Mannen unstable rock slope (Møre og Romsdal): Geological and engineering geological logging of drill core KH-02-11 and grain size distribution and XRD analysis of fine-grained breccia

Abstract

Mannen is an unstable rock slope in the Romsdal Valley in the Møre og Romsdal County (western Norway). The slope is under continuous monitoring since 2009 by the Åknes\/Tafjord Beredskap IKS. As part of the detailed site investigations, two more than 130 m deep, vertical cored boreholes have been drilled in 2010 and 2011. This report presents the results from the geological and engineering geological core logging of the lower, second borehole drilled in 2011 (KH-02-11), which complements the logging of the upper, first borehole (KH-01-10) and the geophysical borehole logging using an optical televiewer reported earlier. Results from grain size distribution of fine-grained breccias, as well as XRD identification of clay minerals in breccia layers for both boreholes at Mannen (KH-01-10 and KH-02-11) are also presented.