The Complex Chorate Dinoflagellate Cysts of the Bathonian to Oxfordian (Jurassic): Their Taxonomy and Stratigraphic Significance

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.

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

Upper Cretaceous dinoflagellate cysts events from the sub-tropical northern hemisphere

This paper compiles and correlates for the first time Cretaceous to Eocene palynostratigraphies across the Arctic. It focuses on Greenland and adjacent areas, including the Labrador–Baffin Seaway, onshore Nuussuaq Basin in central West Greenland, onshore southern East Greenland, central East Greenland, North-East Greenland, eastern North Greenland and the Danmarkshavn Basin, but also extends to the Canadian Arctic Archipelago and the Barents Sea region offshore Norway. The paper compiles data from more than three decades of detailed Arctic palynological analyses, based mainly on dinoflagellate cysts. It gives a historical overview of the Cretaceous to Paleogene palaeontological studies of Greenland and presents an overview of 85 palynological intervals and numerous bioevents. The palynological assemblages from the Labrador–Baffin Seaway, Nuussuaq Basin and north-east Baffin Bay reflect the opening of the Labrador–Baffin Seaway, from a brackish to freshwater environment in a large embayment in the Early Cretaceous to an open marine seaway in the Late Cretaceous. Assemblages reveal dinoflagellate cyst provincialism between the opening stages of the Labrador–Baffin Seaway and the already opened Greenland–Norwegian–Barents seaway. The Upper Cretaceous global Oceanic Anoxic Event 2 (OAE2) spanning the Cenomanian/Turonian boundary is recognised from Arctic Canada, north-east Baffin Bay, Nuussuaq Basin in central West Greenland, and North-East Greenland, and is mapped and correlated based on dinoflagellate cyst stratigraphy and carbon isotope (δ13Corg) curves. The dinoflagellate cyst assemblages of the Cretaceous/Paleogene boundary are correlated from the Labrador Sea across to the Nuussuaq Basin in central West Greenland; in both areas the earliest Danian palynological assemblage is represented by incoming warm-water species. The presence of the global Paleocene–Eocene Thermal Maximum (PETM) in the Paleogene successions in North-East Greenland and in exploration wells in the Labrador–Baffin Seaway is indicated by the incoming of the warm-water dinoflagellate cyst species Axiodinium augustum.

in the South Atlantic on the Falkland Plateau yielded suites of well-preserved palynomorphs (spores, pollen, dinoflagellates, acritarchs, and tasmanitids) from Late Jurassic to early Tertiary sediments. The oldest sediments recorded are from Site 330 and are of Oxfordian age. These sediments are separated from those of the late Neocomian to Aptian by an appreciable hiatus. At both Sites 327 and 330 the Late Jurassic and Early Cretaceous sediments are marginal marine and were deposited under reducing euxinic conditions. Palynomorph assemblages are dominated by terrestrial components. Late Cretaceous and early Tertiary sediments at Sites 327 and 328, on the other hand, reflect deep water environments, and the assemblages are dominated by dinoflagellate cysts. A comparison of Early Cretaceous assemblages from Site 249, Mozambique Ridge (Indian Ocean) supports continental reconstructions which would place this site near those on the Falkland Plateau.

The discrepancies in the stratigraphical ranges of selected dinoflagellate cysts recorded in the Boreal and Tethyan realms have revealed two migrational events during the Early Jurassic. The first event occurred at the early-late Pliensbachian boundary and consists of mutual biotic exchanges between the two realms. This is linked to a major Early Jurassic transgression which improved marine communications between the Boreal and Tethyan areas. The second dinoflagellate migrational event occurred during the mid Toarcian and was driven by paleoenvironmental factors. The numerous available Lower Jurassic dinoflagellate cyst data from the Boreal and Tethyan realms indicates that phytoplankton distribution was profoundly affected by paleoecological factors. Information pertaining to the life strategies and the paleoecological requirements of the genera Luehndea, Nannoceratopsis and Valvaeodinium has also been determined. INTRODUCTION The distributions of dinoflagellate cysts are primarily related to paleoenvironmental regimes. Certain dinoflagellate cyst taxa exhibit heterochroneity over wide areas because of differences in paleoecological preferences and overall paleoenvironments (Goodman 1987). This situation has implications for the application of dinoflagellate cysts to intercontinental biostratigraphy (Bucefalo Palliani and Riding 1997a). During the Jurassic two faunal provinces, the Boreal and Tethyan realms, have been distinguished partly on the basis of different ammonite, foraminiferal, brachiopod and calcareous nannofossil assemblages (Arkell 1956; Gordon 1970; Voros 1977; Bown 1987). Biotic differences between these realms may be characterized by relative abundances rather than by the presence or absence of specific taxa (Hallam 1969). The Boreal Realm occupied the northern part of the Northern Hemisphere; the Tethyan Realm lay to the south (Hallam 1969). During the Early Jurassic a broad transitional area with both Boreal and Tethyan biotic characteristics was developed. This intermediate belt comprises southern France, Hungary and Portugal, and was also delineated on the basis of ammonites, calcareous nannofossils and dinoflagellate cysts (Zeigler 1980; Geczy 1984; Cariou et al. 1985; Gardin and Manivit 1994; Baldanza et al. 1995). Within the Tethyan Realm, the macrofaunas allow the Mediterranean and sub-Mediterranean bioprovinces to be distinguished. The former comprises the northern margin of the Tethys Ocean, thus is of European affinity; the sub-Mediterranean is of African affinity, being on the southern margin of Tethys (Pavia and Sarti 1987). Recently these two Tethyan provinces have been differentiated using calcareous nannofossils (Baldanza and Mattioli 1992; Baldanza et al. 1995; Mattioli 1995). The majority of publications on Lower Jurassic dinoflagellate cysts are from the Boreal domain; there are significantly fewer published data from north-west Tethys. The biogeographical distributions of Lower Jurassic dinoflagellate cysts have not been investigated in detail. On the basis of data by Davies (1985) from central Portugal, Tethyan Lower Jurassic microplankton assemblages are broadly similar in generic/specific content to more northerly floras. However, there are several taxa whose stratigraphical ranges differ profoundly from those in the Boreal Realm (Poulsen 1996; Riding and Ioannides 1996). Recently, palynological studies have been carried out on ammoniteand calcareous nannofossil-dated Lower Jurassic Tethyan sections in order to define the stratigraphical ranges of dinoflagellate cysts and to compare them with their ranges in the Boreal Realm (Bucefalo Palliani 1996). The aims of this study are to distinguish and interpret the stratigraphical discrepancies between the two paleogeographical realms, to utilize the stratigraphical data to identify the areas where the main Pliensbachian-Toarcian speciation events occured, to recognize the most important migrational events and consequently the biogeographical factors which drove the dinoflagellate cyst distributions. MATERIAL Samples were collected from several European Pliensbachianearly Toarcian successions (text-fig. 1). The correlations are based on the ammonite, calcareous nannofossil and dinoflagellate cyst content. The Portugese sections, Peniche, Rabacal and Brehna, are outcrop localities in central Portugal, north of Lisbon (text-fig. 2). The Peniche section ranges in age from the early Pliensbachian (Carixian) to the early Toarcian. It consists of intercalations of marls and more calcareous marls with interbedded black shales and detrital crinoidal limestone. The samples studied are from the Lower Pliensbachian (text-fig. 3). The late Sinemurian (Lotharingian) to early Bajocian Brenha road cutting section was dated by Mouterde et al. (1972). The Lower Pliensbachian portion of the section, made up by grey marls with marly limestone beds, has been investigated during this study (text-fig. 3). micropaleontology, vol. 45, no. 2, pp. 201-214, text-figures 1-12, appendix 1, 1999 201 This content downloaded from 207.46.13.51 on Sun, 19 Jun 2016 05:55:42 UTC All use subject to http://about.jstor.org/terms Raffaella B. Palliani and James B. Riding: Early Jurassic dinoflagellate migrations and paleoecology, Boreal and Tethyan realms

Dinoflagellate cysts from the upper Campanian (Upper Cretaceous) of Hornby Island, British Columbia, Canada, with implications for Nanaimo Group biostratigraphy and paleoenvironmental reconstructions

Two new ceratioid cornucavate dinoflagellate cysts from the Upper Cretaceous, Gulf of Suez, Egypt

Integrated stratigraphy and paleontology of the lower Miocene Monte León Formation, southeastern Patagonia, Argentina: Unraveling paleoenvironmental changes and factors controlling sedimentation

Dinoflagellate cyst biostratigraphy of the Turonian (Upper Cretaceous) of southern England

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.

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.

Lower Pliocene dinoflagellate cysts from cored Utsira Formation in the Viking Graben, northern North Sea

Palynomorph assemblages from the Lachman Crags Member of the Santa Marta Formation, north-west James Ross Island, Antarctic Peninsula are described. By basis of comparison with other Southern Hemisphere localities, particularly southern Australia, an early Santonian–early Campanian age is indicated. The results broadly corroborate previous stratigraphical interpretations based on macrofaunal evidence, although the presence of a significant thickness of Santonian strata, not previously recognized, is suggested. The dinoflagellate cyst floras allow the recognition of the local equivalents of the Australian Odontochitina porifera, Isabelidinium cretaceum, Nelsoniella aceras and Xenikoon australis Interval Zones. Some recycling of mid Cretaceous (and possibly Late Jurassic) taxa is also indicated. The miospore flora is composed of relatively long-ranging species, although the local appearance of certain taxa may be of stratigraphical significance. Ranges recorded support previous interpretations of heterochroneity in Southern Hemisphere floras. The palynoflora comprises 76 dinoflagellate cyst, 40 miospore and 7 acritarch, prasinophyte and chlorophyte taxa. Six undescribed species of dinoflagellate cyst are recorded and placed in open nomenclature.

Multivariate statistics have been used to identify the paleoclimatic‐paleoecological affinities of most European Jurassic (Toarcian to Kimmeridgian) dinoflagellate cyst taxa. These analyses were then used to construct dinoflagellate cyst diagrams (abbreviated to ‘cyst diagrams'), which are analogous to pollen diagrams. The marine and terrestrial records were then correlated using both pollen (miospore) and cyst diagrams. These plots appear to include many biostratigraphically significant paleoclimatic events which augment, and in some cases refine, the ammonite‐based biostratigraphy. The integration of the terrestrial spore‐pollen based correlations with the oceans, via dinoflagellate cysts, appears to prove that the oscillations in the palynomorph diagrams reflect widespread temperature changes. This is because the ‘cold’ group of dinoflagellate cysts includes several taxa with north‐polar paleogeographic distributions, and equivalent fluctuations can be matched in the terrestrial spore‐pollen diagrams, which in turn are correlated between the northern and southern hemispheres. In the early mid Jurassic, warming events were noted above the Toarcian‐Aalenian boundary and in the early Bajocian. The paleoclimatic signals in the Bathonian appear to be difficult to interpret consistently. The Callovian‐Oxfordian boundary is characterized by a marked cooling event. The Late Jurassic following the early Oxfordian appears to have been a time of increasing ambient paleotemperatures with a thermal zenith in the Kimmeridgian. This generally rising paleotemperature trend for the Callovian to Kimmeridgian interval, including specific variations, is consistent with other Jurassic paleoclimatic results derived using different methods such as clay mineral analyses, isotopic methods, miospore eco‐groups and macropaleobotany.