Séminaire
Late Quaternary Environmental Change of Kamchatka
Date
le 13-05-2011 à 10:45Lieu Salle Stendhal, DGO, Bâtiment B18
Intervenant(s) Research assistant, School of Geography, Archaeology and Palaeoecology, Queen's University Belfast |
Résumé
Holocene vegetational developments in Russia are relatively unknown, and among the least studied areas of the country is the peninsula of Kamchatka. Late Quaternary research has focussed on aspects such as volcanology, tephrochronology, glacier fluctuations and prehistoric archaeology. The present study is a interdisciplinary enquiry into the late-Quaternary environmental change of Kamchatka. The palynological and sedimentological investigations (this study) will be supplemented by analyses of diatoms (Dr Elinor Andren, Sodertorn University College, Huddinge, Sweden), d
18O, d
13C and d
15N (Natalie St Amour, University of Waterloo, Canada and Prof Dan Hammarlund, Lund University, Sweden), testate amoebe (Prof Lena Barnekow, Lund University, Sweden) and tephra analyses (Dr Sarah Coulter, Queen's University Belfast). The results of all analyses will be compared to each other in future publications.
Four sediment cores from three lakes and a peat bog, located in different parts of the peninsula, were investigated. They provide a survey of environmental change in diverse landscapes in Kamchatka. All cores were analysed for pollen and loss-on-ignition and were dated by the radiocarbon method using an AMS machine. The pollen diagrams of Pechora Lake, Lifebuoy Lake and Olive-backed Lake display low frequencies of herbaceous and aquatic taxa. Wet and moist areas surrounding the lakes are primarily represented by
Betula,
Alnus viridis and
Cyperaceae.
Pinus pumila dominates the vegetation of the well-drained soils of the hill slopes. The vegetation at Utka is, after a strong decrease of grasses, sedges and ferns, mainly dominated by
Betula,
Alnus viridis and
Thalictrum. Upper parts of the pollen diagram are characterised by higher frequencies of
Filipendula and
Myrica.
All three lake sites illustrate a relatively simultaneous spread of
Pinus pumila between 4100 to 4300 cal yr BP. At Utka, evidence of
Pinus pumila is rare. Pollen grains of
Picea and
Larix, identified at Olivebacked Lake, support the concept of existence of local retreat areas in Kamchatka during glacial time.
This study gives new insights into the late Quaternary vegetation and landscape development of Kamchatka. The composition of the forests and the way in which they were assembled over time is examined, as well as whether plants survived within the peninsula, or if they migrated in from elsewhere in east Asia following the last glaciation.