Chapter 9: Brittle Behavior
This limestone bed (see above) from Lilstock Beach on the southern margin
of the Bristol Channel, England, is broken by numerous fractures, providing
visual evidence of inelastic behavior (Rawnsley et al., 1998; Engelder
and Peacock, 2001). In this chapter we contemplate this singular phenomenon
and describe the modern concepts, laboratory data, and fracture mechanics
required to understand it. We infer from the fractures that these rocks
have deformed in a brittle state and seek to understand the consequences
of brittle behavior for the state of stress and strain, the nature of
the physical mechanisms that operate during such deformation, and the
reasons why inelastic deformation may be localized into thin tabular zones.
Brittle deformation is manifest in rock structures including microcracks,
joints, veins, dikes, deformation bands, compaction bands, and faults.