American Journal of Science · 1968 · 221 citations · 0 references
EngineeringGeologyPetrophysicsRheologySurface ScienceRheology Of Biological MaterialsShear ThinningBulk ViscosityFold MechanicsQuartzViscosity
Folds occur in quartz veins, slate, and phyllite. The study tested the Biot theory by measuring wavelengths of 818 folds from six sites and then applied a modified version that incorporates uniform shortening and thickening of the layer. Measured wavelengths yielded viscosity ratios of 2–8, too low for the original Biot theory, but the modified theory produced ratios of 3–14 with uniform shortening/thickening ranging from 1:2.7 to 1:5.7.
The Biot theory was tested by measuring wavelengths of 818 folds from six different locations. The folds are in quartz veins and in slate and phyllite. The mean relative wavelength (4.0 to 6.8) leads to ratios of layer viscosity to medium viscosity of 2 to 8, too low for the Biot theory to apply directly. A modified Biot theory was applied, taking into account uniform shortening and thickening of the layer that accompanies the folding process. The new viscosity ratio values range from 14 to 3, and the uniform shortening and thickening ranges from 1:2.7 to 1:5.7.