Microtextures of quartz sand grains in coastal and shelf sediments, Møre, western Norway

Abstract

Investigations of surface textures on quartz sand grains from coastal and continental shelf sediments indicate that terrestrial sediments have been exposed to considerable weathering. In two till samples, resedimented material can be recognized. Littoral sediments are primarily composed of resedimented till. Eolian sediments from coastal dunes are resedimented till which have also undergone a littoral phase. Eolian textures are relatively poorly developed. Assumed Mesozoic—Tertiary rocks contain well-rounded grains characterized by diagenetic processes. One of the assumed pre-Pleistocene sandstones shows grains with obvious glacial textures. This may be assumed to be evidence of glaciations in western Norway during the Late Tertiary. Sediments from the continental shelf are derived from Quaternary diamictons and Mesozoic—Tertiary sediments. Subaquatic textures and grain-size distribution indicate that sea level during the Weichselian was more than 100 m lower than the present level. Incipient diagenesis has been observed on assumed Weichselian-age quartz grains.