Summit peats ('peat cakes') on the fells of Finnish Lapland: continental fragments of blanket mires?

Peat deposits of area up to 50 m(2) and thickness of 10-50 cm on fell summi ts at 370-622 m a.s.l. in northern Finland have been mapped, analysed and d ared. These summit 'peat cakes' are most frequent in northwestern Inari Lap land, in a relatively continental climate and close to the Arctic Ocean. It seems that the most important local factor for their development are irreg ularities in microtopography, which collect drift snow and shelter plants f rom destructive winds. Most sites are dominated by Empetrum nigrum ssp. her maphroditum. Accumulation of peat started after the Atlantic period c. 4000 C-14 years BP, when the climate became more humid. The mean annual growth of seven investigated deposits ranged from 0.11 to 0.44 mm yr(-1). Plant ma cro-remains at Kuovdaoaivi provide evidence of gradual vegetation developme nt from an Empetrum-dominated community to a more diverse one: macro-remain concentration and the number of species rise gradually to the top of the d eposit. At present, summit peats are being eroded by deflation, enhanced by needle ice and reindeer overgrazing. It seems that these peat deposits rep resent embryonic blanket mires at the continental limit of high-latitude bl anket mire distribution.