Swedish peat bogs as climatic archives
by
Anders Borgmark
Department of Physical Geography and Quaternary Geology, Stockholm University, Sweden

Peat-stratigraphy as an archive of past climate changes has been in focus of an increasing research interest during the last decades. In this project a number of Swedish peat bogs are investigated to determine possible regional trends in climatic change. The main method used is studies of peat humification combined with AMS ¹⁴C and tephrochronology for dating and correlation.

In Sweden, studies of peat stratigraphy were performed already in the early 1900´s by e.g. Sernander and Granlund. Granlund proposed the term recurrence surface (Swedish: rekurrensyta = RY) to describe distinct changes from dark well-humified peat to less humified peat. He described five recurrence surfaces from peat bogs in middle and southern Sweden, which he dated mainly by correlation of pollen analyses with archaeological findings and with varve-dated isolation sequences. The recurrence surfaces were dated to c: 2300 BC, 1200 BC, 600 BC, 400 AD and 1200 AD and were numbered from V to I, where I is the youngest. Of these RYIII (600 BC) was best developed and widespread.

Results from the bog Stömyren located in western Sweden indicate that Granlund´s theory is correct. In the present study, the combination of AMS-dates and tephra dates provides an excellent time control to the peat profile. A number of wet-shifts is clearly detectable and fall well into Granlund´s scheme of recurrence surfaces. Gullbergbymossen (eastern Sweden) and Ängstugsmossen (south-eastern Sweden) are other investigated bogs that show similar trends. These bogs are, however, yet undated by ¹⁴C and tephrochronology.

Date received: March 29, 2001

Copyright © 2001 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cagc-53.