Abstract: The mineralogy and geochemistry of the ela y fraction ( <2f.!) of the Quater nary deposits in the Numedal area, southern Norway, have been studied. The Numedal clays contain considerable amounts of illite, but chlorite, vermiculite, mixed layer minerals, quartz, microcline, and acid plagioclase are also usually found. Amphibole is present in most of the samples. Traces of montmorillonite are occasionally found. During weathering the amount of vermiculite and mixed layered illite vermiculite increases at the expense of trioctahedral illite and chlorite. The average chemical composition of the clay fraction ( <2!!) corresponds to that of coarse clays. The clay material is only slightly weathered, and the residual indexes correspond to those of fresh rocks. Comparison of the mineralogical and chemical data shows the physico chemical variations during weathering, transport and sedimentation, and the composition of the parent material to be of significant importance to the clay composition.
Publication Year: 1972
Publication Date: 1972-01-01
Language: en
Type: article
Access and Citation
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot