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Integrated Ocean Drilling Program Expedition 313 recovered Miocene sequences at Holes M0027A and M0029A on the New Jersey shallow shelf that contain a characteristic acid-resistant organic component. The palynofacies within each sequence reflects variations in terrigenous versus authigenic flux through the Miocene that are associated with sea-level change. Very high ratios of terrigenous versus marine palynomorphs and of oxidation-resistant versus susceptible dinocysts are associated with seismic sequence boundaries, consistent with their interpretation as sequence-bounding unconformities generated at times of low sea level. Comparison of palynological distance from shoreline estimates with paleodepth estimates derived from foraminiferal data allows relative sea level to be reconstructed at both sites. Ages assigned using dinocyst biostratigraphy are consistent with other chronostratigraphic indicators allowing sequence boundaries to be correlated with Miocene oxygen isotope (Mi) events. Paleoclimatic evidence from the pollen record supports the global climate changes seen in the oxygen isotope data. Although chronological control is relatively crude, Milankovitch-scale periodicity is suggested for parasequences visible in thick sequences deposited in relatively deep water where substantial accommodation existed, such as during the early Langhian at Site 29 (Middle Miocene Climatic Optimum). Palynological analysis thus supports the long-held hypothesis that glacioeustasy is a dominant process controlling the architecture of continental margins.

Two discontinuous sediment trap records of organic-walled dinoflagellate cyst (dinocyst) flux, each sampling > 300 days within the years 2005–2009, were derived from two time-incremental traps deployed at 1500 m water depth east of New Zealand. The traps sampled flux from beneath two distinct surface water masses on either side of the Subtropical Front: (i) warm, seasonally macronutrient-depleted Subtropical and (ii) cold, micronutrient-limited Subantarctic waters. Nineteen dinocyst taxa or taxonomic groups were identified from the trap samples. Trap assemblages at both sites were dominated by cysts of Protoperidiniaceae, notably Brigantedinium spp., which comprised almost ~ 98% of the dinocyst flux. The seasonality of the dinocyst flux differed between the traps, with a pronounced spring flux in the Subtropical trap, while seasonal variation in the Subantarctic trap was relatively muted. In Subtropical waters, moderate correlation was observed between Protoperidiniaceae cyst flux and chlorophyll a concentrations in surface waters in the 3–4 weeks prior to sampling. In Subantarctic waters, there was a weak correlation between Protoperidiniaceae cyst flux and reduced intensity of storm-induced turbulence during the preceding 2–3 weeks. There was a large discrepancy between dinocyst assemblages in the traps and those observed in nearby sea-floor sediments. Protoperidiniaceae dinocysts, particularly Echinidinium and Brigantedinium , were highly under-represented in the sea-floor assemblages. These forms are more susceptible to degradation in oxygenated sediments than other dinocysts, but inter-annual variability in cyst flux, or short-term variation not covered by sampling discontinuities in the current study could also have contributed to this discrepancy. The major differences in the seasonality of dinocyst fluxes between the two water masses examined in this initial study, suggest that mean-annual rather than seasonal climatologies are more appropriate for dinocyst-based quantitative palaeoenvironmental reconstructions in the New Zealand region.

The analyses of coccoliths and dinocysts from the IMAGES core MD95-2033, collected on the Laurentian Fan (44°39.87N, 55°37.21W; water depth = 1412 m) in the northwest North Atlantic provide a new dataset to assess the magnitude of climatic changes during the Holocene with a millennial time resolution. Coccolith and dinocyst data were combined to reconstruct changes in past sea surface conditions. In addition, the dinocyst assemblages were used to reconstruct the sea-surface temperature (SST) and salinity (SSS) based on the modern analog technique. The distribution of the coccolith and dinocyst assemblages, suggests a succession of climatic events during the late Quaternary and early Holocene, linked to change in the influence of the Labrador Current and/or the St. Lawrence River discharge. The dinocyst assemblages recorded a thermal optimum during the mid-Holocene. In the late Holocene, coccolith concentrations show two peaks at 2.3 and 1.1 ky, which coincide with the presence of species with different ecological properties, likely due to the localized influence of the Slope Water Jet (SWJ) current. The presence of this current has played a role in the development of the coccolith and dinocyst assemblages and SST fluctuations, especially in the last 2 ky. Overall, the interaction between the St. Lawrence River, the SWJ, the LC, and the NAC has all controlled the SSS, SSTs, and the development of the coccolith and dinocyst assemblages, confirming a significant regionalism of the entire area.

International audience; Dinoflagellate cyst assemblages were analysed in four short sediment cores collected in the south Basin of the Caspian Sea for assessing environmental changes over the last few millennia. Two of these cores were dated by radionuclides. The sedimentation rate of one of them was very high, in the order of 20 mm per year. The interpretation of the four sequences is supported by a collection of 27 lagoonal or marine surface sediment samples. A sharp increase in the concentration of the dinocyst occurs after 1967, especially owing to Lingulodinium machaerophorum. Considering nine other cores covering parts or the whole of Holocene, it became clear that this species started to develop in the Caspian Sea only during the last three millennia. By analysing instrumental data and collating existing reconstructions of sea level changes over the last decades, we show that the main forcing for the recent increase of L. machaerophorum percentages and concentration is global climate change, especially sea surface temperature increase. Sea level fluctuations likely only have a minor impact. We argue that the recent increase in L. machaerophorum indicates that the Caspian Sea clearly is in the Anthropocene.

A 30,000 yr dinocyst and pollen record from the eastern equatorial Atlantic (off Cameroon) has been investigated in order to identify land–ocean linkages during the last deglacial transition. A strong correlation between the abundance of Brigantedinium spp. and the Ca/Fe ratio during the last glacial period suggests enhanced marine productivity in association with cool seawater temperatures and nutrient input linked to coastal upwelling and/or a proximal river mouth. Dry conditions are recorded on the adjacent continent with a significant representation of open vegetation indicators and the Afromontane taxon Podocarpus. After 17 calka BP these indicators register a sharp decline as a result of a climatic transition from the dry/cooler conditions of the last glacial period to the wetter/warmer conditions of the deglaciation. Simultaneously, dinocysts show a significant shift from dominant heterotrophs to an increasing abundance of autotrophs, reflecting warmer conditions. Significant changes are observed during the Younger Dryas, with a return to drier conditions and higher salinities. The start of the Holocene is marked by very low-salinity conditions, reflecting optimal monsoonal conditions over west equatorial Africa. The end of the African Humid Period is observed between 6 and 5 calka BP, followed by significant fluctuations in both terrestrial and oceanic proxies.

In order to investigate a possible connection between tropical northeast (NE) Atlantic primary productivity, Atlantic meridional overturning circulation (AMOC), and drought in the Sahel region during Heinrich Stadial 1 (HS1), we used dinoflagellate cyst (dinocyst) assemblages, Mg/Ca based reconstructed temperatures, stable carbon isotopes (δ13C) and geochemical parameters of a marine sediment core (GeoB 9508-5) from the continental slope offshore Senegal. Our results show a two-phase productivity pattern within HS1 that progressed from an interval of low marine productivity between ~ 19 and 16 kyr BP to a phase with an abrupt and large productivity increase from ~ 16 to 15 kyr BP. The second phase is characterized by distinct heavy planktonic δ13C values and high concentrations of heterotrophic dinocysts in addition to a significant cooling signal based on the reconstructions of past sea surface temperatures (SSTs). We conclude that productivity variations within HS1 can be attributed to a substantial shift of West African atmospheric processes. Taken together our results indicate a significant intensification of the North East (NE) trade winds over West Africa leading to more intense upwelling during the last millennium of HS1 between ~ 16 and 15 kyr BP, thus leaving a strong imprint on the dinocyst assemblages and sea surface conditions. Therefore, the two-phase productivity pattern indicates a complex hydrographic setting suggesting that HS1 cannot be regarded as uniform as previously thought.

The palynological investigation of core TM (27.7 m long) taken in a dried out lagoon reveals both Holocene vegetation history in the north-eastern foothills of the Alborz Mountains and past water level changes of the Caspian Sea (CS).The delay in woodland expansion at the beginning of the Holocene, which is typical of eastern Turkey, the Iranian plateau and recorded in the CS south basin, is only weakly felt as the region is close to glacial refugia of trees.The succession of the main trees out of their refugia has been established as deciduous Quercus, Carpinus betulus, Parrotia persica, and Fagus orientalis-Pterocarya fraxinifolia, presenting therefore close affinities to south European interglacials of the Early Pleistocene. This suggests a similarity in climate.A Pterocarya decline is observed after AD 495. The studied region is close to the easternmost tree distribution; this could explain why it has been affected earlier than elsewhere in the northern Alborz and the Caucasus. In addition human activities during the Sasanian Empire and the subsequent drying of the climate contributed to weakening the spread of this tree.A maximal sea level occurs in the first part of the Holocene from 10.6 to 7.2 cal. ka. It is suggested that the CS levels were significantly influenced by the monsoon precipitations over the western Himalayas (via the Uzboy inflow). This is followed by low levels from 7.2 to 3.5 cal. ka with a minimum at 3.9 cal. ka.The Neocaspian period should be considered a biozone rather than a chronozone, as the environmental conditions reconstructed from dinocyst assemblages are different in shallow shelf waters and in the deep basins.

Assemblages of organic-walled dinoflagellate cysts (dinocysts) from 116 marine surface samples have been analysed to assess the relationship between the spatial distribution of dinocysts and modern local environmental conditions [e.g. sea surface temperature (SST), sea surface salinity (SSS), productivity] in the eastern Indian Ocean. Results from the percentage analysis and statistical methods such as multivariate ordination analysis and end-member modelling, indicate the existence of three distinct environmental and oceanographic regions in the study area. Region 1 is located in western and eastern Indonesia and controlled by high SSTs and a low nutrient content of the surface waters. The Indonesian Throughflow (ITF) region (Region 2) is dominated by heterotrophic dinocyst species reflecting the region's high productivity. Region 3 is encompassing the area offshore north-west and west Australia which is characterised by the water masses of the Leeuwin Current, a saline and nutrient depleted southward current featuring energetic eddies.

Organic-walled dinoflagellate cyst (dinocyst) assemblages were examined in 120 sea floor sediment samples from the Southwest (SW) Pacific to highlight dinocyst distribution in the region. From these 120 samples, census counts of 40 samples were added to previously published census data from the Southern Hemisphere to form a modern dataset of 311 samples (SH-311). Cluster analysis (k-means clustering) of a 98-sample sub-set from the SW Pacific (NZ-98) reveals four distinct assemblages which coincide with modern Subantarctic surface water, the Subtropical Front and two clusters from Subtropical surface water. A similar clustering of the SH-311 dataset reveals an additional three assemblages, two associated with Polar waters colder than those sampled in the SW Pacific, and one that may be endemic to the South Atlantic Ocean. Multivariate ordination (canonical correspondence analysis and redundancy analysis) indicates that the dinocyst assemblages change most along a sea surface temperature (SST) gradient, in both the regional SW Pacific and Southern Hemisphere datasets. SST accounts for 38% to 56% of the species-environmental relationship after removal of covarying variables, and contributes 2-3 times the explainable inertia than the other environmental variables tested. Both modern datasets (SH-311 and NZ-98) are suitable as a training set for quantitative palaeotemperature transfer functions applied to Late Quaternary records, with the caveat that the modern assemblage also displays sensitivity to productivity, shoreline proximity, bottom water oxygen, and water mass; variation that may be exploited in certain situations. (c) 2013 Elsevier B.V. All rights reserved.

This article is made available through the Brunel Open Access Publishing Fund. Tsunami, storm and flood events are destructive agents that have the potential to cause much damage and cost lives. The coastal regions around the north-western Arabian Sea are prone to these natural disasters with recent events including the storm and flood of AD 1842, the Makran tsunami of 1945, and Cyclone Gonu in 2007. Despite their severity, the paucity of reliable historical records does not allow us to answer pertinent questions concerning their frequency, intensity and impact. Palaeo-event analysis from the geological record allows us to extend, and test, the historical record. Here we have dated and examined a 92 cm long sediment core from the tectonically active, cyclone and storm prone Chabahar Bay area (southern Iran). Our appraisal directly tests conventional proxies for identifying abrupt events (e.g. grain-size, geochemical data), which we supplement with a novel palynological (pollen and dinocyst) approach. Both sedimentological and palynological approaches suggest a large event whichwas dated at bAD 1808 ± 41, whereas geochemical approaches remain inconclusive. The increase of continentally derived pollen (Pinaceae, Salix, Betula and Typha–Sparganium), increases in Brigantedinium sp. and S. ramosus as well as decreases in Lingulodinium machaerophorum suggest enhanced fluvial delivery in association with a flood. This investigation provides evidence of a major flash-flood affecting the Chabahar Bay region at bAD 1808 ± 41 which we infer is the geological expression of the storm and associated flash flood of AD 1842. Moreover, our study demonstrates the utility of palynology in identifying and understanding the causes of abrupt events to complement more widely applied techniques.

Surface sediments from six box cores along the north-eastern Antarctic Peninsula document the dinoflagellate cyst (= dinocyst) and other non-pollen palynomorph (NPP) content soon after overlying ice shelves collapsed. Prince Gustav Channel (PGC) and Larsen-A (LA) areas exhibited markedly different dinocyst abundances, concentrations being low in LA (0–20 cysts g-1) and high in PGC (2600–9100 cysts g-1, average: c. 3800 cysts g-1). Since similar water masses impact both areas, differences may be due to low biological productivity, limited sediment accumulation, and/or restricted fine-grain deposition at Larsen-A. Islandinium minutum (Harland & Reid in Harland et al.) Head et al. dominated dinocyst assemblages, occurring as both excysted and encysted forms (lesser abundance). Other taxa (Echinidinium cf. transparantum Zonneveld, Impagidinium pallidum Bujak, Bitectatodinium tepikiense Wilson, Operculodinium centrocarpum Wall & Dale, Brigantedinium spp., Selenopemphix antarctica Marret & de Vernal, Polykrikos? sp. A, and Polykrikos schwartzii Bütschli) were rare. Such assemblage composition is unusual compared to previously published Southern Ocean data, but may be specific to ice shelf and/or recently ice-free environments. Alternatively, it may be attributable to excessive production facilitated by environmental factors and/or abundant food, or similar cyst morphologies produced by different dinoflagellates. Accompanying NPPs included zooplankton remains, acritarchs, and freshwater algae. Tintinnid loricae were most abundant (max. 800 g-1), followed by foraminiferal linings (max. 320 g-1), and the acritarch Palaeostomocystis fritilla (Bujak) Roncaglia (max. 150 g-1). Collectively, NPPs were more abundant in PGC compared to LA samples.

Dinoflagellate cyst (dinocyst), coccolith and planktic foraminiferal assemblages from a core in the western Iceland Sea were used to reconstruct and compare the surface ocean developments of the Holocene and the Last Interglacial (Marine Isotopic Stage or MIS 5e). While increasing subpolar planktic foraminifers from ~ 10 ka indicate subsurface warming peaking around 7.5 ka, the dinocyst data suggest that the uppermost ocean remained dominated by cold waters until ~ 6.5 ka. A reduced advection of cold polar waters through the East Greenland/East Icelandic Current thereafter entailed warmest and most saline Holocene conditions between 6.5 and 5 ka, in turn followed by a general cooling trend. By contrast, both planktic foraminifers and dinocysts show an increased presence of Atlantic (-type) waters from ~ 122 ka onward resulting in a MIS 5e thermal optimum around 120.5 ka. Nonetheless, occasional freshwater input from melting drift ice created stratified but also seasonally variable conditions during this first half of MIS 5e. This stratification signature disappeared at ~ 120 ka when a marked repositioning of the oceanographic fronts occurred. Slightly colder conditions are indicated by both phyto- and zooplankton from there on until the end of MIS 5e around ~ 117 ka. A late MIS 5e cooling at the Iceland Plateau is opposite to a late MIS 5e optimum observed in the eastern Nordic seas. This regional difference is likely explained by various feedback mechanisms following the major reorganisation of the oceanic fronts at ~ 120 ka. The Holocene and MIS 5e interglacial variability is not reflected in the (quasi-monospecific) coccolith assemblages and illustrates the low sensitivity of living coccolithophore communities to subtle temperature changes in the low-temperature regions of the Nordic seas. Overall, quite different surface water properties appear to have characterised both interglacial intervals, with a higher share of warm, Atlantic elements in the planktic communities during MIS 5e. This suggests a higher contribution of Atlantic waters in the southwestern Nordic seas probably due to a more northward expansion of the Irminger Current under weakened polar East Greenland/East Icelandic currents. Such a reduced influence of polar waters in the southwestern Nordic seas may thus explain other evidence for relatively warm conditions in MIS 5e all around southern Greenland.

This work presents results of complex research (palynological, macro- and microfaunistic, and paleomagnetic) of Upper Cretaceous deposits, opened by borehole no. 8 in the Russkaya Polyana District (the southern margin of the Omsk Depression, Southwestern Siberia). The paleontological data obtained allowed us to establish the age of deposits. Based on dinocysts, nannoplankton and spore-pollen complexes, the section of borehole no. 8 has been divided into Pokur, Kuznetsovo, Ipatovo, Slavgorod, and Gan’kino Formations. This work gives data on the composition of zonal palynomorphs, nannoplankton, and microfaunistic complexes. Based on the complex data obtained, the magnetostratigraphic section of Upper Cretaceous deposits has been developed. The section consists of three magnetozones: normal and two reversed polarity magnetozones. The Pokur, Kuznetsovo and Ipatovo Formation (Cenomanian-Santonian) belong to the long normal polarity magnetozone; the Slavgorod and Gan’kino Formations (Campanian-Maastrichtian), separated by a stratigraphic break, belong to reversed polarity magnetozones. The magnetostratigraphic section has been correlated with the general magnetostratigraphic and magnetochronological time scales.

Marine sedimentary section across the Paleocene/Eocene (P/E) boundary interval is preserved in the Dungan Formation (Lower Indus Basin), Pakistan. Four dinoflagellate zones in the P/E interval of the Rakhi Nala section (Lower Indus Basin) are identified and correlated. The quantitative analysis of the dinoflagellate cyst assemblages together with geochemical data are used to reconstruct the palaeoenvironment across the P/E interval. The dinocyst assemblages allow the local correlation of the Dungan Formation (part) of the Sulaiman Range with the Patala Formation (part) of the Upper Indus Basin and global correlation of the Zone Pak-DV with the Apectodinium acme Zone of the Northern and Southern hemispheres. The onset of the carbon isotopic excursion (CIE) associated with Paleocene Eocene Thermal Maximum (PETM) is used globally to identify the P/E boundary. The CIE for the total organic carbon (fine fraction) δ13CFF is of a magnitude of −1.7‰ is recorded for the first time in the Indus Basin. The Apectodinium acme precedes and straddles the onset of the CIE in the Indus Basin. This Apectodinium acme is also accompanied by a planktonic and benthonic foraminifera “barren zone.” The CIE in the Indus Basin, coupled with the changes in the dinocyst distribution and the benthonic and planktonic foraminifera assemblages, provides evidence of the changes associated with the PETM in this little-known part of the world. The benthonic foraminiferal assemblage indicates bathyal environment of deposition at the time of P/E boundary interval; the presence of dominantly open marine dinoflagellates and high planktonic foraminiferal ratio suggest that the water column at this site was well connected with the rest of the Tethys.

The Messinian salinity crisis (late Miocene) is one of the most fascinating paleoceanographic events in the recent geological history of the Mediterranean Sea, defining a time when it partly or nearly completely dried out. However, the relative roles of tectonic processes and sea-level changes, as triggers for restriction and isolation of the Mediterranean Sea from the open ocean, are still under debate. In this study, we present a detailed pollen, dinoflagellate cyst (dinocyst), and magnetic susceptibility analysis of a sequence of late Neogene (between ca. 7.3 and 5.2 Ma) marine sediments from the Montemayor-1 core (lower Guadalquivir Basin, southwestern Spain), which provides a continuous record of paleoenvironmental variations in the Atlantic side of the Betic corridors during the late Miocene. Our results show that significant paired vegetation and sea-level changes occurred during the Messinian, likely triggered by orbital-scale climate change. Important cooling events and corresponding glacio-eustatic sea-level drops are observed in this study at ca. 5.95 and 5.75 Ma, coinciding with the timing and duration of oxygen isotopic events TG32 and TG22–20 recorded in marine sediments worldwide. It is generally accepted that the onset of the Messinian salinity crisis began at ca. 5.96 ± 0.02 Ma. Therefore, this study suggests that the restriction of the Mediterranean could have been triggered, at least in part, by a strong glacio-eustatic sea-level drop linked to a climate cooling event occurring at the time of initiation of the Messinian salinity crisis.

The Ultrahelvetic Rehkogelgraben section of the Eastern Alps of Austria comprises a c. 5 m thick sequence of upper Cenomanian to lower Turonian pelagic sediments including black shales in a northwestern Tethyan paleogeographic setting. The following calcareous nannofossil events were recognized in stratigraphic order: The first occurrence (FO) of Quadrum intermedium , the LOs of Lithraphidites acutus and Corollithion kennedyi , the FO of Eprolithus octopetalus , and the FO of Quadrum gartneri . Thus, nannofossil zones UC 4, UC 5c, UC 6 and UC 7 could be recognized. Palynological investigations and palynofacies analysis give additional information especially from the black shale layers and the carbonate-free interval in the section. Five out of seven samples from this interval have yielded some low diversity but distinctive palynological associations. Sporomorphs dominate in the associations, being represented mainly by age diagnostic Normapolles species as Atlantopollis microreticulatus , Atlantopollis reticulatus together with Complexiopollis praeatumescens, Complexiopollis christae and Complexiopollis funiculus . The concurrent presence of these pollen species is regarded as characteristic for latest Cenomanian and early Turonian assemblages. A low diversity dinocyst association is identified, dominated by the Cyclonephelium compactum – Cyclonephelium membraniphorum complex, together with Isabelidinium and Circulodinium species. The dinocyst association is encountered in palynofacies rich in marine organic matter of granular amorphous composition. The palynofacies points to deposition in a distal, low-energy, stressed anoxic environment with high continental input. The palaeoenvironmental significance of the low diversity Cyclonephelium / Eurydinium association is typical for Cenomanian-Turonian black shale sequences. Nannofossil indices and dinoflagellate associations indicate rather low-productivity, low-nutrient settings during at least the later part of OAE 2, and thus confirm interpretations based on foraminiferal assemblages.

The Oligocene epoch represents a somewhat neglected chapter in paleoclimate and paleoceanographic history, which is at least partially due to the scarcity of complete Oligocene sedimentary archives and poor biostratigraphic age control. Many of the biotic events registered in Oligocene microfossils are strongly diachronous across latitudes as a response to increased global cooling and enhanced meridional temperature gradients. To improve biostratigraphic age control for the Oligocene of the North Atlantic Ocean, we carried out a high-resolution study of dinoflagellate cysts from Integrated Ocean Drilling Program (IODP) Sites U1405, U1406 and U1411 off Newfoundland. Together the sites comprise an apparently complete uppermost Eocene (34.9 Ma) to lowermost Miocene (21.7 Ma) sequence with good magnetostratigraphic age control. This allows us to firmly tie identified dinoflagellate cyst bioevents to the geomagnetic polarity timescale. In the dinoflagellate cyst assemblages studied we have identified and magnetostratigraphically-calibrated ten first and 19 last appearance datums. Our magnetostratigraphically-calibrated dinocyst-based biostratigraphy, which is based on an average sample resolution of a sample every ~ 150 kyrs, will contribute to an improved age framework for future paleoceanographical studies in the higher-latitude North Atlantic.

New dinoflagellate cyst (dinocyst) analyses were carried out at high-resolution in core MD99-2339, retrieved from a contouritic field in the central part of the Gulf of Cadiz, for the Marine Isotope Stage (MIS) 3 interval, allowing to discuss paleohydrological changes over the last 50 ky in the subtropical NE Atlantic Ocean. Some index dinocyst taxa, according to their (paleo) ecological significance, shed light on significant sea-surface changes. Superimposed on the general decreasing pattern of dinocyst export to the seafloor over the last 50 ky, paralleling the general context of decreasing aeolian dust fertilization, a complex variability in dinocyst assemblages was detected at millennial timescale. Enhanced fluvial discharges occurred during Greenland Interstadials (GI) and especially GI 1, 8 and 12, while enhanced upwelling cell dynamics were suggested during the Last Glacial Maximum and Heinrich Stadials. Finally, during the early Holocene, and more specifically during the Sapropel 1 interval (around 7–9 ka BP), we evidenced a strong decrease in dinocyst fluxes, which occurred synchronously to a strong reduction in Mediterranean Outflow Water strength, and that we attributed to an advection of warm and nutrient-poor subtropical North Atlantic Central Waters. Over the last 50 ky, our study thus allows capturing and documenting the fine tuning existing between terrestrial and marine realms in North Atlantic subtropical latitudes, not only in response to the regional climate pattern, but also to monsoonal forcing interfering during precession-driven northern hemisphere insolation maxima. This mechanism, well expressed during the Holocene, is superimposed on the pervasive role of the obliquity as a first major trigger for explaining migration of dinocyst productive centres in the NE Atlantic margin to the subtropical (temperate) latitudes during glacial (interglacial) periods.

A new 44 kyr long record of dinoflagellate (phytoplanktonic organisms) cysts (dinocysts) is presented from a marine sediment core collected on the Congolese margin with the aim of reconstructing past hydrological changes in the equatorial eastern Atlantic Ocean since Marine Isotopic Stage (MIS) 3. Our high-resolution dinocyst record indicates that significant temperature and moisture variations occurred across the glacial period, the last deglaciation and the Holocene. The use of specific dinocyst taxa, indicative of fluvial, upwelling and Benguela Current past environments for instance, provides insights into the main forcing mechanisms controlling palaeohydrological changes on orbital timescales. In particular, we are able, for the last 44 kyr, to correlate fluvial-sensitive taxa to monsoonal mechanisms related to precession minima–obliquity maxima combinations. While upwelling mechanisms appear as the main drivers for dinoflagellate productivity during MIS 2, dissolved nutrient-enriched Congo River inputs to the ocean also played a significant role in promoting dinoflagellate productivity between approximately 15.5 and 5 ka BP. Finally, this high-resolution dinocyst study permits us to precisely investigate the suborbital timing of the last glacial–interglacial termination, including an atypical warm and wet oceanic LGM signature, northern high-latitude abrupt climate change impacts in the equatorial eastern Atlantic, as well as a two-step decrease in moisture conditions during the Holocene at around 7–6 and 4–3.5 ka BP.

A palynological study of uppermost Maastrichtian to Lower Paleocene deposits from a stratigraphic section of the Vrancea Nappe (Eastern Carpathians), reveals the presence of diverse and well-preserved dinoflagellate cyst assemblages. The biostratigraphic interpretation of these dinocyst assemblages suggests that (1) the Cretaceous-Paleogene boundary lies within a ~8 m thick sedimentary interval, between the Lepsa Formation (uppermost Maastrichtian) and Putna-Piatra Uscata Formation (Lower Danian), based on the Last Appearance Datum of latest Maastrichtian markers such as Pterodinium cretaceum and Palynodinium cf. grallator and on the First Appearance Datum of Danian markers such as Senoniasphaera inornata, Xenicodinium lubricum, Tectatodinium rugulatum and Eisenackia circumtabulata , and (2) a discontinuity between the two formations. The palynofacies analysis from this geological section indicates an abundance of continental organic matter (mainly opaque phytoclasts), deposited in a distal setting of the sedimentary basin. The occurrences in the palynological assemblage of some oceanic dinocyst taxa such as Impagidinium and Pterodinium suggest the same depositional environment for the geological formations analysed.

During the late Miocene, the Mediterranean developed into a hypersaline basin wherein ultimately gypsum and halite precipitated. Little is known about the evolution of the Paratethys Sea, which was situated northeast of the Mediterranean. The results described in this thesis provide valuable new insights in the late Miocene evolution of the Paratethys Sea. The migration patterns of dinoflagellate cysts and strontium isotope ratios confirm previous studies that the Pontian Flooding event (re-) connected the major Paratethyan basins at ~6.1 Ma. Furthermore, this thesis provides evidence that the Paratethys Sea did not desiccate during the Messinian Salinity Crisis (MSC; 5.97-5.33 Myr ago). The claim that the deep Black Sea Basin desiccated in response to the MSC is based on incorrect age constraints for a peculiar layer (the so-called “Pebbly Breccia”) in DSDP Hole 380A. During the MSC, dinocyst assemblages in the Paratethys seem unaffected by the events occurring in the adjacent Mediterranean Basin. Indications of continuous presence of fresh and brackish waters in the Paratethys suggest that the Paratethys with its enormous hinterland could have played a major role in MSC.

During the late Miocene, the Mediterranean developed into a hypersaline basin wherein ultimately gypsum and halite precipitated. Little is known about the evolution of the Paratethys Sea, which was situated northeast of the Mediterranean. The results described in this thesis provide valuable new insights in the late Miocene evolution of the Paratethys Sea. The migration patterns of dinoflagellate cysts and strontium isotope ratios confirm previous studies that the Pontian Flooding event (re-) connected the major Paratethyan basins at ~6.1 Ma. Furthermore, this thesis provides evidence that the Paratethys Sea did not desiccate during the Messinian Salinity Crisis (MSC; 5.97-5.33 Myr ago). The claim that the deep Black Sea Basin desiccated in response to the MSC is based on incorrect age constraints for a peculiar layer (the so-called “Pebbly Breccia”) in DSDP Hole 380A. During the MSC, dinocyst assemblages in the Paratethys seem unaffected by the events occurring in the adjacent Mediterranean Basin. Indications of continuous presence of fresh and brackish waters in the Paratethys suggest that the Paratethys with its enormous hinterland could have played a major role in MSC.

Estuaries are dynamic systems that collect terrestrial, aerial, fluvial, and marine inputs, including organic microfossils, which, when fossilized and observed on palynological slides, are also referred to as palynomorphs (pollen and non-pollen palynomorphs including dinoflagellate cysts or dinocysts). To understand these organic microfossil deposit arrangements across the Loire estuary, palynomorph counts were undertaken in 31 surface sediments collected across longitudinal and perpendicular transects of the Loire active riverbed, from the upper inner estuary to the river mouth. Main results suggest a large homogeneity of the pollen content throughout the entire upstream-downstream transect, with a dominance of arboreal taxa (Pinus, Quercus, Alnus) and Poaceae. Also, perpendicular transects across the channel show a great similarity between the muddy surface layers and the underlying consolidated clay layers. This is probably due to: i) homogeneity of the landscape at a regional scale (large catchment area of the Loire River), and ii) complex hydrodynamic processes involving strong mixing of the palynological signal. Furthermore, despite scarce woodlands in the regional landscape, arboreal pollen (especially Pinus and Quercus) represents > 60% of the total pollen percentages. This could be explained by several factors: i) generally higher arboreal pollen production and dispersion as compared to herbaceous taxa, ii) distant inputs from marine areas downstream and/or forested regions far upstream, and iii) differential selection or inheritance from underlying sediments. Differentiation between the outer and inner estuarine environments was furthermore possible using a ratio of terrestrial versus marine palynological indicators. Among the dinocyst assemblages (marine realm), the euryhaline species Lingulodinium machaerophorum predominates; this taxon being very sensitive to strong water column stratification. Also, total dinocyst concentration increased upstream, which may result from the tidal forcing pushing salinity upriver beneath outflowing river water, and thus signing the estuarine turbidity maximum influence within the Loire River.

International audience; Seasonal distribution of dinoflagellate cysts were studied at five surface sediment study stations in Ghar El MelhLagoon (GML) (Tunisia) in relation to physicochemical parameters and phytoplankton abundance in the watercolumn. At least sixteen dinocyst types were identified, dominated mainly by Protoperidinium spp., Scrippsiellatrochoidea complex, Lingulodinum machaerophorum, Alexandrium spp. and Gymnodinium spp., along with manyround brown cysts. Cyst abundance ranged from 0 to 229 g−1 dry sediment. No significant differences in cyst distributionwere found among stations, though a significant variation was observed among seasons with cyst dominancein autumn. No significant variation was found between cyst abundance and the different abiotic factorsmonitored, neither in the water column (physicochemical parameters) nor in the sediment (% H2O). Low dinocystabundance was consistent with the dominance of non-cyst-forming dinoflagellates in the GML water column.

The Contessa Valley and the Bottaccione Gorge located close to Gubbio (central Italy) include some of the most complete successions of Paleogene sediments known from the Tethyan realm. Owing to the continuous deposition in a pelagic setting, a rather modest tectonic overprint, and the availability of excellent age control through magnetostratigraphy, biostratigraphy, chronostratigraphy, and tephrostratigraphy, and direct radioisotopic dates from interbedded volcaniclastic layers, these sediments have played a prominent role in the establishment of standard Paleogene time scales. We present here a complete and well-preserved Paleogene pelagic composite succession of the Gubbio area that provides the means for a more accurate and precise calibration of the Paleogene time scale. As a necessary step toward the compilation of a more robust database on a wide scale so to improve the magnetostratigraphic, biostratigraphic, and chronostratigraphic framework of the classical Tethyan zonations, enabling regional and supraregional correlations, we have constructed a record of reliable Paleogene planktonic foraminifera, calcareous nannofossil, and dinocyst biohorizons commonly used in tropical to subtropical Cenozoic zonations. In addition, an age model is provided for the Paleogene pelagic composite succession based on magnetostratigraphy, planktonic foraminifera, calcareous nannofossils, and dinocysts that contributes to an integrated chronology for the Paleogene Tethyan sediments from 66 to 23 Ma.

For the first time a combined palynological and δ13C-isotope study has identified the Oligocene–Miocene boundary — and thus the base of the Neogene — within the North Sea Basin. The type section, the Lemme–Carrosio section in northern Italy, is correlated with the Frida-1 well in the eastern (Danish) part of the North Sea Basin using a combination of data from a previous dinocyst stratigraphic study and new δ13C-isotope data. The results show that the Oligocene–Miocene boundary is located at a depth of 1440 m in the Frida-1 well. The Frida-1 δ13C-isotope curve further reflects the Mi-1 glaciation event also recorded in the Lemme–Carrosio section. The dinocyst events bracketing the boundary in Frida-1 are; the last occurrence (LO) of Distatodinium biffii at 1630 m, below the boundary, the LO of Chiropteridium spp. at 1370 m and first occurrence (FO) of Ectosphaeropsis burdigalensis at 1330 m, both above the boundary. An influx of Deflandrea phosphoritica is found in an interval immediately below the boundary (1532–1490 m), while the genus Homotryblium occurs abundantly in a broader interval (1650–1330 m) encompassing the boundary. Hitherto unpublished data combined with new data provide a series of stratigraphically important nanno- and micropalaeontological events that frame/characterise the Oligocene–Miocene boundary within the North Sea Basin; an almost monospecific assemblage of Reticulofenestra bisecta at 1630 m, the LO of Elphidium subnodosum at 1625 m, the LO of Aulacodiscus insignis quadrata (Diatom sp. 3 of King, 1983) at 1610 m, the LO of Karreriella seigliei at 1580 m and the LO of Pararotalia canui at 1570 m, all below the boundary, and the FO of Aulacodiscus aemulans (Diatom sp. 5 of King, 1983) at 1410 m and the LO of Aulacodiscus aemulans at 1250 m, both above the boundary. The dinocyst, nanno- and micropalaeontological studies thus provide a series of bioevents and abundance variations which can be used to locate and to correlate the Oligocene–Miocene boundary within the eastern North Sea Basin more precisely than was previously possible.

Dinoflagellate cysts (dinocyst) are often used to trace environmental history within the marine realm. However, the recognition of a eutrophication signal in dinocyst records is ambiguous. In addition, as few studies have focussed on the climate signal as recorded by dinocyst proxies over a moderately short time scale, a moderately short temporal record of dinocysts in sediments from two cores recovered in the Changjiang estuary, East China Sea was investigated. Total cyst concentrations and Paralytic Shellfish Poison (PSP) cyst concentrations increased with eutrophication, and total cyst concentrations, run-off from the Changjiang River and Oceanic Nino Index peaks co-occurred. Total cyst concentrations and PSP cyst concentrations may be a potential eutrophication signal in subtropical estuaries and the climate signal could be recorded in the cyst assemblages in estuaries within a moderately short time scale as the run-off from rivers and their nutrient load changed over time.

From the exploration core S75 that covers the Cenomanian/Turonian Boundary Event (CTBE) and lower Turonian at Tarfaya, Morocco, northwest Africa, 96 samples from a section 24.5 m thick was analysed palynologically. The palynological data are discussed with various data on isotope- and bio-geochemistry as well as on time series analyses published by Kolonic et al. (2005, Paleoceanography 20, PA 1006) and Kuhnt et al. (2005, Int. J. Earth Sci. 94, 147–159). The dinocyst assemblage is of low to moderate diversity and strongly dominated by peridinioids throughout most of the section. It is suggested, that potentially eccentricity controlled cycles of increased total organic carbon (TOC) accumulation are closely related to increases of the ratio in proportions of peridinioid to gonaulacoid dinocysts (p/g ratio) and proportions of Botryocccus as well as of Bosedinia spp., a peridinioid cyst of probable strongly reduced-salinity water. At higher resolution, however, episodic increases in the p/g ratio are more punctuated in distribution and largely inversely correlated to abundances of Bosedinia spp. It is suggested that warm-humid climatic boundary conditions prevailed in the Tafaya region, episodically superimposed by upwelling events, reflected by increased proportions of Palaeohystrichophora spp. and Subtilisphaera spp. Accordingly, enhanced preservation, supported by strong episodic production pulses, is proposed for the TOC accumulation in the Tarfaya Basin. The p/g ratio peaks decrease both in prominence and frequency when pre-excursion values of δ 13 C isotopes are re-established after the positive anomaly. This may reflect a moderate shift in control from production to preservation of TOC following the CTBE proper. With respect to δ 18 O isotopes, episodes of pre-excursion values, possibly reflecting moderate cooling intervals and eustatic sea-level fall, are characterised by the appearance of dinocyst taxa diagnostic of neritic waters. This may reflect the gradual change from pelagic sedimentation characteristic of the plateau- and early recovery-period of δ 13 C isotopes towards neritic conditions within the late recovery and post-excursion period. Biomarkers suggestive of photic zone oxygen deficiency show only a limited relationship to the distribution of the different algal groups. However, according to the quantitative distribution of prasinophytes, considered to be critically controlled by ammonium availability, denitrification was more prominent during the late Cenomanian interval of the section and decreased significantly with the onset of the Turonian.

This work discusses the complex characteristic of the Upper Cretaceous (Turonian-Lower Maastrichtian) section recovered by two boreholes in the southern part of the Volgograd region (right side of the Volga River) in the Gremyach’e potash deposit. Lithological and paleontological data (benthic foraminifers, radiolarians, and dinocysts) suggest several lithological-facies and biotic reorganizations. The analysis of the distribution of these microfossils through the section allowed the ages of the Zakharovo Group, Mozhzhevelovyi Ovrag, Mezino-Lapshinovka, Pudovkino, Zarya, Nalitovo, and Bereslavka Formations to be specified. Benthic foraminifers characterize zones of the Upper Cretaceous high-resolution scale available for the East European Platform and local (facies) units, while radiolarians and dinocysts reveal stratigraphic units in a bed rank. Using complex paleontological characteristics (benthic foraminifers, radiolarians, dinocysts), the defined biostratigraphic units are correlated between each other and with their counterparts in neighboring and remote regions of different paleobiogeographic regions and provinces. The Upper Cretaceous biostratigraphic scale is supplemented by the first defined dinocyst and radiolarian biostratigraphic units of the East European Platform. The new data provides evidence in favor of a three-substage division of the Campanian Stage instead the two-substage system presently accepted in Russia. It is shown that the traditional position of the lower boundary of the Maastrichtian Stage in the East European Platform is close to that of this boundary in the Standard Stratigraphic Scale. Some aspects of environmental and biotic evolution in the Volgograd region through the Late Cretaceous Epoch are considered.

There has been much debates on the geologic age of the sediments of the Domi Basin, since age results varied after research methods and fossil groups. This study carried out palynological analysis and seismic interpretation to establish a stratigraphy and environmental reconstruction mainly based on fossil dinoflagellates and Seismic data from the Domi-1 and Sora-1 wells. The dinocyst assemblages found enabled zonation of the well sediment sequence resulting in 4 ecozones. Index fossils among dinocysts and palynomorphic substances indicate geologic age of the well ranges from Eocene to Pleistocene, and paleoenvironment varies from freshwater to inner-neritic marine. The fossil association also suggests strong relationship to Japanese Tertiary basins in Kyushu area in terms of stratigraphy and basin developmental history.

The first comprehensive 87Sr/86Sr analysis of the Lower Cretaceous of Australia is presented, derived from a suite of well-preserved Barremian–Cenomanian belemnite rostra. Samples were obtained from the east Australian platform (northern Eromanga Basin, with additional material from selected Aptian and Albian stratigraphic horizons in the southern Eromanga, Carpentaria and Laura basins) and the Carnarvon Basin. Strontium-isotope ratios plotted for the Carnarvon Basin and a composite curve for the east Australian platform permit close correlation of their lithostratigraphic successions. Comparison to the global strontium-isotope reference curve confirms stage assignments and significant disconformities in both successions as recognised from biostratigraphy. Adjustments are required to the ages of some dinocyst biozones of importance in the Australian early Cretaceous time scale. On the basis of the strontium-isotope data the Muderongia australis/Odontochitina operculata boundary is Barremian, and the Pseudoceratium ludbrookiae Zone is longer ranging, extending across the late Albian and into the earliest Cenomanian. A small but persistent offset in Albian strontium-isotope ratio values for samples from the east Australian platform relative to those from the Carnarvon Basin might be attributed to the local influence of siliceous volcanism along the east Australian margin. Eustatic trends for the epeiric sea, which related to the east Australian platform succession and the west Australian continental shelf represented by the Carnarvon Basin succession, are closely matched in time. An Aptian excursion to less radiogenic strontium-isotope values is correlative with transgressive marine inundation of the Australian continent, consistent with the enhanced global generation of new ocean floor as the driving mechanism for both sea-level rise and the isotopic trend. An excursion towards more radiogenic values in the Albian, also associated with transgression, is attributed to global warming and an enhanced continental strontium flux as a result of weathering.

The Paleocene-Eocene transition is one of the most remarkable Cenozoic periods coinciding with the global thermal maximum (PETM). Based on the complex biostratigraphic analysis of diatoms, silicoflagellates, and dinocysts, this global event is revealed in three sections of the Middle Trans-Urals region (Kamyshlov, Korkino, Chumlyak) represented by marine biosiliceous sediments of the Serov and Irbit formations. The interval of the Trinacra ventriculosa-Hemiaulus proteus-Coscinodiscus uralensis diatom zones is marked by the appearance of new genera Moisseevia, Solium, Fenestrella, Craspedodiscus, Podosira, Pseudotriceratium, intense radiations of Grunoweiella and Coscinodiscus, and development of extreme morphotypes among silicoflagellates. The defined diatom assemblages differ slightly from their coeval counterparts from the Middle Volga region, which casts doubt upon the assumed stable water exchange between these basins. On the contrary, the dinocyst assemblages are lacking zonal index species (Appectodinium homomorphum, A. augustum) and Apectodinium acme characteristic of the transitional Paleocene-Eocene strata in many worldwide localities. The facies settings of his period with intense vertical mixing and relatively low temperatures and salinity are characterized by the dominant role of dinocysts belonging to the genera Areoligera, Deflandrea, Spiniferites, and Operculodinium.

Dinocysts recovered from sediments related to the Chesapeake Bay impact structure in Virginia and the earliest Eocene suboxic environment in Maryland show strange and intriguing details of preservation. Features such as curled processes, opaque debris, breakage, microborings and cyst ghosts, among others, invite speculation about catastrophic depositional processes, rapid burial and biological and chemical decay. Selected specimens from seven cores taken in the coastal plain of Virginia and Maryland show abnormal preservation features in various combinations that merit illustration, description, discussion and further study. Although the depositional environments described are extreme, many of the features discussed are known from, or could be found in, other environments. These environments will show both similarities to and differences from the extreme environments here.

A high-resolution palynological study carried out across the Cretaceous/Palaeogene (K/Pg) boundary in two sections (Knappengraben and Gamsbach) of the Gosau Group near Gams (Gams Basin, Northern Calcareous Alps, Austria) has identified over 178 dinoflagellate species and subspecies from 89 rock samples. In most samples, the dinocysts are moderately well to well preserved, but associated with reworked material. Some well-known marker species around the K/Pg boundary, such as Carpatella cornuta, Spongodinium delitiense, Trithyrodinium evittii, Palynodinium grallator, Manumiella druggii, Cordosphaeridium fibrospinosum, Membranilarnacia? tenella, Senoniasphaera inornata, Damassadinium californicum, and Dinogymnium acuminatum have been recorded from the samples studied. In addition to these, Trabeculidinium quinquetrum, Lejeunecysta izerzenensis, Batiacasphaera rifensis, Impagidinium maghribensis and Cyclonophelium compactum represent local markers. A Spongodinium delitiense acme is recorded in both sections above the K/Pg boundary and is interpreted to indicate a transient cooling event of oceanic surface waters. The stratigraphic distribution of the dinocyst species indicates that they were not seriously affected by the mass extinction event at the K/Pg boundary, but their diversity slightly increases above it. The composition of the assemblages, however, changes drastically. Six dinocyst assemblages and four palynofacies assemblages were identified by means of cluster analysis. Their distribution does not show any regular pattern. The increase of phytoclasts in the Danian clearly indicates enhanced terrestrially derived input into the basin. The palynological and sedimentological differences between the two sections can be explained by small scale local lateral variations.

In order to document long-term climate cycles and predict future climate trends for the Arctic, geological records archived in ocean sediments can help establish the link between historical and pre-historical sea-surface parameters. Dinoflagellate cysts (dinocysts) are used as proxy indicators of sea-surface parameters (temperature, salinity, sea-ice cover, primary productivity) jointly with transfer functions and a modern dinocyst reference database, to reconstruct the evolution of sea-surface conditions at decadal and millennial timescales. Here we present the surface distribution of recent dinocyst assemblages in 13 surface samples collected in four Nunatsiavut fjords (northern Labrador, Canada) along a latitudinal gradient, and their relationship with various environmental and biological parameters. Dinocyst concentrations in surface sediments increased from the inner to the outer part of each fjord and also from the northernmost to the southernmost fjords. There was also a southward increase in the species diversity with an occurrence and a dominance of cysts from autotrophic dinoflagellates. The presence of cysts of the calcareous dinoflagellate species Scrippsiella cf. S. crystallina in Anaktalak Fjord, where mining activities are underway, appears to be an indicator of human-related pollution within the fjord.

Two sections from the Cenomanian–Turonian boundary event (CTBE) at Tarfaya, northwest Africa, were analysed fully quantitatively by marine palynology. The results are compared and integrated with published data from micropalaeontology, total organic carbon content (TOC), isotope geochemistry and, for selected intervals, the distribution of chlorobactanes. A rise in eustatic sea level, composed of several third-order transgression pulses, is reflected by various palynologic proxies. A combination of productivity and preservation is proposed as the main control on TOC accumulation preceding and across the CTBE. Strong episodic upwelling events, reflected by significant increases of the peridinioid/gonyaulacoid (p/g) ratio of dinocysts, are documented at the onset of eustatic transgression and closely preceding the onset as well as within the plateau stage of the positive δ13C anomaly. These events are considered as initial and sustaining causes respectively for TOC accumulation. The peak abundance of both green algal groups, Botryococcus and prasinophytes, is coincident with pelagic sedimentation and is strongly related to the increase of both oxygen deficiency in the water column and total organic carbon content. An episodic halocline stratification of the water column is suggested, possibly related to both a globally intensified hydrologic cycle and a current induced input of high- to middle-latitude surface waters into the Tarfaya Basin. This is corroborated by the prominent episodic appearance of Bosedinia, a peridinioid dinocyst with probable freshwater/reduced salinity affinity, as well as several euryhaline taxa common within late Mesozoic high to mid-latitude waters. A slight correlation with contents of chlorobactanes is documented at least for the prasinophyte distribution, which may reflect a moderate availability of reduced nitrogen within photic zone waters. However, maxima of chlorobactanes are related to palynologically barren or depleted intervals, possibly reflecting the sulfidic stage of redox conditions within photic zone waters. The almost coeval appearance of the suggested high-latitude taxon ?Ginginodinium sp. close to the onset of the δ13C anomaly both at Tarfaya and at Wunstorf, northwest Germany, corroborates a connection of surface water circulation between high and low latitude sites during the eustatic sea-level high.

Palynological analyses were performed on 53 surface sediment samples from the North Pacific Ocean, including the Bering and Okhotsk Seas (37–64°N, 144°E–148°W), in order to document the relationships between the dinocyst distribution and sea-surface conditions (temperatures, salinities, primary productivity and sea-ice cover). Samples are characterized by concentrations ranging from 18 to 143 816 cysts/cm3 and the occurrence of 32 species. A canonical correspondence analysis (CCA) was carried out to determine the relationship between environmental variables and the distribution of dinocyst taxa. The first and second axes represent, respectively, 47% and 17.8% of the canonical variance. Axis 1 is positively correlated with all parameters except to the sea-ice and primary productivity in August, which are on the negative side. Results indicate that the composition of dinocyst assemblages is mostly controlled by temperature and that all environmental variables are correlated together. The CCA distinguishes 3 groups of dinocysts: the heterotrophic taxa, the genera Impagidinium and Spiniferites as well as the cyst of Pentapharsodinium dalei and Operculodinium centrocarpum. Five assemblage zones can be distinguished: 1) the Okhotsk Sea zone, which is associated to temperate and eutrophic conditions, seasonal upwellings and Amur River discharges. It is characterized by the dominance of O. centrocarpum, Brigantedinium spp. and Islandinium minutum; 2) the Western Subarctic Gyre zone with subpolar and mesotrophic conditions due to the Kamchatka Current and Alaska Stream inflows. Assemblages are dominated by Nematosphaeropsis labyrinthus, Pyxidinopsis reticulata and Brigantedinium spp.; 3) the Bering Sea zone, depicting a subpolar environment, influenced by seasonal upwellings and inputs from the Anadyr and Yukon Rivers. It is characterized by the dominance of I. minutum and Brigantedinium spp.; 4) the Alaska Gyre zone with temperate conditions and nutrient-enriched surface waters, which is dominated by N. labyrinthus and Brigantedinium spp. and 5) the Kuroshio Extension-North Pacific-Subarctic Current zone characterized by a subtropical and oligotrophic environment, which is dominated by O. centrocarpum, N. labyrinthus and warm taxa of the genus Impagidinium. Transfer functions were tested using the modern analog technique (MAT) on the North Pacific Ocean (= 359 sites) and the entire Northern Hemisphere databases (= 1419 sites). Results confirm that the updated Northern Hemisphere database is suitable for further paleoenvironmental reconstructions, and the best results are obtained for temperatures with an accuracy of ± 1.7 °C.

Using the analysis of dinoflagellate cysts in three deep-sea sediments cores situated in the Sicilian-Tunisian Strait, in the Gulf of Lions and in the Alboran Sea, we reconstruct the paleoenvironmental changes that took place during the last glacial-interglacial transition in the western Mediterranean Sea. The development of the warm microflora Impagidinium aculeatum and especially Spiniferites mirabilis appears to be an important proxy for recognizing warm periods as the Bolling/Allerod and the Early Holocene. Bitectatodinium tepikiense , Spiniferites elongatus and Nematosphaeropsis labyrinthus mark the end of the Heinrich event 1 and the Younger Dryas. This cold microfloral association confirms the drastic climate changes in the western Mediterranean Sea synchronous to the dry and cold climate which occurred in the South European margin. The dinocyst N. labyrinthus shows high percentages in all studied regions during the Younger Dryas. Its distribution reveals a significant increase from the South to the North of this basin during this cold brief event. Thus, we note that this species can be considered as a new eco-stratigraphical tracer of the Younger Dryas in the western Mediterranean Sea.

Late Holocene paleoceanography and climate variability of the Southeastern Beaufort Sea (Canadian Arctic) have been investigated on the basis of sedimentary cores collected over the Mackenzie Slope. Piston, trigger and box cores were sampled at station 803 in 2004 aboard the CCGS Amundsen at 218 m water depth. The chronology of the piston core is constrained by 4 AMS-14C dates, as the sedimentation rate in the box core is assessed from 210Pb data. We obtain a continuous composite sequence covering the last 4600 years, with a sedimentation rate of ~ 140 cm.kyr− 1. Transfer functions (modern analogue technique) based on dinoflagellate cyst (dinocyst) assemblages were used to reconstruct the evolution of sea-surface conditions over the time period covered by the cores. Palynological data reveal that dinocyst assemblages are dominated by Operculodinium centrocarpum sensu lato (mean of 43.3%) throughout the core, with the accompanying taxa Brigantedinium spp. (19.6%), Islandinium minutum (15.6%) and cysts of Pentapharsodinium dalei (13.7%). Four zones have been established on the basis of dinocyst relative abundances. Dinocyst assemblage zone 1 (D1), from 4600 to 2700 cal years BP, is dominated by O. centrocarpum (mean of 49.0%). In zone D2 (2700–1500 cal years BP), the relative abundances of O. centrocarpum decrease (34.4%) in favour of the opportunistic, heterotrophic taxa Brigantedinium spp. (28.8%) and cysts of Polykrikos sp. var. arctic/quadratus (2.8%). Dinocyst zone D3 (1500–30 cal years BP or 450–1920 AD) is characterised by the high relative abundance of the peridinioid taxa I. minutum (19.9%). The last zone (D4), spanning from 1920 to 2004 AD, is again dominated by O. centrocarpum (44.5%), and shows low relative abundances of Brigantedinium spp. and cf. Echinidinium karaense. Quantitative reconstructions of past sea-surface parameters (August sea-surface temperature: SST, August sea-surface salinity: SSS, and duration of sea-ice cover) indicate relatively stable conditions over the last 4.6 kyr, with episodic cooling events (SST of ~ 1.5 °C below the modern value of 6 °C) that took place between 700 and 1820 AD. We associate the last and the longest of these cooling events (1560–1820 AD) with the Little Ice Age. Reconstructed SSS shows decadal oscillations since 1920 AD that we tentatively associate with the accumulation of freshwater by the Beaufort Gyre and the subsequent Great Salinity Anomalies. Our data suggest that similar salinity anomalies could have occurred ca. 1860 and 1790 AD. Stable isotopic data show a slight increase in δ13C values (from ~−27.1‰ at the base to ~−25.8‰ at the top) over the last 4.6 kyr that we associate with the gradual increase in atmospheric CO2 concentration as recorded by Antarctic ice cores. Variations in the δ15N profile suggest variations in Pacific water influence from 4600 to ~ 1300 cal years BP, associated with centennial scale shifts of the Arctic Oscillation phases.

The Oxfordian–Lower Hauterivian section of the Nordvik Peninsula (northern Central Siberia) is a reference for developing zonal scales for various fossil groups and improving the Boreal zonal standard. In the middle 1950s–late 1980s, it was studied extensively by geologists, stratigraphers, lithologists, and experts on various fossil groups. These studies yielded rich fossil and microfossil collections and a set of parallel zonal scales for various faunal groups. Recently, a new detailed ammonite zonation of the Oxfordian and Kimmeridgian units of this section has been proposed. These results contradict the previous biostratigraphic data on ammonites, foraminifers, and palynomorphs. In the present paper, all the biostratigraphic data on the Oxfordian and Kimmeridgian units of the Nordvik Peninsula (Cape Urdyuk-Khaya) and northern Central Siberia undergo a comprehensive analysis and comparison with those on the Boreal Realm. The ammonite-constrained stratigraphic position of the lower Upper Jurassic in the Cape Urdyuk-Khaya section is interpreted as Upper Oxfordian or Middle Oxfordian. In our view, this difference in the understanding is due to the misidentification of some Oxfordian ammonite forms. The zones based on other fossil groups (foraminifers, dinocysts) which were distinguished in the Upper Oxfordian and Kimmeridgian sections of the Nordvik Peninsula are well traceable circumarctically. Their stratigraphic position in various regions of the Northern Hemisphere is constrained by ammonites and bivalves. However, if we use the last alternative ammonite zonation of this section part, hardly explicable contradictions will appear in interregional foraminiferal and dinocyst correlations.

The study of nannofossils and dinoflagelate cysts from the Paleocene-Eocene transition in the Nasypnoe section, Eastern Crimea identified the bed corresponding to the global event referred as the Paleocene-Eocene Thermal Maximum (PETM). The assemblages of both groups of microphytoplankton display significant changes including the appearance of Rhomboaster spp., Discoaster anartios and D. araneus nannofossils and Apectodinium augustum and Wilsonidium pechoricum dinocysts featured for this event and major variations in the ratio of taxa resulted in domination of eutrophic and warm-water species. The paleoecological interpretation of nannofossil and dinocyst distribution suggests a drastic sea-level fall preceded the PETM and occurrence of two transgressive episodes during it.

In an attempt to document the palaeoecological affinities of individual extant and extinct dinoflagellate cysts, Late Pliocene and Early Pleistocene dinoflagellate cyst assemblages have been compared with geochemical data from the same samples. Mg/Ca ratios of Globigerina bulloides were measured to estimate the spring–summer sea-surface temperatures from four North Atlantic IODP/DSDP sites. Currently, our Pliocene–Pleistocene database contains 204 dinoflagellate cyst samples calibrated to geochemical data. This palaeo-database is compared with modern North Atlantic and global datasets. The focus lies in the quantitative relationship between Mg/Ca-based (i.e. spring–summer) sea-surface temperatures (SSTMg/Ca) and dinoflagellate cyst distributions. In general, extant species are shown to have comparable spring–summer SST ranges in the past (SSTMg/Ca) and today (SST from World Ocean Atlas 2005, Locarnini et al., 2006), demonstrating that our new approach is valid for inferring spring–summer SST ranges for extinct species. For example, Habibacysta tectata represents SSTMg/Ca values between 10 and 15 °C when it exceeds 30% of the assemblage, and Invertocysta lacrymosa exceeds 15% when SSTMg/Ca values are between 18.6 and 23.5 °C. However, comparing Pliocene and Pleistocene SSTMg/Ca values with present day summer values for the extant Impagidinium pallidum suggests a greater tolerance of higher temperatures in the past. This species occupies more than 5% of the assemblage at SSTMg/Ca values of 11.6–17.9 °C in the Pliocene and Pleistocene, whereas present day summer SSTs are around − 1.7 to 6.9 °C. This observation questions the value of Impagidinium pallidum as reliable indicator of cold waters in older deposits, and may explain its bipolar distribution.

The palynological assemblages from three Cenomanian–Turonian sections from the Castilian Platform are described. The 49 levels analysed yielded a well-diversified palynological content including dinoflagellate cysts, acritarchs, prasinophytes and miospores. The comparison of the terrestrial and marine assemblages from these three sections reveals significant differences that are mainly related to their relative palaeogeographical locations. The quantitative study performed on dinocyst assemblages suggests an association interpreted as inner neritic including Xenascus ceratioides , Cribroperidinium exilicristatum , Canningia reticulata and Kallosphaeridium ? ringnesiorum . On the contrary, the group inferred to show outer neritic preferences is integrated by Palaeohystrichophora infusorioides , Spiniferites spp., Odontochitina spp., Trichodinium castanea and Impletosphaeridium polytrichum . In the Castilian Platform, the Cenomanian–Turonian Boundary Event (CTBE) may be manifested by a higher proportion of Cyclonephelium spp. in the distal dinocyst assemblages.

EuroCLIMATE project RESOLuTION; International audience; Abstract Dinoflagellate cyst (dinocyst) analysis was conducted on two cores from the SW Iberian margin and central Alboran Sea from which high quality records of Marine Isotope Stage 3 have been previously derived. Our aim in this study is to compare the dinocyst signature between 50 and 25 ka BP with existing datasets of foraminiferal and geochemical proxies related to hydrological parameters. Quantitative reconstructions of sea-surface temperatures (SSTs) and salinities (SSS) based on dinocysts are performed for the first time in this area. The results are compared to SSTs derived from planktonic foraminifera and alkenone measurements, and to SSS calculated from planktonic δ18O and foraminiferal SST. Significant oscillations related to Dansgaard-Oeschger cycles are recorded in both cores. Dinocyst-derived hydrological parameters exhibit synchronous fluctuations and similar values to those derived from the other methods, in particular when considering quantitative reconstructions for February based on foraminifera and dinocysts. Our study shows that the influence of subpolar waters was felt during each Greenland Stadial (GS) off Portugal, and that the amplification of the Heinrich Stadial cooling in the Alboran Sea was related to the penetration of subpolar waters through the Strait of Gibraltar. During Greenland Interstadials (GI), we provide evidence for the occurrence of warm and nutrient-rich sea-surface waters in the Alboran Sea, probably due to gyre-induced upwelling. Finally, the difference between August and February dinocyst SST estimates suggests higher seasonal contrasts during GS compared to GI at the two core sites. Additionally, precession appears to have an imprint on dinocyst-derived long-term seasonality record. However, this observation needs to be confirmed by longer records. Research Highlights ► We provide new dinocyst data on core MD95-2043 (Alboran Sea) during MIS 3. ► Quantitative dinocyst sea-surface parameters (SST, SSS) are reconstructed. ► A multi-proxies compilation (microfossils, alkenones, isotopes) is established. ► This dataset has been compared with the one of a SW Iberian margin core. ► Millennial-scale climatic variability is perfectly apparent from each side of Gibraltar.

A palynological study of uppermost Maastrichtian to lower Paleocene marine strata from two stratigraphic sections in the Clarence Valley, Marlborough, New Zealand, revealed diverse organic-walled dinoflagellate cyst (dinocyst) assemblages. One hundred and twelve samples were investigated and 86 dinocyst species were identified, from the two sections studied: Branch and Mead streams. Nine new species are described herein: Cerodinium nielsii, Impagidinium agremon, I. cavea, I. crouchiae, I. hannahii, Lejeunecysta kammae, Pyxidinopsis epakros, P. everriculum and P. meadensis. Stratigraphic correlations are achieved using nine new index species and eight cyst acme intervals, named A to H, integrated with foraminiferal datums and the radiolarian zonation for the South Pacific. The first occurrence of Carpatella septata combined with a high relative abundance of Diconidinium martianum characterizes the interval directly below the Cretaceous–Paleogene (K–Pg) boundary or uppermost part of the Manumiella druggii Z...

Two internationally important Ramsar lagoons on the south coast of the Caspian Sea (CS) have been studied by palynology on short sediment cores for palaeoenvironmental and palaeoclimatic investigations. The sites lie within a small area of very high precipitation in a region that is otherwise dry. Vegetation surveys and geomorphological investigations have been used to provide a background to a multidisciplinary interpretation of the two sequences covering the last four centuries. In the small lagoon of Amirkola, the dense alder forested wetland has been briefly disturbed by fire, followed by the expansion of rice paddies from AD1720 to 1800. On the contrary, the terrestrial vegetation reflecting the diversity of the Hyrcanian vegetation around the lagoon of Anzali remained fairly complacent over time. The dinocyst and non-pollen palynomorph assemblages, revealing changes that have occurred in water salinity and water levels, indicate a high stand during the late Little Ice Age (LIA), from AD

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...

A review of pollen, spores, non-pollen palynomorphs and dinocyst analyses made in the last two decades is proposed here. Building on spare palynological analyses before 1990, a series of new projects have allowed taking cores in the deeper parts of the Caspian Sea, hence providing access to low-stand sediment. However, still nowadays no complete record exists for the Holocene. The first steps towards quantification of the palynological spectra have been taken. Some of the most urgent problems to solve are the uncertainties related to radiocarbon dating, which are especially acute in the Caspian Sea.

A dinocyst zonation for the Neogene succession in the eastern part of the North Sea Basin (Denmark) is presented. The zonation is based on an extensive database comprising data from more than fifty onshore and offshore boreholes and about twenty five outcrops. Most of the nineteen dinocyst zones described and defined herein, are new. The zonation is correlated with previously published dinocyst zonations within the North Sea Basin, in the North Atlantic and with the revised Northwest European zonation. The presented zonation gives a detailed subdivision of the Oligocene–Miocene transition, of the Lower Miocene, and of the Upper Miocene and Pliocene successions. The previous zonation of the onshore Danish Middle Miocene is reconsidered and partly redefined. The zonation is correlated with other biostratigraphic subdivisions of the Neogene succession in the Danish region in addition to litho- and sequence stratigraphy. The dinocyst zonation and the foraminifer zonation of the Danish Miocene (based upon analysis of the same boreholes) were independently calibrated with the established nannoplankton zonation. This correlation revealed a mismatch generally corresponding to one nannoplankton zone. Absolute ages of the new dinocyst zones are proposed based on correlation from the studied succession within the North Sea Basin with the international zonations and stratigraphic schemes. In addition, parts of the succession have been dated by strontium isotope analysis of mollusc shells. Inconsistencies due to first and last occurrences of some dinocyst species in previous studies and the present study, especially within the Lower Miocene, implied that new Sr-isotope datings from mollusc shells from the cored Sdr. Vium borehole and other localities in this study would be invaluable. Indeed, this method allowed the previous last occurrence of Cordosphaeridium cantharellus (one of the zonal index fossils) dated as between 17.95 My and 19.5 My in previous studies, to be assigned a new dating of 18.4 My. The timespan of the zones range from 2.6 My for the Amiculospharea umbraculum Zone to 0.4 My for the Achomosphaera andalousiensis Zone. Neogene biostratigraphy in the North Sea Basin has been problematic due to the periodically limited connection between the North Sea Basin and the North Atlantic Ocean, especially with respect to stratigraphy based on foraminifers and calcareous nannoplankton. Many of the stratigraphically most important taxa, e.g. those defining stratigraphic boundaries in type sections, have not been found within the North Sea Basin. This problem seems to be solved by correlation based on the new dinocyst stratigraphy, because stratigraphically significant taxa do occur in the North Sea deposits, even in marginal marine settings.

The initially obtained data characterize organic-walled phytoplankton (dinocysts), nannoplankton, spores, and pollen from the Upper Argun, Alkun, and Lower Assa deposits of the Fiagdon and Mairamadag sections situated on the southeast of North Ossetia (North Caucasus) in the Alkun Formation stratotype area. The lithology of the formation is described, and its position in the Oligocene-Miocene succession is considered. According to the analyzed data on organic-walled phytoplankton from the Fiagdon and Mairamadag sections, the transitional late Oligocene-early Miocene dinoflora from the top of the Argun Formation and the lower part of the Alkun Formation is in general of the Miocene aspect. Based on the dinocysts, deposits from the upper part of the Alkun Formation coupled with the Assa Formation are attributed to the lower Miocene. The entire interval of the studied deposits corresponds to the acme subzone Def of the Ebu Zone in the Mediterranean dinocyst zonation by D. Zevenboom, where it spans the top of the Chattian and lower part of the Aquitanian Stage. Nannoplankton assemblages from the Alkun deposits are tentatively correlated with the nannoplankton assemblage of Zone NN1 in the standard zonation by E. Martini. It is impossible to date precisely the Alkun Formation based on nannoplankton, as the respective deposits are lacking index species and characteristic taxa of the standard zonation. The dominance of the cosmopolitan species Cyclicargolithus floridanus is a peculiar feature of nannoplankton assemblages from the Alkun Formation. Palynological data are used to consider the dynamics of the evolution of the vegetation cover and climate. Four episodes of relative cooling are distinguished against a background of warm-temperate climatic conditions in general. The most significant episodes occurred in the mid-Alkun time and during the early phase of the Assa time.