The northern part of the North American Western Interior Sedimentary Basin has yielded well-preserved terrestrial palynomorphs whose occurrences allow the biostratigraphic characterization of the basin. Data have been compiled from sections that in composite span the latest Turonian to Paleocene. These data allow for the identification of species that are biostratigraphically useful within Alberta and adjacent portions of the basin. Progress has been made in establishing a stable biostratigraphic context for the basin using the first and last occurrences of 103 taxa. These palynomorphs provide a refined chronostratigraphic framework when combined with radiometric ages, polarity chronologies and ammonite biozonations. This framework has allowed the intrabasinal correlation of widely distributed sections in the Alberta and Montana portion of the basin and can be applied to stratigraphic problems in the more northern portion of the Western Interior Basin.

This study documents the terrestrial palynological record at the John's Nose section, a new Cretaceous—Paleogene (K—Pg) boundary site in North Dakota, USA. In addition to Mud Buttes and Pyramid Butte, John's Nose represents the third K—Pg section in southwestern North Dakota that preserves direct evidence of the Chicxulub asteroid impact, allowing for direct comparison over the timing and trends of the palynological record in respect to this event. The palynological analysis of John's Nose section reveals the presence of 68 pollen and spore taxa. Immediately above the boundary clay, a high abundance of fern spores of the genera Cyathidites and Laevigatosporites is recorded (with 59% of the assemblage being represented by Cyathidites). This very distinctive K—Pg ‘fern spike’ event is correlated with the devastation of land plants immediately following the asteroid impact and matches the composition generally reported from other sites in southwestern North Dakota. Palynostratigraphy demonstrates that the placement of the K—Pg boundary based upon the identification of the Last Appearance Datum (LAD) of typical Maastrichtian taxa (K-taxa) may be misleading. The presence of occasional K-taxa up to a few meters above the boundary clay at John's Nose represents an important difference when compared to previous reports. In light of this observation, LADs should be used cautiously as the primary criteria to identify the boundary; some K-taxa may have a short-term presence in the earliest Paleogene, or be reworked. In the John's Nose section, major changes and extinction in the palynological record occur at the geochemical K—Pg boundary, indicating that a catastrophic turnover took place over a short time.

A palynological investigation of marine uppermost Maastrichtian to lower Paleocene strata in two New Zealand sections, mid-Waipara River and Fairfield Quarry, revealed well-preserved dinoflagellate cyst assemblages including three new dinoflagellate cyst species. A formal description of the new dinoflagellate cyst species are presented here. Furthermore a variation of Carpatella cornuta, named C. aff. cornuta is discussed. In the mid-Waipara River section the ranges of the new species Adnatosphaeridium regulatum sp. nov., Alterbidinium mcmillanii sp. nov. and Canningia fairfieldensis sp. nov. are calibrated directly with other microfossil groups including foraminifera, radiolarian and terrestrially derived spores and pollen. The last occurrence of Adnatosphaeridium regulatum sp. nov. is within the lowermost Danian foraminiferal zone Pa and this event is recorded in sections located in several New Zealand sedimentary basins. Alterbidinium mcmillanii sp. nov. has a very restricted range within the latest Maastrichtian to basal Danian with its last occurrence within foraminferal zone PO. Canningia fairfieldensis sp. nov. has so far only been recorded in lower Danian strata and occurs within the foraminiferal zones Pα to P1c and radiolarian zones RP1?—RP2. A morphological variation of Carpatella cornuta named Carpatella aff. cornuta is only observed in a very narrow interval across the Cretaceous—Paleogene (K-Pg) boundary in the mid-Waipara River section. Based on comparison with other New Zealand K-Pg boundary sections, A. mcmillanii sp. nov. and C. fairfieldensis sp. nov. seem to have a palaeoenvironmental affinity for shallow marine to inner neritic depositional environments.

Upper Cretaceous and lower Paleogene sedimentary rocks in southeastern Missouri record the northwest extension of the Mississippi Embayment, yet very little information exists about them due to rarity of outcrops and borehole material. This has hindered a clearer understanding of the depositional conditions before and after the terminal Cretaceous impact event. Access to freshly excavated sediments of the Owl Creek, Clayton and Porters Creek formations and to material from several US Geological Survey boreholes has provided a wealth of data to study this time interval in the area. In this study, detailed palynomorph and palynofacies data have been used to infer palynostratigraphy and paleovegetation. Characteristics of lithology, ichnofossils, invertebrate fossils, foraminifera and well logs have provided the framework for reconstructing the depositional history. Palynomorphs indicate Late Maastrichtian, Danian and Thanetian—Selandian ages for the Owl Creek, Clayton and Porters Creek formations, respectively. Although the Cretaceous—Paleogene (K—Pg) boundary itself is marked by an unconformity, the basal part of the overlying Clayton Formation was apparently deposited as a single megatsunamite following the Chicxulub impact event. Palynofloras suggest mixed coastal and inland subtropical forest vegetation dominated by angiosperm taxa, although abundant records of gymnosperm pollen production occurred at various times during the deposition of the Porters Creek. While terrestrially derived organic components dominate the four palynofacies assemblages (A–D) identified by cluster analysis, lithologic, ichnofacies, macrofossil and dinoflagellate cysts suggest that assemblages C and D, which are characterized by higher percentages of amorphous organic matter, represent more distal marine depositional environments.

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.

The palynology of the Eocene Esmeraldas Formation in the Middle Magdalena Valley Basin, Colombia was analyzed in order to constrain the age of the unit. This formation is a very important oil reservoir in the Middle Magdalena Valley Basin, which is a product of the fragmentation of a Cenozoic foreland basin by the uplift of the Northern Andes. The lateral continuity of the formation, as well as its correlations with lithostratigraphic units in adjacent basins is not clearly understood. The Los Corros Fossil Horizon, a molluscan horizon in the upper part of the Esmeraldas Formation, has been used to trace the top of the formation. This horizon is not laterally continuous over the basin and its age is still debatable. Data from 82 samples from an outcrop section in the Nuevo Mundo Syncline area and from seven previously studied wells have been integrated with a palynological zonation of northern South America in order to date the Esmeraldas Formation. The age ranges from the late Early Eocene to the Late Eocene. The Esmeraldas Formation is correlative with the upper Picacho Formation and the lower part of the Concentracion Formation in the Eastern Cordillera, and the upper Mirador Formation and the base of the Carbonera Formation in the Llanos Foothills. The Los Corros Fossil Horizon is Late Eocene and is time-correlative with a marine transgression in the central Llanos Foothills. A non-metric multidimensional scaling analysis suggests that floras from the Middle Magdalena Valley were different from those in the Llanos Foothills area during the Middle to Late Eocene. This is apparently due to taphonomic effects. The results of this study will contribute to a better understanding of the overall evolution of the Middle Magdalena Valley Basin.

This paper presents a sequence-stratigraphic interpretation from the palynological analysis and lithologic data of two outcrop sections on the NE flank of the Upper Magdalena Valley (UMV) basin primarily comprising the Santonian—Lower Maastrichtian interval. Important stratal horizons are identified in the northeastern part of the UMV basin and ages assigned to them. A cyclic pattern of palynomorph distribution was recognized in both sections and tied to the different stages of the stratigraphic chart. Spikes in abundance of spores accompanied by pollen characterize the lowstand systems tracts and are replaced by the occurrence of euryhaline dinoflagellate cysts (ceratioids and/or gymnodinioids) during the subsequent transgressive phase. Maximum flooding surfaces (MFS) are recognized by a sudden increase in open marine palynomorphs (peridinioids and/or gonyaulacoids) and the scarcity of terrestrial representatives. As sea level starts to fall, the gradual decrease in open marine dinoflagellates along with the occurrence of euryhaline dinoflagellate cysts and terrestrial representatives corresponds to highstand systems tracts. The sequence-stratigraphic interpretation from palynological analysis was correlated to the global sea-level curve allowing the identification of the Santonian—Campanian and Campanian—Maastrichtian boundaries. System tracts from supercycles ZC-3, ZC-4 and TA-1 were recognized from the palynological data.

Grimsdalea magnaclavata was first described by Germeraad, Hopping and Muller from Miocene and Pliocene deposits of northern South America, specifically Colombia and Venezuela. The specific epithet, ‘magnaclavata’, was selected by the authors to draw attention to the distinctive clavate processes of the pollen. A revised taxonomic description is supported by illustrations of fossil specimens from outcrop and well sections that show the range in morphology not previously recorded in the original description; the key difference is the wide variation in process morphology from clavae to clavae with interspersed echinae. Based on the new observations of the pollen morphology we conclude that the records from Cretaceous and Paleogene sediments in North and West Africa are invalid. G. magnaclavata is clearly restricted to northern South America from the Miocene to Pleistocene. The parent plant of G. magnaclavata probably grew in upper coastal plain or around swamps, commonly associated with shrubs and herbaceous savannah plants. The botanical affinity of G. magnaclavata has always been in question. Based on a review of pollen from several palm genera presently extant in northern South America we consider that the nearest living relatives, if indeed G. magnaclavata is an ancient palm, are the genera Mauritia and Mauritiella. The basis for this conclusion is the distinctive foot layer morphology of the processes in the fossil and the modern examples.

The structure of the sporopollenin wall of fossil megaspores can be usefully applied to the determination of morphological similarities and differences between species and genera, which in turn can aid determinations of botanical relationships. Nine species belonging to seven genera of lycopsid megaspores from European Mesozoic successions that have been examined in thin section under a transmission electron microscope are discussed in this paper. Of these, seven are considered to be referable to the Selaginellales, namely Bacutriletes pragensis, Echitriletes zemechensis, Erlansonisporites sp. ‘pseudomoravica’ type, Horstisporites cenomanicensis, Kerhartisporites kleinii, K. srebrecensis, Ricinospora sp. and Verrutriletes maloninensis. The structure of the exospore of Aneuletes patera, an alete species of hitherto uncertain affinity, also suggests that this has selaginellalean origins. The construction of the wall of Echitriletes lanatus, however, resembles that of representatives of the Isoetales and implies derivation from a family within, or related to, one or other of these lycopsid orders that is now extinct. Along with aspects of their gross morphology, significant differences between the structure of the exospore of E. lanatus and E. zemechensis suggest that they do not belong in the same morphological genus. The value of the differentiating Kerhartisporites from Erlansonisporites is questioned.