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The steep sides of Mount Pilatus, south of Lucerne, are seen on the left. The rocks are mostly Cretaceous sediments.
View to the west (left) near the top of Mount Pilatus, south of Lucerne. Note the very contorted layers. The mountain was overthrust about 50 km from the south (left of picture).
A monocline is a fold with a subhorizontal flank passing into a high angle flank. It is usually related to the activity of a tectonic lineament, like a thrust.
SEDIMENTARY - CHEMICAL: Pennsylvanian Eagle Valley evaporites, Rt.82 south of Glenwood Springs --- Gypsum is assumed to have formed in a hot, arid climate by evaporation of sea water in a closed basin causing the precipitation of calcium sulfate. After burial, this soft rock easily flows forming the chevron fold seen in this picture.
SMALL-SCALE FOLDING: S-folds in banded gneiss, Big Thompson Canyon.
TECTONIC FOLDING: Large fold in gypsum layers, Sweetwater Canyon --- Folding is the result of enormous tectonic forces.