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Understanding the nature of moisture availability in the Eocene, Oligocene, and Miocene of Antarctica is imperative for climate reconstructions and for understanding the potential influence of future climate change on modern landscapes. Previous studies have used traditional palynological techniques, fossil leaf margins, hydrogen isotope leaf waxes, and palynomorph δ 13 C values to indicate changes in moisture on the southernmost continent. Here, we explore the relationship between pollen width (equatorial diameter) and climate as a potential indicator of changes in moisture availability in Antarctica, a technique that had not been widely applied previously. To date, studies of pollen grain size response to environmental stress and the applicability of using fossil pollen grain size as a climate change proxy are limited. In this paper, we explore the relationship between pollen grain size and environmental stress (desiccation intensity) and whether such a relationship can be applied to fossil pollen from Antarctica. We measured the widths of 157 modern specimens of Nothofagus spp. (the genus of Southern beech) pollen from throughout the Southern Hemisphere and compared them with mean annual precipitation records to assess the relationship between pollen grain size and moisture availability. The widths of 458 Antarctic Nothofagidites lachlaniae -complex pollen grains (from Eocene, Oligocene, and Miocene cores) were then measured and compared to other paleoenvironmental proxies to evaluate whether or not a significant trend in size variability can be associated with a change in moisture availability through geological time. Modern data show a significant relationship between decreased moisture availability and increased pollen grain size and are consistent with a previous study, providing confidence for using changes in pollen grain size as an indicator of moisture. Fossil data show a 23% increase in average pollen grain size from the late Eocene through the early to mid Miocene, indicating a decrease in moisture availability in Antarctica during this time. [ABSTRACT FROM AUTHOR]

The paper presents results of a palaeobotanical investigation of the borehole core Komorniki 97/72 from the Ruja lignite deposit, Lower Silesia. In the deposit lignites of three (2nd Lusatian, 2nd A Lubin, and 1st mid-Polish) middle Miocene groups of seams are present. The lignites of the 1st and 2nd groups are important correlation horizons throughout much of the Polish Lowlands and eastern Germany. The results of the palynological studies (spore–pollen, algae and fungi) and plant macroremains studies show that during the mid-Miocene mires' development, the vegetation was characteristic of wetlands (i.e., swamp and riparian forests, shrub bogs, and reed marshes) as well as mesophytic forests. The results were also used for palaeoclimatic investigation. The mean annual temperature (MAT), for each of the three sections, based on the coexistence approach (CA) method, was estimated in the range of 15.7–17.8 °C. Nevertheless, the frequency of thermophilous (palaeotropical and palaeotropical/warm-temperate) taxa indicate climate changes during the formation of the studied sediments. Composition of the spore–pollen spectra from the 2nd Lusatian seam (i.e., the presence of Meliaceae and Sapotaceae, which currently have pantropical distribution) show that the climate was humid and warm, close to subtropical. Later, many palaeotropical taxa disappeared, and the composition of the spore–pollen spectra indicates a warm temperate climate with slight fluctuations. Above the 1st mid-Polish seam, the climatic conditions changed in a way that did not favor the further formation of lignite deposits. These results correspond with the current understanding of climate change in the middle Miocene in Europe. • The Ruja deposit contains lignite of the three youngest groups of seams. • Middle Miocene vegetation and palaeoclimate of the Ruja area are discussed. • Palynological analysis and plant macroremains are used for the palaeointerpretations. • The results correspond with the current understanding of climate change in Europe. [ABSTRACT FROM AUTHOR]

Abstract: The accurate and consistent identification of fossil pollen is essential to allow robust inferences to be drawn with regard to past climate and vegetation change. Identifications are best achieved through the direct inspection of reference material. Most substantial reference collections are held at prestigious universities in Europe or the United States of America which can restrict access for researchers trying to advance palynology in less developed countries. Digital imaging and fast spreading access to the internet means that it is now possible to produce and disseminate high quality images from pollen reference collections. In this paper we contribute to this growing body of work by presenting images of 364 pollen taxa from West Tropical Africa both as printed plates with a key, and within an associated online searchable database. [Copyright &y& Elsevier]

Abstract: The evolutionary history of Pennsylvanian tropical dryland/upland communities remains enigmatic. In this paper, we describe conifer-dominated palynofloras in a facies context from the early to mid-Moscovian (Middle Pennsylvanian) interval of the De Lutte-6 borehole (the Netherlands) that shed light on this issue. Our data suggest that, in the upper Bolsovian–lowermost Asturian part of the borehole succession, Florinites-producing cordaitaleans with subordinate tree-ferns, pteridosperms, calamiteans, and lycopsids, covered low-lying braidplains draining the rising Variscan Orogen, while Cordaitina/Latensina-producing cordaitaleans, walchian conifers and enigmatic pteridosperms mostly grew in hinterland regions (Assemblage I). At one relatively brief interval, a mire dominated by calamiteans and arborescent lycopsids developed within this braidplain complex (Assemblage II). In the mid-Asturian part of the borehole succession, following a switch from humid to seasonally-dry climates (indicated by paleosols), palynofloras associated with a shallow, but extensive, lake deposit imply that communities of walchian conifers, Cordaitina/Latensina-producing cordaitaleans, and engimatic pteridosperms covered low-lying drylands, but were cyclically replaced by lycopsid ‘ephemerals’ during short-term pluvial events (Assemblage III). Across tropical Pangaea, the climate-driven migration of diverse conifers from Bolsovian hinterlands to mid-Asturian basins coincides with (1) the more frequent appearance of conifer megafloral remains in the fossil record, (2) a gradual increase in the frequency of tree-ferns in clastic swamps, (3) a decline in the abundance of arborescent lycopsids in mires, and (4) a change from perhumid raised mires to humid planar mires in cratonic areas. We therefore highlight that the mid-Asturian (mid-Moscovian) interval is an under-appreciated event in the evolution of Pennsylvanian tropical vegetation, on a par with the better-known climate-driven floral changeovers that occurred in the earliest Kasimovian and Gzhelian–Asselian. Our palaeoecological findings also clarify a long-running biostratigraphic controversy by showing that conifer dominance in the De Lutte-6 borehole is completely consistent with its Bolsovian–Asturian age, and does not require the invocation of an unconformity separating an inferred Westphalian part of the succession from an inferred upper Stephanian/Permian part of the succession, as suggested by some earlier workers. This, in turn, emphases the importance of selecting isotaphonomic (isoclimatic) samples for biostratigraphic purposes. [Copyright &y& Elsevier]