David J. Batten

Dinoflagellate cyst associations in Cenomanian-Turonian “black shale” sequences of Northern Europe

Abstract Assemblages of dinoflagellate cysts of Cenomanian-Turonian age recovered from sequences containing bituminous marls (“black shales” of most authors) in the Lower Saxony Basin, Helgoland and eastern England vary in composition according to lithofacies and palynofacies. Two main associations have been recognised. The first is dominated by Spiniferites and generally occurs in chalks and marls that accumulated in an open marine environment. It is, however, also present locally in comparatively organic-rich marls where it suggests the presence of well-oxygenated conditions above an oxygen-depleted zone in a stratified water column. Species of Cyclophelium and/or Eurydinium ( E. saxoniensis sp. nov.) dominate the second association which usually occurs in samples that contain an abundance of granular amorphous organic matter. This palynofacies points to deposition in a stressed environment with a low level of oxygen extending high up the water column, a phenomenon that is believed to have been caused by the formation of temporarily silled basins within which circulation was restricted. The position of the Cenomanian-Turonian boundary in the Lower Saxony sequences has yet to be determined precisely but the stratigraphic distribution of the dinoflagellate cysts Adnatosphaeridium tutulosum, Carpodinium obliquicostalum and Lithosphaeridium siphoniphorum supports a recent assessment based on macrofossils.

Worldwide stratigraphic occurrences of Mesozoic and tertiary megaspores

Abstract This paper presents data on the stratigraphic ranges of all known Mesozoic and Tertiary megaspores from around the world and demonstrates the potential of these palynomorphs for dating and correlating sedimentary sequences. Forms referable to more “natural”; genera such as Ariadnaesporites and Paxillitriletes, as opposed to those that are based solely on sculptural morphology, are particularly important because not only are they among the most reliable of biostratigraphic indicators but they also have the greatest value to biologists concerned with the evolution of heterosporous plants. There is, however, much work to be done before megaspores can be used on a regular basis for solving geological problems.

Stratigraphic, palaeogeographic and evolutionary significance of late cretaceous and early tertiary normapolles pollen

Abstract Pollen grains referable to the Normapolles group first appeared during the Cenomanian. They diversified rapidly through the remainder of the Cretaceous and during the early Palaeogene, but by the end of the Eocene they were virtually extinct. They were most numerous in a province which extended from what is now West Siberia across Europe to eastern North America. The Western Interior of North America and West Siberia are considered to delimit the longitudinal boundaries of this province. These areas were submerged during the Late Cretaceous and formed physical barriers to wider dispersal of many Normapolles-producing plants. The Normapolles that have been reported from further afield comprise only minor elements of palynofloras except locally in a few areas where they are apparently relatively abundant. Such records do not invalidate the Siberian and American longitudinal limits but they do require that the concept of the province be altered somewhat to indicate region within which Normapolles are more consistently abundant than elsewhere. Climate must have been as significant an influence on the evolution of the parent plants as it appears to have been in determining the northern and southern boundaries of the province, however vaguely defined these are at present. Palynological analyses of core and cuttings samples from the U.K. continental shelf have helped to refine the northern limit to some extent. Until recently, published maps have included both Svalbard and Greenland in the Normapolles Province. Whilst possibly correct for some of the early Tertiary, Late Cretaceous (Campanian-Maastrichtian) strata in the Northern North Sea and west of the Shetland Islands have yielded Aquilapollenites, Wodehouseia and other taxa typical of the Aquilapollenites Province. The transition between the flora of this boreal region and the European part of the Normapolles Province, which is known to extend as far north as southern Sweden, would thus appear to lie approximately on the latitude of the central North Sea.

Late cretaceous megaspores from southern Sweden: Morphology and paleoenvironmental significance

Abstract The poorly consolidated clastic sediments of Late Cretaceous age in the vicinity of Asen, southern Sweden (Scania) are noted for the variety of fossil flowers and Normapolles pollen grains they have yielded. Megaspores have also been recovered from a number of horizons. Comments on, and illustrations of all but a few indeterminate remains of these are provided in this paper, and four new species, Bacutriletes ferulus, B. majorinus, Erlan‐sonisporites scanicus and E. septus, are erected. Comparison of the total recovery with the relatively small number of Late Cretaceous assemblages that have been described from elsewhere reveals only a few taxa in common. As a result, it is not possible to improve on the late Santonian‐early Campanian age determination that has already been established for the Asen deposits. It is reasonable to infer from the wall structure of the majority of the spores that they were shed by plants of either selaginellalean or isoetalean affinity. Their distribution within the A...

The early cretaceous megaspore Arcellites and closely associated Crybelosporites microspores from northeast Inner Mongolia, P.R. China

The megasporesArcellites plicatus sp. nov. and A. yiminensis sp. nov. and adherent microspores Crybelosporites minor (Qian and Wang 1981) comb. nov. and C. astrictus sp. nov. are described and illustrated from the Damoguihe and Yimin Formations of the Jalainor Group of northeast Inner Mongolia. Transmission electron micrographs of thin-sectioned specimens reveal a close similarity between the wall structure of the megaspores and microspores, thus lending further support to previously recognised indications of a natural relationship between Arcellites and Crybelosporites. Comparison with the morphology, and consideration of the stratigraphic distribution of all known species of Arcellites suggest that the strata from which the new taxa were recorded range from Barremian to Aptian in age. Single specimens of Arcellites sp. cf. A. rugosus Singh 1964 and an unnamed species of the genus are also described, and Triletes fecheri Huckriede 1982 is reported to be a junior synonym of Arcellites pyriformis (Dijkstra) Potter 1963.

Celyphus rallus, probable early cretaceous rivulariacean blue-green alga

Abstract The morphological resemblance between the sheaths of modern Gloeotrichia and Early Cretaceous Celyphus rallus Batten strongly suggests that the latter is a Mesozoic relative of extant blue-green algal species belonging to the family Rivulariaceae. The fossils are typically encountered in argillaceous sediments that were deposited in non-marine environments. When living, they could have been planktonic, but because all the colonies recovered to date are compressed, the possibility that they formed hemispherical rather than spherical masses and grew attached to a substrate cannot be entirely excluded. In common with many blue-greens, C. rallus may have been a pioneering species, perhaps at the transition from brackish to fresh water deposition. Local abundances might well reflect “blooms” in neutral or slightly alkaline conditions at this juncture, but could also be connected with seasonal changes and fixing nitrogen from the atmosphere in nitrogen-poor environments.

Morphology and occurrence of the Normapolles pollen genus Papillopollis in the cretaceous of Portugal

Abstract Rationalization of the taxonomy of pollen grains referable to Papillopollis has been necessary so that the majority of specimens encountered in the Senonian succession of Portugal can be identified. Revised diagnoses are provided for P. aradaensis Kedves & Pittau, P. aveiroensis Kedves & Pittau, P. minimalis Pacltova & Krutzsch, P. rugulatus Kedves & Pittau and P. santonius Pacltova & Krutzsch; one new species, P. barbosae, is erected. The degree of morphological variation allowed for these species is greater than in previous descriptions of forms of Papillopollis and enables the removal of seventeen other taxa which lack reliable distinguishing characters by placing them in synonymy. The sculpture of the pollen grains described ranges from essentially granulate to minutely papillate. The sexine at the poles is typically fissured or reduced to small granular or papillate masses or bodies, but can be absent altogether. These areas of modified exine may have had a harmomegathic function. Thin secti...

Note on the European-Turanian part of the Normapolles Province

Abstract The European to West Siberian/Central Asian part of the Late Cretaceous—early Tertiary Normapolles Province in known as the European-Turanian palaeofloristic region and has nothing to do with the Turonian Stage.