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Evaluating the methods of pollen analysis and optically stimulated luminescence in respect of recovering the climate history of a site near Yabroud, Syria.
Speciale, 3. modul, 2004/05, id:216
Vejleder:Tage Christensen (fysik)
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English abstract
We have made investigations on a site near Yabroud in Syria in order to describe the climate conditions under which the formation of the site has taken place. To do this it is important to consider the process of deposition. We have applied two methods on samples from the site: An older, pollen analysis, and a younger, optically stimulated luminescence (OSL) and we have investigated their applicability at this location. Pollen analysis has not been developed for the Syrian environment and the OSL-measurement method has not previously been used on this location. We have identified a total of 255 pollen and spores stemming from 42 species found in 15 different layers in the profile of the site. These do not represent a well-founded statistical material so we choose to base our conclusion on the pollen from the two layers in which we have found most pollen (111 cm and 711 cm below the baseline). From the distribution of species found in these two layers we conclude that they have been deposited during a warm period. Pollen analysis has proved to be less successful at this location especially because of the limited amount of pollen and because our pollen slides were blurry even after additional refinement. We took ten soil samples down trough the profile that were subjected to OSL analysis. The results of the individual samples are highly credible and this encourages us to believe that the OSL-measurement procedure works well on our samples, even though their ages are relatively high. We get the following results and as seen there in no clear chronology in the distribution of the ages. We do, however, believe that there is a possibility that the samples have been deposited within a relatively short period of time. (Figure) From the investigations made by us and others it is not possible to give a clear explanation of how the site was deposited or of the climate conditions during the time of deposition. The age distribution of our samples (see the figure above) leads us to believe that the profile was deposited during a relatively short period of time. The ages also correspond well to ages estimates obtained by others on material from the site. We assume that the geologists who have previously examined the site are right when they calim that part of the profile is deposited during an interglacial. In respect of our date estimates we conclude that this must have been the Holsteinian.

Database opslag den: 25-01-2021