Sökning: "varved lake sediments"
Visar resultat 1 - 5 av 12 avhandlingar innehållade orden varved lake sediments.
1. Varved lake sediments and diagenetic processes
Sammanfattning : Varved (annually laminated) sediments are of great interest for inference of past environmental conditions, as they provide dated records with high time resolution. After deposition, the sediment varves are affected by diagenesis; i.e., chemical, physical and biological changes that occur within the sediment. LÄS MER
2. Setting the Holocene clock using varved lake sediments in Sweden
Sammanfattning : The aim of this thesis was to study annually laminated (varved) Holocene lake sediment in Sweden, their formation and their potential as chronological and palaeoecological archives. Five lakes with continuous Holocene varved lake sediment sequences in northern (Västerbotten) and west central Sweden (Värmland) were investigated. LÄS MER
3. Combining limnology and paleolimnology : a refined understanding of environmental sediment signal formation in a varved lake
Sammanfattning : Paleoclimatic archives, such as lake sediments, extend our understanding of terrestrial and aquatic ecosystem dynamics in relation to climate variability beyond the period covered by instrumental data. In this context, annually laminated (i.e. LÄS MER
4. Studies of an elusive element : processes that influence the net retention of mercury in lake sediments and peatlands
Sammanfattning : Because of its toxic nature mercury is a threat to both wildlife and human health, and thus, it is an element of concern in the environment. Currently much of the mercury emitted to the atmosphere is derived from anthropogenic sources – both direct emissions and re-emission of already deposited anthropogenic mercury. LÄS MER
5. The natural holocene vegetation development and the introduction of agriculture in northern Norrland, Sweden : studies of soil, peat and especially varved lake sediments
Sammanfattning : The Holocene vegetation history of northern Norrland was studied by pollen analysis of sediement, peat and soil samples, with the aim to improve our knowledge about vegetation development in northern Norrland, and also about the history of man and the introduction of agriculture in the area. Earlier made pollen analyses from the four northernmost provinces were summarized and a series of new analyses from northern Norrland added. LÄS MER