Soil formation in marine sediments and beach deposits of southern Norway: investigations of soil chronosequences in the Oslofjord region

Abstract

We investigated the development of Albeluvisols and Podzols with time in southern Norway. The\nVestfold region at the western shore of the Oslofjord was chosen because it is characterized by continuous\nglacio-isostatic uplift for the last 12,000 years. Due to the permanent elevation process, no distinct\nmarine terraces have been built, and the age of the sediments continuously increases with distance from\nthe modern coastline. Albeluvisol development was assessed in a soil chronosequence on loamy marine\nsediments with ages ranging from approximately 1,800 to 10,200 years. The most obvious change during\nsoil development was that after 4,500 ¿ 5,000 years light tongues intruded from the E horizon into the B\nhorizon, and became more pronounced with time. The combined thickness of the A and E-horizons was\nconstant at 40 ± 3 cm in 9 of the 12 profi les and did not change with age. The organic matter content of\nthe A-horizons, the fi ne silt to coarse silt ratio of the Btg horizons and the Feo/Fed ratio all decreased\nwith soil age, whereas the thickness of the organic surface horizon and B horizon, as well as the Fed/Fet\nratio all increased.\nPodzol development was investigated in a chronosequence on sandy beach sediments, the ages of the\nsoils ranging from 2,400 to 8,500 years. All soil properties investigated ¿the organic matter content of the\nB horizons, clay content, Feo, Alo, Sio, Feo/Fed and Fed/Fet ¿ tend to increase with advancing podzolization,\nand are strongly correlated with soil age. Topsoil pH values decrease with age. The characteristic Bh\nand Bs horizons had developed after approximately 4,000 years.