THE SALTS IN ANTARCTIC SOILS, THEIR DISTRIBUTION AND RELATIONSHIP TO SOIL PROCESSES

Abstract

One of the prominent features of Antarctic soils, and one which shows their relationship with soils in other arid regions of the world, is the high content of soluble salts. These salts consist largely of the sulphates, chlorides, and nitrates of sodium, potassium, magnesium, and calcium. Almost all of the possible crystalline phases that may be formed by combination of these anions and cations are found. The origin of the salts has been a matter of controversy for many years. Various origins have been postulated, including chemical weathering of rocks, deposition of marine salts, and leaching from sedimentary rocks. Soils sampled along the length of the Trans-Antarctic Mountains during the last 17 years have formed from a wide range of soil parent materials, under significantly different climatic conditions and age of weathering surface. From the relationship between these factors and the nature of the salts found in the soils, soil pH, and the distribution of calcite crusts, it is possible to show that the greater part of the salt is derived from marine salts, although there are significant contributions from chemical weathering processes. The chemistry of the salts clearly shows that chemical weathering takes place in Antarctic soils, even in the coldest and most arid regions of the Trans-Antarctic Mountains.