The Holocene evolution of Rheban Spit, Tasmania. 2. Soil development trends

Calcareous sands and podzols of four different ages (0, 3 100, 4200 and 5500 calendar years) form a soil chronosequence at Rheban Spit, a prograded sand barrier, near Orford on the east coast of Tasmania. In terms of profile morphology the soils range from undifferentiated quartz sand with shell at the youngest site, to a well-developed podzol with prominent AI, A, and B horizons at the oldest site. Age trends are derived for a number of soil features, the most significant of which are the leaching from the sediments of detrital marine shell carbonate, the increase in organic matter content in the A and B horizons, the decrease in profile pH, the progressive development of A, and B horizons in terms of acid-extractable iron and aluminium, the increase in thickness of the B horizon and the decrease in the average concentration of cations in the profiles. Most of these age trends are in accord with those derived from soil chronosequences in New South Wales and overseas, but some are markedly different.