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Taxonomic identification of small fragments of burned plant tissue in lake sediment profiles can enhance reconstructions of past vegetation, fire regimes, and climate. Vouchered reference collections of charcoal prepared from both soft and woody plant tissues, analogous to modern pollen reference collections, will be required for making rigorous identifications and for knowing the level of certainty achieved. Published methods of laboratory production of charcoal may only poorly mimic pyrolysis as it occurs in wildfires, and tend to require large volumes of plant material. We present a method for preparing reference charcoal from dried plant specimens that is simple, provides a high degree of control, yet requires only small tissue samples. Based on results of a series of experiments, we recommend placing dried samples in 25 cm3 perforated-base porcelain Gooch filtering crucibles, surrounded by 250–500 µm sand; saturating the sand with water and draining; and placing for eight to nine minutes in a furnace heated to 550°C. The wet sand delays heating so that temperature rise is steep. Pyrolysis is brief and occurs under hypoxic conditions due to temporary oxygen flushing by water vapor. Using our method we achieved excellent results on both woody and soft tissues from a variety of plant taxa.
The Late Jurassic (early Oxfordian to earliest Tithonian) dinoflagellate cyst Scriniodinium ceratophorumCookson & 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.
Palynomorph assemblages from an extended succession of Mississippian (Viséan) sediments ranging in age from probable late Arundian to the latest Brigantian exposed on the East Fife coast of Scotland, United Kingdom have been investigated. The stratigraphical distribution of miospores closely reflects that established elsewhere in central and southern Scotland. The occurrence of certain stratigraphically significant miospore taxa permits the assignment of chronostratigraphic ages to locally defined lithostratigraphic units. The latest Asbian to Brigantian (VF miospore Biozone) age of the upper part of the Sandy Craig, Pathhead and Lower Limestone formations is confirmed. The Pittenweem Formation and remainder of the Sandy Craig Formation are both assigned to the NM miospore Biozone of Asbian age and the Anstruther Formation is assigned a late Arundian or Holkerian (TC miospore Biozone) age. The Fife Ness Formation, originally assigned to the early Asbian and considered older than the Anstruther Formation, yielded evidence of both the uppermost part of the TC and lower NM miospore biozones and is suggested to be a member of the Pittenweem Formation.
Dinoflagellate cysts and associated aquatic palynomorphs have been recovered from the dinosaur-bearing Tendaguru Beds (Upper Jurassic–Lower Cretaceous) at Tendaguru, a hill in southeast Tanzania. Palynofloras from these beds are generally dominated by pollen grains of Mesozoic conifers (mainly Classopollis), but dinoflagellate cysts occur sporadically throughout the succession. They attain highest relative abundances and diversities in the marine intercalations between the Saurian Beds, namely in the Nerinea Bed (between the Lower and Middle Saurian Beds) and even more so in the Trigonia smeei Bed (between the Middle and Upper Saurian Beds). Peak levels of dinoflagellate cysts correspond to times when the shallow marine environments of the Nerinea and Trigonia smeei Beds had access to the open sea, while scarcity or absence of dinoflagellate cysts in the Saurian Beds is related to intervals of restricted access to the sea in tidal flat and coastal plain environments.
Four informal dinoflagellate cyst assemblages can be distinguished in the Tendaguru Beds:
the Rigaudella aemula-Chlamydophorella wallala assemblage from the Nerinea Bed (Oxfordian to Kimmeridgian);
the Endoscrinium attadalense-Ctenidodinium sellwoodii group assemblage from the Middle Saurian Bed (late Kimmeridgian);
the Dingodinium jurassicum-Kilwacysta assemblage from the Trigonia smeei Bed (Tithonian);
the Muderongia-Oligosphaeridium assemblage probably from the Trigonia schwarzi Bed at Namunda Plateau, 8 km south of Tendaguru (late Valanginian to Hauterivian).
The age determinations are based on correlation with known dinoflagellate cyst ranges and zonations in Australia, Europe and elsewhere. However, the stratigraphic position and previous biostratigraphic interpretations of the Tendaguru Beds based on ammonites, charophytes and ostracods were also taken into consideration. One new genus (Kilwacysta), three new species (Kilwacysta multiramosa, Kilwacysta semiseptata and Protobatioladinium lindiensis) and the new combination Barbatacysta capitata are proposed.
The Brora Coal, Brora Argillaceous, Brora Arenaceous, Balintore and Kimmeridge Clay formations of the onshore Moray Firth Basin represent an important Middle to Upper Jurassic (Callovian to Lower Kimmeridgian) reference section close to hydrocarbon-rich North Sea basins. This composite succession at Brora and Balintore is c. 233 m thick; it is mudstone/siltstone-dominated and largely rich in zonal and subzonal ammonites. For example, the Callovian succession at Brora is virtually complete, with coverage of all seven ammonite zones. All the five formations examined have yielded abundant palynofloras. The lithostratigraphic units sampled, except the Brora Coal Formation, have yielded rich associations of dinoflagellate cysts. The majority of the Inverbrora Member of the Brora Coal Formation at its type section at Brora is of early Callovian age based on dinoflagellate cysts; this member yielded Meiourogonyaulax caytonensis and Mendicodinium groenlandicum and these species preclude a Bathonian age. This member has been previously attributed to the late Bathonian. Dinoflagellate cysts are diverse and abundant in the overlying Brora Argillaceous to Kimmeridge Clay formations, therefore indicating open marine conditions. The stratigraphic distributions and relative proportions of these Callovian to Lower Kimmeridgian dinoflagellate cyst floras are largely consistent with those reported elsewhere in northern Europe, and the established dinoflagellate cyst biozonations can be readily applied to the Inner Moray Firth Basin. Some taxa, such as Gonyaulacysta dentata, are of distinct Boreal affinity. Furthermore, some minor stratigraphic anomalies were noted, including the range base of Scriniodinium crystallinum being in the early Oxfordian at Balintore. In England and Germany, this bioevent occurs in the late Callovian. Some notable dinoflagellate cyst abundance phenomena were observed. An example of this is the prominence of Korystocysta spp. in the Middle Callovian. This and other quantitative phenomena are of correlative significance. Marine palynomorph diversity increased markedly during the Callovian, stabilizing in the Lower Oxfordian. A suite of characteristic dinoflagellate cysts became extinct in the Middle Oxfordian, and some typically Late Jurassic elements became more prominent at this time. The early Kimmeridgian palynofloras from Ethie are entirely typical of this interval elsewhere in Europe.
Rich and well-preserved assemblages of organic walled dinoflagellate cysts in 50 samples from a 154 m thick and almost complete, Middle Eocene to ?lowermost Oligocene section from the Kysing Research Borehole in eastern Jylland, Denmark are systematically described. One genus Costacysta gen. nov., and twelve species Chiropteridium eocaenicum sp. nov., Costacysta bucina gen. et sp. nov., Distatodinium pilosum sp. nov., Echinidinium? lucidum sp. nov., Hapsocysta kysingensis sp. nov., Horologinella? pentagonalis sp. nov., Operculodinium eisenackii sp. nov., Phthanoperidinium cornutum sp. nov., Selenopemphix septum sp. nov., Svalbardella partimtabulata sp. nov., Thalassiphora gracilis sp. nov. and Thalassiphora microperforata sp. nov. are formally described. The genus Hapsocysta is emended, and is considered to be a senior synonym of Piccoladinium. The gradual change of the dinoflagellate cyst assemblages in this section demonstrates that sedimentation was almost continuous during the time span of ca. 12 Ma. The biostratigraphic resolution based on dinoflagellate cyst events is generally finer than the calcareous nannofossil NP biozonation. A comparison with published dinoflagellate cyst data from the Norwegian–Greenland Sea shows that several important events are mainly synchronous throughout the region, suggesting a general similarity of the water masses. An isolated occurrence of Svalbardella suggests a short cooling event during early Bartonian times. The palynofacies in most of the section is almost purely of pelagic type. A more proximal, mid shelf palynofacies and a distinctive episode of reworking coincide with the Upper Eocene Moesgaard Clay and indicate a brief, but rather large sea level fall during the deposition of this unit. The Eocene/Oligocene boundary is tentatively identified near the base of the Viborg Formation, and approximately coincides with increased reworking of dinoflagellate cysts and a strong increase in bisaccate pollen, indicating more proximal conditions and possibly also a climatic cooling.
A study of the Homerian type section in the upper Beluga Formation (Upper Miocene) of the Kenai Group of southern Alaska has yielded two surprising discoveries: (1) warmth-loving taxa and (2) the presence in Alaska of a ‘new’ gymnosperm family, Podocarpaceae. A well-preserved pollen and spore flora is present in Upper Miocene coal beds of the Kenai lowland, near Homer, Alaska. Stump horizons, abundant wood fragments, wood grain, and amber within the coal attest to a forested swamp. Pollen assemblages from the Homerian type section include elements of both Mixed Northern Hardwood and warm-temperate Mesophytic forests and are far richer than the flora previously defining the Homerian type section, which had suggested a less diverse, cooler assemblage. Within the Homerian type section, the flora exhibits no definite taxonomic chronology; in general, Alnus dominates, with up to 45% of the total counts, followed by Pinaceae and Taxodiaceae pollen types (30 to 35%) and thermophiles (c. 14%). At least 36 genera are represented, including Carya type, Corylus, Ilex, Juglans, Myrica, Ostrya/Carpinus, Pterocarya, Quercus/Quercus-type, and Ulmus/Zelkova, eight dicot genera have not previously been reported from the type Homerian. Presence of these hardwoods in moderate to minor amounts suggests that the climate during the Homerian (Late Miocene) was only slightly cooler than that of the Seldovian (Early to Middle Miocene).
Unexpectedly, Dacrydium and Podocarpus are present as minor elements in most of the samples. They apparently coexisted with the other Miocene taxa, because the pre-Paleogene Kenai–Chugach terrane to the southeast, which supplied sediments to the Kenai Group, is mostly of oceanic plate provenance and is unlikely to have been the source of the pollen. A uniform orange fluorescence of all the pollen, including the podocarps and any potentially reworked pollen, also suggests a contemporaneous origin for all the taxa.
The flora from the Homerian type section may precede or coincide with uplift of the Alaska Range to the north. Thus, further comparison with Homerian taxa at localities north and south of the Alaska Range will be important as it may reveal a possible rain shadow effect.