General Characteristics of Exfoliation Joints
- Commonly follow topography (Gilbert, 1904; Matthes, 1930; Goodman, 1993).
- Divide the rock into sub-planar slabs (Goodman, 1993).
- Joint spacing increases with depth from a few centimeters near the surface to a few meters (Dale, 1923; Jahns, 1943; Goodman, 1993).
- Maximum depth of observed occurrence is around 100 meters (Dale, 1923; Jahns, 1943; Holzhausen, 1989; Goodman, 1993).
- Deeper joints have a larger radius of curvature, which tends to round the corners of the landscape as material is eroded (Gilbert, 1904; Dale, 1923; Matthes, 1930; Jahns, 1943; Goodman, 1993).
- Fracture mode is tensile (Bahat et al., 1999; Mandl, 2005).
- Occur in many different lithologies and climate zones, not unique to glaciated landscapes (Bradley 1963; Twidale, 1973; Goodman, 1993).
- Host rock is generally sparsely jointed, fairly isotropic, and has high compressive strength (Gilbert, 1904; Jahns, 1943; Twidale, 1973).
- Can have concave and convex upwards curvatures (Gilbert, 1904; Matthes, 1930; Romani and Twidale, 1999).
- Often associated with secondary compressive forms such as arching, buckling, and A-tents (buckled slabs) (Romani and Twidale, 1999).
Read more about this topic: Exfoliation Joint
Famous quotes containing the words general and/or joints:
“Private property is held sacred in all good governments, and particularly in our own. Yet shall the fear of invading it prevent a general from marching his army over a cornfield or burning a house which protects the enemy? A thousand other instances might be cited to show that laws must sometimes be silent when necessity speaks.”
—Andrew Jackson (1767–1845)
“Opinions are to the vast apparatus of social existence what oil is to machines: one does not go up to a turbine and pour machine oil over it; one applies a little to hidden spindles and joints that one has to know.”
—Walter Benjamin (1892–1940)