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| Titel |
Late Quaternary palaeoenvironmental reconstruction from Lakes Ohrid and Prespa (Macedonia/Albania border) using stable isotopes |
| VerfasserIn |
M. J. Leng, I. Baneschi, G. Zanchetta, C. N. Jex, B. Wagner, H. Vogel |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 10 ; Nr. 7, no. 10 (2010-10-13), S.3109-3122 |
| Datensatznummer |
250005012
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| Publikation (Nr.) |
 copernicus.org/bg-7-3109-2010.pdf |
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| Zusammenfassung |
| Here we present stable isotope data from three sediment
records from lakes that lie along the Macedonian-Albanian border (Lake
Prespa: 1 core, and Lake Ohrid: 2 cores). The records only overlap for the
last 40 kyr, although the longest record contains the MIS 5/6 transition
(Lake Ohrid). The sedimentary characteristics of both lakes differ
significantly between the glacial and interglacial phases. At the end of MIS
6 Lake Ohrid's water level was low (high δ18Ocalcite) and,
although productivity was increasing (high calcite content), the carbon
supply was mainly from inorganic catchment rock sources (high δ13Ccarb). During the last interglacial, calcite and TOC
production and preservation increased, progressively lower δ18Ocalcite suggest increase in humidity and lake levels until
around 115 ka. During ca. 80 ka to 11 ka the lake records suggest cold
conditions as indicated by negligible calcite precipitation and low organic
matter content. In Lake Ohrid, δ13Corg are complacent; in
contrast, Lake Prespa shows consistently higher δ13Corg suggesting a low oxidation of 13C-depleted organic matter in agreement
with a general deterioration of climate conditions during the glacial. From
15 ka to the onset of the Holocene, calcite and TOC begin to increase,
suggesting lake levels were probably low (high δ18Ocalcite). In the Holocene (11 ka to present) enhanced
productivity is manifested by high calcite and organic matter content. All
three cores show an early Holocene characterised by low δ18Ocalcite, apart from the very early Holocene phase in
Prespa where the lowest δ18Ocalcite occurs at ca. 7.5 ka,
suggesting a phase of higher lake level only in (the more sensitive) Lake
Prespa. From 6 ka, δ18Ocalcite suggest progressive
aridification, in agreement with many other records in the Mediterranean,
although the uppermost sediments in one core records low δ18Ocalcite which we interpret as a result of human activity.
Overall, the isotope data present here confirm that these two big lakes have
captured the large scale, low frequency palaeoclimate variation that is seen
in Mediterranean lakes, although in detail there is much palaeoclimate
information that could be gained, especially small scale, high frequency
differences between this region and the Mediterranean. |
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