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| Titel |
Badenian planktonic foraminifera as climate proxies at the southern margin of the Central Paratethys (Ugljevik, Bosnia and Herzegovina) |
| VerfasserIn |
D. Theobalt, O. Mandic |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250063695
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| Zusammenfassung |
| Badenian transgression is well exposed in the open coal pit Bogutovo Selo near Ugljevik in
NE Bosnia and Herzegovina, located at the southern margin of the Pannonian Basin. Middle
Miocene marine sediments superpose Late Oligocene lignite bearing lacustrine deposits. The
studied succession is about 62 m thick and includes the uppermost part of the lake
deposits, comprising clays, sands and coal seams, followed by marine sediments. These
consist mainly of gray marls, which show some intercalations of thin, dark clay
layers, volcanic ash layers and fossiliferous beds as well as carbonate bodies of
different thicknesses. The presence of Orbulina suturalis allows a biostratigraphic
correlation of the marine transgression horizon with the upper part of the Lower
Badenian.
28 planktonic foraminiferal assemblages were investigated using quantitative
analysis to evaluate the climate development during the initial marine flooding by the
Paratethys Sea. Further on the samples were statistically treated to find out if there
are significant differences in assemblages from the marine sediments deposited
before and after the initial Serravallian cooling event coinciding with the onset of the
Middle Badenian (Wielician) Salinity Crisis. 17 planktonic foraminiferal species were
grouped by their palaeoclimatic significance into cool (Globigerina bulloides, G.
praebulloides, G. diplostoma, G. concinna, G. tarchanensis, G. falconensis, Turborotalita
quinqueloba), temperate (Globorotalia bykovae, G. transsylvanica, G. peripheroronda,
Globoturborotalita woodi), warm-temperate (Globigerinella regularis, Tenuitellinata
angustiumbilicata) and warm indicators (Globigerinoides trilobus, G. quadrilobatus,
Orbulina suturalis, Globoquadrina cf. altispira). The counts were performed mainly on
generic level.
Upper Lower Badenian (Upper Lagenidae Zone) is represented in the marly succession in
the lower part of the section, where the foraminiferal assemblages indicate warmer conditions
with high percentages of warm water indicators. A distinct cooling is shown in the
uppermost passage of the lower part, which is followed by a 13Â m thick carbonate
platform of Wielician age. This transition corresponds to the gradual shift from
Greenhouse into Icehouse climate after the late Middle Miocene Climatic Optimum. The
superposing marly deposits of the late Wielician age (Earliest Serravallian) contain
planktonic foraminiferal assemblages that indicate cooler conditions. The general
percentage of cool water indicators is much higher than in the lower Badenian sediments. |
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