Behavior of REE and other trace and major elements during weathering of granitic rocks, Évora, Portugal

Abstract

The distribution of elements within a weathering profile depends on several factors, including the relative stability of the mineral phases of the parent rock, redox and leaching conditions. Three main processes are involved in weathering: ( 1 ) the breakdown of the parent minerals; (2) the removal in solution of some of the released constituents; and (3) the formation of secondary phases with components from the atmosphere (water, oxygen and carbon dioxide), from the parent rock and from shallower levels, and transported by the percolating solutions (Fritz and Ragland, 1980; Nesbitt, 1980; Chesworth et al., 1981 ). The purpose of this work is to investigate how major and trace elements behave during the weathering of granitic rocks from l~vora, Portugal. The prevailing climatic characteristics of this region are: 700 mm annual rainfall; dry summers; and a mean annual temperature of 16°C.