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  • Chris, Mays
    et al.
    Swedish Museum of Natural History, Department of Paleobiology. Monash University.
    Bevitt, Joseph
    Australian Nuclear Science and Technology Organisation, Research Office, Lucas Heights, Australia.
    Stilwell, Jeffrey
    School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria, Australia.
    Pushing the limits of neutron tomography in palaeontology: Three-dimensional modelling of in situ resin within fossil plants2017In: Palaeontologia Electronica, ISSN 1935-3952, E-ISSN 1094-8074, Vol. 20, no 3, 1-12 p., 20.3.57AArticle in journal (Refereed)
    Abstract [en]

    Computed tomography is an increasingly popular technique for the non-destructivestudy of fossils. Whilst the science of X-ray computed tomography (CT) has greatlymatured since its first fossil applications in the early 1980s, the applications and limitationsof neutron tomography (NT) remain relatively unexplored in palaeontology. Thesehighest resolution neutron tomographic scans in palaeontology to date were conductedon a specimen of Austrosequoia novae-zeelandiae (Ettingshausen) Mays and Cantrillrecovered from mid-Cretaceous (Cenomanian; ~100–94 Ma) strata of the ChathamIslands, eastern Zealandia. Previously, the species has been identified with in situ fossilresin (amber); the new neutron tomographic analyses demonstrated an anomalouslyhigh neutron attenuation signal for fossil resin. The resulting data provided astrong contrast between, and distinct three-dimensional representations of the: 1) fossilresin; 2) coalified plant matter; and 3) sedimentary matrix. These data facilitated ananatomical model of endogenous resin bodies within the cone axis and bract-scalecomplexes. The types and distributions of resin bodies support a close alliance withSequoia Endlicher (Cupressaceae), a group of conifers whose extant members areonly found in the Northern Hemisphere. This study demonstrates the feasibility of NTas a means to differentiate chemically distinct organic compounds within fossils.Herein, we make specific recommendations regarding: 1) the suitability of fossil preservationstyles for NT; 2) the conservation of organic specimens with hydrogenous consolidantsand adhesives; and 3) the application of emerging methods (e.g., neutronphase contrast) for further improvements when imaging fine-detailed anatomical structures.These findings demonstrate that we are still far from reaching the conceptuallimits of NT as a means of virtually extracting fossils, or imaging their internal anatomyeven when embedded within a rock matrix.

  • Mays, Chris
    et al.
    Swedish Museum of Natural History, Department of Paleobiology. Monash University.
    Cantrill, David
    Royal Botanic Gardens Victoria, Private Bag 2000, South Yarra, VIC 3141, Australia.
    Bevitt, Joseph J.
    Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia.
    Polar wildfires and conifer serotiny during the Cretaceous globalhothouse2017In: Geology, ISSN 0091-7613, E-ISSN 1943-2682, Vol. 45, no 12, 1119-1122 p.Article in journal (Refereed)
    Abstract [en]

    Several highly effective fire-adaptive traits first evolved among modern plants duringthe mid-Cretaceous, in response to the widespread wildfires promoted by anomalously highatmospheric oxygen (O2) and extreme temperatures. Serotiny, or long-term canopy seedstorage, is a fire-adaptive strategy common among plants living in fire-prone areas today,but evidence of this strategy has been lacking from the fossil record. Deposits of abundantfossil charcoal from sedimentary successions of the Chatham Islands, New Zealand, recordwildfires in the south polar regions (75°–80°S) during the mid-Cretaceous (ca. 99–90 Ma).Newly discovered fossil conifer reproductive structures were consistently associated withthese charcoal-rich deposits. The morphology and internal anatomy as revealed by neutrontomography exhibit a range of serotiny-associated characters. Numerous related fossils fromsimilar, contemporaneous deposits of the Northern Hemisphere suggest that serotiny was akey adaptive strategy during the high-fire world of the Cretaceous.

  • Hryniewicz, Krzysztof
    et al.
    Institute of Paleobiology, Polish Academy of Sciences, Warszawa.
    Amano, Kazutaka
    Department of Geoscience, Joetsu University of Education, Niigata.
    Jenkins, Robert
    School of Natural System, College of Science and Engineering, Kanazawa University, Kanazawa City, Ishikawa .
    Kiel, Steffen
    Swedish Museum of Natural History, Department of Paleobiology.
    Thyasirid bivalves from Cretaceous and Paleogene cold seeps2017In: Acta Palaeontologica Polonica, ISSN 0567-7920, E-ISSN 1732-2421, Vol. 62, no 4, 705-728 p.Article in journal (Refereed)
    Abstract [en]

    We present a systematic study of thyasirid bivalves from Cretaceous to Oligocene seep carbonates worldwide. Eleven species of thyasirid bivalves are identified belonging to three genera: Conchocele, Maorithyas, and Thyasira. Two species are new: Maorithyas humptulipsensis sp. nov. from middle Eocene seep carbonates in the Humptulips Formation, Washington State, USA, and Conchocele kiritachiensis sp. nov. from the late Eocene seep deposit at Kiritachi, Hokkaido, Japan. Two new combinations are provided: Conchocele townsendi (White, 1890) from Maastrichtian strata of the James Ross Basin, Antarctica, and Maorithyas folgeri (Wagner and Schilling, 1923) from Oligocene rocks from California, USA. Three species are left in open nomenclature. We show that thyasirids have Mesozoic origins and appear at seeps before appearing in “normal” marine environments. These data are interpreted as a record of seep origination of thyasirids, and their subsequent dispersal to non-seep environments. We discuss the age of origination of thyasirids in the context of the origin of the modern deep sea fauna and conclude that thyasirids could have deep sea origins. This hypothesis is supported by the observed lack of influence of the Cretaceous and Paleogene Oceanic Anoxic Events on the main evolutionary lineages of the thyasirids, as seen in several other members of the deep sea fauna.

  • ENGELBRECHT, Andrea
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    REGUERO, Marcelo
    KRIWET, Jürgen
    Skatesand Rays (Elasmobranchii, Batomorphii) from the Eocene La Meseta and Submesetaformations, Seymour Island, Antarctica2018In: Historical Biology, ISSN 0891-2963, E-ISSN 1029-2381Article in journal (Refereed)
  • Mörs, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    HUGUENEY, Marguerite
    A Hystrix Linnaeus, 1758 incisor(Mammalia, Rodentia) from the Early Pleistocene of Senèze, France2017In: Geodiversitas, ISSN 1280-9659, E-ISSN 1638-9395Article in journal (Refereed)
  • Helander, Björn
    et al.
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Bignert, Anders
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Indikator för äggskalstjocklek havsörn: Överenskommelse 1723-17 med Havs- och Vattenmyndigheten2017Report (Other academic)
  • Helander, Björn
    Swedish Museum of Natural History, Department of Environmental research and monitoring.
    Havsörnen larmar om miljögifterna2017In: Havet 1988, Göteborg: Havsmiljöinstitutet , 2017, 46-48 p.Chapter in book (Other academic)
  • Cui, Ying
    et al.
    Department of Geosciences, The Pennsylvania State University, University Park, PA, United States.
    Bercovici, Antoine
    Department of Geology, Lund University, Lund, Sweden.
    Yu, Jianxin
    State Key Laboratory of Biogeology and Environmental Geology of Ministry of Education, China University of Geosciences (Wuhan), People's Republic of China.
    Kump, Lee R.
    Department of Geosciences, The Pennsylvania State University, University Park, PA, United States.
    Freeman, Katherine
    Department of Geosciences, The Pennsylvania State University, University Park, PA, United States.
    Su, Shangguo
    School of Earth Sciences and Resources, China University of Geosciences (Beijing), People's Republic of China.
    Vajda, Vivi
    Swedish Museum of Natural History, Department of Paleobiology. Department of Geology, Lund University, Sweden.
    Carbon cycle perturbation expressed in terrestrial Permian–Triassic boundary sections in South China2017In: Global and Planetary Change, ISSN 0921-8181, E-ISSN 1872-6364, Vol. 148, 272-285 p.Article in journal (Refereed)
    Abstract [en]

    Stable isotopes of inorganic and organic carbon are commonly used in chemostratigraphy to correlatemarine andterrestrial sedimentary sequences based on the assumption that the carbon isotopic signature of the exogenic carbon pool dominates other sources of variability. Here, sediment samples fromfour Permian–Triassic boundary (PTB) sections ofwesternGuizhou and eastern Yunnan provinces in South China, representing a terrestrial tomarine transitional setting,were analyzed for δ13C of organic matter (δ13Corg). These valueswere 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 aremore 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.

  • Sha, Jingeng
    et al.
    LPS, Nanjing Institute of Geology & Paleontology, Nanjing 210008, China.
    Pan, Yanhong
    LPS, Nanjing Institute of Geology & Paleontology, Nanjing 210008, China.
    Gong, Enpu
    Northeastern University, Shenyang 110004, China.
    Vajda, Vivi
    Swedish Museum of Natural History, Department of Paleobiology. Department of Geology, Lund University, Sweden.
    IGCP 632, The Jurassic–Cretaceous transition in North Eastern China (westernLiaoning and Inner Mongolia): An IGCP meeting and field excursion on the continentalJurassic2017In: Episodes, ISSN 0705-3797, Vol. 40, no 1, 79-84 p.Article in journal (Refereed)
    Abstract [en]

    Exposures of strata spanning the Jurassic–Cretaceous boundary occur within several basins in western Liaoning and adjacent Inner Mongolia. These continental successions host world-renowned plant and animal fossils including feathered dinosaurs and the oldest flowering plant, Archaeofructus.

  • Yuan, Qin
    et al.
    baKey Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining,Qinghai 810008, China.
    Vajda, Vivi
    Swedish Museum of Natural History, Department of Paleobiology. Department of Geology, Lund University, Sweden.
    Li, Qing-Kuan
    University of Chinese Academy of Sciences, Beijing 100049, China.
    Fan, Qi-Shun
    Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, China.
    Wei, Hai-Cheng
    Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, China.
    Qin, Zhan-Jie
    Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, China.
    Zhang, Xiang-Ru
    University of Chinese Academy of Sciences, Beijing 100049, China.
    Shan, Fa-Shou
    Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, China.
    A late Eocene palynological record from the Nangqian Basin, TibetanPlateau: Implications for stratigraphy and paleoclimate2017In: Palaeoworld, ISSN 1871-174X, Vol. 26, 369-379 p.Article in journal (Refereed)
    Abstract [en]

    With the uplifting, large-scale thrusting and striking of the Tibetan Plateau, several Paleogene intracontinental basins formed within the northernTibetan Plateau (TP). Stratigraphical and paleoenvironmental studies of the sedimentary successions within these basins are critical for understandingPaleogene climatological changes in Eurasia. The Nangqian Basin, one of such basins, formed in the Yushu area of the northeastern Tibetan Plateau.A set of lacustrine sediments, dominated by red clasolite, marlite, and gypsum, developed in the Yang Ala section in this basin. Paleontologicalrecords from the Nangqian Basin remain poorly known. Here, we investigate the palynological assemblages of one sedimentary succession at theYang Ala section that belongs to the Gongjue Formation, and their implications regarding the geological age and paleoclimate are discussed. Theresults reveal that the assemblages are dominated mainly by angiosperm pollen (tricolpates and tricolporate), including

    Nitrariadites (Pokrovskaja), Quercoidites, and Labitricolpites, followed by gymnosperm pollen taxa, such as Ephedripites and Taxodiaceaepollenites, and sparse pteridophytespores produced by ferns. A late Eocene age is inferred based on palynostratigraphy and comparison with other pollen assemblages in the TP. Arelatively dry climate with brief humid periods is indicated by the high abundance of xerophytic pollen taxa, such as Ephedripites and Nitrariadites,which are associated with broadleaved deciduous and evergreen plants. The characteristics of the pollen assemblages from the studied Yang Alasection are consistent with other Cenozoic palynofloras from the Mahalagou Formation in the Xining Basin and with those of the Yaxicuo Groupin the Hoh Xil Basin. These results provide an improved stratigraphical scheme for parts of the Cenozoic and enrich the current knowledge of thevegetation history of the northeastern Tibetan Plateau.

  • 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, 793-802 p.Article 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.

  • Davies, Thomas G.
    et al.
    Rahman, Imran A.
    Lautenschlager, Stephan
    Cunningham, John A.
    Swedish Museum of Natural History, Department of Paleobiology. University of Bristol.
    Asher, Robert J.
    Barrett, Paul M.
    Bates, Karl T.
    Bengtson, Stefan
    Swedish Museum of Natural History, Department of Paleobiology.
    Benson, Roger B. J.
    Boyer, Doug M.
    Braga, José
    Bright, Jen A.
    Claessens, Leon P. A. M.
    Cox, Philip G.
    Dong, Xi-Ping
    Evans, Alistair R.
    Falkingham, Peter L.
    Friedman, Matt
    Garwood, Russell J.
    Goswami, Anjali
    Hutchinson, John R.
    Jeffery, Nathan S.
    Johanson, Zerina
    Lebrun, Renaud
    Martínez-Pérez, Carlos
    Marugán-Lobón, Jesús
    O’Higgins, Paul M.
    Metscher, Brian
    Orliac, Maeva
    Rowe, Timothy B.
    Rücklin, Martin
    Sánchez-Villagra, Marcelo R.
    Shubin, Neil H.
    Smith, Selena Y.
    Starck, J. Matthias
    Stringer, Chris
    Summers, Adam P.
    Sutton, Mark D.
    Walsh, Stig A.
    Weisbecker, Vera
    Witmer, Lawrence M.
    Wroe, Stephen
    Yin, Zongjun
    Rayfield, Emily J.
    Donoghue, Philip C.J.
    University of Bristol.
    Open data and digital morphology.2017In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 284, no 1852, 1-10 p.Article in journal (Refereed)
    Abstract [en]

    Over the past two decades, the development of methods for visualizing and analysing specimens digitally, in three and even four dimensions, has transformed the study of living and fossil organisms. However, the initial promise that the widespread application of such methods would facilitate access to the underlying digital data has not been fully achieved. The underlying datasets for many published studies are not readily or freely available, introducing a barrier to verification and reproducibility, and the reuse of data. There is no current agreement or policy on the amount and type of data that should be made available alongside studies that use, and in some cases are wholly reliant on, digital morphology. Here, we propose a set of recommendations for minimum standards and additional best practice for three-dimensional digital data publication, and review the issues around data storage, management and accessibility.

  • Ivarsson, Magnus
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Bengtson, Stefan
    Swedish Museum of Natural History, Department of Paleobiology.
    Oceanbottnarnas hemliga liv.2017In: Havsutsikt, ISSN 1104-0513, Vol. 2017, no 2, 16-18 p.Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Berggrunden under havens bottensediment är en vidsträckt men svårtillgänglig och outforskad del av vår planet, särskilt när det gäller liv. Paradoxalt nog är det, förutom haven, världens volymmässigt största livsmiljö för mikroorganismer. Med nya metoder har forskare från Naturhistoriska riksmuseet vänt upp och ner på den gängse vetenskapliga uppfattningen. I den spruckna berggrunden under havssedimenten bor inte bara de förväntade extremt tåliga bakterierna och arkéerna – de har även gott sällskap av svampar.

  • Denk, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Güner, Tuncay H.
    , Istanbul University, Istanbul, Turkey.
    Kvaček, Zlatko
    Charles University, Prague, Czech Republic.
    Bouchal, Johannes M.
    Swedish Museum of Natural History, Department of Paleobiology. johannes.bouchal@nrm.se.
    The early Miocene flora of Güvem (Central Anatolia, Turkey): a window into early Neogene vegetation and environments in the Eastern Mediterranean2017In: Acta Palaeobotanica, ISSN 0001-6594, E-ISSN 1427-6402, Vol. 57, no 2, 237-338 p.Article in journal (Refereed)
    Abstract [en]

    The early Burdigalian (MN3) plant assemblage of the Güvem area (northwestern Central Anatolia) is preserved in lacustrine sediments of the Dereköy pyroclastics. Its age is well constrained by radiometric dates of basaltic rocks bracketing the pyroclastics, making the Güvem flora one of the extremely few precisely dated early Miocene floras in the Mediterranean region. The rich assemblage of impression fossils comprises ferns and fern allies (2 species), gymnosperms (12 spp.) and angiosperms (129 spp.). Ilex miodipyrena sp. nov. is described as a new fossil-species. The most diverse families in the assemblage are the Fagaceae with 12 taxa and the Fabaceae with 12 leaf morphotypes and one fruit taxon. Aquatic plants are represented by seven taxa, riparian (including palms) and swamp forest elements by >35 taxa, and lianas by three taxa (Smilax spp., Chaneya). The relatively large number of aquatic and riparian/swamp elements is congruent with the rich fish, amphibian and reptile record of the Güvem area. Another characteristic feature of the plant assemblage is the presence of various lobed leaves which show similarities with modern species of different families (e.g. Alangium, various Malvales). Trees and shrubs growing on well-drained soils and forming closed-canopy and open-canopy forests are the most diversified group (>70 taxa). In terms of number of specimens in the collection and based on field observations, by far the most abundant leaf fossils belong to evergreen oaks of Quercus drymeja and Q. mediterranea and to various types of foliage that cannot be assigned to a particular extant or extinct genus of Fagaceae. These sclerophyllous trees must have covered vast areas surrounding the wetlands that developed during the early Miocene in the Güvem Basin. Based on a recent reassessment of the ecology and taxonomic affinity of these trees, they are considered to reflect humid temperate climatic conditions but with a brief drier season during the winter months. These forests are more similar to the laurel forests of the southeastern United States and those stretching in a narrow belt south of the Himalayas to eastern central China. The large number of Fabaceae may indicate the presence of warm subtropical environments but this is difficult to assess, as they are known for having wide ecological ranges today and in the past. All in all, a larger part of the plant taxa point to forested vegetation. This is in agreement with previous palynological studies which detected only small amounts of herbaceous and grass pollen. Open patches of vegetation may have been restricted to river banks and to rocky areas in a volcanic landscape. The biogeographic patterns detected for the early Miocene of the Güvem assemblage are manifold; most taxa are widespread Northern Hemispheric elements. A substantial part of the species migrated from Asia into Europe during the (late) Paleogene and reached Anatolia during the early Miocene (Fagus, Paliurus, Chaneya, Ailanthus, Quercus kubinyii, Davallia haidingeri, Acer angustilobum, A. palaeosaccharinum). Fewer taxa may have been in Anatolia before they migrated to Europe (e.g. Nerium, Smilax miohavanensis, Quercus sosnowskyi). Finally, very few taxa are Anatolian endemics (e.g. Ilex miodipyrena).

  • Haenel, Quiterie
    et al.
    Göteborgs Universitet.
    Holovachov, Oleksandr
    Swedish Museum of Natural History, Department of Zoology.
    Jondelius, Ulf
    Swedish Museum of Natural History, Department of Zoology.
    sundberg, per
    Göteborgs Universitet.
    Bourlat, Sarah
    Göteborgs Universitet.
    NGS-based biodiversity and community structure analysis of meiofaunal eukaryotes in shell sand from Hållö island, Smögen, and soft mud from Gullmarn Fjord, Sweden2017In: Biodiversity Data Journal, ISSN 1314-2836, E-ISSN 1314-2828, Vol. 5Article in journal (Refereed)
  • Holovachov, Oleksandr
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Haenel, Quiterie
    Bourlat, Sarah
    Jondelius, Ulf
    Swedish Museum of Natural History, Department of Zoology.
    Taxonomy assignment approach determines the efficiency of identification of OTUs in marine nematodes2017In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 4, no 8Article in journal (Refereed)
  • Riley, T.R.
    et al.
    Flowerdew, M.J.
    Pankhurst, R.J.
    Leat, P.T.
    Millar, I.L.
    Fanning, C.M.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    A revised geochronology of Thurston Island, West Antarctica, and correlations along the proto-Pacific margin of Gondwana.2017In: Antarctic Science, ISSN 0954-1020, E-ISSN 1365-2079, Vol. 29, 47-60 p.Article in journal (Refereed)
    Abstract [en]

    The continental margin of Gondwana preserves a record of long-lived magmatism from the Andean Cordillera to Australia. The crustal blocks of West Antarctica form part of this margin, with Palaeozoic–Mesozoic magmatism particularly well preserved in the Antarctic Peninsula and Marie Byrd Land. Magmatic events on the intervening Thurston Island crustal block are poorly defined, which has hindered accurate correlations along the margin. Six samples are dated here using U-Pb geochronology and cover the geological history on Thurston Island. The basement gneisses from Morgan Inlet have a protolith age of 349±2 Ma and correlate closely with the Devonian–Carboniferous magmatism of Marie Byrd Land and New Zealand. Triassic (240–220 Ma) magmatism is identified at two sites on Thurston Island, with Hf isotopes indicating magma extraction from Mesoproterozoic-age lower crust. Several sites on Thurston Island preserve rhyolitic tuffs that have been dated at 182 Ma and are likely to correlate with the successions in the Antarctic Peninsula, particularly given the pre-break-up position of the Thurston Island crustal block. Silicic volcanism was widespread in Patagonia and the Antarctic Peninsula at ~ 183 Ma forming the extensive Chon Aike Province. The most extensive episode of magmatism along the active margin took place during the mid-Cretaceous. This Cordillera ‘flare-up’ event of the Gondwana margin is also developed on Thurston Island with granitoid magmatism dated in the interval 110–100 Ma.

  • Riley, T.R.
    et al.
    Flowerdew, M.J.
    Pankhust, R.J.
    Curtis, M.L.
    Fanning, C.M.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Early Jurassic magmatism on the Antarctic Peninsula and potential correlation with the Subcordilleran plutonic belt of Patagonia.2017In: Journal of the Geological Society, ISSN 0016-7649, E-ISSN 2041-479X, Vol. 174, 365-376 p.Article in journal (Refereed)
    Abstract [en]

    Early Jurassic silicic volcanic rocks of the Chon Aike Province (V1: 187 – 182 Ma) are 30 recognised from many localities in the southern Antarctic Peninsula and northeast Patagonia and are 31 essentially coeval with the extensive Karoo (182 Ma) and Ferrar (183 Ma) large igneous provinces of 32 pre-breakup Gondwana. Until recently, plutonic rocks of this age were considered either rare or 33 absent from the Antarctic Peninsula batholith, which was thought to have been mainly constructed 34 during the Middle Jurassic and the mid-Cretaceous. New U-Pb zircon geochronology from the 35 Antarctic Peninsula and recently published U-Pb ages from elsewhere on the Peninsula and 36 Patagonia are used to demonstrate the more widespread nature of Early Jurassic plutonism. Eight 37 samples are dated here from the central and southern Antarctic Peninsula. They are all moderately 38 to strongly foliated granitoids (tonalite, granite, granodiorite) and locally represent the crystalline 39 basement. They yield ages in the range 188 – 181 Ma, and overlap with published ages of 185 – 180 40 Ma from granitoids from elsewhere on the Antarctic Peninsula and from the Subcordilleran plutonic 41 belt of Patagonia (185 – 181 Ma). Whilst Early Jurassic plutons of the Subcordilleran plutonic belt of 42 Patagonia are directly related to subduction processes along the proto-Pacific margin of Gondwana, 43 coeval volcanic rocks of the Chon Aike Province are interpreted to be directly associated with 44 extension and plume activity during the initial stages of Gondwana break-up. This indicates that 45 subduction was ongoing when Chon Aike Province volcanism started. The Early Jurassic plutonism on 46 the Antarctic Peninsula is transitional between subduction-related and break-up related 47 magamatism.