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- Bouchal, Johannes M., 1979-
(författare)
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Pollen and spores of the uppermost Eocene Florissant Formation, Colorado: A combined light and scanning electron microscopy study
- 2016
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Ingår i: Grana. - : Taylor & Francis Group. - 0017-3134 .- 1651-2049. ; 55:3, s. 179-245
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Tidskriftsartikel (refereegranskat)abstract
- The uppermost Eocene Florissant Formation, Rocky Mountains, Colorado, has yielded numerous insect, vertebrate, and plant fossils. Three previous comprehensive palynological studies investigated sections of lacustrine deposits of the Florissant Formation and documented the response of plant communities to volcanic eruptive phases but overall found little change in plant composition throughout the investigated sections. These studies reported up to 150 pollen and spore phenotypes. In the present paper we used a taxonomic approach to the investigation of dispersed pollen and spores of the Florissant Formation. Sediment samples from the shale units containing macrofossils were investigated using light microscopy (LM) and scanning electron microscopy (SEM). The general picture of the palynoflora is in agreement with previous studies. However, the combined LM and SEM investigation provides important complementary information to previous LM studies. While a fairly large amount of previous pollen determinations could be confirmed, the purported taxonomic affinities of several pollen phenotypes need to be revised. For example, pollen referred to as Podocarpus or Podocarpidites sp. belongs to the Pinaceae Cathaya, Malus/Pyrus actually belongs to Dryadoideae, pollen of the form genus Boehlensipollis referred to as Proteaceae/Sapindaceae/Elaeagnaceae or Cardiospermum belongs to Sapindaceae but not to Cardiospermum, and pollen of Persicarioipollis sp. B with previously assumed affinities to Polygonaceae actually belongs to Thymelaeaceae. Pandaniidites and one type of Malvacipollis cannot be linked with Pandanaceae and Malvaceae. A few taxa are new records for Florissant (Ebenaceae: Diospyros; Mernispermaceae; Trochodendraceae: Tetracentron). In general, SEM investigations complement the LM palynological studies and improve the identification of dispersed pollen and spores and enable integration of data from dispersed fossil pollen into a wide range of comparative morphological, taxonomic, evolutionary, biogeographic, and phylogenetic studies.
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| 2. |
- Bouchal, Johannes M., 1979-, et al.
(författare)
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Some new pollen taxa from the middle Miocene of south western Anatolia
- 2016
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In an ongoing study, focussing on the plant fossils and palynofloras of the lignite strip mines of the Yatağan basin(Muğla province), a number of pollen taxa, previously not reported from middle Miocene terrestrial sediments of Anatolia were encountered.
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| 3. |
- Bouchal, Johannes M., 1979-, et al.
(författare)
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The middle Miocene palynoflora and palaeoenvironments of Eskihisar (Yatağan Basin, southwestern Anatolia): : a combined LM and SEM investigation
- 2016
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Ingår i: Botanical journal of the Linnean Society. - : John Wiley & Sons. - 0024-4074 .- 1095-8339. ; 182:1, s. 14-79
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Tidskriftsartikel (refereegranskat)abstract
- Anatolia was a crossroads for mammal migration during the Miocene due to intermittent land connections between Africa and Anatolia and persisting warm conditions. Here, we investigated a palynological section from middle Miocene sediments of Eskihisar (southwestern Anatolia) in order to establish biogeographic links of the palynoflora and to infer the palaeoenvironment. Four algal palynomorphs, nine spore taxa, eight gymnosperms, three monocots, and 67 dicot pollen types were encountered and investigated using the “single grain method” that combines light microscopy and scanning electron microscopy. Two pollen zones reflect different phases of basin development. Zonal vegetation remained fairly stable across the section and reflects heterogeneous environments including broad-leaved deciduous forest, subtropical forest, and sclerophyllous and semi-evergreen oak forest. Conifers were accessory elements in the broad-leaved deciduous forest communities and replaced these at higher elevations. Some herbaceous taxa (Plumbaginaceae) indicate scattered occurrences of sandy and/or rocky soils. Biogeographic affinities are general Northern Hemispheric, North American, and East Asian as also suggested by the macro fossil record. Only two taxa provide potential biogeographic links with the African flora. This suggests that biome shifts of plant taxa between African subtropical /tropical biomes and Anatolian (western Eurasian) temperate forests and shrublands may have been rare in the middle Miocene.
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| 4. |
- Grímsson, F.
(författare)
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Combined LM and SEM study of the middle Miocene (Sarmatian) palynoflora from the Lavanttal Basin, Austria: part IV. Magnoliophyta 2 – Fagales to Rosales
- 2016
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Ingår i: Grana. - : Informa UK Limited. - 0017-3134 .- 1651-2049.
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Tidskriftsartikel (refereegranskat)abstract
- An ongoing investigation of the middle Miocene (Sarmatian) palynoflora from the Lavanttal Basin continues to show that it contains an extremely rich assemblage of angiosperm taxa. The Fagales to Rosales pollen record documented here contains 34 different taxa belonging to the Betulaceae (Alnus, Betula, Carpinus, Corylus, Ostrya), Fagaceae (Castanea, Fagus, Quercus Groups Cerris, Ilex, Cyclobalanopsis, Quercus/Lobatae), Juglandaceae (Engelhardioideae, Carya, Juglans, Pterocarya), Myricaceae (Morrella vel Myrica), Cannabaceae (Celtis), Elaeagnaceae (Elaeagnus), Rhamnaceae, Rosaceae (Prunus) and Ulmaceae (Cedrelospermum, Ulmus, Zelkova). Two of the pollen types represent extinct genera, Trigonobalanopsis and Cedrelospermum, and are also reported for the first time from the Lavanttal Basin along with pollen of Rhamnaceae and Prunus. The different types of Quercus pollen are now affiliated with Groups Cerris, Cyclobalanopsis, Ilex and Quercus/Lobatae based on sculpturing elements observed using scanning electron microscopy (SEM). Köppen signatures of potential modern analogues of the fossil Fagales and Rosales suggest a subtropical (Cfa, Cwa) climate at lower elevation and subsequent subtropical to temperate climate with altitudinal succession (Cfa→Cfb/Dfa→Dfb; Cwa→Cwb→Dwb) in the Lavanttal area during accumulation of the palynoflora. Most of the fossil taxa have potential modern analogues that can be grouped as nemoral and/or merido-nemoral vegetation elements, and the diversity of Fagales indicates a varying landscape with a high variety of niches.
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| 5. |
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| 6. |
- Grímsson, F., et al.
(författare)
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Evaluating the mid Miocene paleoclimate of Lower Carinthia (Austria) based on high resolution palynological studies from the Lavanttal Basin
- 2016
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Köppen signatures (Denk et al. 2013, Grímsson et al. 2015) can be used to generalize the climatic niche occupied by potential modern analogues (PMA) of fossil plants (here: palynological) assemblages. The Köppen climate system distinguishes climate zones by certain abiotic parameters or combinations thereof and represents them in a three letter code referring to the general climate types (first letter), the seasonal distribution of precipitation (second letter) and the seasonal distribution or general level of warmth (third letter). Based on their Köppen signatures PMAs can be categorized as arctic-alpine, boreal, nemoral, meridio-nemoral, tropical-meridional, tropical, eurytropical, and/or semihumid meridional vegetation elements (see also Denk et al. 2013, Velitzelos et al. 2014, Grímsson et al. 2015). Based on the climatic preferences of their PMAs, the Fagales and Rosales lineages present at the Lavanttal site rule out tropical (A-)climates and climates with pronounced (summer) draught (B-, Cs-, Ds-climates). The same holds for boreal/subarctic climates with short but humid summers (Cfc, Dfc, Dfd, Dwc). The Fagales are represented by 23 lineages at the Lavanttal site including genera that are today composed (predominately or exclusively) of nemoral and meridio-nemoral elements. This points to climate conditions not unlike those found today in the lowlands and adjacent mountain regions of the (south-)eastern United States, the humid-meridional region of western Eurasia (e.g. northern Italy, Black Sea region, western Caucasus), central and southern China, or Honshu (Japan). These regions are characterised by subtropical conditions at lower elevations (Cfa-, Cwa-climates) and subsequent altitudinal successions: Cfa! Cfb/Dfa! Dfb in eastern United States, western Eurasia, central China and Japan, or Cwa! Cwb! Dwb in southern China. The climax vegetation in these areas are mixed mesophytic forests and various mixed evergreen/deciduous broad-leaved forests, characteristic for the humid and semi-humid, summer-rain areas of the meridional and nemoral zone. (Co-)Dominant genera in these forests are the various members of the northern hemispheric Fagales. Important indicator taxa include Fagus , one of the most common and widespread genera in temperate, mixed mesophytic forests of North America, China and Japan, and Quercus Group Ilex, a co-dominant group in the East Asian monsoon influenced, winter-dry or fully humid southern foothills of the Himalayas and montane regions of south-western and central China. Equally informative is Corylus, and the co-occurrence of Carya , Juglans , Pterocarya and Engelhardioideae, pinpointing towards forests as today found in south-western China and the warm subtropical parts of the southeastern United States.
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