The Micromorphology of Young Soils from South-East Iceland

The micromorphology of a chronosequence of lowland soils developed on till exposed by the retreating Breidamerkur glacier is compared with that of a palaeosol buried by the advancing glacier about 1700 A. D. and with three soils from the mountainous hinterland.As first exposed the wet highly dispersed till has a dense matrix with a few spherical bubble pores near the surface and an incipient platy structure below the surface layer. In the early years after deglaciation, on freely drained sites, the surface layers develop a porous spongy fabric and silt is gradually washed down into the lower part of the solum to form a dense silty layer. Within thirty years a weakly developed silt droplet fabric is present in the surface layer and reaches a depth of more than 50 cm in the oldest soil of the sequence on the 1894 moraine. A similar weakly developed silt droplet fabric is present in the Fjall palaeosol and in two of the three mountain soils.The weak patchy silt droplet fabric currently developing in these immature Icelandic soils is very similar to the fabric which developed in upland soils at the southern margin of the zone of discontinuous permafrost in the British Isles at the beginning of the present cycle of soil profile development in the Pre-Boreal Period.