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| Titel |
Evaluating the mid Miocene paleoclimate of Lower Carinthia (Austria) based
on high resolution palynological studies from the Lavanttal Basin |
| VerfasserIn |
Friðgeir Grímsson, Johannes Martin Bouchal, Reinhard Zetter, Guido Grimm |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250125909
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| Publikation (Nr.) |
 EGU/EGU2016-5562.pdf |
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| Zusammenfassung |
| 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.
References:
Denk T, Grimm GW, Grímsson F, Zetter R. 2013. Evidence from “Köppen signatures” of
fossil plant assemblages for effective heat transport of Gulf Stream to subarctic North
Atlantic during Miocene cooling. Biogeosciences 10: 7927–7942.
Grímsson F, Grimm GW, Meller B, Bouchal JM, Zetter R. 2015. Combined
LM and SEM study of the middle Miocene (Sarmatian) palynoflora from the
Lavanttal Basin, Austria: part IV. Magnoliophyta 2 – Fagales to Rosales. Grana:
http://dx.doi.org/10.1080/00173134.2015.1096566
Velitzelos D, Bouchal JM, Denk T. 2014. Review of the Cenozoic floras and vegetation of
Greece. Review of Palaeobotany and Palynology 204: 56–117. |
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