Well-preserved marine fossils in carbonate rocks permit detailed studies of the end-Permian extin... more 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.
Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 2015
A palynological study of the upper Silurian Ö ved-Ramsåsa Group in Skåne, Sweden yields a well pr... more A palynological study of the upper Silurian Ö ved-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.
Well-preserved marine fossils in carbonate rocks permit detailed studies of the end-Permian extin... more 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.
This study documents the terrestrial palynological record at the John’s Nose section, a new Creta... more This study documents the terrestrial palynological record at the John’s Nose section, a new Cretaceous–Paleogene (K–Pg) boundary site in North Dakota, USA. In addition to Mud Buttes and Pyramid Butte, John’s Nose represents the third K–Pg section in southwestern North Dakota that preserves direct evidence of the Chicxulub asteroid impact, allowing for direct comparison over the timing and trends of the palynological record in respect to this event. The palynological analysis of John’s Nose section reveals the presence of 68 pollen and spore taxa. Immediately above the boundary clay, a high abundance of fern spores of the genera Cyathidites and Laevigatosporites is recorded (with 59% of the assemblage being represented by Cyathidites). This very distinctive K–Pg ‘fern spike’ event is correlated with the devastation of land plants immediately following the asteroid impact and matches the composition generally reported from other sites in southwestern North Dakota. Palynostratigraphy demonstrates that the placement of the K–Pg boundary based upon the identification of the Last Appearance Datum (LAD) of typical Maastrichtian taxa (K-taxa) may be misleading. The presence of occasional K-taxa up to a few meters above the boundary clay at John’s Nose represents an important difference when compared to previous reports. In light of this observation, LADs should be used cautiously as the primary criteria to identify the boundary; some K-taxa may have a short-term presence in the earliest Paleogene, or be reworked. In the John’s Nose section, major changes and extinction in the palynological record occur at the geochemical K–Pg boundary, indicating that a catastrophic turnover took place over a short time.
For a long time, debate has taken place regarding the trends and extinction rates associated with... more For a long time, debate has taken place regarding the trends and extinction rates associated with the Cretaceous-Paleogene (K-Pg) mass extinction event on land. While mainly focused on vertebrates and more particularly non-avian dinosaurs, the dynamics of the plant cover remains nonetheless a major component of the biological response across the K-Pg interval and associated ecosystem destabilization. In this paper, we present a review of the late Cretaceous to Paleogene pollen and spore stratigraphy in the Northern Hemisphere Aquilapollenites paleophytogeographic province. In the United States of America, Late Cretaceous assemblages are marked by the appearance of a series of key taxa: the Santonian-Campanian transition is characterized by the appearance of Aquilapollenites and associated triprojectate genera, whereas the base of the Maastrichtian is marked by the appearance of the oculate genus Wodehouseia as well as Kurtzipites sp. The K-Pg extinction event remains easily identifiable in the palynological record with the disappearance of a series of angiospermous taxa, part of the Wodehouseia spinata Assemblage Zone, which are characterized by relatively large size and a complex wall structure. The recovery palynoflora in the Paleocene is represented by assemblages dominated by porate grains, with key species from the Momipites and Caryapollenites genera. As current data mostly cover the North American terrestrial record, more research efforts are needed in Chinese, European and Southern Hemisphere localities to provide for a better understanding of the global response of the terrestrial biosphere to the K-Pg impact event.
The palynofloral changes around the Cretaceous-Paleogene (K-Pg) mass extinction event reveal the ... more The palynofloral changes around the Cretaceous-Paleogene (K-Pg) mass extinction event reveal the fine details of vegetation response to a global environmental crisis-in this case an asteroid impact in Mexico 65.5 million years ago. Due to the extinction of several plant taxa at the K-Pg boundary, palynostratigraphy is a prime tool for localizing the Cretaceous-Paleogene boundary in non-marine successions. The Southern Hemisphere includes the tropical to sub-tropical Palmae Province, the high-latitude Nothofagidites/Proteacidites Province, and a transitional zone of mixed floristic composition. Maastrichtian key-species that go extinct at the Cretaceous-Paleogene boundary within the Palmae Province include Aquilapollenites magnus, Buttinia andreevi, Crassitricolporites brasiliensis, Proteacidites dehaani and Gabonisporis vigourouxii. In the Nothofagidites/Proteacidites Province, taxa such as Tricolporites lilliei, Triporopollenites sectilis, Quadraplanus brossus, Nothofagidites kaitangata, and Grapnelispora evansii have their last appearances at the boundary. It is obvious that more thorough analyses of the palynological signals across the K-Pg boundary in the Southern Hemisphere and China are required to elucidate the detailed patterns of vegetation response at different latitudes and at varying distances from the impact site in Yucatan, Mexico.
A palynological investigation of sedimentary rocks enclosing an exceptionally well-preserved foss... more 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 – an environment where this specific hadrosaur roamed over 66 million years ago.
The stomatal index (a measure of stomatal density) of an extinct Australian Early Jurassic arauca... more 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 con- strain pCO2 during this period. Our results are the first pCO2 estimates produced using Jurassic leaves from the Southern Hemisphere and show that 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.
A palynological investigation of sedimentary rocks enclosing an exceptionally well-preserved foss... more 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.
I describe dispersed miospore assemblages recovered from 35 drill-core samples from Hijllviken 2,... more I describe dispersed miospore assemblages recovered from 35 drill-core samples from Hijllviken 2, NorrevAng 1, and Svedala 1 wells, all in SW Scania, Sweden. Over eighty taxa of pollen and spores, ranging from the Aalenian to the Cenomanian were identified. Four pollen/spore zones have been defined on the basis of key taxa and on the variation in the frequency of miospore groups. The palynofacies analysis indicates that a continental depositional environment prevailed during the Aalenian in Scania.
A new heterosporous fern species, Azolla boliviensis sp. nov., is described from latest Maastrich... more A new heterosporous fern species, Azolla boliviensis sp. nov., is described from latest Maastrichtian (latest Cretaceous) to Paleocene (earliest Palaeogene) terrestrial sediments
of the Eslabón and Flora Formations, Subandean belt, Bolivia. The species is represented by dissociated but abundantly co-preserved megasporocarps, megaspores, microsporangia, massulae and microspores. The genus consistently characterizes warm-climate lacustrine settings. Fossil Azolla is first identified around the Early to mid-Cretaceous but the genus
apparently underwent dramatic radiation during the Late Cretaceous. Abundant Azolla remains in Bolivia add to this portrait of rapid geographic dispersal and diversification
near the close of the Cretaceous. The ranges of many Azolla species span the Cretaceous- Palaeogene boundary and the potential of Azolla to withstand altered environmental conditions, such as periodic frost damage, drought, and salinity change, and its ability to undergo rapid vegetative regeneration in association with nitrogen-fixing cyanobacterial symbionts, suggest that the survival of this group was favoured during the adverse conditions of the end-Cretaceous event.
Alcheringa: An Australasian Journal of …, Jan 1, 2010
A palynological investigation of lower Paleocene (lower Teurian) marine sediments of the Abbotsfo... more A palynological investigation of lower Paleocene (lower Teurian) marine sediments of the Abbotsford Formation, exposed in the Fairfield Quarry, Dunedin, New Zealand, reveals a well-preserved association of dinoflagellate cysts and miospores. Thirty-six dinoflagellate species representing 26 genera were recorded, including one new peridinioid dinoflagellate species, Trithyrodinium partridgei characterized by a three-layered wall and a distinct brown, foveolate mesophragm. Trithyrodinium partridgei has a narrow range and at Fairfield Quarry co-occurs with typical New Zealand late Danian to Selandian index species such as Glaphyrocysta perforata and Alterbidinium pentaradiatum;
hence it may prove an additional useful stratigraphic marker. The terrestrial palynomorph assemblage from samples within the range of Trithyrodinium partridgei includes 36 spore-pollen species dominated by the podocarp pollen Phyllocladidites mawsonii. The presence of Nothofagidites waipawaensis and Tricolpites phillipsii confirms a Paleocene age for the
assemblage. The abundance of terrestrial palynomorphs and the composition of the dinocyst assemblages suggest a marine nearshore depositional environment.
High-palaeolatitude plesiosaur, mosasaur and, more rarely, dinosaur fossils are well known from t... more High-palaeolatitude plesiosaur, mosasaur and, more rarely, dinosaur fossils are well known from the Maungataniwha Sandstone Member of the Tahora Formation in Mangahouanga Stream, Hawkes Bay, New Zealand. A palynological investigation of strata exposed along Mangahouanga Stream and of transported boulders hosting vertebrate fossils reveals well preserved assemblages dominated by terrestrial pollen and spores but also including marine dinoflagellate cysts in some samples. The palynofacies are strongly dominated by wood fragments including charcoal; one outcrop sample and the sample taken from a boulder hosting plesiosaur vertebrae contain entirely terrestrially derived palynoassemblages, suggesting a freshwater habitat for at least some of the plesiosaurs. The host unit spans the Santonian to lowermost Maastrichtian, while the key pollen taxa Nothofagidites senectus and Tricolpites lilliei, together with the dinocyst Isabelidinium pellucidum and the megaspore Grapnelispora evansii, indicate a late Campanian to earlyMaastrichtian age for the fossiliferous boulders. The palynoflora indicates a mixed local vegetation dominated by podocarp conifers and angiosperms with a significant tree-fern subcanopy. The presence of taxa with modern temperate distributions, such as Nothofagus (southern beech), Proteaceae and Cyatheaceae (tree-ferns), indicates a mild-temperate climate and lack of severe winter freezing during the latest Cretaceous, providing an ecosystem that most probably made it possible for polar dinosaurs to overwinter in thispart of the world.
A low-diversity Early Jurassic flora preserved in floodbasin siltstones of the Marburg Subgroup a... more A low-diversity Early Jurassic flora preserved in floodbasin siltstones of the Marburg Subgroup at Inverleigh Quarry in the Clarence-Moreton Basin, eastern Australia, is dominated by Allocladus helgei Jansson sp. nov., a conifer with denticulate leaves tentatively attributed to Araucariaceae. The assemblage also includes Rintoulia variabilis and Caytoniales, (Caytonia cucullata McLoughlin sp. nov. and cf. Sagenopteris nilssoniana), reinforcing the wide distribution of this order in Early to Middle Jurassic floras of Gondwana. Ferns (Cladophlebis and Sphenopteris species) and isoetalean lycophytes (Isoetites sp.) constitute the herbaceous elements of the flora. The palynoflora is dominated by cheirolepidiacean (Classopollis) pollen and is attributable to the upper part of the Corollina (= Classopollis) torosa Zone of late Pliensbachianearly Toarcian age (180-185 Ma). The Inverleigh flora represents one of the few Australian assemblages dated between the major phases of floristic turnover at the end of the Triassic and the Toarcian. Sedimentological characteristics, cuticular features of the conifer leaves and the abundance of free-sporing plants indicate a relatively humid palaeoclimate for the Clarence-Moreton Basin Early Jurassic.
Abstract A palynological analysis of a Lower Miocene cored section from S⊘ nder Vium in western J... more Abstract A palynological analysis of a Lower Miocene cored section from S⊘ nder Vium in western Jylland, Denmark, provides new data regarding the vegetation and climate during the earliest Neogene. Most samples yielded well-preserved palynomorphs. Terrestrial pollen and spores dominate, with lesser proportions of dinoflagellates. A fluvial input into the marine setting is corroborated by the presence of freshwater algae, indicating an inner-neritic setting.
A small assemblage of clitellate annelid cocoons (egg cases) is described from the Early Jurassic... more A small assemblage of clitellate annelid cocoons (egg cases) is described from the Early Jurassic Marburg Subgroup, Clarence-Moreton Basin, eastern Australia. Two complete specimens are preserved on bedding planes, and numerous fragments were recovered from organic residues prepared for mesofossil analysis. The complete specimens are assigned to Burejospermum Krassilov emend. Manum, Bose & Sawyer, 1991, having a well-developed mesh-like hapsine and a solid layer of underlying alytine.
10 GEOLOGISKT FORUM nr 56/2007 ter är de vanligast förekommande. Asteroidnedslaget fick katastrof... more 10 GEOLOGISKT FORUM nr 56/2007 ter är de vanligast förekommande. Asteroidnedslaget fick katastrofala konsekvenser så som eldstormar i direkt anslutning till nedslaget och skogsbränder kan spåras i nordamerikanska sediment. Enorma mängder stoft fyllde atmosfären och skapade ett mörker som, enligt fysikaliska modeller, varade upp till två år. Dessa händelser går också att utläsa ur de palynologiska signalerna. Ja, spåren av asteroidnedslaget avspeglar sig i vegetationen.
Well-preserved marine fossils in carbonate rocks permit detailed studies of the end-Permian extin... more 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.
Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 2015
A palynological study of the upper Silurian Ö ved-Ramsåsa Group in Skåne, Sweden yields a well pr... more A palynological study of the upper Silurian Ö ved-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.
Well-preserved marine fossils in carbonate rocks permit detailed studies of the end-Permian extin... more 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.
This study documents the terrestrial palynological record at the John’s Nose section, a new Creta... more This study documents the terrestrial palynological record at the John’s Nose section, a new Cretaceous–Paleogene (K–Pg) boundary site in North Dakota, USA. In addition to Mud Buttes and Pyramid Butte, John’s Nose represents the third K–Pg section in southwestern North Dakota that preserves direct evidence of the Chicxulub asteroid impact, allowing for direct comparison over the timing and trends of the palynological record in respect to this event. The palynological analysis of John’s Nose section reveals the presence of 68 pollen and spore taxa. Immediately above the boundary clay, a high abundance of fern spores of the genera Cyathidites and Laevigatosporites is recorded (with 59% of the assemblage being represented by Cyathidites). This very distinctive K–Pg ‘fern spike’ event is correlated with the devastation of land plants immediately following the asteroid impact and matches the composition generally reported from other sites in southwestern North Dakota. Palynostratigraphy demonstrates that the placement of the K–Pg boundary based upon the identification of the Last Appearance Datum (LAD) of typical Maastrichtian taxa (K-taxa) may be misleading. The presence of occasional K-taxa up to a few meters above the boundary clay at John’s Nose represents an important difference when compared to previous reports. In light of this observation, LADs should be used cautiously as the primary criteria to identify the boundary; some K-taxa may have a short-term presence in the earliest Paleogene, or be reworked. In the John’s Nose section, major changes and extinction in the palynological record occur at the geochemical K–Pg boundary, indicating that a catastrophic turnover took place over a short time.
For a long time, debate has taken place regarding the trends and extinction rates associated with... more For a long time, debate has taken place regarding the trends and extinction rates associated with the Cretaceous-Paleogene (K-Pg) mass extinction event on land. While mainly focused on vertebrates and more particularly non-avian dinosaurs, the dynamics of the plant cover remains nonetheless a major component of the biological response across the K-Pg interval and associated ecosystem destabilization. In this paper, we present a review of the late Cretaceous to Paleogene pollen and spore stratigraphy in the Northern Hemisphere Aquilapollenites paleophytogeographic province. In the United States of America, Late Cretaceous assemblages are marked by the appearance of a series of key taxa: the Santonian-Campanian transition is characterized by the appearance of Aquilapollenites and associated triprojectate genera, whereas the base of the Maastrichtian is marked by the appearance of the oculate genus Wodehouseia as well as Kurtzipites sp. The K-Pg extinction event remains easily identifiable in the palynological record with the disappearance of a series of angiospermous taxa, part of the Wodehouseia spinata Assemblage Zone, which are characterized by relatively large size and a complex wall structure. The recovery palynoflora in the Paleocene is represented by assemblages dominated by porate grains, with key species from the Momipites and Caryapollenites genera. As current data mostly cover the North American terrestrial record, more research efforts are needed in Chinese, European and Southern Hemisphere localities to provide for a better understanding of the global response of the terrestrial biosphere to the K-Pg impact event.
The palynofloral changes around the Cretaceous-Paleogene (K-Pg) mass extinction event reveal the ... more The palynofloral changes around the Cretaceous-Paleogene (K-Pg) mass extinction event reveal the fine details of vegetation response to a global environmental crisis-in this case an asteroid impact in Mexico 65.5 million years ago. Due to the extinction of several plant taxa at the K-Pg boundary, palynostratigraphy is a prime tool for localizing the Cretaceous-Paleogene boundary in non-marine successions. The Southern Hemisphere includes the tropical to sub-tropical Palmae Province, the high-latitude Nothofagidites/Proteacidites Province, and a transitional zone of mixed floristic composition. Maastrichtian key-species that go extinct at the Cretaceous-Paleogene boundary within the Palmae Province include Aquilapollenites magnus, Buttinia andreevi, Crassitricolporites brasiliensis, Proteacidites dehaani and Gabonisporis vigourouxii. In the Nothofagidites/Proteacidites Province, taxa such as Tricolporites lilliei, Triporopollenites sectilis, Quadraplanus brossus, Nothofagidites kaitangata, and Grapnelispora evansii have their last appearances at the boundary. It is obvious that more thorough analyses of the palynological signals across the K-Pg boundary in the Southern Hemisphere and China are required to elucidate the detailed patterns of vegetation response at different latitudes and at varying distances from the impact site in Yucatan, Mexico.
A palynological investigation of sedimentary rocks enclosing an exceptionally well-preserved foss... more 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 – an environment where this specific hadrosaur roamed over 66 million years ago.
The stomatal index (a measure of stomatal density) of an extinct Australian Early Jurassic arauca... more 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 con- strain pCO2 during this period. Our results are the first pCO2 estimates produced using Jurassic leaves from the Southern Hemisphere and show that 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.
A palynological investigation of sedimentary rocks enclosing an exceptionally well-preserved foss... more 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.
I describe dispersed miospore assemblages recovered from 35 drill-core samples from Hijllviken 2,... more I describe dispersed miospore assemblages recovered from 35 drill-core samples from Hijllviken 2, NorrevAng 1, and Svedala 1 wells, all in SW Scania, Sweden. Over eighty taxa of pollen and spores, ranging from the Aalenian to the Cenomanian were identified. Four pollen/spore zones have been defined on the basis of key taxa and on the variation in the frequency of miospore groups. The palynofacies analysis indicates that a continental depositional environment prevailed during the Aalenian in Scania.
A new heterosporous fern species, Azolla boliviensis sp. nov., is described from latest Maastrich... more A new heterosporous fern species, Azolla boliviensis sp. nov., is described from latest Maastrichtian (latest Cretaceous) to Paleocene (earliest Palaeogene) terrestrial sediments
of the Eslabón and Flora Formations, Subandean belt, Bolivia. The species is represented by dissociated but abundantly co-preserved megasporocarps, megaspores, microsporangia, massulae and microspores. The genus consistently characterizes warm-climate lacustrine settings. Fossil Azolla is first identified around the Early to mid-Cretaceous but the genus
apparently underwent dramatic radiation during the Late Cretaceous. Abundant Azolla remains in Bolivia add to this portrait of rapid geographic dispersal and diversification
near the close of the Cretaceous. The ranges of many Azolla species span the Cretaceous- Palaeogene boundary and the potential of Azolla to withstand altered environmental conditions, such as periodic frost damage, drought, and salinity change, and its ability to undergo rapid vegetative regeneration in association with nitrogen-fixing cyanobacterial symbionts, suggest that the survival of this group was favoured during the adverse conditions of the end-Cretaceous event.
Alcheringa: An Australasian Journal of …, Jan 1, 2010
A palynological investigation of lower Paleocene (lower Teurian) marine sediments of the Abbotsfo... more A palynological investigation of lower Paleocene (lower Teurian) marine sediments of the Abbotsford Formation, exposed in the Fairfield Quarry, Dunedin, New Zealand, reveals a well-preserved association of dinoflagellate cysts and miospores. Thirty-six dinoflagellate species representing 26 genera were recorded, including one new peridinioid dinoflagellate species, Trithyrodinium partridgei characterized by a three-layered wall and a distinct brown, foveolate mesophragm. Trithyrodinium partridgei has a narrow range and at Fairfield Quarry co-occurs with typical New Zealand late Danian to Selandian index species such as Glaphyrocysta perforata and Alterbidinium pentaradiatum;
hence it may prove an additional useful stratigraphic marker. The terrestrial palynomorph assemblage from samples within the range of Trithyrodinium partridgei includes 36 spore-pollen species dominated by the podocarp pollen Phyllocladidites mawsonii. The presence of Nothofagidites waipawaensis and Tricolpites phillipsii confirms a Paleocene age for the
assemblage. The abundance of terrestrial palynomorphs and the composition of the dinocyst assemblages suggest a marine nearshore depositional environment.
High-palaeolatitude plesiosaur, mosasaur and, more rarely, dinosaur fossils are well known from t... more High-palaeolatitude plesiosaur, mosasaur and, more rarely, dinosaur fossils are well known from the Maungataniwha Sandstone Member of the Tahora Formation in Mangahouanga Stream, Hawkes Bay, New Zealand. A palynological investigation of strata exposed along Mangahouanga Stream and of transported boulders hosting vertebrate fossils reveals well preserved assemblages dominated by terrestrial pollen and spores but also including marine dinoflagellate cysts in some samples. The palynofacies are strongly dominated by wood fragments including charcoal; one outcrop sample and the sample taken from a boulder hosting plesiosaur vertebrae contain entirely terrestrially derived palynoassemblages, suggesting a freshwater habitat for at least some of the plesiosaurs. The host unit spans the Santonian to lowermost Maastrichtian, while the key pollen taxa Nothofagidites senectus and Tricolpites lilliei, together with the dinocyst Isabelidinium pellucidum and the megaspore Grapnelispora evansii, indicate a late Campanian to earlyMaastrichtian age for the fossiliferous boulders. The palynoflora indicates a mixed local vegetation dominated by podocarp conifers and angiosperms with a significant tree-fern subcanopy. The presence of taxa with modern temperate distributions, such as Nothofagus (southern beech), Proteaceae and Cyatheaceae (tree-ferns), indicates a mild-temperate climate and lack of severe winter freezing during the latest Cretaceous, providing an ecosystem that most probably made it possible for polar dinosaurs to overwinter in thispart of the world.
A low-diversity Early Jurassic flora preserved in floodbasin siltstones of the Marburg Subgroup a... more A low-diversity Early Jurassic flora preserved in floodbasin siltstones of the Marburg Subgroup at Inverleigh Quarry in the Clarence-Moreton Basin, eastern Australia, is dominated by Allocladus helgei Jansson sp. nov., a conifer with denticulate leaves tentatively attributed to Araucariaceae. The assemblage also includes Rintoulia variabilis and Caytoniales, (Caytonia cucullata McLoughlin sp. nov. and cf. Sagenopteris nilssoniana), reinforcing the wide distribution of this order in Early to Middle Jurassic floras of Gondwana. Ferns (Cladophlebis and Sphenopteris species) and isoetalean lycophytes (Isoetites sp.) constitute the herbaceous elements of the flora. The palynoflora is dominated by cheirolepidiacean (Classopollis) pollen and is attributable to the upper part of the Corollina (= Classopollis) torosa Zone of late Pliensbachianearly Toarcian age (180-185 Ma). The Inverleigh flora represents one of the few Australian assemblages dated between the major phases of floristic turnover at the end of the Triassic and the Toarcian. Sedimentological characteristics, cuticular features of the conifer leaves and the abundance of free-sporing plants indicate a relatively humid palaeoclimate for the Clarence-Moreton Basin Early Jurassic.
Abstract A palynological analysis of a Lower Miocene cored section from S⊘ nder Vium in western J... more Abstract A palynological analysis of a Lower Miocene cored section from S⊘ nder Vium in western Jylland, Denmark, provides new data regarding the vegetation and climate during the earliest Neogene. Most samples yielded well-preserved palynomorphs. Terrestrial pollen and spores dominate, with lesser proportions of dinoflagellates. A fluvial input into the marine setting is corroborated by the presence of freshwater algae, indicating an inner-neritic setting.
A small assemblage of clitellate annelid cocoons (egg cases) is described from the Early Jurassic... more A small assemblage of clitellate annelid cocoons (egg cases) is described from the Early Jurassic Marburg Subgroup, Clarence-Moreton Basin, eastern Australia. Two complete specimens are preserved on bedding planes, and numerous fragments were recovered from organic residues prepared for mesofossil analysis. The complete specimens are assigned to Burejospermum Krassilov emend. Manum, Bose & Sawyer, 1991, having a well-developed mesh-like hapsine and a solid layer of underlying alytine.
10 GEOLOGISKT FORUM nr 56/2007 ter är de vanligast förekommande. Asteroidnedslaget fick katastrof... more 10 GEOLOGISKT FORUM nr 56/2007 ter är de vanligast förekommande. Asteroidnedslaget fick katastrofala konsekvenser så som eldstormar i direkt anslutning till nedslaget och skogsbränder kan spåras i nordamerikanska sediment. Enorma mängder stoft fyllde atmosfären och skapade ett mörker som, enligt fysikaliska modeller, varade upp till två år. Dessa händelser går också att utläsa ur de palynologiska signalerna. Ja, spåren av asteroidnedslaget avspeglar sig i vegetationen.
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Papers by Vivi Vajda
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.
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.
of the Eslabón and Flora Formations, Subandean belt, Bolivia. The species is represented by dissociated but abundantly co-preserved megasporocarps, megaspores, microsporangia, massulae and microspores. The genus consistently characterizes warm-climate lacustrine settings. Fossil Azolla is first identified around the Early to mid-Cretaceous but the genus
apparently underwent dramatic radiation during the Late Cretaceous. Abundant Azolla remains in Bolivia add to this portrait of rapid geographic dispersal and diversification
near the close of the Cretaceous. The ranges of many Azolla species span the Cretaceous- Palaeogene boundary and the potential of Azolla to withstand altered environmental conditions, such as periodic frost damage, drought, and salinity change, and its ability to undergo rapid vegetative regeneration in association with nitrogen-fixing cyanobacterial symbionts, suggest that the survival of this group was favoured during the adverse conditions of the end-Cretaceous event.
hence it may prove an additional useful stratigraphic marker. The terrestrial palynomorph assemblage from samples within the range of Trithyrodinium partridgei includes 36 spore-pollen species dominated by the podocarp pollen Phyllocladidites mawsonii. The presence of Nothofagidites waipawaensis and Tricolpites phillipsii confirms a Paleocene age for the
assemblage. The abundance of terrestrial palynomorphs and the composition of the dinocyst assemblages suggest a marine nearshore depositional environment.
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.
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.
of the Eslabón and Flora Formations, Subandean belt, Bolivia. The species is represented by dissociated but abundantly co-preserved megasporocarps, megaspores, microsporangia, massulae and microspores. The genus consistently characterizes warm-climate lacustrine settings. Fossil Azolla is first identified around the Early to mid-Cretaceous but the genus
apparently underwent dramatic radiation during the Late Cretaceous. Abundant Azolla remains in Bolivia add to this portrait of rapid geographic dispersal and diversification
near the close of the Cretaceous. The ranges of many Azolla species span the Cretaceous- Palaeogene boundary and the potential of Azolla to withstand altered environmental conditions, such as periodic frost damage, drought, and salinity change, and its ability to undergo rapid vegetative regeneration in association with nitrogen-fixing cyanobacterial symbionts, suggest that the survival of this group was favoured during the adverse conditions of the end-Cretaceous event.
hence it may prove an additional useful stratigraphic marker. The terrestrial palynomorph assemblage from samples within the range of Trithyrodinium partridgei includes 36 spore-pollen species dominated by the podocarp pollen Phyllocladidites mawsonii. The presence of Nothofagidites waipawaensis and Tricolpites phillipsii confirms a Paleocene age for the
assemblage. The abundance of terrestrial palynomorphs and the composition of the dinocyst assemblages suggest a marine nearshore depositional environment.