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| Titel |
Orbital- and millennial-scale environmental changes between 64 and 20 ka BP recorded in Black Sea sediments |
| VerfasserIn |
L. S. Shumilovskikh, D. Fleitmann, N. R. Nowaczyk, H. Behling, F. Marret, A. Wegwerth, H. W. Arz |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 10, no. 3 ; Nr. 10, no. 3 (2014-05-14), S.939-954 |
| Datensatznummer |
250116971
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| Publikation (Nr.) |
 copernicus.org/cp-10-939-2014.pdf |
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| Zusammenfassung |
| High-resolution pollen and dinoflagellate cyst records from sediment core
M72/5-25-GC1 were used to reconstruct vegetation dynamics in northern
Anatolia and surface conditions of the Black Sea between 64 and 20 ka BP.
During this period, the dominance of Artemisia in the pollen record indicates a
steppe landscape and arid climate conditions. However, the concomitant
presence of temperate arboreal pollen suggests the existence of glacial
refugia in northern Anatolia. Long-term glacial vegetation dynamics reveal
two major arid phases ~64–55 and 40–32 ka BP, and two major
humid phases ~54–45 and 28–20 ka BP, correlating with higher
and lower summer insolation, respectively. Dansgaard–Oeschger (D–O) cycles
are clearly indicated by the 25-GC1 pollen record. Greenland interstadials
are characterized by a marked increase in temperate tree pollen, indicating
a spread of forests due to warm/wet conditions in northern Anatolia,
whereas Greenland stadials reveal cold and arid conditions as indicated by
spread of xerophytic biomes. There is evidence for a phase lag of
~500 to 1500 yr between initial warming and forest expansion,
possibly due to successive changes in atmospheric circulation in the North
Atlantic sector. The dominance of Pyxidinopsis psilata and
Spiniferites cruciformis in the dinocyst record indicates
brackish Black Sea conditions during the entire glacial period. The decrease
of marine indicators (marine dinocysts, acritarchs) at ~54 ka
BP and increase of freshwater algae (Pediastrum, Botryococcus) from 32 to 25 ka BP reveals
freshening of the Black Sea surface water. This freshening is possibly
related to humid phases in the region, to connection between Caspian Sea and
Black Sea, to seasonal freshening by floating ice, and/or to closer position
of river mouths due to low sea level. In the southern Black Sea, Greenland
interstadials are clearly indicated by high dinocyst concentrations and
calcium carbonate content, as a result of an increase in primary
productivity. Heinrich events show a similar impact on the environment in the
northern Anatolia/Black Sea region as Greenland stadials. |
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