Papers by Sofie Lindström
Geological Magazine, 2015
A review of the palynofloral succession at the well-documented Triassic-Jurassic boundary sites -... more A review of the palynofloral succession at the well-documented Triassic-Jurassic boundary sites -Kuhjoch (Austria), St Audrie's Bay (UK), Stenlille (Denmark), Astartekløft (Greenland), Sverdrup Basin (Arctic Canada), Northern Carnarvon Basin (Western Australia), Southeast Queensland (eastern Australia) and New Zealand -show all sites experienced major to moderate re-organization of the terrestrial vegetation during the end-Triassic event. The changes led to subsequent taxonomic losses of between 17 % and 73 % of the Rhaetian pre-extinction palynoflora. The majority of the typical Rhaetian taxa that disappear are so far not known from in situ occurrences in reproductive structures of macrofossil plant taxa. From an ecological perspective, the most dramatic changes occurred in the Sverdrup Basin, Stenlille, Kuhjoch and Carnarvon Basin, where the pre-and post-extinction palynofloras were fundamentally different in both composition and dominance. These changes correspond to ecological severity Category I of , while the remaining sites are placed in their Subcategory IIa because there the pre-extinction ecosystems are disrupted, but recover and are not replaced post-extinction. Increased total abundances of spores on both hemispheres during the extinction and recovery intervals may indicate that environmental and/or climatic conditions became less favourable for seed plants. Such conditions may include expected effects of volcanism in the Central Atlantic Magmatic Province, such as acid rain, terrestrial soil and freshwater acidification due to volcanic sulfur dioxide emissions, fluctuating ultraviolet flux due to ozone depletion caused by halogens and halocarbon compounds, and drastic changes in climatic conditions due to greenhouse gas emissions.
The end-Triassic biotic crisis is generally explained by massive input of CO2 and/or methane to t... more The end-Triassic biotic crisis is generally explained by massive input of CO2 and/or methane to the atmosphere linked to the formation of the Central Atlantic Magmatic Province. Such massive volcanism can be compared to industrial pollution releasing large amounts of the greenhouse gases CO2 and SO2 to the atmosphere. Indeed, the fossil record provides evidence of major perturbations in the �13C-record of both calcareous and organic material. In the marine realm loss of calcifying organisms provides evidence of ocean acidification due to the increased pCO2, while in the terrestrial realm physiological responses in fossil plants indicate intense global warming across the Triassic-Jurassic boundary. Changing climatic conditions is further indicated by charcoal records from Greenland, Denmark, Sweden and Poland showing increased wildfire activity. Increased reworking of palynological material and marked changes in fluvial style in terrestrial successions seem to indicate an increased h...
The East Greenland Ridge (EGR) is a submarine elevation that juts out from the Northeast Greenlan... more The East Greenland Ridge (EGR) is a submarine elevation that juts out from the Northeast Greenland shelf, separating the modern Boreas Basin in north from the Greenland Basin in south. The EGR strikes roughly northwest-southeast and lies almost perpendicular to the Mohns Spreading Ridge and sub-parallel to the Knipovich Spreading Ridge. The EGR is about 320 km long and includes several en-echelon elongated crests. The flanks on either side of the EGR are generally high and steep, with escarpments exposing outcropping sub-strata. The EGR has been characterized as a continental sliver. However, this is based on analysis of seismic data only, while no direct evidence has hitherto been published to strengthen this interpretation. In 2012, two up-slope transects on the northeastern lower flank of the EGR were dredged by GEUS and UiT in order to obtain in-situ samples of the outcropping strata. Subsequent work by GEUS on the dredged samples was concentrated on lithological description and...
Proceedings of the National Academy of Sciences, 2015
A major unresolved aspect of the rise of dinosaurs is why early dinosaurs and their relatives wer... more A major unresolved aspect of the rise of dinosaurs is why early dinosaurs and their relatives were rare and species-poor at low paleolatitudes throughout the Late Triassic Period, a pattern persisting 30 million years after their origin and 10-15 million years after they became abundant and speciose at higher latitudes. New palynological, wildfire, organic carbon isotope, and atmospheric pCO 2 data from early dinosaur-bearing strata of low paleolatitudes in western North America show that large, high-frequency, tightly correlated variations in δ 13 C org and palynomorph ecotypes occurred within a context of elevated and increasing pCO 2 and pervasive wildfires. Whereas pseudosuchian archosaur-dominated communities were able to persist in these same regions under rapidly fluctuating extreme climatic conditions until the end-Triassic, large-bodied, fastgrowing tachymetabolic dinosaurian herbivores requiring greater resources were unable to adapt to unstable high CO 2 environmental conditions of the Late Triassic.
Multiple levels of earthquake induced soft-sediment deformations (seismites) are concentrated in ... more Multiple levels of earthquake induced soft-sediment deformations (seismites) are concentrated in the end-Triassic mass extinction interval across Europe. The repetitive nature of the seismites rules out an origin by an extraterrestrial impact. Instead, this intense seismic activity is linked to the formation of the Central Atlantic Magmatic Province (CAMP). By the earliest Jurassic the seismic activity had ceased, while extrusive volcanism still continued and biotic recovery was on its way. This suggests that magmatic intrusions into sedimentary strata during early stages of CAMP formation caused emission of gases (SO2, halocarbons, polycyclic aromatic hydrocarbons) that may have played a major part in the biotic crisis.
Two uppermost Triassic (Rhaetian) coal beds (A-and B-bed; Bjuv Member, southern Sweden) deposited... more Two uppermost Triassic (Rhaetian) coal beds (A-and B-bed; Bjuv Member, southern Sweden) deposited at the margin of the Danish Basin were investigated in order to interpret the peat-forming environments in a sequence stratigraphic context and to establish the peat-forming vegetations of the precursor mires. Peat formed close to the coastline and was governed by base-level (watertable) rise linked to relative sea-level rise, which is emphasized by rare occurrences of marine phytoplankton, Micrhystridium, Lunnomidinium scaniense and Rhaetogonyaulax rhaetica, in the B-bed. A maximum flooding surface (MFS7) between the coal beds A and B shows that peat accumulation occurred as a coastal response to the continued transgression of the Danish Basin that culminated with deposition of the coal-bearing Bjuv Member. The lower B-bed accumulated in a transgressive systems tract (TST) and the upper A-bed in a highstand systems tract (HST). The B-bed consists of coal and coaly mudstone intervals showing that peat formation repeatedly was outpaced by relative watertable rise. The huminite-rich coal intervals indicate peat formation under oxygen-deficient stagnant water conditions, where the peat accumulation rate balanced the watertable rise. Overall low TS values indicate a freshwater mire. The base of coal bed B marks the start of a relative decrease in creation of accommodation space, and the surface between the sediments and coal bed B represents a Terrestrialisation Surface (TeS). The palynofloral composition suggests that the initial mire was characterised by dipterid/dicksoniacean tree ferns and marattialean ground ferns, and few canopy trees dominated by cupressacean/taxodiacean wet-loving conifers with subordinate bennettitalean and caytonialean trees. The coal intervals in the B-bed represent Terrestrialisation situations characterised by a reduced ratio of accommodation rate/peat accumulation rate. The palynology of these intervals indicates establishment of canopy trees, primarily cupressacean/taxodiacean conifers accompanied by bennettitaleans and caytonialeans, with an understory of marattialean ground ferns and rarer tree ferns. Flooding Surfaces (FS) and Accommodation Reversal Surfaces (ARS) in the B-bed reflect changes in the rate of watertable rise. The coaly mudstone intervals represent Paludification situations with an upward increasing ratio of accommodation rate/peat accumulation rate. In general the palynology of the B-bed suggests a coal floral composition that was dominated by mid and upper canopy plants consisting of cupcressaceaen/taxodiaceaen trees, probably occupying areas with standing water, while ginkgos, cycads, Bennettiales, and Caytoniales and other seed ferns grew in less wet areas. Understory plants were less abundant, whereas a ground cover of ferns, mainly of the families Marattiales and Osmundales, as well as lycophytes may have been pronounced. The upper surface of the B-bed is a Give-up Transgressive Surface (GUTS) above which peat accumulation was replaced by siliciclastic deposition. The palynofloral composition suggests an open-mire dominated by ground ferns and probable tree ferns, with minor bennettitalean and caytonialean mid canopy trees, and with hardly any upper canopy trees. The A-bed is considerably richer in inertinite compared to the B-bed. The palynofloral and petrographic change correlates with an increase in fire activity across the Triassic-Jurassic boundary and deforestation of the Early Jurassic mires.
Plos One. volume 7, issue 10, e47236
The end-Triassic mass extinction event (201.4 million years ago) caused major faunal and floral t... more The end-Triassic mass extinction event (201.4 million years ago) caused major faunal and floral turnovers in both the marine and terrestrial realms. The biotic changes have been attributed to extreme greenhouse warming across the Triassic–Jurassic (T–J)boundary caused by massive release of carbondioxide and/or methane related to extensive volcanism in the Central Atlantic Magmatic Province(CAMP), resulting in a more humid climate with increased storminess and lightning activity. Lightning strikes are considered the primary source of wildfires, producing charcoal, microscopically recognized as inertinite macerals. The presence of polycyclic aromatic hydrocarbons (PAHs) of pyrolytic origin and allochthonous charcoal in siliciclastic T–J boundary strata has suggested widespread wildfire activity at the time. We have investigated largely autochthonous coal and coaly beds across the T–J boundary in Sweden and Denmark. These beds consist of predominantly organic material from the in situ vegetation in the mires, and as the coaly beds represent a substantial period of time they are excellent environmental archives. We document a remarkable increase in inertinite content in the coal and coaly beds across the T–J boundary. We show estimated burning temperatures derived from inertinite reflectance measurements coupled with palynological data andconclude that pre-boundary late Rhaetian mire wildfires included high-temperature crownfires, whereas latest Rhaetian–Sinemurian mire wildfires were more frequent but dominated by lower temperature surface fires. Our results suggest a major change in the mire ecosystems across the T–J boundary from forested, conifer dominated mires to mires with a predominantly herbaceous and shrubby vegetation. Contrary to the overall regional vegetation for which onset of recovery commenced in the early Hettangian, the sensitive mire ecosystem remained affected during the Hettangian and did not start to recover until around the Hettangian–Sinemurian boundary. Decreasing inertinite content through the Lower Jurassic suggests that fire activity gradually resumed to considerable lower levels.
The evolution of complex life over the past 600 million years was disrupted by at least five mass... more The evolution of complex life over the past 600 million years was disrupted by at least five mass extinctions, one of which occurred at the close of the Triassic period. The end-Triassic extinction corresponds to a period of high atmospheric-CO2 concentrations caused by massive volcanism and biomass burning; most extinction scenarios invoke the resulting environmental perturbations in accounting for the loss of marine and terrestrial biodiversity. Here we reconstruct changes in Tethyan shallow marine ecosystems and ocean redox chemistry from earliest Jurassic (Hettangian)-aged black shales from Germany and Luxemburg. The shales contain increased concentrations of the biomarker isorenieratane, a fossilized pigment from green sulphur bacteria. The abundance of green sulphur bacteria suggests that the photic zone underwent prolonged periods of high concentrations of hydrogen sulphide. This interval is also marked by the proliferation of green algae, an indicator of anoxia. We conclude that the redox changes in the entire water column reflect sluggish circulation in marginal regions of the Tethys Ocean. We suggest that the resultant repeated poisoning of shallow epicontinental seas—hotspots of Mesozoic biodiversity—with hydrogen sulphide may have slowed the recovery of marine ecosystems during the Early Jurassic.
The probable zygnematacean zygospore Tetranguladinium is for the first time recorded in Mesozoic ... more The probable zygnematacean zygospore Tetranguladinium is for the first time recorded in Mesozoic strata from southern Scandinavia. Tetranguladinium, which exhibits morphological similarities to the extant filamentous green alga Mougeotia, occurs in Jurassic-Cretaceous (J/K) boundary (latest Tithonian-early Berriasian) assemblages from the Vomb Trough, southern Sweden, and on the Danish island of Bornholm. The J/K boundary strata of southern Scandinavia were deposited in marginal marine settings, varying from freshwater marshes, lakes and floodplains, to lagoons, shore-face, and shallow marine to fully marine environments. The assemblages containing Tetranguladinium are diverse, consisting of spores and pollen, the colonial green alga Botryococcus, various other zygnematacean zygospores e.g. Ovoidites, Schizosporis and Tetraporina, and rare marine dinoflagellate cysts.
A review of published fossil occurrences of Tetranguladinium reveals that its stratigraphic range extends at least from the late Guadalupian (Middle Permian) to the Holocene. It has been recorded from Africa (Tanzania), Asia (China, Korea), Australia, NW Europe (Denmark, Great Britain, Sweden), North America (Canada, USA), and South America (Argentina). Depositional and palaeoclimatological data for the known localities of Tetranguladinium confirm a preference for freshwater settings in a humid warm temperate to subtropical-tropical climate often with a pronounced dry season. The palaeogeographical positions of all the known Tetranguladinium localities indicate that it is has stayed restricted within narrow belts between 30-40º south and 30-60° north of the palaeoequator since the Late Jurassic.
Profound changes in both marine and terrestrial biota during the end-Triassic mass extinction eve... more Profound changes in both marine and terrestrial biota during the end-Triassic mass extinction event and associated successive carbon cycle perturbations across the Triassic-Jurassic boundary (T-J, 201.3 Ma) have primarily been attributed to volcanic emissions from the Central Atlantic Magmatic Province and/or injection of methane. Here we present a new extended organic carbon isotope record from a cored T-J boundary succession in the Danish Basin, dated by high-resolution palynostratigraphy and supplemented by a marine faunal record. Correlated with reference C-isotope and biotic records from the UK, it provides new evidence that the major biotic changes, both on land and in the oceans, commenced prior to the most prominent negative C-isotope excursion. If massive methane release was involved, it did not trigger the end-Triassic mass extinction. Instead, this negative C-isotope excursion is contemporaneous with the onset of floral recovery on land, whereas marine ecosystems remained perturbed. The decoupling between ecosystem recovery on land and in the sea is more likely explained by long-term flood basalt volcanism releasing both SO2 and CO2 with short- and long-term effects, respectively.
Palaeogeography Palaeoclimatology Palaeoecology, Jan 1, 2007
The end-Triassic mass extinction event is estimated to have caused the disappearance of several m... more The end-Triassic mass extinction event is estimated to have caused the disappearance of several marine families (23%) and genera (50%) on a global scale (Hallam and Wignall, 1999; van de Schootbrugge et al. 2007). In the terrestrial realm regional to supraregional losses of vertebrate families (up to 42%) and plant species (up to 95%) have been recorded (McElwain et al, 1999, 2007; Olsen et al., 2002; Whiteside et al., 2007). The event is temporally linked to the flood basalt volcanism of the Central Atlantic Magmatic Province (CAMP)(Schoene et al. 2010) and major perturbations in the carbon cycle recorded in stable carbon isotope records globally are generally attributed to the effects of outgassing of 12C-enriched CO2 from this large igneous province (Hesselbo et al., 2002). However, recently injection of methane was put forward as a more likely cause for the most prominent C-isotope excursion, and thus also as a trigger of the end-Triassic mass extinction (Ruhl and Kürschner, 2011; Ruhl et al, 2011).
High resolution palynological and bulk organic C-isotope data from Triassic–Jurassic (T/J) successions in Denmark and Sweden provide evidence of major and partly coeval shifts in the marine and terrestrial palynofloras. The demise of typical Rhaetian dinoflagellate cysts and the temporary disappearance of these phytoplankton appear to coincide with an interval indicating terrestrial deforestation marked by a major decline in pollen from conifers, cycads and ginkgos. Instead high abundances of fern spores, the enigmatic pollen Ricciisporites tuberculatus and sphaeromorphs totally dominate the assemblages. Additional significant features of this interval within the basin, include increased erosion and reworking, changes in fluvial style and temporary loss of peat-forming vegetation.
Correlation between the organic C-isotope record and the terrestrial and marine biotic changes in the Danish Basin show that the major environmental perturbations took place prior to the most prominent negative C-isotope excursion. The subsequent reorganisation and recovery of the terrestrial ecosystem already commenced during this peak, hence negating injection of methane as a major cause of the end-Triassic mass extinction event. Instead we favour a scenario in which repeated episodic CO2 and SO2 release from the CAMP played a prominent role (van de Schootbrugge et al., 2009). Many of the changes recorded in the T/J-boundary succession of the Danish Basin can be attributed to outgassing of SO2 from the CAMP, and subsequent acid rain and acid deposition, and subsequent feedback effects.
References
Hallam, A. and Wignall, P.B. (1999). Mass extinctions and sea-level changes. Earth Sci. Rev., 48, 217-250.
Hesselbo, S.P., Robinson, S.A., Surlyk, F. and Piasecki, S. (2002). Terrestrial and marine extinction at the Triassic-Jurassic boundary synchronized with major carbon-cycle perturbations: A link to initiation of massive volcanism? Geology 30, 251-254.
McElwain, J.C., Beerling, D.J. and Woodward, F.I. (1999). Fossil plants and global warming at the Triassic-Jurassic boundary. Science 285, 1386-1390.
McElwain, J.C., Popa, M.E., Hesselbo, S.P., Haworth, M. and Surlyk, F. (2007). Macroecological responses of terrestrial vegetation to climate and atmospheric change across the Triassic/Jurassic boundary in East Greenland. Paleobiology 33, 547-573.
Olsen, P.E., Kent, D.V., Sues, H.D., Koeberl, C., Huberm H., Montanari, A., Rainforth, E.C., Fowell, S.J., Szajna, M.J. and Hartline, B.W. (2002). Ascent of dinosaurs linked to Ir anomaly at Triassic–Jurassic boundary. Science 296, 1305-1307.
Ruhl, M. and Kürschner, W.M., 2011, Multiple phases of carbon cycle disturbance from large igneous province formation at the Triassic-Jurassic transition: Geology, 39, p. 431-434.
Ruhl, M., Bonis, N.R., Reichart, G.-J., Sinninghe Damsté, J.S., and Kürschner, W.M., 2011, Atmospheric carbon injection linked to end-Triassic mass extinction: Science, v. 333, p. 430-434.
Schoene, B., Guex, J., Bartolini, A., Schaltegger, U. and Blackburn, T.J. (2010). Correlating the end-Triassic mass extinction and flood basalt volcanism at the 100 ka level. Geology 38, 387-390.
van de Schootbrugge, B., Tremolada, F., Bailey, T.R., Rosenthal, Y., Feist-Burkhardt, S., Brinkhuis, H., Pross, J., Kent, D.V. and Falkowski, P.G. (2007). End-Triassic calcification crisis and blooms of organic-walled disaster species. Palaeogeogr. Palaeoclimatol. Palaeoecol. 244, 126-141.
van de Schootbrugge, B., Quan, T.M., Lindström, S., Püttmann, W., Heunisch, C., Pross, J., Fiebig, J., Petschik, R., Röhling, H.-G., Richoz, S., Rosenthal, Y. and Falkowski, P.G. (2009). Floral changes across the Triassic/Jurassic boundary linked to flood basalt volcanism. Nature Geoscience 2, 589-594.
Whiteside, J.H., Olsen, P.E., Kent, D.V., Fowell, S.J. and Et-Touhami, M. (2007). Synchrony between the Central Atlantic magmatic province and the Triassic–Jurassic mass-extinction event? Palaeogeogr. Palaeoclimatol. Palaeoecol., 244, 345-367.
Palaeogeography, Palaeoclimatology, …, Jan 1, 2011
The 116 m deep Fårarp-1 core drilled in the Vomb Trough in southernmost Sweden is dated by integr... more The 116 m deep Fårarp-1 core drilled in the Vomb Trough in southernmost Sweden is dated by integrated terrestrial and marine palynostratigraphy. The lower part of the succession (ca 84 m) encompasses uppermost Jurassic to lowermost Cretaceous (uppermost Tithonian to Valanginian) strata. An unconformity separates the Valanginian strata from an overlying ca 1 m thick interval of upper Albian to Cenomanian Arnager Greensand Formation. The uppermost part of the core is a repetitive succession of lowermost Cretaceous sediments.
During the Jurassic–Cretaceous (J/K) transition NW Europe was located in mid latitudes, and comprised an archipelago of large and small islands separated by deeper grabens and epicontinental seaways that connected the Boreal Sea to the north with the warmer Tethys Ocean to the south. Boundary strata in England, France, the Netherlands and Germany are characterised by relatively prominent climatic change from arid/semi arid to subhumid/humid conditions. Southernmost Sweden was located on the margin of a large landmass comprising most of the Fennoscandian Shield bordering a large epicontinental sea to the west. By combining sedimentology, clay mineralogy and palynofacies the Tithonian to Valanginian cored succession of the Fårarp-1 core provides complementary information on how marginal deposits from the eastern part of the epicontinental sea reflect the climatological and environmental changes observed in other parts of NW Europe.
The Fårarp-1 core shows that during the Tithonian to earliest Berriasian deposition took place in a terrestrial but near-marine depositional setting, in coastal lakes or lagoons with little marine influence. A dry climatic regime favoured stagnant water conditions with common algal blooms of primarily Botryococcus and zygnemataceae. Palynofacies and sedimentology indicate limited transport of freshwater and material to the basin. The stagnant depositional environment was terminated by a marine flooding in the early Berriasian. During the remaining Berriasian and the early Valanginian conditions shifted between near marine and marine settings in a dynamic coastal environment, similar to contemporaneous assemblages reported from the Danish Island of Bornholm.
A shift in clay mineralogy, from a dominance of 10 Å minerals to increasing amounts of mixed layer and kaolinite indicates a change to more humid conditions in the latest Tithonian. Cheirolepidacean pollen (Classopollis) are present but never common in the cored succession, and a similar conspicuous decrease of these pollen, as previously reported from England, Germany and France, is not evident in the Fårarp-1 core. Instead a subsequent shift in both palynofacies and palynoflora, marked by an increase in abundance of heavy terrigenous material, i.e. wood and coal particles, upland pollen grains and reworked palynomorphs is also observed in the uppermost Tithonian–lowermost Berriasian interval. At the same level spores and pollen classified as warmer/drier elements decrease in abundance. This is interpreted as representing a shift to more humid climatic conditions with increased runoff from the hinterland. Thus, the combined sedimentological and palynological data from the Fårarp-1 core suggest that climatic conditions in the area changed from more seasonally dry (semi-arid) to more humid (semi-humid) across the J/K boundary (latest Tithonian to earliest Berriasian) and hence earlier than the mid-Berriasian climatic shift recorded from e.g. England and the Netherlands.
AASP Southampton …, Jan 1, 2011
The end-Triassic mass extinction event is estimated to have caused the disappearance of several m... more The end-Triassic mass extinction event is estimated to have caused the disappearance of several marine families (23%) and genera (50%) on a global scale (Hallam and Wignall, 1999; van de Schootbrugge et al. 2007). In the terrestrial realm regional to supraregional losses of vertebrate families (up to 42%) and plant species (up to 95%) have been recorded (McElwain et al, 1999, 2007; Olsen et al., 2002; Whiteside et al., 2007). The event is temporally linked to the flood basalt volcanism of the Central Atlantic Magmatic Province (CAMP)(Schoene et al. 2010) and major perturbations in the carbon cycle recorded in stable carbon isotope records globally are generally attributed to the effects of outgassing of 12C-enriched CO2 from this large igneous province (Hesselbo et al., 2002).
High resolution palynological and bulk organic C-isotope data from Triassic–Jurassic (T/J) successions in Denmark and Sweden provide evidence of major and partly coeval shifts in the marine and terrestrial palynofloras. The demise of typical Rhaetian dinoflagellate cysts and the temporary disappearance of these phytoplankton appear to coincide with an interval indicating terrestrial deforestation marked by a major decline in pollen from conifers, cycads and ginkgos. Instead high abundances of fern spores, the enigmatic pollen Ricciisporites tuberculatus and sphaeromorphs totally dominate the assemblages. Additional significant features of this interval within the basin, include increased erosion and reworking, changes in fluvial style and temporary loss of peat-forming vegetation.
Many of the changes recorded in the T/J-boundary succession of the Danish Basin can be attributed to outgassing of SO2 from the CAMP, and subsequent acid rain and acid deposition (van de Schootbrugge et al. 2009). However, the high abundance of sphaeromorphs within the end-Triassic event interval of the Danish Basin remains enigmatic. There are two working hypotheses for the mass occurrence of these sphaeromorphs: 1) They are in situ and represent a prasinophycean algal bloom. 2) They are reworked and represent a phase of increased weathering and erosion. The possible causes, consequences, as well as palaeoecological significance of these two hypotheses on the interpretation of the end-Triassic event will be discussed.
References
Hallam, A. and Wignall, P.B. (1999). Mass extinctions and sea-level changes. Earth Sci. Rev., 48, 217-250.
Hesselbo, S.P., Robinson, S.A., Surlyk, F. and Piasecki, S. (2002). Terrestrial and marine extinction at the Triassic-Jurassic boundary synchronized with major carbon-cycle perturbations: A link to initiation of massive volcanism? Geology 30, 251-254.
McElwain, J.C., Beerling, D.J. and Woodward, F.I. (1999). Fossil plants and global warming at the Triassic-Jurassic boundary. Science 285, 1386-1390.
McElwain, J.C., Popa, M.E., Hesselbo, S.P., Haworth, M. and Surlyk, F. (2007). Macroecological responses of terrestrial vegetation to climate and atmospheric change across the Triassic/Jurassic boundary in East Greenland. Paleobiology 33, 547-573.
Olsen, P.E., Kent, D.V., Sues, H.D., Koeberl, C., Huberm H., Montanari, A., Rainforth, E.C., Fowell, S.J., Szajna, M.J. and Hartline, B.W. (2002). Ascent of dinosaurs linked to Ir anomaly at Triassic–Jurassic boundary. Science 296, 1305-1307.
Schoene, B., Guex, J., Bartolini, A., Schaltegger, U. and Blackburn, T.J. (2010). Correlating the end-Triassic mass extinction and flood basalt volcanism at the 100 ka level. Geology 38, 387-390.
van de Schootbrugge, B., Tremolada, F., Bailey, T.R., Rosenthal, Y., Feist-Burkhardt, S., Brinkhuis, H., Pross, J., Kent, D.V. and Falkowski, P.G. (2007). End-Triassic calcification crisis and blooms of organic-walled disaster species. Palaeogeogr. Palaeoclimatol. Palaeoecol. 244, 126-141.
van de Schootbrugge, B., Quan, T.M., Lindström, S., Püttmann, W., Heunisch, C., Pross, J., Fiebig, J., Petschik, R., Röhling, H.-G., Richoz, S., Rosenthal, Y. and Falkowski, P.G. (2009). Floral changes across the Triassic/Jurassic boundary linked to flood basalt volcanism. Nature Geoscience 2, 589-594.
Whiteside, J.H., Olsen, P.E., Kent, D.V., Fowell, S.J. and Et-Touhami, M. (2007). Synchrony between the Central Atlantic magmatic province and the Triassic–Jurassic mass-extinction event? Palaeogeogr. Palaeoclimatol. Palaeoecol., 244, 345-367.
Nature …, Jan 1, 2009
One of the five largest mass extinctions of the past 600 million years occurred at the boundary o... more One of the five largest mass extinctions of the past 600 million years occurred at the boundary of the Triassic and Jurassic periods, 201.6 million years ago. The loss of marine biodiversity at the time has been linked to extreme greenhouse warming, triggered by the release of carbon dioxide from flood basalt volcanism in the central Atlantic Ocean. In contrast, the biotic turnover in terrestrial ecosystems is not well understood, and cannot be readily reconciled with the effects of massive volcanism. Here we present pollen, spore and geochemical analyses across the Triassic/Jurassic boundary from three drill cores from Germany and Sweden. We show that gymnosperm forests in northwest Europe were transiently replaced by fern and fern-associated vegetation, a pioneer assemblage commonly found in disturbed ecosystems. The Triassic/Jurassic
boundary is also marked by an enrichment of polycyclic aromatic hydrocarbons, which, in the absence of charcoal peaks, we interpret as an indication of incomplete combustion of organic matter by ascending flood basalt lava. We conclude that the terrestrial vegetation shift is so severe and wide ranging that it is unlikely to have been triggered by greenhouse warming
alone. Instead, we suggest that the release of pollutants such as sulphur dioxide and toxic compounds such as the polycyclic
aromatic hydrocarbons may have contributed to the extinction.
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Papers by Sofie Lindström
A review of published fossil occurrences of Tetranguladinium reveals that its stratigraphic range extends at least from the late Guadalupian (Middle Permian) to the Holocene. It has been recorded from Africa (Tanzania), Asia (China, Korea), Australia, NW Europe (Denmark, Great Britain, Sweden), North America (Canada, USA), and South America (Argentina). Depositional and palaeoclimatological data for the known localities of Tetranguladinium confirm a preference for freshwater settings in a humid warm temperate to subtropical-tropical climate often with a pronounced dry season. The palaeogeographical positions of all the known Tetranguladinium localities indicate that it is has stayed restricted within narrow belts between 30-40º south and 30-60° north of the palaeoequator since the Late Jurassic.
High resolution palynological and bulk organic C-isotope data from Triassic–Jurassic (T/J) successions in Denmark and Sweden provide evidence of major and partly coeval shifts in the marine and terrestrial palynofloras. The demise of typical Rhaetian dinoflagellate cysts and the temporary disappearance of these phytoplankton appear to coincide with an interval indicating terrestrial deforestation marked by a major decline in pollen from conifers, cycads and ginkgos. Instead high abundances of fern spores, the enigmatic pollen Ricciisporites tuberculatus and sphaeromorphs totally dominate the assemblages. Additional significant features of this interval within the basin, include increased erosion and reworking, changes in fluvial style and temporary loss of peat-forming vegetation.
Correlation between the organic C-isotope record and the terrestrial and marine biotic changes in the Danish Basin show that the major environmental perturbations took place prior to the most prominent negative C-isotope excursion. The subsequent reorganisation and recovery of the terrestrial ecosystem already commenced during this peak, hence negating injection of methane as a major cause of the end-Triassic mass extinction event. Instead we favour a scenario in which repeated episodic CO2 and SO2 release from the CAMP played a prominent role (van de Schootbrugge et al., 2009). Many of the changes recorded in the T/J-boundary succession of the Danish Basin can be attributed to outgassing of SO2 from the CAMP, and subsequent acid rain and acid deposition, and subsequent feedback effects.
References
Hallam, A. and Wignall, P.B. (1999). Mass extinctions and sea-level changes. Earth Sci. Rev., 48, 217-250.
Hesselbo, S.P., Robinson, S.A., Surlyk, F. and Piasecki, S. (2002). Terrestrial and marine extinction at the Triassic-Jurassic boundary synchronized with major carbon-cycle perturbations: A link to initiation of massive volcanism? Geology 30, 251-254.
McElwain, J.C., Beerling, D.J. and Woodward, F.I. (1999). Fossil plants and global warming at the Triassic-Jurassic boundary. Science 285, 1386-1390.
McElwain, J.C., Popa, M.E., Hesselbo, S.P., Haworth, M. and Surlyk, F. (2007). Macroecological responses of terrestrial vegetation to climate and atmospheric change across the Triassic/Jurassic boundary in East Greenland. Paleobiology 33, 547-573.
Olsen, P.E., Kent, D.V., Sues, H.D., Koeberl, C., Huberm H., Montanari, A., Rainforth, E.C., Fowell, S.J., Szajna, M.J. and Hartline, B.W. (2002). Ascent of dinosaurs linked to Ir anomaly at Triassic–Jurassic boundary. Science 296, 1305-1307.
Ruhl, M. and Kürschner, W.M., 2011, Multiple phases of carbon cycle disturbance from large igneous province formation at the Triassic-Jurassic transition: Geology, 39, p. 431-434.
Ruhl, M., Bonis, N.R., Reichart, G.-J., Sinninghe Damsté, J.S., and Kürschner, W.M., 2011, Atmospheric carbon injection linked to end-Triassic mass extinction: Science, v. 333, p. 430-434.
Schoene, B., Guex, J., Bartolini, A., Schaltegger, U. and Blackburn, T.J. (2010). Correlating the end-Triassic mass extinction and flood basalt volcanism at the 100 ka level. Geology 38, 387-390.
van de Schootbrugge, B., Tremolada, F., Bailey, T.R., Rosenthal, Y., Feist-Burkhardt, S., Brinkhuis, H., Pross, J., Kent, D.V. and Falkowski, P.G. (2007). End-Triassic calcification crisis and blooms of organic-walled disaster species. Palaeogeogr. Palaeoclimatol. Palaeoecol. 244, 126-141.
van de Schootbrugge, B., Quan, T.M., Lindström, S., Püttmann, W., Heunisch, C., Pross, J., Fiebig, J., Petschik, R., Röhling, H.-G., Richoz, S., Rosenthal, Y. and Falkowski, P.G. (2009). Floral changes across the Triassic/Jurassic boundary linked to flood basalt volcanism. Nature Geoscience 2, 589-594.
Whiteside, J.H., Olsen, P.E., Kent, D.V., Fowell, S.J. and Et-Touhami, M. (2007). Synchrony between the Central Atlantic magmatic province and the Triassic–Jurassic mass-extinction event? Palaeogeogr. Palaeoclimatol. Palaeoecol., 244, 345-367.
During the Jurassic–Cretaceous (J/K) transition NW Europe was located in mid latitudes, and comprised an archipelago of large and small islands separated by deeper grabens and epicontinental seaways that connected the Boreal Sea to the north with the warmer Tethys Ocean to the south. Boundary strata in England, France, the Netherlands and Germany are characterised by relatively prominent climatic change from arid/semi arid to subhumid/humid conditions. Southernmost Sweden was located on the margin of a large landmass comprising most of the Fennoscandian Shield bordering a large epicontinental sea to the west. By combining sedimentology, clay mineralogy and palynofacies the Tithonian to Valanginian cored succession of the Fårarp-1 core provides complementary information on how marginal deposits from the eastern part of the epicontinental sea reflect the climatological and environmental changes observed in other parts of NW Europe.
The Fårarp-1 core shows that during the Tithonian to earliest Berriasian deposition took place in a terrestrial but near-marine depositional setting, in coastal lakes or lagoons with little marine influence. A dry climatic regime favoured stagnant water conditions with common algal blooms of primarily Botryococcus and zygnemataceae. Palynofacies and sedimentology indicate limited transport of freshwater and material to the basin. The stagnant depositional environment was terminated by a marine flooding in the early Berriasian. During the remaining Berriasian and the early Valanginian conditions shifted between near marine and marine settings in a dynamic coastal environment, similar to contemporaneous assemblages reported from the Danish Island of Bornholm.
A shift in clay mineralogy, from a dominance of 10 Å minerals to increasing amounts of mixed layer and kaolinite indicates a change to more humid conditions in the latest Tithonian. Cheirolepidacean pollen (Classopollis) are present but never common in the cored succession, and a similar conspicuous decrease of these pollen, as previously reported from England, Germany and France, is not evident in the Fårarp-1 core. Instead a subsequent shift in both palynofacies and palynoflora, marked by an increase in abundance of heavy terrigenous material, i.e. wood and coal particles, upland pollen grains and reworked palynomorphs is also observed in the uppermost Tithonian–lowermost Berriasian interval. At the same level spores and pollen classified as warmer/drier elements decrease in abundance. This is interpreted as representing a shift to more humid climatic conditions with increased runoff from the hinterland. Thus, the combined sedimentological and palynological data from the Fårarp-1 core suggest that climatic conditions in the area changed from more seasonally dry (semi-arid) to more humid (semi-humid) across the J/K boundary (latest Tithonian to earliest Berriasian) and hence earlier than the mid-Berriasian climatic shift recorded from e.g. England and the Netherlands.
High resolution palynological and bulk organic C-isotope data from Triassic–Jurassic (T/J) successions in Denmark and Sweden provide evidence of major and partly coeval shifts in the marine and terrestrial palynofloras. The demise of typical Rhaetian dinoflagellate cysts and the temporary disappearance of these phytoplankton appear to coincide with an interval indicating terrestrial deforestation marked by a major decline in pollen from conifers, cycads and ginkgos. Instead high abundances of fern spores, the enigmatic pollen Ricciisporites tuberculatus and sphaeromorphs totally dominate the assemblages. Additional significant features of this interval within the basin, include increased erosion and reworking, changes in fluvial style and temporary loss of peat-forming vegetation.
Many of the changes recorded in the T/J-boundary succession of the Danish Basin can be attributed to outgassing of SO2 from the CAMP, and subsequent acid rain and acid deposition (van de Schootbrugge et al. 2009). However, the high abundance of sphaeromorphs within the end-Triassic event interval of the Danish Basin remains enigmatic. There are two working hypotheses for the mass occurrence of these sphaeromorphs: 1) They are in situ and represent a prasinophycean algal bloom. 2) They are reworked and represent a phase of increased weathering and erosion. The possible causes, consequences, as well as palaeoecological significance of these two hypotheses on the interpretation of the end-Triassic event will be discussed.
References
Hallam, A. and Wignall, P.B. (1999). Mass extinctions and sea-level changes. Earth Sci. Rev., 48, 217-250.
Hesselbo, S.P., Robinson, S.A., Surlyk, F. and Piasecki, S. (2002). Terrestrial and marine extinction at the Triassic-Jurassic boundary synchronized with major carbon-cycle perturbations: A link to initiation of massive volcanism? Geology 30, 251-254.
McElwain, J.C., Beerling, D.J. and Woodward, F.I. (1999). Fossil plants and global warming at the Triassic-Jurassic boundary. Science 285, 1386-1390.
McElwain, J.C., Popa, M.E., Hesselbo, S.P., Haworth, M. and Surlyk, F. (2007). Macroecological responses of terrestrial vegetation to climate and atmospheric change across the Triassic/Jurassic boundary in East Greenland. Paleobiology 33, 547-573.
Olsen, P.E., Kent, D.V., Sues, H.D., Koeberl, C., Huberm H., Montanari, A., Rainforth, E.C., Fowell, S.J., Szajna, M.J. and Hartline, B.W. (2002). Ascent of dinosaurs linked to Ir anomaly at Triassic–Jurassic boundary. Science 296, 1305-1307.
Schoene, B., Guex, J., Bartolini, A., Schaltegger, U. and Blackburn, T.J. (2010). Correlating the end-Triassic mass extinction and flood basalt volcanism at the 100 ka level. Geology 38, 387-390.
van de Schootbrugge, B., Tremolada, F., Bailey, T.R., Rosenthal, Y., Feist-Burkhardt, S., Brinkhuis, H., Pross, J., Kent, D.V. and Falkowski, P.G. (2007). End-Triassic calcification crisis and blooms of organic-walled disaster species. Palaeogeogr. Palaeoclimatol. Palaeoecol. 244, 126-141.
van de Schootbrugge, B., Quan, T.M., Lindström, S., Püttmann, W., Heunisch, C., Pross, J., Fiebig, J., Petschik, R., Röhling, H.-G., Richoz, S., Rosenthal, Y. and Falkowski, P.G. (2009). Floral changes across the Triassic/Jurassic boundary linked to flood basalt volcanism. Nature Geoscience 2, 589-594.
Whiteside, J.H., Olsen, P.E., Kent, D.V., Fowell, S.J. and Et-Touhami, M. (2007). Synchrony between the Central Atlantic magmatic province and the Triassic–Jurassic mass-extinction event? Palaeogeogr. Palaeoclimatol. Palaeoecol., 244, 345-367.
boundary is also marked by an enrichment of polycyclic aromatic hydrocarbons, which, in the absence of charcoal peaks, we interpret as an indication of incomplete combustion of organic matter by ascending flood basalt lava. We conclude that the terrestrial vegetation shift is so severe and wide ranging that it is unlikely to have been triggered by greenhouse warming
alone. Instead, we suggest that the release of pollutants such as sulphur dioxide and toxic compounds such as the polycyclic
aromatic hydrocarbons may have contributed to the extinction.
A review of published fossil occurrences of Tetranguladinium reveals that its stratigraphic range extends at least from the late Guadalupian (Middle Permian) to the Holocene. It has been recorded from Africa (Tanzania), Asia (China, Korea), Australia, NW Europe (Denmark, Great Britain, Sweden), North America (Canada, USA), and South America (Argentina). Depositional and palaeoclimatological data for the known localities of Tetranguladinium confirm a preference for freshwater settings in a humid warm temperate to subtropical-tropical climate often with a pronounced dry season. The palaeogeographical positions of all the known Tetranguladinium localities indicate that it is has stayed restricted within narrow belts between 30-40º south and 30-60° north of the palaeoequator since the Late Jurassic.
High resolution palynological and bulk organic C-isotope data from Triassic–Jurassic (T/J) successions in Denmark and Sweden provide evidence of major and partly coeval shifts in the marine and terrestrial palynofloras. The demise of typical Rhaetian dinoflagellate cysts and the temporary disappearance of these phytoplankton appear to coincide with an interval indicating terrestrial deforestation marked by a major decline in pollen from conifers, cycads and ginkgos. Instead high abundances of fern spores, the enigmatic pollen Ricciisporites tuberculatus and sphaeromorphs totally dominate the assemblages. Additional significant features of this interval within the basin, include increased erosion and reworking, changes in fluvial style and temporary loss of peat-forming vegetation.
Correlation between the organic C-isotope record and the terrestrial and marine biotic changes in the Danish Basin show that the major environmental perturbations took place prior to the most prominent negative C-isotope excursion. The subsequent reorganisation and recovery of the terrestrial ecosystem already commenced during this peak, hence negating injection of methane as a major cause of the end-Triassic mass extinction event. Instead we favour a scenario in which repeated episodic CO2 and SO2 release from the CAMP played a prominent role (van de Schootbrugge et al., 2009). Many of the changes recorded in the T/J-boundary succession of the Danish Basin can be attributed to outgassing of SO2 from the CAMP, and subsequent acid rain and acid deposition, and subsequent feedback effects.
References
Hallam, A. and Wignall, P.B. (1999). Mass extinctions and sea-level changes. Earth Sci. Rev., 48, 217-250.
Hesselbo, S.P., Robinson, S.A., Surlyk, F. and Piasecki, S. (2002). Terrestrial and marine extinction at the Triassic-Jurassic boundary synchronized with major carbon-cycle perturbations: A link to initiation of massive volcanism? Geology 30, 251-254.
McElwain, J.C., Beerling, D.J. and Woodward, F.I. (1999). Fossil plants and global warming at the Triassic-Jurassic boundary. Science 285, 1386-1390.
McElwain, J.C., Popa, M.E., Hesselbo, S.P., Haworth, M. and Surlyk, F. (2007). Macroecological responses of terrestrial vegetation to climate and atmospheric change across the Triassic/Jurassic boundary in East Greenland. Paleobiology 33, 547-573.
Olsen, P.E., Kent, D.V., Sues, H.D., Koeberl, C., Huberm H., Montanari, A., Rainforth, E.C., Fowell, S.J., Szajna, M.J. and Hartline, B.W. (2002). Ascent of dinosaurs linked to Ir anomaly at Triassic–Jurassic boundary. Science 296, 1305-1307.
Ruhl, M. and Kürschner, W.M., 2011, Multiple phases of carbon cycle disturbance from large igneous province formation at the Triassic-Jurassic transition: Geology, 39, p. 431-434.
Ruhl, M., Bonis, N.R., Reichart, G.-J., Sinninghe Damsté, J.S., and Kürschner, W.M., 2011, Atmospheric carbon injection linked to end-Triassic mass extinction: Science, v. 333, p. 430-434.
Schoene, B., Guex, J., Bartolini, A., Schaltegger, U. and Blackburn, T.J. (2010). Correlating the end-Triassic mass extinction and flood basalt volcanism at the 100 ka level. Geology 38, 387-390.
van de Schootbrugge, B., Tremolada, F., Bailey, T.R., Rosenthal, Y., Feist-Burkhardt, S., Brinkhuis, H., Pross, J., Kent, D.V. and Falkowski, P.G. (2007). End-Triassic calcification crisis and blooms of organic-walled disaster species. Palaeogeogr. Palaeoclimatol. Palaeoecol. 244, 126-141.
van de Schootbrugge, B., Quan, T.M., Lindström, S., Püttmann, W., Heunisch, C., Pross, J., Fiebig, J., Petschik, R., Röhling, H.-G., Richoz, S., Rosenthal, Y. and Falkowski, P.G. (2009). Floral changes across the Triassic/Jurassic boundary linked to flood basalt volcanism. Nature Geoscience 2, 589-594.
Whiteside, J.H., Olsen, P.E., Kent, D.V., Fowell, S.J. and Et-Touhami, M. (2007). Synchrony between the Central Atlantic magmatic province and the Triassic–Jurassic mass-extinction event? Palaeogeogr. Palaeoclimatol. Palaeoecol., 244, 345-367.
During the Jurassic–Cretaceous (J/K) transition NW Europe was located in mid latitudes, and comprised an archipelago of large and small islands separated by deeper grabens and epicontinental seaways that connected the Boreal Sea to the north with the warmer Tethys Ocean to the south. Boundary strata in England, France, the Netherlands and Germany are characterised by relatively prominent climatic change from arid/semi arid to subhumid/humid conditions. Southernmost Sweden was located on the margin of a large landmass comprising most of the Fennoscandian Shield bordering a large epicontinental sea to the west. By combining sedimentology, clay mineralogy and palynofacies the Tithonian to Valanginian cored succession of the Fårarp-1 core provides complementary information on how marginal deposits from the eastern part of the epicontinental sea reflect the climatological and environmental changes observed in other parts of NW Europe.
The Fårarp-1 core shows that during the Tithonian to earliest Berriasian deposition took place in a terrestrial but near-marine depositional setting, in coastal lakes or lagoons with little marine influence. A dry climatic regime favoured stagnant water conditions with common algal blooms of primarily Botryococcus and zygnemataceae. Palynofacies and sedimentology indicate limited transport of freshwater and material to the basin. The stagnant depositional environment was terminated by a marine flooding in the early Berriasian. During the remaining Berriasian and the early Valanginian conditions shifted between near marine and marine settings in a dynamic coastal environment, similar to contemporaneous assemblages reported from the Danish Island of Bornholm.
A shift in clay mineralogy, from a dominance of 10 Å minerals to increasing amounts of mixed layer and kaolinite indicates a change to more humid conditions in the latest Tithonian. Cheirolepidacean pollen (Classopollis) are present but never common in the cored succession, and a similar conspicuous decrease of these pollen, as previously reported from England, Germany and France, is not evident in the Fårarp-1 core. Instead a subsequent shift in both palynofacies and palynoflora, marked by an increase in abundance of heavy terrigenous material, i.e. wood and coal particles, upland pollen grains and reworked palynomorphs is also observed in the uppermost Tithonian–lowermost Berriasian interval. At the same level spores and pollen classified as warmer/drier elements decrease in abundance. This is interpreted as representing a shift to more humid climatic conditions with increased runoff from the hinterland. Thus, the combined sedimentological and palynological data from the Fårarp-1 core suggest that climatic conditions in the area changed from more seasonally dry (semi-arid) to more humid (semi-humid) across the J/K boundary (latest Tithonian to earliest Berriasian) and hence earlier than the mid-Berriasian climatic shift recorded from e.g. England and the Netherlands.
High resolution palynological and bulk organic C-isotope data from Triassic–Jurassic (T/J) successions in Denmark and Sweden provide evidence of major and partly coeval shifts in the marine and terrestrial palynofloras. The demise of typical Rhaetian dinoflagellate cysts and the temporary disappearance of these phytoplankton appear to coincide with an interval indicating terrestrial deforestation marked by a major decline in pollen from conifers, cycads and ginkgos. Instead high abundances of fern spores, the enigmatic pollen Ricciisporites tuberculatus and sphaeromorphs totally dominate the assemblages. Additional significant features of this interval within the basin, include increased erosion and reworking, changes in fluvial style and temporary loss of peat-forming vegetation.
Many of the changes recorded in the T/J-boundary succession of the Danish Basin can be attributed to outgassing of SO2 from the CAMP, and subsequent acid rain and acid deposition (van de Schootbrugge et al. 2009). However, the high abundance of sphaeromorphs within the end-Triassic event interval of the Danish Basin remains enigmatic. There are two working hypotheses for the mass occurrence of these sphaeromorphs: 1) They are in situ and represent a prasinophycean algal bloom. 2) They are reworked and represent a phase of increased weathering and erosion. The possible causes, consequences, as well as palaeoecological significance of these two hypotheses on the interpretation of the end-Triassic event will be discussed.
References
Hallam, A. and Wignall, P.B. (1999). Mass extinctions and sea-level changes. Earth Sci. Rev., 48, 217-250.
Hesselbo, S.P., Robinson, S.A., Surlyk, F. and Piasecki, S. (2002). Terrestrial and marine extinction at the Triassic-Jurassic boundary synchronized with major carbon-cycle perturbations: A link to initiation of massive volcanism? Geology 30, 251-254.
McElwain, J.C., Beerling, D.J. and Woodward, F.I. (1999). Fossil plants and global warming at the Triassic-Jurassic boundary. Science 285, 1386-1390.
McElwain, J.C., Popa, M.E., Hesselbo, S.P., Haworth, M. and Surlyk, F. (2007). Macroecological responses of terrestrial vegetation to climate and atmospheric change across the Triassic/Jurassic boundary in East Greenland. Paleobiology 33, 547-573.
Olsen, P.E., Kent, D.V., Sues, H.D., Koeberl, C., Huberm H., Montanari, A., Rainforth, E.C., Fowell, S.J., Szajna, M.J. and Hartline, B.W. (2002). Ascent of dinosaurs linked to Ir anomaly at Triassic–Jurassic boundary. Science 296, 1305-1307.
Schoene, B., Guex, J., Bartolini, A., Schaltegger, U. and Blackburn, T.J. (2010). Correlating the end-Triassic mass extinction and flood basalt volcanism at the 100 ka level. Geology 38, 387-390.
van de Schootbrugge, B., Tremolada, F., Bailey, T.R., Rosenthal, Y., Feist-Burkhardt, S., Brinkhuis, H., Pross, J., Kent, D.V. and Falkowski, P.G. (2007). End-Triassic calcification crisis and blooms of organic-walled disaster species. Palaeogeogr. Palaeoclimatol. Palaeoecol. 244, 126-141.
van de Schootbrugge, B., Quan, T.M., Lindström, S., Püttmann, W., Heunisch, C., Pross, J., Fiebig, J., Petschik, R., Röhling, H.-G., Richoz, S., Rosenthal, Y. and Falkowski, P.G. (2009). Floral changes across the Triassic/Jurassic boundary linked to flood basalt volcanism. Nature Geoscience 2, 589-594.
Whiteside, J.H., Olsen, P.E., Kent, D.V., Fowell, S.J. and Et-Touhami, M. (2007). Synchrony between the Central Atlantic magmatic province and the Triassic–Jurassic mass-extinction event? Palaeogeogr. Palaeoclimatol. Palaeoecol., 244, 345-367.
boundary is also marked by an enrichment of polycyclic aromatic hydrocarbons, which, in the absence of charcoal peaks, we interpret as an indication of incomplete combustion of organic matter by ascending flood basalt lava. We conclude that the terrestrial vegetation shift is so severe and wide ranging that it is unlikely to have been triggered by greenhouse warming
alone. Instead, we suggest that the release of pollutants such as sulphur dioxide and toxic compounds such as the polycyclic
aromatic hydrocarbons may have contributed to the extinction.