The diversity, abundance, and geographic distribution of dinoflagellate cysts in recent sediments serve as bioindicators to specific regions' environmental conditions and productivity. We present ...dinoflagellate cysts assemblages from 53 superficial sediment samples from the upper Gulf of California (uGC) obtained in July 2016 and February 2017. Forty-seven species were identified, of which twenty-seven are considered heterotrophic (Het) and twenty autotrophic (Aut). Ten species of this last group are potentially toxin producers (PTxS). The total concentration (Tot) of cysts in all the samples was 3481 cysts/g in 2016 and 4223 cysts/g in 2017. Aut represented 59%, Het 41%, while the PTxS represented ∼36.5% of the Tot cysts. The higher abundance of the Aut is likely to manifest the local high sea surface temperature and salinity. The increase in the Tot of cysts in the 2017 set was related to a Gymnodinium catenatum harmful algal bloom. Copepod eggs abundance was 7137 eggs/g in 2016 and 6555 eggs/g in 2017. The Aut Gymnodinium spp., Spiniferites spp., Operculodinium spp, and the Het Protoperidinium americanum, Quinquecuspis concreta, Selenopemphix nephroides, Brigantedinium spp., and Echinidinium spp., were typical in both seasons but differed on their concentrations between each season. The cysts distribution between both sampling periods reflects local currents and the sediment dynamics of the uGC, and the high species diversity in this area reflects the elevated primary productivity in this area.
•Total cyst concentration was 3481 cysts/g in July 2016 and 4223 cysts/g in February 2017 samples.•47 species were identified, slightly dominated by autotrophic taxa (59%).•Differences in geographic distribution between autotroph and heterotroph cysts.•Affinity of the distribution of dinoflagellate cysts with environmental factors.•Presence of potentially toxic species in surface sediments.
Palynological investigations in the Sumbe region of the Kwanza Basin, Angola, have identified Albian to Turonian assemblages in four sections of the Quissonde Facies of the Mucanzo, Cabo Ledo, and ...Itombe formations. These studies aimed to determine their biostratigraphic ages and infer paleoenvironmental, paleoclimatic, and paleogeographic models. The presence of Odontochitina costata, Palaeohystrichophora infusorioides, and Xiphophoridium alatum cysts supports an upper Albian to lower Cenomanian age for the Mucanzo Formation. Litosphaeridium siphoniphorum cyst and the Elateroplicites africaensis pollen found In the Cabo Ledo Formation suggest a Cenomanian age, while Conosphaeridium striatoconum, Heterosphaeridium difficile, and Dinogymnium acuminatum supports a Turonian age for the lower part of the Itombe Formation. All samples predominantly contain fluorescent amorphous organic matter (AOM) derived from phytoplankton degradation, with increasing AOM in the uppermost units, indicating inner neritic marine deposition under dysoxic-anoxic conditions. During the Lower to mid-Cretaceous, the Gondwana breakup caused significant changes, with the palynological indicating a Tethyan affinity with some high-latitude taxa, suggesting a cosmopolitan distribution. The subtropical to tropical nature of the assemblages, along with high-latitude species, indicates a mid-Cretaceous water connection between the Central Atlantic and the South Atlantic oceans, extending to the Kwanza Basin.
•Palynological assemblages from the Sumbe region, Kwanza Basin were analysed.•Palynoflora and palynofacies analysis were performed.•Palynomorph assemblages ranging from the late Albian to the Turonian age.•Palynofacies suggests an inner marine deposition, under dysoxic-anoxic conditions.•A predominant Tethyan influence was recorded.
Palynological analysis of 200 ditch cuttings of wells M6 and M7 from the western Niger Delta yield a diverse assemblage of pollen, spores, freshwater algae, foraminiferal wall linings and ...dinoflagellate cysts. Based on pollen and spore marker species, the wells date middle – late Miocene (P720-P860). The regular occurrence of dinoflagellate cysts enhances the subdivision of the sequences into eight and seven tentative dinoflagellate cysts assemblage zones for the M6 and M7 wells respectively. The proposed Niger Delta Dinoflagellate Cysts (C-I) zones are viz: the Lingulodinium machaerophorum Assemblage zone; Homotryblium spp./Sumatradinium spp. Assemblage zone; Operculodinium centrocarpum Assemblage zone; Nematosphaeropsis labyrinthus Assemblage zone; and the Protoperidinium spp./Selenopemphix spp. Assemblage zone. The boundaries are marked by remarkable dinocysts events such as first downhole occurrences or highest stratigraphic occurrences, supplemented with last downhole occurrences or lowest stratigraphic occurrences as the samples were ditch cuttings. The common presence of dinoflagellate cysts and the dominance of Nematosphaeropsis labyrinthus and Impagidinium spp. indicate open marine conditions during the deposition of the studied section.
During the transition from the Pleistocene to the Holocene, significant changes occurred on the Brazilian continental shelf. In this study, we investigated the environmental changes that occurred ...during this period through the quantification and classification of cosmopolitan dinoflagellate cysts. We used three cores collected in the northern part of the Santos Basin and analyzed a total of 42 samples. The results showed a predominance of cysts of O. centrocarpum, L. machaerophorum and T. vancampoae, whose occurrence was influenced by sea-level fluctuations during the Pleistocene-Holocene transition and by changes in ocean currents due to temperature variations. Oligotrophic species were established during the Late Pleistocene, followed by mixotrophic species from the Holocene. Analysis of the dinocysts showed the presence of colder waters due to upwelling and the entry of waters with lower salinity due to the formation of transitional estuarine systems. These environmental changes have contributed to the configuration of the current Brazilian coastal scenario.
•Study of dinoflagellates cysts in sediments of Brazilian shelf.•Changes in dinoflagellate assemblages on the shelf during the LGM and later periods.•Sea-level transition from Last Glacial Maximum (LGM) to Holocene.•Climatic variations.
Major sea-level cycles occurred in the Cenomanian-early Turonian greenhouse world and impacted depositional conditions and ecosystems across the paleo-shelf seas. These sea-level cycles have been ...interpreted from various paleogeographic settings around the globe, such as the Western Interior Seaway (North America), the Proto-North Atlantic, Western Europe, and eastern Tethys (SE India). However, their drivers remain poorly understood and may include glacio-, aquifer-, thermo-, and/or tectono-eustasy. Uncertainties also persist regarding the timing, synchronicity, and magnitude of Cenomanian-early Turonian eustatic cycles. By combining palynological data from northern Africa (Gindi Basin, Egypt) with data available in the literature, a detailed synthesis of Cenomanian palynostratigraphy and sea-level dynamics is presented. Age-diagnostic spores, pollen, and organic walled dinoflagellate cysts (dinocysts) are correlated to global marine biozonation schemes, which provide a comprehensive biostratigraphic framework for the Cenomanian-early Turonian. Additionally, palynological data enable the identification of an early late Cenomanian Dinopterygium bio-event marked by the highest abundances of dinocysts. This bio-event can be correlated to the Neolobites ammonite bio-event and the Jukes-Browne Carbon Isotope Event. The bio-events stratigraphically constrain with a major transgression, which occurred in the early late Cenomanian, slightly preceding Oceanic Anoxic Event 2 (OAE2). Another major transgression spans the late Cenomanian-early Turonian, referred to the Plenus transgression bio-event, and consistent with the onset of the OAE2. Regional to global correlations indicate that these transgressive events reflect eustatic sea-level rises that can be recognized throughout the Tethys, Proto-North Atlantic, Europe, Western Interior Seaway, and India. These transgressions occurred within <1.0 Myr with modest magnitudes of 10–60 m. Rates of sea-level change has commonly been attributed to glacio-eustasy, which is however difficult to reconcile with a probably ice-free Cenomanian-early Turonian greenhouse world. Both transgressions coincide with phases of rising temperatures, whereby warming was most pronounced during the early late Cenomanian transgression. However, we can only speculate whether rising temperatures indicate the demise of polar glaciations. Eustatic processes, including tectono-eustasy, and to some extent aquifer- and thermo-eustasy, likely played a role in the sea-level rise during the early late Cenomanian and early Turonian. Environmental changes associated with the early late Cenomanian transgression may have triggered the onset of OAE2 possibly exacerbated by sluggish ocean circulation in a warming greenhouse world where sea ice formation was limited.
•Palynological and Paleontological data indicate a marine transgression during the early late Cenomanian and early Turonian•Data synthesis suggests coeval records of these transgressive events in the Tethys, Atlantic, North America, and India•The latest Cenomanian-early Turonian represents the maximum transgression event throughout the Cretaceous•Aquifer- and thermo-eustasy controlled short-term eustatic processes
Rich and well preserved organic-walled dinoflagellate cyst assemblages recovered from the Scisti a Fucoidi Formation at Piobbico, central Italy are presented. Distributions of 83 taxa, plotted ...against the independent stratigraphic framework established from planktonic foraminifers and nannofossils, are compared with ranges documented in the literature in order to identify and calibrate reference horizons for the Albian dinoflagellate cyst stratigraphy of the Tethyan Realm. The following events have been selected: the lowest occurrences of Kleithriasphaeridium atlasiense and Tehamadinium coummia at the Aptian/Albian boundary, of Leberidocysta defloccata in the Lower Albian, of Adnatosphaeridium tutulosum, Litosphaeridium arundum and Ovoidinium sp. A sensu Davey (1979) in the Middle Albian, of Dapsilidinium? pumilum, Litosphaeridium conispinum, Tehamadinium mazaganense and Hapsocysta dictyota in the Upper Albian; the highest consistent occurrences of Hapsocysta peridictya in the Lower Albian, of Codoniella psygma and Damassadinium chibane in the Middle Albian, of Tehamadinium sousense in the Upper Albian.
Organic-walled resting cysts of planktonic dinoflagellates occur commonly in modern marine sediment where they represent, with rare exceptions, the only geologically preservable part of the life ...cycle. Although many species do not produce fossilizable resting cysts, upper Quaternary sediments contain a diverse cyst record that is used frequently for paleoenvironmental reconstruction and stratigraphic analysis. Reconstructions of past sea-surface conditions rely on an understanding of the distributions of dinoflagellate cysts in modern sediments linked to their respective environmental parameters, underpinned by sound taxonomy and standardized nomenclature. Stratigraphic studies additionally require knowledge of morphological details to distinguish extant from similar extinct taxa. Here, 51 dinoflagellate cyst species and two informal cyst morphotypes that are commonly encountered during routine palynological analysis of upper Quaternary marine sediments from the Northern Hemisphere are briefly described taxonomically and illustrated. In addition, their lowest stratigraphic occurrences are provided.
•51 common extant dinoflagellate cyst species and two morphotypes are briefly described and illustrated.•2 belong to the Gymnodiniales, 30 to the Gonyaulacales and 21 to the Peridiniales.•their lowest stratigraphic occurrences are provided.
The genus Trinovantedinium Reid 1977 comprises eleven NeogeneQuaternary and one Paleogene dinoflagellate cyst taxa that have been successfully used for biostratigraphy. Combining new and published ...records of Trinovantedinium species in the Neogene of the tropical Americas, we report preliminary stratigraphic ranges for T. applanatum (AquitanianRecent), T. ferugnomatum (BurdigalianZanclean), T. glorianum (BurdigalianMessinian), T. papula (AquitanianZanclean), T. uitpensis (AquitanianTortonian), T. variabile (AquitanianRecent) and T.? xylochoporum (AquitanianMessinian) in the region. Although the stratigraphic ranges of T. applanatum, T. variabile and T.? xylochoporum in the tropical Americas seem to be coetaneous with previous records elsewhere, the first appearance datums of T. ferugnomatum, T. glorianum and T. papula seem to be at least ∼2–3 Myr. older in the tropical Americas. In contrast, only the last appearance datum of T. glorianum seems to be ∼4 Myr. younger in the Northern Hemisphere. Our results demonstrate that the Cenozoic marine palynological record of the tropical Americas is therefore key to discriminate dinoflagellate cyst stratigraphic ranges across latitudes.
•Seven out of twelve Trinovantedinium taxa are reported in the tropical Americas.•Five calibrated marine palynological events are used to correlate Neogene rocks.•The stratigraphic record of T. pallidifulvum might be restricted to the Quaternary.•FADs of T. ferugnomatum, T. glorianum and T. papula are ∼2–3 Myr. older.
Cretaceous marine sedimentary rocks from the Austral-Magallanes Basin have provided a valuable organic-walled dinoflagellate cyst record as a useful tool for biostratigraphical interpretations and ...paleo-oceanographical reconstructions. This paper contains a revision of the main dinoflagellate cyst information previously published in southwest Patagonia and the Continental Platform, encompassing two time intervals, the Late Hauterivian to Early Cenomanian and the Campanian to Maastrichtian. We present for the first time a sequence of Cretaceous diagnostic dinoflagellate cyst events identified at surface and subsurface sections throughout the Austral-Magallanes Basin. In ascending order, nineteen primary bioevents of first occurrence (FO), last occurrence (LO) and acme were recognized. Eleven biovents were identified in the Early Cretaceous: LO of Senoniasphaera tabulata, LO of Kleithriaphaeridium fasciatum, FO of Prolixosphaeridium parvispinum, LO of Phoberocysta neocomica, FO of Herendeenia postprojecta, FO of Odontochitina operculata, LO of Cassiculosphaeridia magna and the LO of Kaiwaradinium scrutillinum, Ovoidinium sp. Acme, LO of Dingodinium cerviculum and LO of Muderongia tetracantha. Nine bioevents were identified in the Late Cretaceous: FO of Odontochitina porifera, FO of Palaeohystrichophora infusorioides, FO of Nelsoniella aceras, FO of Nelsoniella tuberculata, FO of Xenikoon australis, LO Nelsoniella aceras, LO of Odontochitina spinosa, FO of Manumiella druggii and FO of Eisenackia circumtabulata. In general, the Austral-Magallanes Basin assemblages compare well with those coeval from the middle to high Southern Hemisphere latitudes sites, suggesting paleo-oceanographical connections between the southernmost tip of South America, Antarctica, New Zealand and Australia during the Cretaceous.
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