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Jörg Pross - One of the best experts on this subject based on the ideXlab platform.
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paleoceanography and ice sheet variability offshore wilkes land antarctica part 2 insights from oligocene miocene dinoflagellate cyst assemblages
Climate of The Past, 2018Co-Authors: Peter K Bijl, Jörg Pross, Alexander J P Houben, Julian D Hartman, Ariadna Salabarnada, Carlota Escutia, Francesca SangiorgiAbstract:Abstract. Next to atmospheric CO2 concentrations, ice-proximal oceanographic conditions are a critical factor for the stability of Antarctic marine-terminating ice sheets. The Oligocene and Miocene epochs ( ∼ 34–5 Myr ago) were time intervals with atmospheric CO2 concentrations between those of present-day and those expected for the near future. As such, these past analogues may provide insights into ice-sheet volume stability under warmer-than-present-day climates. We present organic-walled dinoflagellate cyst (Dinocyst) assemblages from chronostratigraphically well-constrained Oligocene to mid-Miocene sediments from Integrated Ocean Drilling Program (IODP) Site U1356. Situated offshore the Wilkes Land continental margin, East Antarctica, the sediments from Site U1356 have archived the dynamics of an ice sheet that is today mostly grounded below sea level. We interpret Dinocyst assemblages in terms of paleoceanographic change on different timescales, i.e. with regard to both glacial–interglacial and long-term variability. Our record shows that a sea-ice-related Dinocyst species, Selenopemphix antarctica, occurs only for the first 1.5 Myr of the early Oligocene, following the onset of full continental glaciation on Antarctica, and after the Mid-Miocene Climatic Optimum. Dinocysts suggest a weaker-than-modern sea-ice season for the remainder of the Oligocene and Miocene. The assemblages generally bear strong similarity to present-day open-ocean, high-nutrient settings north of the sea-ice edge, with episodic dominance of temperate species similar to those found in the present-day subtropical front. Oligotrophic and temperate surface waters prevailed over the site notably during interglacial times, suggesting that the positions of the (subpolar) oceanic frontal systems have varied in concordance with Oligocene–Miocene glacial–interglacial climate variability.
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Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica – Part 2: Insights from Oligocene–Miocene dinoflagellate cyst assemblages
Copernicus Publications, 2018Co-Authors: Jörg Pross, Alexander J P Houben, Julian D Hartman, Ariadna Salabarnada, Carlota Escutia, Pk Bijl, Francesca SangiorgiAbstract:Next to atmospheric CO2 concentrations, ice-proximal oceanographic conditions are a critical factor for the stability of Antarctic marine-terminating ice sheets. The Oligocene and Miocene epochs ( ∼ 34–5 Myr ago) were time intervals with atmospheric CO2 concentrations between those of present-day and those expected for the near future. As such, these past analogues may provide insights into ice-sheet volume stability under warmer-than-present-day climates. We present organic-walled dinoflagellate cyst (Dinocyst) assemblages from chronostratigraphically well-constrained Oligocene to mid-Miocene sediments from Integrated Ocean Drilling Program (IODP) Site U1356. Situated offshore the Wilkes Land continental margin, East Antarctica, the sediments from Site U1356 have archived the dynamics of an ice sheet that is today mostly grounded below sea level. We interpret Dinocyst assemblages in terms of paleoceanographic change on different timescales, i.e. with regard to both glacial–interglacial and long-term variability. Our record shows that a sea-ice-related Dinocyst species, Selenopemphix antarctica, occurs only for the first 1.5 Myr of the early Oligocene, following the onset of full continental glaciation on Antarctica, and after the Mid-Miocene Climatic Optimum. Dinocysts suggest a weaker-than-modern sea-ice season for the remainder of the Oligocene and Miocene. The assemblages generally bear strong similarity to present-day open-ocean, high-nutrient settings north of the sea-ice edge, with episodic dominance of temperate species similar to those found in the present-day subtropical front. Oligotrophic and temperate surface waters prevailed over the site notably during interglacial times, suggesting that the positions of the (subpolar) oceanic frontal systems have varied in concordance with Oligocene–Miocene glacial–interglacial climate variability.
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Organic-walled dinoflagellate cysts as paleoenvironmental indicators in the Paleogene; a synopsis of concepts
Paläontologische Zeitschrift, 2005Co-Authors: Jörg Pross, Henk BrinkhuisAbstract:The organic-walled, hypnozygotic cysts of dinoflagellates (“Dinocysts”) provide a rich, albeit incomplete, history of this eukaryotic plankton group in ancient sediments. Building on pioneering studies of the late 1970s and 1980s, recent ocean drilling and more detailed, integrated studies of surface sections have provided a wealth of dino-cyst data spanning the entire Paleogene. Based on multidisciplinary approaches, these studies have been instrumental in refining existing and furnishing new concepts of Paleogene paleoenvironmental and paleoclimatic reconstructions by means of Dinocysts. Since Dinocysts typically exhibit high abundances in neritic settings, the dinoeyst-based environmental and paleoclimatic information is complementary to that derived from typically more offshore groups such as planktonic foraminifera, coccolithophorids, diatoms, and radiolaria. While in a recent paper we gave a broad overview of case studies from around the globe ( Sluijs et al. 2005), here we focus on a summary of these analyses and present a synopsis of applied paleoecological concepts in Paleogene (65–24 ma) Dinocyst studies. Representing Earth’s greenhouse-icehouse transition, this episode holds the key to the understanding of extreme transient climatic change. The present paper offers guidelines for the application of Dinocyst palaeoecology to the reconstruction of Paleogene sea-surface productivity, temperature, salinity, stratification, and paleo-oxygenation as well as their application in sequence stratigraphy, oceanic circulation and general watermass reconstructions. Die organischwandigen, hypnozygoten Zysten von Dinoflagellaten („Dinozysten“) spiegeln die Entwicklung dieser eukaryoten Planktongruppe in der Erdgeschichte wider, wobei dieser Fossilbericht allerdings nicht vollständig ist, da er auf Zysten beruht. Aufbauend auf ersten richtungsweisenden Arbeiten der späten 70er und 80er Jahre haben neue, integrierende Untersuchungen an marinen Kernbohrungen und Landaufschlüssen zu einer Fülle neuer Erkenntnisse über Dinozysten des gesamten Paläogens geführt. Diese waren maßgeblich daran beteiligt, dass bestehende Vorstellungen zur Paläoumwelt- und Paläoklimaentwicklung des Paläogens verfeinert und neue Vorstellungen entwickelt werden konnten. Da Dinozysten üblicher Weise in neritischen Ablagerungsräumen häufig vorkommen, liefern die aus ihnen abgeleiteten Paläoumwelt- und Paläoklimasignale eine wertvolle Ergänzung zu den Signalen von Planktongruppen mit eher offenmarinem Verbreitungsschwerpunkt wie planktischen Foraminiferen, Coccolithophoriden, Diatomeen und Radiolarien. Da der Zeitraum des Paläogens den Übergang vom Treibhaus- zum Eishausklima der Erde umfasst, spielt er eine Schlüsselrolle zum Verständnis extremen Klimawandels auf kurzfristigen Zeitskalen. In einem vor kurzem erschienenen Beitrag ( Sluijs et al. 2005) gaben wir einen Überblick über Fallstudien zur Dinozysten-Ökologie aus dem Paläogen (65–24 ma) beider Hemisphären. Der vorliegende Beitrag präsentiert eine Zusammenfassung dieser Fallstudien und gibt eine Synopsis der verwendeten paläoökologischen Konzepte. Er bietet Leitlinien für die Verwendung der Paläoökologie von Dinozysten zur Rekonstruktion von Ober-flächenwasserproduktivität, -temperatur, -Salzgehalt, -stratifizierung, zur Rekonstruktion der Sauerstoff Versorgung sowie zur Nutzung dieser Signale in der Sequenzstratigraphic und bei der Rekonstruktion ozeanischer Zirkulationsmuster während des Paläogens.
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from greenhouse to icehouse organic walled dinoflagellate cysts as paleoenvironmental indicators in the paleogene
Earth-Science Reviews, 2005Co-Authors: Appy Sluijs, Jörg Pross, Henk BrinkhuisAbstract:Abstract Dinoflagellates are an important component of the extant eukaryotic plankton. Their organic-walled, hypnozygotic cysts (Dinocysts) provide a rich, albeit incomplete, history of the group in ancient sediments. Building on pioneering studies of the late 1970s and 1980s, recent drilling in the Southern Ocean has provided a wealth of new Dinocyst data spanning the entire Paleogene. Such multidisciplinary studies have been instrumental in refining existing and furnishing new concepts of Paleogene paleoenvironmental and paleoclimatic reconstructions by means of Dinocysts. Because Dinocysts notably exhibit high abundances in neritic settings, Dinocyst-based environmental and paleoclimatic information is important and complementary to the data derived from typically more offshore groups as planktonic foraminifera, coccolithophorids, diatoms and radiolaria. By presenting case-studies from around the globe, this contribution provides a concise review of our present understanding of the paleoenvironmental significance of Dinocysts in the Paleogene (65–25 Ma). Representing Earth's greenhouse–icehouse transition, this episode holds the key to the understanding of extreme transient climatic change. We discuss the potential of Dinocysts for the reconstruction of Paleogene sea-surface productivity, temperature, salinity, stratification and paleo-oxygenation along with their application in sequence stratigraphy, oceanic circulation and general watermass reconstructions.
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Die Anwendung organischwandiger Dinoflagellatenzysten zur Rekonstruktion von Paläoumwelt, Paläoklima und Paläozeanographie: Möglichkeiten und Grenzen
Paläontologische Zeitschrift, 2004Co-Authors: Jörg Pross, Ulrich Kotthoff, Karin A F ZonneveldAbstract:Organischwandige Dinoflagellatenzysten (Dinozysten) aus marinen Sedimenten werden in den vergangenen zwei Jahrzehnten zunehmend als Indikatoren der Paläoumweltbedingungen, des Paläoklimas und der Paläozeanographie des jüngeren Mesozoikums und Känozoikums genutzt. Da Dinozysten lösungsresistent sind und in fast allen aquatischen Lebensräumen vorkommen, liefern die aus ihnen abgeleiteten Signale eine wertvolle Ergänzung zu den Signalen kalkiger und kieseliger Mikrofossilgruppen wie Foraminiferen, kalkigem Nannoplankton, Diatomeen und Radiolarien. Zum Teil geht die Aussagekraft von Dinozysten zur Paläoum-welt-Rekonstruktion sogar über diejenige kalkiger und kieseliger Mikrofossilien hinaus. Der vorliegende Beitrag gibt einen Überblick über den gegenwärtigen Wissensstand zur Paläoökologie von Dinozysten. Er diskutiert das Potenzial von Dinozysten zur Rekonstruktion von Produktivital, Temperatur und Salzgehalt in der oberen Wassersäule, zur Verwendung in der Sequenzstratigraphie sowie zur Rekonstruktion der Sauerstoffversorgung im Boden- und Porenwasser mariner Lebensräume und in der Wassersäule epikontinentaler Flachmeere. Over the past two decades, organic-walled dinoflagellate cysts (Dinocysts) have been increasingly used as paleoenvironmental and paleoclimatic indicators in marine sediments from the Mesozoic and Cenozoic. Because Dinocysts are acid-resistant and abundant in nearly all aquatic settings, the Dinocyst-based environmental and paleoclimatic information is complementary to the data derived from calcareous and siliceous microfossil groups such as foraminifers, calcareous nannoplankton, diatoms, and radiolarians. In some cases, the environmental information of Dinocysts even exceeds that of calcareous and siliceous microfossils. The present contribution provides an outline of the present-day knowledge on Dinocyst paleoecology. It reviews the potential of Dinocysts for the reconstruction of sea-surface productivity, temperature, and salinity as well as their application in sequence stratigraphy. Finally, it evaluates the applicability of Dinocysts in reconstructing the paleo-oxygenation in the bottom and pore waters of marine environments and in the lower water column of epeiric seas.
Karin A F Zonneveld - One of the best experts on this subject based on the ideXlab platform.
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late quaternary environmental dynamics inferred from marine sediment core geob6211 2 off southern brazil
Palaeogeography Palaeoclimatology Palaeoecology, 2018Co-Authors: Cristiano Mazur Chiessi, Karin A F Zonneveld, Hermann BehlingAbstract:Abstract Vegetation and climate changes in southern Brazil, as well as the dynamics of the adjacent South Atlantic were investigated through the analyses of pollen, spores and Dinocysts from marine sediment core GeoB6211-2 that covers the last 19.3 kyr. The pollen record indicates the dominance of grassland (campos) in southeastern South America (SESA), reflecting cold and/or dry conditions during the Last Glacial Maximum. Forests, mainly gallery forests, expanded slightly during Heinrich Stadial 1, suggesting slightly wetter conditions. A stronger expansion of the Atlantic lowland rainforest is noticed in the record after ca. 5.5 cal kyr BP, likely due to wetter conditions. The relatively high amount of exotic Nothofagus pollen, transported by wind, rivers and then by oceanic currents northwards to the study site, as well as the Dinocyst Brigantedinium spp., indicate a noticeable influence of the Brazilian Coastal Current from the south between 19.3 and 14.8 cal kyr BP. After that, the decrease in Nothofagus and Brigantedinium spp. together with the increase in Dinocyst Operculodinium centrocarpum indicate that the Brazil Current from the north dominated the coring site. The abundance of freshwater algae between ca. 19.3 and 17.0 cal kyr BP suggests that the Rio de la Plata mouth was located close to the coring site during this period, and its discharge of nutrient-rich freshwaters strongly affected the upper water column. Sea level rise decreased this impact during the late glacial phase by moving the coastline further away from the core site. The presence of the Brazil Current at the core site became stronger after ca. 15 cal kyr BP and strongest after 9 cal kyr BP. In summary, the pollen, spores and Dinocyst records from core GeoB6211-2 provide important climatic records to reconstruct the environmental changes in SESA.
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long term vegetation climate and ocean dynamics inferred from a 73 500 years old marine sediment core geob2107 3 off southern brazil
Quaternary Science Reviews, 2017Co-Authors: Karin A F Zonneveld, Cristiano Mazur Chiessi, Helge W Arz, Jurgen Patzold, Hermann BehlingAbstract:Abstract Long-term changes in vegetation and climate of southern Brazil, as well as ocean dynamics of the adjacent South Atlantic, were studied by analyses of pollen, spores and organic-walled dinoflagellate cysts (Dinocysts) in marine sediment core GeoB2107-3 collected offshore southern Brazil covering the last 73.5 cal kyr BP. The pollen record indicates that grasslands were much more frequent in the landscapes of southern Brazil during the last glacial period if compared to the late Holocene, reflecting relatively colder and/or less humid climatic conditions. Patches of forest occurred in the lowlands and probably also on the exposed continental shelf that was mainly covered by salt marshes. Interestingly, drought-susceptible Araucaria trees were frequent in the highlands (with a similar abundance as during the late Holocene) until 65 cal kyr BP, but were rare during the following glacial period. Atlantic rainforest was present in the northern lowlands of southern Brazil during the recorded last glacial period, but was strongly reduced from 38.5 until 13.0 cal kyr BP. The reduction was probably controlled by colder and/or less humid climatic conditions. Atlantic rainforest expanded to the south since the Lateglacial period, while Araucaria forests advanced in the highlands only during the late Holocene. Dinocysts data indicate that the Brazil Current (BC) with its warm, salty and nutrient-poor waters influenced the study area throughout the investigated period. However, variations in the proportion of Dinocyst taxa indicating an eutrophic environment reflect the input of nutrients transported mainly by the Brazilian Coastal Current (BCC) and partly discharged by the Rio Itajai (the major river closest to the core site). This was strongly related to changes in sea level. A stronger influence of the BCC with nutrient rich waters occurred during Marine Isotope Stage (MIS) 4 and in particular during the late MIS 3 and MIS 2 under low sea level. Evidence of Nothofagus pollen grains from the southern Andes during late MIS 3 and MIS 2 suggests an efficient transport by the southern westerlies and Argentinean rivers, then by the Malvinas Current and finally by the BCC to the study site. Major changes in the pollen/spore and Dinocyst assemblages occur with similar pacing, indicating strongly interlinked continental and marine environmental changes. Proxy comparisons suggest that the changes were driven by similar overarching factors, of which the most important was orbital obliquity.
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Variability in fossil dinoflagellate cyst wall composition as determined by micro-Fourier transform infrared (FTIR) spectroscopy
2011Co-Authors: Kara Bogus, Gerard J M Versteegh, Ian C. Harding, Ulrike Holzwarth, Karin A F ZonneveldAbstract:Dinoflagellate cyst (Dinocyst) walls are composed of dinosporin, which most likely represents a suite of chemically different biopolymers that could be species specific. This is suggested by evidence of selective cyst degradation as well as studies from different dinoflagellate lineages, which report different macromolecular structures varying between aliphatic, carbohydrate-like, and predominantly aromatic. In order to investigate both the nature of dinosporin, the extent to which it may differ between dinoflagellate cyst taxa, and structural changes through time, we analyzed numerous species of Dinocysts with micro-Fourier transform infrared (FTIR) analysis. Both Recent and Cretaceous age Dinocysts were used. Initial results demonstrate that the chemical diversity of components making up Dinocysts is great. It is quite probable that the Cretaceous-aged Dinocyst spectra also incorporate post-depositional alteration of the original cyst wall, which complicates the interpretation of the original dinosporin structure. However, attempts to group different dinosporins on the basis of structural features are ongoing. Very preliminary results indicate it may be possible to distinguish some ecological features from the FTIR spectra of the Recent Dinocysts.
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The potential of organic-walled dinoflagellate cysts for the reconstruction of past sea-surface conditions in the Southern Ocean
Marine Micropaleontology, 2007Co-Authors: Oliver Esper, Karin A F ZonneveldAbstract:Abstract In this study we investigate the potential of organic-walled dinoflagellate cysts (Dinocysts) as tools for quantifying past sea-surface temperatures (SST) in the Southern Ocean. For this purpose, a Dinocyst reference dataset has been formed, based on 138 surface sediment samples from different circum-Antarctic environments. The Dinocyst assemblages of these samples are composed of phototrophic (gonyaulacoid) and heterotrophic (protoperidinioid) species that provide a broad spectrum of palaeoenvironmental information. The relationship between the environmental parameters in the upper water column and the Dinocyst distribution patterns of individual species has been established using the statistical method of Canonical Correspondence Analysis (CCA). Among the variables tested, summer SST appeared to correspond to the maximum variance represented in the dataset. To establish quantitative summer SST reconstructions, a Modern Analogue Technique (MAT) has been performed on data from three Late Quaternary Dinocyst records recovered from locations adjacent to prominent oceanic fronts in the Atlantic sector of the Southern Ocean. These Dinocyst time series exhibit periodic changes in the Dinocyst assemblage during the last two glacial/interglacial-cycles. During glacial conditions the relative abundance of protoperidinioid cysts was highest, whereas interglacial conditions are characterised by generally lower cyst concentrations and increased relative abundance of gonyaulacoid cysts. The MAT palaeotemperature estimates show trends in summer SST changes following the global oxygen isotope signal and a strong correlation with past temperatures of the last 140 000 years based on other proxies. However, by comparing the Dinocyst results to quantitative estimates of summer SSTs based on diatoms, radiolarians and foraminifer-derived stable isotope records it can be shown that in several core intervals the Dinocyst-based summer SSTs appeared to be extremely high. In these intervals the Dinocyst record seems to be highly influenced by selective degradation, leading to unusual temperature ranges and to unrealistic palaeotemperatures. We used the selective degradation index (kt-index) to determine those intervals that have been biased by selective degradation in order to correct the palaeotemperature estimates. We show that after correction the Dinocyst based SSTs correspond reasonably well with other palaeotemperature estimates for this region, supporting the great potential of dinoflagellate cysts as a basis for quantitative palaeoenvironmental studies.
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Die Anwendung organischwandiger Dinoflagellatenzysten zur Rekonstruktion von Paläoumwelt, Paläoklima und Paläozeanographie: Möglichkeiten und Grenzen
Paläontologische Zeitschrift, 2004Co-Authors: Jörg Pross, Ulrich Kotthoff, Karin A F ZonneveldAbstract:Organischwandige Dinoflagellatenzysten (Dinozysten) aus marinen Sedimenten werden in den vergangenen zwei Jahrzehnten zunehmend als Indikatoren der Paläoumweltbedingungen, des Paläoklimas und der Paläozeanographie des jüngeren Mesozoikums und Känozoikums genutzt. Da Dinozysten lösungsresistent sind und in fast allen aquatischen Lebensräumen vorkommen, liefern die aus ihnen abgeleiteten Signale eine wertvolle Ergänzung zu den Signalen kalkiger und kieseliger Mikrofossilgruppen wie Foraminiferen, kalkigem Nannoplankton, Diatomeen und Radiolarien. Zum Teil geht die Aussagekraft von Dinozysten zur Paläoum-welt-Rekonstruktion sogar über diejenige kalkiger und kieseliger Mikrofossilien hinaus. Der vorliegende Beitrag gibt einen Überblick über den gegenwärtigen Wissensstand zur Paläoökologie von Dinozysten. Er diskutiert das Potenzial von Dinozysten zur Rekonstruktion von Produktivital, Temperatur und Salzgehalt in der oberen Wassersäule, zur Verwendung in der Sequenzstratigraphie sowie zur Rekonstruktion der Sauerstoffversorgung im Boden- und Porenwasser mariner Lebensräume und in der Wassersäule epikontinentaler Flachmeere. Over the past two decades, organic-walled dinoflagellate cysts (Dinocysts) have been increasingly used as paleoenvironmental and paleoclimatic indicators in marine sediments from the Mesozoic and Cenozoic. Because Dinocysts are acid-resistant and abundant in nearly all aquatic settings, the Dinocyst-based environmental and paleoclimatic information is complementary to the data derived from calcareous and siliceous microfossil groups such as foraminifers, calcareous nannoplankton, diatoms, and radiolarians. In some cases, the environmental information of Dinocysts even exceeds that of calcareous and siliceous microfossils. The present contribution provides an outline of the present-day knowledge on Dinocyst paleoecology. It reviews the potential of Dinocysts for the reconstruction of sea-surface productivity, temperature, and salinity as well as their application in sequence stratigraphy. Finally, it evaluates the applicability of Dinocysts in reconstructing the paleo-oxygenation in the bottom and pore waters of marine environments and in the lower water column of epeiric seas.
Henk Brinkhuis - One of the best experts on this subject based on the ideXlab platform.
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brackish to freshwater dinoflagellate cyst assemblages from the la colonia formation paleocene northeastern patagonia argentina
Ameghiniana, 2014Co-Authors: Henk Brinkhuis, Veronica M Guler, Marcela C Borel, Edgardo Navarro, Ricardo A AstiniAbstract:A palynological analysis of the section of La Colonia Formation exposed at Estancia San Miguel yielded conspicuous assemblages of organic-walled dinoflagellate cysts (Dinocysts) and green algae. The monotypic palaeoperidinioid Dinocyst assemblage of ?Ginginodinium sp. in the basal beds of this section indicates low-salinity water conditions in a restricted shallow marine paleoenvironment. The green-algae- dominated assemblages together with specimens of ?Morkallacysta spp., Dinocysts type P and ?Vesperopsis sp. recorded in the middle and upper part of the San Miguel section indicate brackish to freshwater and freshwater depositional conditions, respectively. The changes in the composition of the palynological assemblages, in agreement with the analysis of the sedimentary facies, reflect a salinity-drop in the water bodies and a progressive upward-shallowing trend. The occurrence of specimens of the neritic open marine Cribroperidinium spp., Apteodi- nium sp., Circulodinium sp. and Areoligera sp. cf. A. circumsenonensis Fensome et al. is here considered as reflecting contemporaneous trans- ported material from the adjacent shelf. The marine part of the La Colonia Formation is associated to Late Cretaceous and Paleocene ages. Nevertheless, palynomorphs together with a stratigraphical criterion suggest an age non older than Paleocene for the deposits of the unit at the San Miguel section.
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Correlation of Barremian-Aptian (mid-Cretaceous) dinoflagellate cyst assemblages between the Tethyan and Austral realms
Cretaceous Research, 2006Co-Authors: A M Oosting, H Leereveld, Gerald R. Dickens, Robert A. Henderson, Henk BrinkhuisAbstract:Quantified organic-walled dinoflagellate cyst (Dinocyst) assemblages are presented for two sedimentary successions deposited in neritic environments of the Tethys Ocean during the Barremian and Aptian in an attempt to reconcile established Dinocyst biostratigraphic schemes for Tethyan and Austral regions. One section is at Angles, southeast France (the Barremian stratotype section); the other is at Deep Sea Drilling Project Site 263, off northwest Australia. We also construct a carbon isotope record for Site 263 using bulk organic carbon. Both sections contain abundant, well-preserved Dinocyst assemblages. These are diverse, with 89 taxa identified at Angles and 103 taxa identified at Site 263. Of these, more than 93% are cosmopolitan. When combined with other work at Angles and Site 263, we found that nine Dinocysts have their first occurrence (FO) or last occurrence (LO) at both locations. These Dinocyst events are, in alphabetical order: LO of Cassiculosphaeridia magna, FO of Criboperidinium? tenuiceras, LO of Kleithriasphaeridium fasciatum, LO of Muderongia staurota, FO of Odontochitina operculata, LO of Phoberocysta neocomica, FO of Prolixosphaeridium parvispinum, FO of Pseudoceratium retusum var. securigerum, and FO of Tehamadinium sousense. Although these events support a Barremian–Aptian age for both sections, their stratigraphic order is not the same in the sections. The δ13Corg record at Site 263 displays a characteristic series of changes that have also been recorded in other carbon isotope curves spanning the Late Barremian–Early Aptian. Such independent dating (along with ammonite zones at Angles) suggests that three of the nine Dinocyst events are approximately isochronous at Angles and Site 263: the LO of K. fasciatum in the mid Barremian, the FO of P. retusum var. securigerum and the FO of C.? tenuiceras in the earliest Aptian; the other six Dinocyst events are diachronous. Dinocyst assemblages at Site 263 can be loosely placed within existing Australian zonation schemes, providing much-needed calibration. Our data suggest that the Muderongia testudinaria Zone ends in sediments of mid Barremian age, the succeeding Muderongia australis Zone extends into the Early Aptian, and the younger Odontochitina operculata Zone begins in Early Aptian deposits. The boundary between the M. australis and O. operculata zones, and the Ovoidinium cinctum (as Ascodinium) Subzone, positioned at the top of the M. australis Zone when present, could not be recognized incontrovertibly. Interestingly, however, this horizon broadly correlates with the onset and extent of the Selli Event, a time of major biogeochemical change.
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Organic-walled dinoflagellate cysts as paleoenvironmental indicators in the Paleogene; a synopsis of concepts
Paläontologische Zeitschrift, 2005Co-Authors: Jörg Pross, Henk BrinkhuisAbstract:The organic-walled, hypnozygotic cysts of dinoflagellates (“Dinocysts”) provide a rich, albeit incomplete, history of this eukaryotic plankton group in ancient sediments. Building on pioneering studies of the late 1970s and 1980s, recent ocean drilling and more detailed, integrated studies of surface sections have provided a wealth of dino-cyst data spanning the entire Paleogene. Based on multidisciplinary approaches, these studies have been instrumental in refining existing and furnishing new concepts of Paleogene paleoenvironmental and paleoclimatic reconstructions by means of Dinocysts. Since Dinocysts typically exhibit high abundances in neritic settings, the dinoeyst-based environmental and paleoclimatic information is complementary to that derived from typically more offshore groups such as planktonic foraminifera, coccolithophorids, diatoms, and radiolaria. While in a recent paper we gave a broad overview of case studies from around the globe ( Sluijs et al. 2005), here we focus on a summary of these analyses and present a synopsis of applied paleoecological concepts in Paleogene (65–24 ma) Dinocyst studies. Representing Earth’s greenhouse-icehouse transition, this episode holds the key to the understanding of extreme transient climatic change. The present paper offers guidelines for the application of Dinocyst palaeoecology to the reconstruction of Paleogene sea-surface productivity, temperature, salinity, stratification, and paleo-oxygenation as well as their application in sequence stratigraphy, oceanic circulation and general watermass reconstructions. Die organischwandigen, hypnozygoten Zysten von Dinoflagellaten („Dinozysten“) spiegeln die Entwicklung dieser eukaryoten Planktongruppe in der Erdgeschichte wider, wobei dieser Fossilbericht allerdings nicht vollständig ist, da er auf Zysten beruht. Aufbauend auf ersten richtungsweisenden Arbeiten der späten 70er und 80er Jahre haben neue, integrierende Untersuchungen an marinen Kernbohrungen und Landaufschlüssen zu einer Fülle neuer Erkenntnisse über Dinozysten des gesamten Paläogens geführt. Diese waren maßgeblich daran beteiligt, dass bestehende Vorstellungen zur Paläoumwelt- und Paläoklimaentwicklung des Paläogens verfeinert und neue Vorstellungen entwickelt werden konnten. Da Dinozysten üblicher Weise in neritischen Ablagerungsräumen häufig vorkommen, liefern die aus ihnen abgeleiteten Paläoumwelt- und Paläoklimasignale eine wertvolle Ergänzung zu den Signalen von Planktongruppen mit eher offenmarinem Verbreitungsschwerpunkt wie planktischen Foraminiferen, Coccolithophoriden, Diatomeen und Radiolarien. Da der Zeitraum des Paläogens den Übergang vom Treibhaus- zum Eishausklima der Erde umfasst, spielt er eine Schlüsselrolle zum Verständnis extremen Klimawandels auf kurzfristigen Zeitskalen. In einem vor kurzem erschienenen Beitrag ( Sluijs et al. 2005) gaben wir einen Überblick über Fallstudien zur Dinozysten-Ökologie aus dem Paläogen (65–24 ma) beider Hemisphären. Der vorliegende Beitrag präsentiert eine Zusammenfassung dieser Fallstudien und gibt eine Synopsis der verwendeten paläoökologischen Konzepte. Er bietet Leitlinien für die Verwendung der Paläoökologie von Dinozysten zur Rekonstruktion von Ober-flächenwasserproduktivität, -temperatur, -Salzgehalt, -stratifizierung, zur Rekonstruktion der Sauerstoff Versorgung sowie zur Nutzung dieser Signale in der Sequenzstratigraphic und bei der Rekonstruktion ozeanischer Zirkulationsmuster während des Paläogens.
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Oligocene dinoflagellate cyst biostratigraphy of the southern North Sea Basin
Review of Palaeobotany and Palynology, 2005Co-Authors: Stefaan Van Simaeys, Dirk K. Munsterman, Henk BrinkhuisAbstract:Abstract The Rupelian (Lower Oligocene) and Chattian (Upper Oligocene) stratotype sections are both defined on the basis of the southern North Sea Basin sedimentary successions. The characterisation of biotic events occurring within the stratotypes (and equivalents) is vital for the recognition of these stages outside the North Sea Basin. Although the restricted marine setting of the North Sea Basin during most of the Paleogene clearly hampers ‘traditional’ calcareous microfossil calibration, organic-walled dinoflagellate cysts (Dinocysts) are increasingly successful in the stratigraphic analysis and calibration of the marginal-marine North Sea Basin successions. Here we present a high-resolution Oligocene Dinocyst biostratigraphic zonation scheme for the southern North Sea Basin based on previously published and new Dinocyst studies from Belgium, northern Germany and The Netherlands. Eight (southern) North Sea Oligocene (NSO) Dinocyst zones (biozones) and four subzones are here defined. Their application on a regional and inter-regional scale is discussed. The stratigraphic important Late Oligocene Dinocyst taxon Triphragmadinium demaniae gen. and sp. nov. is formally described.
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from greenhouse to icehouse organic walled dinoflagellate cysts as paleoenvironmental indicators in the paleogene
Earth-Science Reviews, 2005Co-Authors: Appy Sluijs, Jörg Pross, Henk BrinkhuisAbstract:Abstract Dinoflagellates are an important component of the extant eukaryotic plankton. Their organic-walled, hypnozygotic cysts (Dinocysts) provide a rich, albeit incomplete, history of the group in ancient sediments. Building on pioneering studies of the late 1970s and 1980s, recent drilling in the Southern Ocean has provided a wealth of new Dinocyst data spanning the entire Paleogene. Such multidisciplinary studies have been instrumental in refining existing and furnishing new concepts of Paleogene paleoenvironmental and paleoclimatic reconstructions by means of Dinocysts. Because Dinocysts notably exhibit high abundances in neritic settings, Dinocyst-based environmental and paleoclimatic information is important and complementary to the data derived from typically more offshore groups as planktonic foraminifera, coccolithophorids, diatoms and radiolaria. By presenting case-studies from around the globe, this contribution provides a concise review of our present understanding of the paleoenvironmental significance of Dinocysts in the Paleogene (65–25 Ma). Representing Earth's greenhouse–icehouse transition, this episode holds the key to the understanding of extreme transient climatic change. We discuss the potential of Dinocysts for the reconstruction of Paleogene sea-surface productivity, temperature, salinity, stratification and paleo-oxygenation along with their application in sequence stratigraphy, oceanic circulation and general watermass reconstructions.
Bruce A Tocher - One of the best experts on this subject based on the ideXlab platform.
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a revised northern european turonian upper cretaceous dinoflagellate cyst biostratigraphy integrating palynology and carbon isotope events
Review of Palaeobotany and Palynology, 2015Co-Authors: Kate Olde, Martin A Pearce, Ian Jarvis, David Ulicný, Bruce A Tocher, Joao Trabuchoalexandre, Darren R GrockeAbstract:Organic walled dinoflagellate cyst (Dinocyst) assemblage data are presented for a new Turonian regional reference core (Bch-1) drilled at Běchary in the Bohemian Cretaceous Basin, east-central Czech Republic. The detailed stratigraphic framework for the section is summarised based on calcareous nannofossil and macrofossil biostratigraphy, regional e-log correlation, sequence stratigraphy and carbon isotope chemostratigraphy. Dinocyst results obtained for 196 samples from the 405 m long core offer the highest resolution (~ 22 kyr) stratigraphically well-constrained data set available to date for the Turonian Stage, 93.9–89.8 Ma. A Dinocyst biostratigraphic framework is presented based on the evolutionary first and last occurrence, first common occurrence, and acmes of key species. Published Dinocyst data from English Turonian Chalk successions in East Sussex, Berkshire, Kent and Norfolk are reviewed within a stratigraphic framework provided by macrofossil records and carbon isotope event (CIE) chemostratigraphy. Critical analysis of existing published Turonian Dinocyst zonation schemes shows them to be untenable. Correlation of the English Chalk data to Bch-1 provides a basis for defining a regional Dinocyst event stratigraphy with 22 datum levels, and a revised Dinocyst zonation scheme constrained within a chemostratigraphic framework of 10 major CIEs. The new zones consist of a Cenomanian Litosphaeridium siphoniphorum Zone, followed by the Cauveridinium membraniphorum Zone spanning the uppermost Cenomanian to Lower Coniacian. This is subdivided into: Senoniasphaera turonica (Lower–mid-Middle Turonian); and Raetiaedinium truncigerum (mid-Middle Turonian–mid-Lower Coniacian) subzones. The Oligosphaeridium pulcherrimum Zone (Senonisphaera rotundata Subzone) characterises the Lower Coniacian. The new stratigraphy offers a basis for improved correlation and dating of Upper Cretaceous successions.
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the cenomanian turonian boundary event oae2 and palaeoenvironmental change in epicontinental seas new insights from the Dinocyst and geochemical records
Palaeogeography Palaeoclimatology Palaeoecology, 2009Co-Authors: Martin A Pearce, Ian Jarvis, Bruce A TocherAbstract:Abstract Organic-walled dinoflagellate cyst (Dinocyst) and geochemical records across the Cenomanian–Turonian boundary (CTB) are presented for the NW European reference section at Eastbourne, England. Dinocyst and nannofossil fertility indexes indicate that an upwelling-driven productivity pulse accompanied a eustatic sea-level fall that preceded, by at least 40 kyr, the global rise in δ 13 C values that marks the onset of Oceanic Anoxic Event 2 (OAE2) and the deposition of black shales in the deep ocean. A marine productivity collapse in the latest Cenomanian is evidenced by the falling absolute and relative abundance of peridinioid Dinocysts, believed to be the product of heterotrophic dinoflagellates. This biotic change accompanied transgression and sharply rising sea-surface temperatures, following an Atlantic-wide episode of short-lived cooling. Geochemical tracers provide evidence of Caribbean–Colombian plateau volcanism. The increase in water depth caused by the latest Cenomanian transgression resulted in less eutrophic waters in epicontinental seas, where CTB biotic turnover was driven largely by water-mass changes rather than oxygen depletion. The species richness/absolute abundance ratio of Dinocysts is proposed as a water-mass stability proxy.
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The Cenomanian–Turonian boundary event, OAE2 and palaeoenvironmental change in epicontinental seas: New insights from the Dinocyst and geochemical records
Palaeogeography Palaeoclimatology Palaeoecology, 2009Co-Authors: Martin A Pearce, Ian Jarvis, Bruce A TocherAbstract:Abstract Organic-walled dinoflagellate cyst (Dinocyst) and geochemical records across the Cenomanian–Turonian boundary (CTB) are presented for the NW European reference section at Eastbourne, England. Dinocyst and nannofossil fertility indexes indicate that an upwelling-driven productivity pulse accompanied a eustatic sea-level fall that preceded, by at least 40 kyr, the global rise in δ 13 C values that marks the onset of Oceanic Anoxic Event 2 (OAE2) and the deposition of black shales in the deep ocean. A marine productivity collapse in the latest Cenomanian is evidenced by the falling absolute and relative abundance of peridinioid Dinocysts, believed to be the product of heterotrophic dinoflagellates. This biotic change accompanied transgression and sharply rising sea-surface temperatures, following an Atlantic-wide episode of short-lived cooling. Geochemical tracers provide evidence of Caribbean–Colombian plateau volcanism. The increase in water depth caused by the latest Cenomanian transgression resulted in less eutrophic waters in epicontinental seas, where CTB biotic turnover was driven largely by water-mass changes rather than oxygen depletion. The species richness/absolute abundance ratio of Dinocysts is proposed as a water-mass stability proxy.
Anne De Vernal - One of the best experts on this subject based on the ideXlab platform.
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Dinocyst and acritarch biostratigraphy of the Late Pliocene to Early Pleistocene at Integrated Ocean Drilling Program Site U1307 in the Labrador Sea
Journal of Micropalaeontology, 2020Co-Authors: Aurelie Aubry, Stijn De Schepper, Anne De VernalAbstract:Abstract. We have analyzed marine palynomorphs (mainly Dinocysts and acritarchs) from the Integrated Ocean Drilling Program Site U1307 in the Labrador Sea in order to establish a detailed biostratigraphy for the Late Pliocene to Early Pleistocene. We have defined three magnetostratigraphically calibrated Dinocyst and acritarch biozones in the Late Pliocene to Early Pleistocene. Zone LS1 is defined based on the highest occurrence of Barssidinium graminosum and covers the later Pliocene from 3.21 to 2.75 Ma. Zone LS2 is marked by the acme of Pyxidinopsis braboi which occurs between 2.75 and 2.57 Ma, thus encompassing the Plio–Pleistocene transition. Finally, zone LS3 extends from 2.57 to 2.23 Ma in the Early Pleistocene. The palynostratigraphic record of IODP Site U1307 is difficult to correlate to other North Atlantic and Nordic Seas sites mainly because of a different temporal resolution and a lack of well-defined biostratigraphic marker species at the basin scale. The low abundance, discontinuous occurrence and asynchronous events of warm-water Pliocene taxa such as Invertocysta lacrymosa, Impagidinium solidum, Ataxiodinium confusum, Melitasphaeridium choanophorum and Operculodinium? eirikianum suggest cooler conditions in the Labrador Sea than elsewhere in the North Atlantic, reflecting a strong regionalism. Nevertheless, as recorded at other locations in the North Atlantic, the disappearance of many Dinocyst and acritarch taxa around 2.75 Ma at Site U1307 reflects a strong ecological response accompanying the intensification of the Northern Hemisphere glaciation.
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Palynology, biostratigraphy, and paleoceanography of the Plio-Pleistocene at Ocean Drilling Program Site 887, Gulf of Alaska
Palaeogeography Palaeoclimatology Palaeoecology, 2020Co-Authors: Coralie Zorzi, Jens Matthiessen, Anne De VernalAbstract:Abstract Analyses of marine palynomorphs, including Dinocysts and acritarchs, from Pliocene-Pleistocene sediments of the Ocean Drilling Program (ODP) Site 887 in the Gulf of Alaska allowed the development of a biostratigraphic scheme, which we compared with bio-events in regional diatom and radiolarian zonations. The Dinocyst biostratigraphic scheme includes five biozones and four major boundaries. A first stratigraphic boundary, at 4.4 Ma, is associated with a change in productivity. The other boundaries, at 2.7 Ma, 1.7 Ma, and 0.7 Ma, correspond to the onset of the modern halocline, an intensified cooling period, and the end of the Mid-Pleistocene Transition respectively. Moreover, the analyses of Dinocyst assemblages illustrate long-term changes in the surface ocean after 5.3 Ma. The occurrence of Ataxiodinium zevenboomii, Impagidinium velorum, and Impagidinium patulum suggests warm-temperate conditions until approximately 4.2 Ma. Between 4.2 and 2.7 Ma, colder and less saline events marked by an increase in cold-tolerant species, such as Habibacysta tectata, suggest regional cooling and/or lower salinity of surface water, which might be related to Alaskan glacier meltwater discharges. From 2.7 to 1.2 Ma, the presence of Impagidinium pallidum and cysts of Pentapharsodinium dalei suggests low-salinity, cold, and stratified surface waters, whereas major drops in Dinocyst fluxes are linked to a decrease in productivity and harsh conditions. Progressive change from cold, stratified waters to warmer and saltier conditions occurred between 1.2 and 0.7 Ma during the Mid-Pleistocene Transition. After 0.7 Ma, Dinocyst assemblages are characterized by the alternating dominance of Brigantedinium spp. and Operculodinium centrocarpum, suggesting fluctuations between nutrient-rich, low-salinity, cold waters and cool-temperate environments.
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Distribution of Dinocyst assemblages in surface sediment samples from the West Greenland margin
Marine Micropaleontology, 2020Co-Authors: Estelle Allan, Anne De Vernal, Taoufik Radi, Diana Krawczyk, Matthias Moros, André Rochon, Marit-solveig Seidenkrantz, Sébastien ZaragosiAbstract:Abstract Palynological analyses of 60 surface sediment samples from West Greenland margin revealed high concentrations of dinoflagellate cysts (Dinocysts), particularly in the Disko Bugt area, where they reach >104 cysts g−1. Dinocyst assemblages are characterized by a relatively high species diversity and are dominated by Operculodinium centrocarpum, cysts of Pentapharsodinium dalei, Islandinium minutum, Islandinium? cezare, and Brigantedinium spp. On a regional scale, the overall assemblages show statistical relationships with sea-ice cover duration, primary productivity, salinity and summer-fall temperature. The cysts of Pentapharsodinium dalei, Operculodinium centrocarpum, and Spiniferites elongatus appear linked to high productivity and to characterize the late summer-fall bloom. Although Islandinium minutum and Islandinium? cezare are generally associated with a seasonally sea-ice covered environment, there is no linear relationship between their relative abundance and sea-ice concentration or duration on a regional scale, along the West Greenland margin. The abundance of these taxa primarily reflects cold and low-salinity water in the study area. Radionuclide measurements (210Pb and 137Cs) allow the distinction between two categories of samples, the “modern” ones likely encompassing the interval younger than 1950 CE, and the others that may be considered “sub-modern”. Statistical analyses indicate that Dinocyst assemblages belonging to “modern” and “sub-modern” categories are not significantly different. Hence, the Dinocyst assemblages of surface sediment samples, both “modern” and “sub-modern”, represent fluxes homogenized over a relatively long time interval, which illustrates a spatial distribution corresponding to the main gradient in oceanographic conditions. Consequently, Dinocyst assemblages in surface sediments can be assumed to represent the average “modern” conditions with a sufficiently high degree of confidence for their use in environmental studies and paleoclimate reconstructions.
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comparison of qualitative and quantitative dinoflagellate cyst approaches in reconstructing glacial interglacial climate variability at west iberian margin iodp shackleton site u1385
Marine Micropaleontology, 2017Co-Authors: Mariska Datema, Francesca Sangiorgi, Anne De Vernal, Gertjan Reichart, Lucas Joost Lourens, Appy SluijsAbstract:Abstract Dinoflagellate cysts (Dinocysts) are commonly used to reconstruct past environmental conditions at the sea surface, such as primary production, temperature and salinity. Abundances of selected Dinocyst taxa are used in qualitative indices, whereas the modern analogue technique (MAT) is used for quantitative reconstructions. Qualitative indices use process-based knowledge of present-day relations between the environmental variables and the distribution of Dinocysts, whereas the MAT is based on the assumption that past assemblages have modern counterparts that correspond to similar sea-surface conditions. Here we explore the potential of both approaches to reconstruct sea surface temperature (SST), production (SSP), salinity (SSS) and seasonality during the last 22 thousand years along the West Iberian Margin (WIM), at Integrated Ocean Drilling Program (IODP) Site U1385. We compare results to published paleoclimatic reconstructions. Our SST and SSS reconstructions provide the first continuous Dinocyst MAT-based SST and SSS records for this area and time interval. Qualitative and quantitative Dinocyst-based SST estimates from the WIM are similar and resemble previous SST estimates from Dinocysts, alkenones and foraminifers from nearby sites. The surface temperature trends and millennial-scale variations largely match those from the Greenland ice core records. Quantitative MAT-based SST estimates show increased seasonality in the glacial stage resulting from strong winter cooling. Dinocyst MAT-based salinity decreases concomitantly with cooling during the Younger Dryas and Heinrich Stadial 1 (HS1), likely related to the melting of icebergs that reached the region during HS1. Our qualitative and quantitative SSP estimates show higher values in the glacial stage compared to the Holocene, which is consistent with published records and supports the usefulness of both approaches. Small differences between SST tracer records may be explained by the limited number of modern analogues from warm ocean regions in the Dinocyst reference dataset for MAT, the small number of Dinocysts used in the qualitative estimates, the possible effect of a parameter other than temperature that might amplify noise, and/or seasonal biases of the tracer species. In any case, the advantage of the qualitative approach is to allow reconstructions in non-analogue situations. Regression of the qualitative index versus present-day SST also allows for a quantitative reconstruction, although over a limited range of SSTs (especially towards the lower end) and with quite some uncertainty, but produces reasonable values beyond the upper limit of the MAT. The MAT reconstructs more reliable SSTs, with a much smaller error of prediction, but only up to present-day WIM values, because it is based on the assumption that past assemblages have modern counterparts that correspond to similar sea-surface conditions, which is not always valid. The advantages of the MAT approach include its quantitative nature and insights into seasonality. Hence both approaches are complementary. At Site U1385, MAT can be used for reconstructions in the colder periods (YD, HS1 and glacial stage), with a small error of prediction and the quantified index can be used to estimate SST beyond the limit of the MAT (Holocene and B-A).
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Oceanographic regimes in the northwest Labrador Sea since Marine Isotope Stage 3 based on Dinocyst and stable isotope proxy records
Quaternary Science Reviews, 2014Co-Authors: Olivia T. Gibb, Claude Hillaire-marcel, Anne De VernalAbstract:Abstract Sea surface temperature (SST), salinity and density gradients in the upper water column of the northwest Labrador Sea have been reconstructed based on high resolution analysis of a core (HU2008-029-004PC) spanning the last ∼36 ka, raised off Hudson Strait. The modern analogue technique was applied to Dinocyst assemblages and combined with stable isotope data from Neogloboquadrina pachyderma left-coiled (Npl) for this purpose. Three oceanographic regimes were identified, broadly corresponding to the “glacial”, “deglacial” and “postglacial” intervals. The site remained under the direct influence of the Laurentide Ice Sheet (LIS) margin until the postglacial and did not record the Bolling-Allerod warming and weakly recorded the Younger Dryas event. The “glacial” regime lasted until ∼12.2 cal ka BP. It was characterized by generally low concentrations of Dinocysts within an assemblage indicative of quasi-perennial sea ice. The “deglacial” regime (ca 12.2–8.3 cal ka BP) was marked by increased biogenic fluxes and more diversified Dinocyst assemblages and possibly an enhanced subsurface inflow of North East Atlantic Deep Water. Warm summer (∼11 °C) but low winter (∼0 °C) sea surface temperatures, sea ice cover during about 3 months per year, and low summer salinity (∼28) suggest strong stratification in the upper water layer in relation to meltwater supply from the LIS. Following the final drainage of glacial Lake Agassiz through Hudson Strait, which is dated here at ∼8.3 cal ka BP, and the subsequent LIS collapse, increased summer salinity (up to ∼35) was accompanied by a reduced seasonal gradient of sea surface temperature from winter (∼3.8 °C) to summer (∼8.6 °C) suggesting enhanced penetration of North Atlantic Water. Weakened stratification of the surface water layer then allowed for winter convection and Labrador Sea Water formation, which is consistent with increased Npl-δ13C values in response to higher ventilation of the subsurface water layer.