, Jingeng
    et al.
    State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Paleontology, Nanjing 210008, China.
    Olsen, Paul E.
    Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10968.
    Pan, Yanhong
    State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Paleontology, Nanjing 210008, China.
    Xu, Daoyi
    Institute of Geology, China Earthquake Administration, Beijing 100029, China.
    Wang, Yaqiang
    State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Paleontology, Nanjing 210008, China.
    Zhang, Xiaolin
    Chinese Academy of Sciences Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Heifei 230026, China.
    Yao, Xiaogang
    State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Paleontology, Nanjing 210008, China.
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Department of Geology, Lund University, Sweden.
    Triassic–Jurassic climate in continental high-latitude Asia was dominated by obliquity-paced variations (Junggar Basin, Ürümqi, China)2015Ingår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 112, nr 12, s. 3624-3629Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Empirical constraints on orbital gravitational solutions for the Solar System can be derived from the Earth’s geological record of past climates. Lithologically based paleoclimate data from the thick, coal-bearing, fluvial-lacustrine sequences of the Junggar Basin of Northwestern China (paleolatitude ∼60°) show that climate variability of the warm and glacier-free high latitudes of the latest Triassic–Early Jurassic (∼198–202 Ma) Pangea was strongly paced by obliquity-dominated (∼40 ky) orbital cyclicity, based on an age model using the 405-ky cycle of eccentricity. In contrast, coeval low-latitude continental climate was much more strongly paced by climatic precession, with virtually no hint of obliquity. Although this previously unknown obliquity dominance at high latitude is not necessarily unexpected in a high CO2 world, these data deviate substantially from published orbital solutions in period and amplitude for eccentricity cycles greater than 405 ky, consistent with chaotic diffusion of the Solar System. In contrast, there are indications that the Earth–Mars orbital resonance was in today’s 2-to-1 ratio of eccentricity to inclination. These empirical data underscore the need for temporally comprehensive, highly reliable data, as well as new gravitational solutions fitting those data.

  • 16.
    Steinthorsdottir, Margret
    Department of Geological Sciences and Bolin Centre for Climate Research, Stockholm University.
    Pole, Mike
    Nanjing Institute of Geology and Palaeontology, The Chinese Academy of Sciences.
    Global trends of pCO2 across the Cretaceous-Paleogene boundary supported by the first Southern Hemisphere stomatal proxy-based pCO2 reconstruction2016Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 464, s. 143-152Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Reliable reconstructions of atmospheric carbon dioxide concentrations (pCO2) are required at higher resolution than currently available to help resolve the relationship between mass extinctions and changes in palaeo-pCO2 levels. Such reconstructions are needed: 1, at a high temporal resolution for constraining the pre- and post-extinction atmospheres; and 2, at a sufficient spatial resolution to constrain potential inter-hemispheric differences. Here we estimate pCO2 based on fossil Lauraceae leaf cuticle specimens derived from three localities with strata spanning the latest Cretaceous to the mid-Paleocene, including a new Cretaceous–Paleogene boundary (K–Pg) locality, in New Zealand. We use two independent methods of stomatal density-based pCO2 reconstructions; a transfer function calibrated using herbarium material and the stomatal ratio method, producing three calibration sets. Our results based on the mean values of each of the three calibration methods indicate pCO2 ranging between ca. 460 and 650 ppm during the latest Cretaceous, falling precipitously to average values between ca. 360 and 430 ppm across the K–Pg boundary, and further to ca. 305–320 ppm in the mid-Paleocene. A ‘spike’ of extremely high pCO2 at the K–Pg could not be confirmed, but our results are, nonetheless, consistent with previously published pCO2 records from the Northern Hemisphere, and show that stomatal density worldwide was responding to significant changes in pCO2 across the K–Pg.

  • 17. Steinthorsdottir, Margret
    et al.
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Department of Geology, Lund University, Sweden.
    Early Jurassic (late Pliensbachian) CO2 concentrations based on stomatalanalysis of fossil conifer leaves from eastern Australia2015Ingår i: Gondwana Research, ISSN 1342-937X, E-ISSN 1878-0571, Vol. 27, s. 932-939Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The stomatal index (a measure of stomatal density) of an extinct Australian Early Jurassic araucariacean conifer species, Allocladus helgei Jansson, is used to reconstruct the atmospheric carbon dioxide concentration (pCO2) in the Early Jurassic. The fossil leaves are preserved in a single bed, palynologically dated to late Pliensbachian (~185–183 Mya). Atmospheric pCO2 is estimated from the ratios between the stomatal index of A. helgei and the stomatal indices of three modern analogs (nearest living equivalent plants). CO2 concentration in the range of ~750–975 ppm was calibrated from the fossil material, with a best-estimated mean of ~900 ppm. The new average pCO2 determined for the late Pliensbachian is thus similar to, although ~10% lower, than previously inferred minimum concentrations of ~1000, based on data from the Northern Hemisphere, but may help constrain pCO2 during this period. Our results are the first pCO2 estimates produced using Jurassic leaves from the Southern Hemisphere and showthat i) paleo-atmospheric pCO2 estimates are consistent at a global scale, though more investigations of Southern Hemisphere material are required, and ii) the stomatal proxy method can now be used without the context of relative change in pCO2 when applying the correct methodology.

  • 18.
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Department of Geology, Lund University, Sweden.
    Villanueva-Amadoz, Uxue
    ERNO, Instituto de Geología, UNAM, L.D. Colosio y Madrid.
    Lehsten, Veiko
    Dept of Physical Geography and Ecosystems Science, Lund University.
    Alcalá, Luis
    Fundación Conjunto Paleontológico de Teruel-Dinópolis/Museo Aragonés de Paleontología.
    Dietary and environmental implications of Early Cretaceous predatory dinosaur coprolites from Teruel, Spain2016Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 464, s. 134-142Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Coprolites from the Early Cretaceous vertebrate bone-bed at Ariño in Teruel, Spain, were analyzed geochemically and palynologically. They contain various inclusions, such as small bone fragments, abundant plant remains, pollen, and spores. We attribute the coprolites to carnivorous dinosaurs based partly on their morphology together with the presence of bone fragments, and a high content of calcium phosphate (hydroxylapatite) with calcite.Well-preserved pollen and spore assemblages were identified in all coprolite samples and a slightly poorer assemblage was obtained from the adjacent sediments, both indicating an Early Cretaceous (Albian) age. This shows that the coprolites are in situ and also confirms previous age determinations for the host strata. The depositional environment is interpreted as a continental wetland based on the palynoflora, which includes several hydrophilic taxa, together with sparse occurrences of fresh-water algae, such as Ovoidites, and the absence of marine palynomorphs. Although the coprolites of Ariño samples generally are dominated by pollen produced by Taxodiaceae (cypress) and Cheirolepidiaceae (a family of extinct conifers), the sediment samples have a slightly higher relative abundance of fern spores. The distribution of major organic components varies between the coprolite and sediment samples, which is manifest by the considerably higher charcoal percentage within the coprolites. The high quantities of charcoal might be explained by a ground-dwelling species, feeding on smaller vertebrates that complemented its diet with plant material from a paleoenvironment were wild fires were a part of the ecosystem. The state of preservation of the spores and pollen is also more detailed in the coprolites, suggesting that encasement in calcium phosphate may inhibit degradation of sporopollenin.

  • 19.
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Department of Geology, Lund University, Sweden.
    Sha, Jingeng
    Nanjing Institute of Geology and Palaeontology, Academia Sinic.
    Mesozoic ecosystems – climate and biotas2016Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 464, s. 1-4Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    This issue of Palaeogeography Palaeoclimatology Palaeoecology is devoted to papers on Mesozoic ecosystems and is an outcome of the International Geoscience Program (IGCP) 632. IGCP is a joint operation by UNESCO and the International Union of Geological Sciences (IUGS), which promote interdisciplinary Earth science research among scientists internationally. Since its formation in 1972, IGCP has supported over 500 projects in about 150 countries.

  • 20.
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Stevns Klint2014Ingår i: Geologiskt forum, Vol. 21, nr 83, s. 14-19Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 21.
    Vajda, Vivi
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Bercovici, Antoine
    Cui, Ying
    Yu, Jianxin
    Forel, Marie-Béatrice
    Terrestrial paleoenvironment characterization across the Permian–Triassic boundary in South China2015Ingår i: Journal of Asian Earth Sciences, ISSN 1367-9120, E-ISSN 1878-5786, Vol. 98, s. 225-246Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Well-preserved marine fossils in carbonate rocks permit detailed studies of the end-Permian extinction event in the marine realm. However, the rarity of fossils in terrestrial depositional environments makes it more challenging to attain a satisfactory degree of resolution to describe the biotic turnover on land. Here we present new sedimentological, paleontological and geochemical (X-ray fluorescence) analysis from the study of four terrestrial sections (Chahe, Zhejue, Mide and Jiucaichong) in Western Guizhou and Eastern Yunnan (Yangtze Platform, South China) to evaluate paleoenvironmental changes through the Permian–Triassic transition.

    Our results show major differences in the depositional environments between the Permian Xuanwei and the Triassic Kayitou formations with a change from fluvial–lacustrine to coastal marine settings. This change is associated with a drastic modification of the preservation mode of the fossil plants, from large compressions to small comminuted debris. Plant fossils spanning the Permian–Triassic boundary show the existence of two distinct assemblages: In the Xuanwei Formation, a Late Permian (Changhsingian) assemblage with characteristic Cathaysian wetland plants (mainly Gigantopteris dictyophylloides, Gigantonoclea guizhouensis, G. nicotianaefolia, G. plumosa, G. hallei, Lobatannularia heinanensis, L. cathaysiana, L. multifolia, Annularia pingloensis, A. shirakii, Paracalamites stenocostatus, Cordaites sp.) is identified. In the lowermost Kayitou Formation, an Early Triassic (Induan) Annalepis–Peltaspermum assemblage is shown, associated with very rare, relictual gigantopterids. Palynological samples are poor, and low yield samples show assemblages almost exclusively represented by spores. A ∼1 m thick zone enriched in putative fungal spores was identified near the top of the Xuanwei Formation, including diverse multicellular forms, such as Reduviasporonites sp. This interval likely corresponds to the PTB “fungal spike” conventionally associated with land denudation and ecosystem collapse. While the floral turnover is evident, further studies based on plant diversity would be required in order to assess contribution linked to the end-Permian mass extinction versus local paleoenvironmental changes associated with the transition between the Xuanwei and Kayitou formations.

  • 22.
    Vajda, Vivi
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Calner, Mikael
    Ahlberg, Anders
    Palynostratigraphy of dinosaur footprint-bearing deposits from theTriassic–Jurassic boundary interval of Sweden2013Ingår i: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 135, s. 120-130Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Triassic–Jurassic boundary (c. 200 Ma) marks one of the five largest Phanerozoic mass extinction events and is characterized by a major turnover in biotas. A palynological study of sedimentary rock slabs bearing dinosaur footprints from Rhaeto–Hettangian strata of Skåne, Sweden was carried out. The theropod dinosaur footprints (Kayentapus soltykovensis) derive from the southern part of the abandoned Vallåkra quarry (Höganäs Formation) and were originally dated as earliest Jurassic (Hettangian) based on lithostratigraphy. Our results reveal that two of the footprints are correlative with the latest Triassic (latest Rhaetian) disaster zone typified by a high abundance of the enigmatic gymnosperm pollen Ricciisporites tuberculatus and Perinopollenites elatoides together with the key taxon Limbosporites lundbladii and fern spores. Two footprints are dated to correlate with the Transitional Spore-spike Interval. One footprint is interpreted as Hettangian in age based on the relatively high abundance of Pinuspollenites spp. together with the presence of the key taxa Retitriletes semimuris and Zebrasporites intercriptus. Our new palynological study suggests that the Kayentapus ichnogenus already appeared in the end of Triassic, and our study highlights the use of palynology as a powerful tool to date historical collections of fossils in museums, universities and elsewhere. The Hettangian footprint reflects a marine influence while all other studied ichnofossil specimens occur in non-marine (floodplain and delta interdistributary) sediments. The sediments associated with the Hettangian footprint include a significant proportion of charcoal transported from land after wildfires. The Rhaeto–Hettangian vegetation was otherwise characterized by multi-storey gymnosperm–pteridophyte communities.

  • 23.
    Vajda, Vivi
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Department of Geology, Lund University, Sweden.
    Linderson, Hans
    Geology Department, University of Lund.
    McLoughlin, Stephen
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Disrupted vegetation as a response to Jurassic volcanism in southern Sweden2016Ingår i: Geological Society of London Special Publications, ISSN ISSN 0305-8719, Vol. 434, s. 127-147Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Central Skåne (Scania) in southern Sweden hosts evidence of extensive Jurassic volcanism in the form of mafic volcanic plugs and associated volcaniclastic deposits that entomb well preserved macro-plant and spore–pollen assemblages. Palynological assemblages recovered from the Höör Sandstone are of Hettangian–Pliensbachian age and those from the overlying lahar deposits are dated as Pliensbachian–early Toarcian (?). Palynomorph assemblages from these units reveal significantly different ecosystems, particularly with respect to the gymnospermous components that represented the main canopy plants. Both palynofloras are dominated by osmundacean, marattiacean and cyatheacean fern spore taxa but, whereas the Höör Sandstone hosts abundant Chasmatosporites spp. pollen produced by plants related to cycadophytes, the volcanogenic deposits are dominated by cypress family pollen (Perinopollenites) with an understorey component rich in putative Erdtmanithecales (or possibly Gnetales), and collectively representing vegetation of disturbed habitats. Permineralized conifer wood attributed to Protophyllocladoxylon sp., belonging to plants that probably produced the abundant Perinopollenites grains, is abundant in the volcanigenic strata, and shows sporadic intraseasonal and multi-year episodes of growth disruption. Together with the relatively narrow but marked annual growth rings, and the annual and mean sensitivity values that span the complacent–sensitive domains, these features suggest growth within Mediterranean-type biomes subject to episodic disturbance.

  • 24.
    Vajda, Vivi
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Lyson, Tyler R.
    Bercovici, Antoine
    Doman, Jessamy H.
    Pearson, Dean
    A snapshot into the terrestrial ecosystem of an exceptionally well preserved dinosaur (Hadrosauridae) from the Upper Cretaceous of North Dakota, USA2013Ingår i: Cretaceous research (Print), ISSN 0195-6671, E-ISSN 1095-998X, Vol. 46, s. 114-122Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A palynological investigation of sedimentary rocks enclosing an exceptionally well-preserved fossil dinosaur (Hadrosauridae) discovered in the upper part of the Hell Creek Formation in south western North Dakota was conducted in order to document the immediate paleoenvironment of this dinosaur. The specimen, an Edmontosaurus annectens is remarkable in having exceptional three-dimensional preservation of soft tissue around the skeleton, indicating rapid burial. A well-preserved palynological assemblage dominated by fern and bryophyte spores, with lesser gymnosperm and angiosperm pollen was recovered. Sparse fresh-water algae and marine dinoflagellate cysts were also recorded. The palynofacies is dominated by wood fragments, including charcoal, with little amorphous organic matter. The presence of some typical pollen taxa of the Wodehouseia spinata Assemblage Zone including Striatellipollis striatellus, Tricolpites microreticulatus, Leptopecopites pocockii as well as a diverse suite of Aquilapollenites, is fully consistent with a Late Cretaceous (late Maastrichtian) age. The palynoflora indicates a local vegetation composed of a canopy of conifers dominated by Pinaceae and a minor sub-canopy of Taxodium and cycads, as well as an understory of hydrophilous ferns, mosses and herbaceous angiosperms, indicative of a warm and humid climate e an environment where this specific hadrosaur roamed over 66 million years ago.

  • 25.
    Vajda, Vivi
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Department of Geology, Lund University, Sweden.
    McLoughlin, Stephen
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Extinction and recovery patterns of the vegetation across the Cretaceous–Palaeogene boundary — a tool for unravelling the causes of the end-Permian mass-extinction2007Ingår i: Review of Palaeobotany and Palynology, ISSN 0034-6667, E-ISSN 1879-0615, Vol. 144, s. 99-112Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High-resolution palynofloral signatures through the Cretaceous–Palaeogene boundary succession show several features in common with the Permian–Triassic transition but there are also important differences. Southern Hemisphere Cretaceous–Palaeogene successions, to date studied at high resolution only in New Zealand, reveal a diverse palynoflora abruptly replaced by fungi-dominated assemblages that are in turn succeeded by low diversity suites dominated by fern spores, then gymnosperm- and angiosperm-dominated palynofloras of equivalent diversity to those of the Late Cretaceous. This palynofloral signature is interpreted to represent instantaneous (days to months) destruction of diverse forest communities associated with the Chicxulub impact event. The pattern of palynofloral change suggests wholesale collapse of vascular plant communities and short-term proliferation of saprotrophs followed by relatively rapid successional recovery of pteridophyte and seed–plant communities. The Permian–Triassic transition records global devastation of gymnosperm-dominated forests in a short zone synchronous with one or more peaks of the fungal/algal palynomorph Reduviasporonites. This zone is typically succeeded by assemblages rich in lycophyte spores and/or acritarchs. Higher in the succession, these assemblages give way to diverse palynofloras dominated by new groups of gymnosperms. Although different plant families were involved in the mass-extinctions, the general pattern of extinction and recovery is consistent between both events. The major difference is the longer duration for each phase of the Triassic recovery vegetation compared to that of the Paleocene. The protracted extinction-recovery succession at the Permian–Triassic boundary is incompatible with an instantaneous causal mechanism such as an impact of a celestial body but is consistent with hypotheses invoking extended environmental perturbations through flood-basalt volcanism and release of methane from continental shelf sediments.

  • 26. Vajda, Vivi
    et al.
    McLoughlin, Stephen
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Fungal proliferation at the Cretaceous-Tertiary boundary.2004Ingår i: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 303, nr 5663, s. 1489-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have found that a fungal spike occurs between the diverse Late Cretaceous palynoflora and the low-diversity fern-dominated early Paleocene assemblages in a New Zealand section. The fungal layer is coincident with the Ir anomaly marking the extinction event.

  • 27.
    Vajda, Vivi
    et al.
    Lund University.
    McLoughlin, Stephen
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Bomfleur, Benjamin
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Fossilfyndet i Korsaröd2014Ingår i: Geologiskt Forum, ISSN 1104-4721, Vol. 82, s. 24-29Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Upptackten av ett extremt valbevarat ormbunksfossil, inkapslat i laharflodena vid Korsarod och Djupadalsmollan, vacker nu hopp hos forskarna om att hitta fler fynd. Dessutom ska ormbunken testas for fossilt DNA.

  • 28.
    Vajda, Vivi
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Ocampo, Adriana
    NASA Headquaters, Washington.
    Ferrow, Embaie
    Department of Geology, Lund University.
    Bender Koch, Christian
    Department of Chemistry, University of Copenhagen.
    Nano particles as the primary cause for long-termsunlight suppression athigh southern latitudes following the Chicxulub impact — evidence fromejecta deposits in Belize and Mexico2015Ingår i: Gondwana Research, ISSN 1342-937X, E-ISSN 1878-0571, Vol. 27, s. 1079-1088Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Life on Earth was sharply disrupted 66 Ma ago as an asteroid hit the sea-floor inwhat is today Yucatan Peninsula, Mexico. Approximately 600 km3 of sedimentary rock were vapourized, ejected into the atmosphere and subsequently deposited globally as an ejecta apron and fallout layer. Proximal ejecta deposits occur in Belize and southern Mexico where the so called Albion Island spheroid bed is superimposed on the target rock (the Barton Creek Formation). We analysed the spheroid bed via Mössbauer spectroscopy, petrology, XRD, and palynology at several sites ~350–500 km distance from the crater centre. Our results show that the relative concentrations of Fe in nano-phase goethite (α-FeOOH) are very high in the spheroid bed samples from Albion Island (Belize) and from Ramonal South (Mexico), but are low to absent in the spheroid bed at Ramonal North, and in the Cretaceous target rock. Moreover, our study shows that goethite and haematite are the dominant Fe-oxide nano-phases and the XRD results show that the target rock consists of both calcite and dolomite. We suggest that the heterogeneous composition of the spheroid bed between the various sites reflects the different types of target rocks that were dispersed within the rapidly expanding vapour plume and the complex sorting processes involved in the formation of the ejecta blanket. The distribution of the vapourized target rock strongly influenced life on Earth at the close of the Mesozoic. However, the comparatively thin K–Pg boundary clay in high-latitude Gondwanan successions combined with evidence of catastrophic changes to the biota in this region implies that the long-term sunlight suppression in the Southern Hemisphere was mainly governed by the large quantities of hydrous aerosols nucleated around sulphuric acid droplets or nano-sized particles, such as the nano-phase Fe-oxides.

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