Portal de Periódicos da CAPES

Mineralogical Composition and Weathering of Some Late Pleistocene Marine Clays from the Kongsvinger Area, Southern Norway

1965; Taylor & Francis; Volume: 87; Issue: 1 Linguagem: Inglês

10.1080/11035896509448303

0016-786X

Per Jørgensen,

Geological and Geophysical Studies Worldwide

Abstract The mineralogical composition was determined by using X-ray and thermal methods. The unweathered samples were composed of dioctahedral illite, chlorite, quartz, and feldspars. The following changes were observed as a function of weathering: chlorite → mixed-layer chlorite-vermiculite → vermiculite, and illite → mixed-layer illite-vermiculite with regular alternation of the two types of layers. The processes which are believed to take place during the weathering are described. The influence of weathering in postglacial times was observed to a depth of 3–4 m. In this zone an increase in ionic exchange capacities was observed as the depth decreased, due to the increasing content of vermiculite. The composition of exchangeable ions gradually changed, and the concentration of H+-ions also gradually increased with decreasing depth. The changes of the clay minerals caused an increase in activity and shear strength.