Miozäne Vegetationsdynamik an der Atlantikküste von New Jersey
Zusammenfassung der Projektergebnisse
Quantitative climate analyses generated in the framework of project KO 3944/5 indicate climate fluctuations during the end of the Oligocene and at the transition between the Oligocene and Miocene. Periodic changes in vegetation units were identified which suggest movements of the plant cover responding to orbital-scale glacial-interglacial changes. The rate between pollen and dinoflagellate cysts was used to exclude transport-induced effects in this context. For the time interval between ~18.0 and ~17.7 Ma, it could be shown that eccentricity induced extensions and retreats of the high-altitude conifer forest, while mesophytic forest on moist/wet soils was affected by obliquity during an overall humid warmtemperate time interval. Eccentricity and obliquity seem to have influenced these units in different altitudes and most likely influenced threshold values, which regulated plant productivity and their competition. The Mid-Miocene Climatic Optimum was not strongly reflected by vegetation in the hinterland of the New Jersey Shallow Shelf. Results for the interval before the climate optimum imply that minor seasonality changes occurred. Diversity in the hinterland increased during regression phases, probably due to an increasing variety of vertical ecological. Most of the taxa occurring in the NJSS hinterland belong to the extended multi-layered broadleaved mesophytic forest that occupied the lowlands. Mesophytic forest was replaced by conifer forest in higher altitudes. Geomorphological changes contributed to the spread and diminution of several vegetation units were probably caused by geomorphological changes. The Appalachian uplift may have contributed to the extent of a conifer forest in the hinterland around ~15.8 to ~15.6 Ma. A subsequent spread of taxa belonging to the Cupressaceae family between ~15.0 and ~14.8 Ma may reflect an interval of enhanced inundation of coastal lowland. Quantitative analyses for the second half of the Mid-Miocene Climatic Optimum and subsequent phases imply mean annual temperatures of ~13°C ± ~5°C, coldest month temperatures of ~4.3°C ± ~5.3°C, and warmest month temperatures of ~21.9°C ± ~4.5°C, while temperatures were generally slightly higher before. Annual precipitation seems never to have decreased below 1000 mm for all sequences analysed. The Gulf Current loop maybe one factor which contributed to the generally stable conditions in the region. The presence of taxa until now not identified from the eastern coast of North America could be shown for the Miocene. In the framework of the module “Public Relations Funding”, results from the project were presented at the Geological-Palaeontological Museum, Center of Natural History, Hamburg University and a related display case is part of the current exhibition.
Projektbezogene Publikationen (Auswahl)
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(2014): Late Eocene to middle Miocene (33 to 13 million years ago) vegetation and climate development on the North American Atlantic Coastal Plain (IODP Expedition 313, Site M0027). Climate of the Past 10, 1523-1539
Kotthoff, U., Greenwood, D.R., McCarthy, F.M.G., Müller-Navarra, K., Prader, S., Hesselbo, S.P.
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(2017): Vegetation and climate development of the New Jersey hinterland during the late Middle Miocene (IODP Expedition 313 Site M0027). Palaeogeography, Palaeoclimatology, Palaeoecology 485, 854-868
Prader, S., Kotthoff, U., McCarthy, F.M.G., Schmiedl, G., Donders, T.H., Greenwood, D.R.
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(2018): Insights into the palaeovegetation and palaeoclimate evolution of the New Jersey hinterland (eastern North America) during the Oligocene and Miocene – a palynological study. PhD thesis, Universität Hamburg
Prader, S.
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(2018): Plants in movement – Floristic and climatic characterization of the New Jersey hinterland during the Palaeogene–Neogene transition in relation to major glaciation events, Biogeosciences Discuss.
Prader, S., Kotthoff, U., McCarthy, F. M. G., Schmiedl, G., Donders, T. H., and Greenwood, D. R.
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2018. Floristic and climatic characterization of the New Jersey hinterland during the Oligocene-Miocene transition in relation to major glaciation events. IODP/ICPD Colloquium, Bochum, Germany
Prader, S., Kotthoff, U., McCarthy, F.M.G., Schmiedl, G., Donders, T., H., Greenwood, D.R.
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2018. Orbitally-driven palaeovegetation changes in the New Jersey hinterland during a short time interval (300.000 yrs) of the Burdigalian. IODP/ICPD Colloquium, Bochum, Germany
Prader, S., Kotthoff, U., Bunzel, D., Milker, Y., McCarthy, F.M.G., Schmiedl, G., Greenwood, D.R.
