Jurassic Dinoflagellate Research Articles

The First Data on Middle Jurassic Dinoflagellate Cysts and Foraminifera of the Russian Far East

The First Data on Middle Jurassic Dinoflagellate Cysts and Foraminifera of the Russian Far East

The literature on Triassic, Jurassic and earliest Cretaceous dinoflagellate cysts: supplement six

Since the publication of six literature compilations issued between 2012 and 2020, 38 further published contributions on Triassic, Jurassic and earliest Cretaceous (Berriasian) dinoflagellate cysts were issued, or have been discovered, during the past 12 months (i.e. between April 2020 and March 2021). Considerable research has been published on the Triassic and Early Jurassic marine palynology of sub-Arctic West Europe and West Russia. All the 38 items are listed herein with doi numbers where applicable, and a description of each item as a string of keywords.

The effects of the Jenkyns Event on the radiation of Early Jurassic dinoflagellate cysts

Abstract This contribution is an overview of the Early Jurassic dinoflagellate cysts of the Lusitanian Basin in Portugal, with particular emphasis on the effects of the Jenkyns Event (Toarcian Oceanic Anoxic Event) on the evolution of this planktonic group. We review and discuss data from 214 samples from six Lower Jurassic successions (upper Sinemurian to upper Toarcian) in the Lusitanian Basin. The late Pliensbachian radiation of dinoflagellate cysts was well recognized in this basin. The pre-Jenkyns Event interval is highly productive, with maximum abundance and species richness values. However, this palaeoenvironmental perturbation severely affected the evolution of this group for the remainder of the Early Jurassic. The prolonged recovery of the dinoflagellates in the Toarcian following the Jenkyns Event is not typical of the northern regions (Arctic and Boreal realms), where new species began to evolve earlier compared with southern European basins.

The literature on Triassic, Jurassic and earliest Cretaceous dinoflagellate cysts: supplement five

Since the publication of five literature compilations issued between 2012 and 2020, 63 further published contributions on Triassic, Jurassic and earliest Cretaceous (Berriasian) dinoflagellate cysts have been discovered, or were issued in the last 14 months (i.e. between February 2019 and March 2020). These studies are on North Africa, Southern Africa, East Arctic, West Arctic, east and west sub-Arctic Canada, China and Japan, East Europe, West Europe, the Middle East, and sub-Arctic Russia west of the Ural Mountains, plus multi-region studies and items with no geographical focus. The single-region studies are mostly focused on Africa, the Arctic, Europe and the Middle East. All the 63 publications are listed herein with doi numbers where applicable, and a description of each item as a string of keywords.

Dinoflagellate cysts and Foraminifera of the Upper Jurassic Lopsiya River sections, Nether-Polar Urals, NW Western Siberia (Russia)

The Upper Jurassic Lopsiya River sections (Nether-Polar Urals) represent the most complete stratigraphical marine sequence throughout Russia. It is characterized by a continuous succession of Kimmeridgian to Lower Volgian deposits and is defined by rich faunal associations including ammonites, belemnites, and bivalves. The Lopsiya River sections were previously studied in detail with palaeontological, lithological, and litho-geochemical purposes. Furthermore, assemblages rich in palynomorphs and foraminifers were found in the currently studied successions of the Lopsiya River sections. It results the establishment of the uppermost Oxfordian to Lower Volgian foraminiferal zones, as well as the Kimmeridgian dinoflagellate cyst zones and palynological assemblage. Then, the Upper Jurassic dinoflagellate cyst and foraminiferal biostratigraphical zonations have been calibrated against the ammonite zones. Finally, current results on the Lopsiya River sections have been compared with biostratigraphic data of the Kimmeridgian dinoflagellate cyst assemblages from northwestern Europe, Russian Platform, and Arctic Siberia. The studied foraminiferal and dinoflagellate cyst assemblages of the Upper Jurassic successions of the Lopsiya River sections hold high potential of correlations, especially for the Kimmeridgian strata.

The Middle Jurassic palynostratigraphy of the northern Lusitanian Basin, Portugal

A composite largely Middle Jurassic succession spanning the Toarcian-Aalenian transition to the lowermost Bathonian exposed at Cabo Mondego and Sao Giao in the northern Lusitanian Basin, western Portugal, was examined palynologically. The 129 samples are correlated to ammonite biozones spanning Pleydellia aalensis to Zigzagiceras zigzag. The Cabo Mondego succession comprises the type section of the Cabo Mondego Formation and spans virtually the entire interval studied. This is a significant interval because it includes the Global Stratotype Section and Point (GSSP) and the Auxiliary Stratigraphical Section and Point (ASSP) for the Bajocian and Bathonian stages respectively. The Cabo Mondego Formation largely yielded relatively abundant palynomorph associations in the 68 productive samples recovered. By contrast, the Povoa da Lomba Formation at Sao Giao only includes the Toarcian-Aalenian transition; the 21 productive horizons produced sparse assemblages. The uppermost Toarcian to lowermost Bajocian is characterised by a low diversity dinoflagellate cyst association, typified by Nannoceratopsis. Above this is a markedly more diverse assemblage. This influx, in the Witchellia laeviuscula ammonite biozone AB, represents a global evolutionary radiation which may be linked to sea level rise. The trend of increasing dinoflagellate cyst diversity continued at the Bajocian-Bathonian transition. The Middle Jurassic dinoflagellate cyst assemblages of the Lusitanian Basin are significantly less diverse than coeval palynobiotas from eastern and northern Europe, and the Arctic. The Toarcian Oceanic Anoxic Event (T-OAE) profoundly inhibited cyst-forming dinoflagellates in this depocentre, and the recovery was protracted. Hence the T-OAE may have suppressed dinoflagellate cyst diversity well into the Middle Jurassic. This phenomenon may have been exacerbated by the absence of typically Arctic taxa through latitudinal controls and/or global cooling during the early Aalenian. These low levels of dinoflagellate cyst species richness may also be related to the palaeogeography of the Lusitanian Basin. This relatively isolated deepwater depocentre close to the Proto Atlantic, may have precluded extensive biotal exchange with the widespread shelfal areas of the western Tethys. The absence of Dissiliodinium giganteum in the Lusitanian Basin is consistent with this scenario. The pollen and spores observed in this study are typical of Middle Jurassic assemblages worldwide. Araucarian pollen, largely Callialasporites, diversified and became prominent during the Aalenian.

Répartition stratigraphique et biozones des kystes de dinoflagellés au passage Jurassique moyen–Jurassique supérieur (Bathonien supérieur–Oxfordien inférieur) dans le Bassin de Guercif, Maroc nord-oriental

Despite the stratigraphical significance of dinoflagellate cysts as reliable markers for correlating and dating Jurassic–Cretaceous strata, investigations into this palynomorph group in the southern Tethyan Realm, specifically northwest Africa, are sparse and somewhat parochial. Most research on Jurassic dinoflagellate cysts is focussed on European depocentres in the Boreal and Sub-Boreal realms. This study is on biostratigraphical data from two petroleum boreholes (MSD1 and KDH1) drilled during 1985 in the Guercif Basin, northeast Morocco by ONAREP (Office National de Recherche et d’Exploitation Pétrolier), now ONHYM (Office National des Hydrocarbures et des Mines). These boreholes penetrated a thick siliciclastic succession, attributed to the Middle and Upper Jurassic, below Miocene marls. Over sixty dinoflagellate cyst taxa were identified. Four dinoflagellate cyst biozones, named GI to GIV, are established for the late Bathonian to early Oxfordian interval. These biozones are defined on the basis of the first appearance datum (FAD) and/or the last appearance datum (LAD) of some biomarker taxa which have wide geographical distributions. These are: Ctenidodinium combazii and Ctenidodinium sellwoodii for the GI Biozone (late Bathonian–early Callovian); Ctenidodinium continuum and Meiourogonyaulax caytonensis for the GII Biozone (middle Callovian); Gonyaulacysta centriconnata and Wanaea thysanota for the GIII Biozone (late Callovian–earliest Oxfordian); and Liesbergia liesbergensis and Systematophora penicillata for the GIV Biozone (early Oxfordian). These biozones are correlated to those already established for the respective intervals in other palaeogeographic regions, such as the Boreal, Sub-boreal and Tethyan realms.

Dinoflagellate cyst biostratigraphy of the Patasar Shale Member (Upper Jurassic) of the Wagad Uplift, Kachchh, Gujarat, western India

Two samples were analysed from the lowermost Patasar Shale Member of the Patasar Tank section on the western margin of the Wagad Uplift in the Kachchh Basin of Gujarat, western India. One of the samples produced an abundant, diverse and well-preserved palynobiota. The other sample produced a significantly sparser association, but of similar character. The overall assemblage is dominated by relatively long-ranging Jurassic gymnospermous pollen grains, but also includes dinoflagellate cysts of definite Gondwanan affinity. The dinoflagellate cysts are confidently correlated to the Australian Dingodinium swanense Interval Zone, which is of Kimmeridgian (Late Jurassic) age. This indicates that the Australasian Jurassic dinoflagellate cyst biostratigraphical scheme can be applied in western India, and probably throughout the Indian subcontinent. Due to evidence from ammonites and calcareous nannofossils in the Patasar Shale Member, allied with other biostratigraphical evidence from New Zealand and Papua New Guinea, the age of the D. swanense Interval Zone is reinterpreted as being of Early Kimmeridgian age. The D. swanense Interval Zone was previously assigned to the Early to Late Kimmeridgian. Its refinement and revision to an older age are entirely consistent with recent reassessments of these dinoflagellate cyst biozones.

Resolving the Middle Jurassic dinoflagellate radiation: The palynology of the Bajocian of Swabia, southwest Germany

Dinoflagellates underwent a major radiation during the Bajocian (Middle Jurassic, ~170–168Ma). The group originated in the Middle Triassic and dinoflagellate cysts were relatively low in diversity until the Bajocian, when over 100 species appeared. The Gonyaulacaceae expanded during this interval to become the dominant family of cyst-forming dinoflagellates, and has remained the principal dinoflagellate family throughout the Mesozoic and Cenozoic. However, Bajocian dinoflagellate cysts have received relatively little study. In order to unravel the pattern of the Bajocian dinoflagellate radiation, we have generated a high resolution, quantitative, palynological record through an expanded Middle Jurassic succession in Swabia, southwest Germany. Previous research has indicated a rapid, stepwise order of first appearances through the Bajocian. By contrast, we clearly demonstrate that there was a more gradual, continuous increase in diversity from the Late Aalenian to the Early Bathonian, although the number of first appearances was highest during the latest Early Bajocian to Late Bajocian. Major experimentation in excystment mode in the gonyaulacaceans occurred during the Late Aalenian and Early Bajocian, when multi-plate precingular, single-plate precingular and epicystal archaeopyle types first appeared. Through the integration of our data with published information from northwest Europe, we demonstrate that the appearance of dinoflagellate cyst taxa through the Late Aalenian–Early Bathonian appears to have been controlled by a major second-order transgression. Although the cause of this radiation is yet to be constrained, given the contemporaneous diversifications of other plankton groups, as well as ammonites, bivalves and fishes, it is likely that it formed part of the wider Mesozoic Marine Revolution. There is a prominent acme of Dissiliodinium giganteum in the Lower Bajocian which is a useful stratigraphical marker. Acanthaulax crispa is confirmed as a key index species for the Bajocian. One new species, Korystocysta aldridgeii sp. nov., is described.

Mid Jurassic (Late Callovian) dinoflagellate cysts from the Lotena Formation of the Neuquén Basin, Argentina and their palaeogeographical significance

The Lotena Formation from two localities, Picún Leufú and Portada Covunco, in the Neuquén Basin of west-central Argentina was studied palynologically. The material examined produced moderately diverse Late Callovian dinoflagellate cyst assemblages. This age assignment is consistent with ammonite evidence. The dinoflagellate cyst floras are reminiscent of the Middle Jurassic associations of northwest Europe and surrounding areas. Marine palynomorphs typical of Australasia and the Arctic are absent. The similarity with Europe is strongly suggestive of an open marine connection between western Tethys and the Neuquén Basin during the Late Callovian. This is interpreted as being via the Hispanic Corridor, with the palynofloras being passively dispersed to the southwest by the circum-Tropical Marine Current. Earlier studies indicate that this trans-Pangean equatorial seaway first began to allow biotic interchange during the Mid Jurassic and this study proves that this open marine connection was established by the Late Callovian. The similarities between the dinoflagellate cyst assemblages of Europe and the Neuquén Basin are consistent with the distribution of other marine fossils and the existence of geographically continuous marine facies belts.

Belowicysta nom. nov., a new name for the Jurassic dinoflagellate cyst Belowia Riding & Helby, 2001

The Jurassic dinoflagellate cyst genus Belowia Riding & Helby, 2001 is a junior homonym of Belowia Moquin-Tandon, 1849, a genus of the Chenopodiaceae. The new generic name Belowicysta is proposed here to replace Belowia Riding & Helby, 2001.

The Late Jurassic dinoflagellate cyst Gonyaulacysta ceratophora (Cookson & Eisenack 1960) comb. nov., emend. nov.

The Late Jurassic (early Oxfordian to earliest Tithonian) dinoflagellate cyst Scriniodinium ceratophorum Cookson & Eisenack 1960 from Australia was originally described as having smooth walls and lacking tabulation except for the archeopyle and the cingulum. The type is an atypical end member of this distinctive species; most forms have partially developed tabulation. The species is closely related to Gonyaulacysta jurassica (Deflandre 1939) Norris & Sarjeant 1965. It has a relatively large epicyst, an apparently similar tabulation pattern to Gonyaulacysta jurassica and exhibits neutral torsion. Scriniodinium ceratophorum is therefore transferred to Gonyaulacysta and emended to include partially tabulate forms.

Fostericysta Riding nom. nov. (Division Dinoflagellata)

AbstractThe Jurassic dinoflagellate cyst genus Fosteria Riding & Helby 2001 is a later (junior) homonym of Fosteria Molseed 1968, a genus of the Iridaceae. The generic name Fostericysta is proposed here to replace Fosteria Riding & Helby 2001.

Derived fossils in the southern English Wealden (non-marine early Cretaceous): a review

Derived fossils occur in all the principal facies associations of the southern English Wealden succession (non-marine early Cretaceous). They confirm the presence of Palaeozoic and early–mid Mesozoic source massifs surrounding the Weald and Wessex depocentres, fringed by scarps and intrabasinal highs of Jurassic strata. The derived macrofossil material is largely siliceous and phosphatic. It gains abundance in lake strandline gravels but also occurs as scattered reptilian gastroliths and among lagoonal shell concentrations. Calcareous fossils are abundant at one site, reflecting proximity to source. Jurassic dinoflagellate cysts are widespread among finer-grained facies.

THE LATE JURASSIC DINOFLAGELLATE CYST GONYAULACYSTA CERATOPHORA (COOKSON & EISENACK 1960) COMB. NOV., EMEND. NOV.

The Late Jurassic (early Oxfordian to earliest Tithonian) dinoflagellate cyst Scriniodinium ceratophorum Cookson & Eisenack 1960 from Australia was originally described as having smooth walls and lacking tabulation except for the archeopyle and the cingulum. The type is an atypical end member of this distinctive species; most forms have partially developed tabulation. The species is closely related to Gonyaulacysta jurassica (Deflandre 1939) Norris & Sarjeant 1965. It has a relatively large epicyst, an apparently similar tabulation pattern to Gonyaulacysta jurassica and exhibits neutral torsion. Scriniodinium ceratophorum is therefore transferred to Gonyaulacysta and emended to include partially tabulate forms.

Jurassic dinoflagellate cyst stratigraphy of Hold with Hope, North-East Greenland

Dinoflagellate cysts of the Middle–Upper Jurassic succession on northern Hold with Hope have been studied in order to establish a biostratigraphic framework and to date the succession. The Pelion Formation is characterised by abundant Chytroeisphaeridia hyalina and Sentusidinium spp., with some Ctenidodinium thulium and Paragonyaulacysta retiphragmata in the lower part. Mendicodinium groenlandicum appears higher in the formation followed by Trichodinium scarburghense in the upper part. The succeeding Payer Dal Formation contains Scriniodinium crystallinum, Rigaudella aemula and Leptodinium subtile in the lower part and Dingodinium jurassicum and Prolixosphaeridium granulosum in the uppermost part. The Bernbjerg Formation contains abundant Sirmiodinium grossii and Gonyaulacysta jurassica. Adnatospahaeridium sp., Cribroperidinium granuligerum, Glossodinium cf. dimorphum and Scriniodinium irregulare appear in the lower part of the formation, followed by Avellodinium spp. in the highest part. The dinoflagellate cyst assemblages in the Pelion Formation indicate an Early–Late Callovian age (C. apertum – P. athleta Chronozones). This is supported by ammonites in the lower part of the formation, which refer to the C. apertum and P. koenigi Chronozones. A significant hiatus, from Late Callovian to Middle Oxfordian, is present between the Pelion Formation and the overlying Payer Dal Formation. The age of the Payer Dal Formation is Middle Oxfordian to earliest Late Oxfordian (C. tenuiserratum – A. glosense Chronozones). The Payer Dal Formation is conformably overlain by the Bernbjerg Formation of Late Oxfordian to possibly earliest Kimmeridgian age (A. glosense – P. baylei Chronozones). The A. glosense Chronozone is also documented by abundant ammonites in the lowermost part of the formation.

Jurassic dinoflagellate cyst stratigraphy of Store Koldewey, North-East Greenland

The Jurassic of Store Koldewey comprises a Middle Jurassic succession towards the south and an Upper Jurassic succession towards the north. Both successions onlap crystalline basement and coarse sediments dominate. Three main lithostratigraphical units are recognised: the Pelion Formation, including the Spath Plateau Member, the Payer Dal Formation and the Bernbjerg Formation. Rich marine macrofaunas include Boreal ammonites and the successions are dated as Late Bathonian – Early Callovian and Late Oxfordian – Early Kimmeridgian on the basis of new collections combined with material in earlier collections. Fine-grained horizons and units have been analysed for dinoflagellate cysts and the stratigraphy of the diverse and well-preserved flora has been integrated with the Boreal ammonite stratigraphy. The dinoflagellate floras correlate with contemporaneous floras from Milne Land, Jameson Land and Hold with Hope farther to the south in East Greenland, and with Peary Land in North Greenland and Svalbard towards the north. The Middle Jurassic flora shows local variations in East Greenland whereas the Upper Jurassic flora gradually changes northwards in East Greenland. A Boreal flora occurs in Peary Land and Svalbard. The characteristic and stratigraphically important species Perisseiasphaeridium pannosum and Oligosphaeridium patulum have their northernmost occurrence on Store Koldewey, whereas Taeniophora iunctispina and Adnatosphaeridium sp. extend as far north as Peary Land. Assemblages of dinoflagellate cysts are used to characterise significant regional flooding events and extensive sequence stratigraphic units.

Biostratigraphy, provincialism and evolution of European early Jurassic (Pliensbachian to early Toarcian) dinoflagellate cysts

New and previously published dinoflagellate cyst data from the Pliensbachian and early Toarcian of northern and southern Europe have been compared in order to define successions of Boreal and Tethyan bioevents respectively. Significant stratigraphical differences between these two regions indicates that strong provincialism affected dinoflagellates in Europe during the Early Jurassic. This therefore precludes the erection of a pan‐European palynostratigraphy for the Pliensbachian to early Toarcian interval. Early Jurassic dinoflagellate cyst provincialism has been quantitatively assessed using the Koch Index of biotal dispersity and the Simpson Coefficient of biotal similarity. These methods conclusively demonstrate that marked provincialism occurred at this time, and that the Boreal and Tethyan realms represent two distinct phytoprovinces, based on their respective dinoflagellate cyst assemblages. The Boreal Realm was characterised by relatively high diversity and the dominance of Luehndea spinosa, Mancodinium semitabulatum and Nannoceratopsis spp. Valvaeodinium may also be abundant and diverse. The Parvocysta suite first appears in the Bifrons Zone and becomes relatively diverse. During the Pliensbachian and early Toarcian, the Tethyan Realm was characterised by low diversity dinoflagellate cyst floras. Mancodinium semitabulatum and Mendicodinium spp. typically dominate the assemblages. Valvaeodinium spp. are present in the early Toarcian (Tenuicostatum Zone) and the Parvocysta suite is extremely rare .represented only by Susadinium scrofoides. The transition between the two realms was diffuse. The intermediate area, between palaeolatitudes 25° and 30°, was characterised by mixed Boreal and Tethyan biotas. Dinoflagellate cyst distributions appear to have been strongly controlled by palaeolatitude, indicating that sea water temperature was a major controlling factor. This phenomenon is best exemplified by the distribution of Valvaeodinium. Dinoflagellate cyst distributions were also strongly sensitive to both coastal/oceanic settings and palaeosalinities. The relationship between Early Jurassic dinoflagellate cyst evolution and global palaeoceanographical changes have been investigated via the evaluation of diversity and the rates of speciation, extinction, and turnover. The differing patterns of evolutionary rates in the Boreal and Tethyan realms are explained as interplay between the two dinoflagellate cyst provinces and palaeogeographical changes.

The Jurassic dinoflagellate cyst zonation of Subboreal Northwest Europe

The Jurassic dinoflagellate cyst zonation for the British–Danish area is revised and discussed in relation to palaeoenvironmental factors, in particular, eustatic changes and fluctuations in palaeotemperature. The stepwise evolution of dinoflagellate cyst assemblages as defined by inceptions and apparent extinctions was largely controlled by sea-level change, particularly during intervals with significant short-term eustatic fluctuations. During times characterised by less pronounced, or longer term, sea-level change, fluctuations in oceanic palaeotemperatures appear to have influenced dinoflagellate evolution. Differences in the ranges of certain taxa between Denmark and the United Kingdom may be partly related to differences in palaeotemperature.

Umbriadinium and Polarella: an example of selectivity in the dinoflagellate fossil record

The extant Antarctic dinoflagellate genus Polarella and the southern European Early Jurassic dinoflagellate cyst Umbriadinium are extremely similar in morphology, particularly in their size, ornamentation and tabulation. Polarella is therefore placed in the subfamily Umbriadinioideae on this morphological evidence. The two genera, however, are maintained as separate entities for several reasons including minor differences in tabulation. This means that the stratigraphical distribution of the subfamily Umbriadinioideae is extended from the Early Jurassic (late Pliensbachian - early Toarcian) to Recent. The two species (Polarella glacialis and Umbriadinium mediterraneense) are separated by around 187 Ma. This large stratigraphical gap is an example of the selectivity of the dinoflagellate fossil record, produced by the loss of the capacity of Polarella/Umbriadinium to produce fossilisable cysts during the early Toarcian. The widely differing records of these genera attests to their longevity and wide geographical and ecological ranges.