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The paleoceanography of Kattegat during the last deglaciation from benthic foraminiferal stable isotopes
| Content Provider | Semantic Scholar |
|---|---|
| Author | Friberg, Yasmin Bokhari |
| Copyright Year | 2015 |
| Abstract | This thesis is based on a sediment record collected from the Kattegat Sea, southwestern Scandinavia (Anholt Island area) during IODP Expedition 347 in autumn 2013, and focuses on a portion of this record spanning ~18—14 thousand years ago (ka BP), representing the last deglaciation at the end of the Weichselian. Benthic foraminifera of the species Elphidium excavatum clavatum were analysed for stable isotopes (δ18O and δ13C) to reconstruct the paleoenvironment and oceanographic setting, such as bottom water salinity, temperature and venti-lation. Additionally, the sediment coarse fraction (>63μm) and mean weight per foraminifera shell were measured as a complement to the isotope analyses to interpret other factors, such as sediment origin and conditions at the sea-floor. δ18O was used to calculate paleosalinities in Kattegat bottom waters by assuming a temperature between 0 and 4°C. These calculations yielded salinities varying between 13 and 27, with a rapid freshening at the beginning of the record, and a subsequent slower, stepwise salinity decrease, followed by a rise in salinity after 15.7 ka. Very negative δ13C values suggest a strong stratification between fresh surface and saline bottom waters, likely due to large amounts of glacial meltwater discharging into the Kattegat as the Scandinavian Ice Sheet (SIS) melted. The δ13C values increase after 15.7 ka, suggesting a weakened stratification, perhaps due to stronger seawater influence. A simultaneous decline in average foraminifera shell weight suggests worse calcification conditions for Elphidium excavatum in Kattegat bottom waters. Percent coarse sediment data shows a high amount of sand size fraction at the very beginning of the record, but very low values between ~18 and 15.7 ka, suggesting that Anholt was situated close to the ice margin at 18 ka, but saw a retreat of the SIS during the subsequent few thousand years. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://lup.lub.lu.se/luur/download?fileOId=8229276&func=downloadFile&recordOId=8229269 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
