Structural Geology

Structural Geology is the branch of geology that deals with the form, arrangement, and internal structure of the rocks, and especially with the description, representation, and analysis of structures, chiefly on a moderate to small scale

Similar to tectonics, but the latter term is used for broader regional or historical structures

A. Primary - Formed by the formation of the rock itself

B. Local gravity-driven - formed due to slip down an inclined surface - Includes: Slumping, at any scale, driven by gravitational potential which exceeds friction

C. Local density-inversion driven - formed because of local lateral rock-density variations, causing local buoyancy forces

D. Fluid-driven pressure: Injection of unconsolidated material due to sudden release of pressure

E. Tectonic - Formed due to interactions between lithospheric plates, or regional interactions between the asthenosphere and the lithosphere. The forces are gravitational, trying to achieve isostatic equilibrium, at crustal to lithospheric scales

A. Syn-formational - Structure forms at the same time as the material that forms the rock

B. Penecontemporaneous - Formed after deposition, but before full lithification

C. Post-formational - Structure forms after the rock has fully formed, as a consequence of forces not related to the formation of the rock

A. Fracturing - related to development or coalescence of fractures in rock

B. Frictional sliding - The slippage of one rock past another, or of grains past each other, resisted by frictional forces

C. Plasticity - Deformation by the internal flow of crystals w/o loss of cohesion, or non-frictional sliding of crystals past each other

D. Diffusion - material transport either in the solid-state or by dissolution in a fluid.