Ten thousand years ago Great Britain was a part of the European continent, where the surface of the North Sea was about 70 metres below present sea level. The large, prehistoric submerged landmass that connected the island of Great Britain to the European continent is now widely known as Doggerland. 85 samples from six different cores, which were collected from this prehistoric landscape, were studied using multi proxy -organic and inorganic- geochemical methods. Thermal analysis determined the organic matter and carbonate content, which were utilized as characterizing indices, dividing each core into various depositional units. In addition, lipid analysis studying three sets of biomarkers (n-alkanes, fatty acids and sterols), was used to distinguish between various depositional environments, especially between terrestrial and aquatic. Furthermore, the cores were mineralogically analysed using the detected clay and non-clay minerals as depositional indicators; significant states such as high and low energy environments, palaeosoil, type of weathering and stone types were identified and used to recognize any mineralogical and thus depositional alteration. Finally, the sulfur isotope analysis identified different sources of sulfur, which were then used as environmental distinguishing proxies. An integration of these analytical results provided a detailed geochemical history of each core; importantly, a Storegga tsunami deposit was detected in core ELF01A. The primary contribution of this thesis was establishing an analytical approach using combined results from a range of analytical methods. The established approach can be used to study the depositional settings for any cored sediments. / Libyan government

The transport of elements by streams from headwater regions to the sea is influenced by landscape characteristics. This thesis focuses on the influence of landscape characteristics (e.g. proportion of wetland/forest coverage) on temporal and spatial variations of Fe, Mn, S and trace elements (As, Co, Pb) in streams located in northern Sweden, a boreal region characterized by coniferous forests and peat wetlands. Water samples from a network of 15 streams revealed a different hydrogeochemistry in forested catchments compared to wetland catchments. The temporal variation was dominated by spring flood, when concentrations of Fe, Mn and trace elements increased in forested headwaters. However, in streams of wetland catchments concentrations decreased, but Pb concentrations were higher in comparison to other streams. Both Fe and Pb showed positive correlations with wetland area, while Co correlated with forest coverage. The anthropogenic contribution of As and Pb appear to be larger than the supply from natural sources. During spring flood SO42- decreased in most streams, although concentrations increased in streams of wetland catchments. Concentrations of SO42- were higher in streams of forested catchments than in wetland dominated streams, the former being net exporters of S and the latter net accumulators. Isotope values of stream water SO42- (δ34SSO4) were close to that of precipitation during spring flood, indicating that the major source of S is from deposition. The results show that, although emissions of anthropogenic S have been reduced, there is still a strong influence of past and current S deposition on runoff in this region. In conclusion, wetlands are key areas for the hydrogeochemistry in this boreal landscape. The findings emphasize the importance of understanding stream water chemistry and element cycling from a landscape perspective. This may be important for predicting how boreal regions respond to environmental disturbances such as climate change.