Print this pageCharacteristics for Recognition of Compressive Compartmental Deformation
BROWN, W. G.
Structural compartmentalization occurs across several orders of magnitude. Compartmental faults may be recognized using the following characteristics:
1. Compartmental faults are of limited areal extent. A compartmental fault is typically oriented transverse to a fold trend, with the length often confined to the width of a single fold, resulting in a decrease from maximum vertical separation, to zero, at the finite ends of the fault, resulting in oblique slip.
2. Folds may terminate abruptly against a compartmental fault. Antidines in one compartment may terminate abruptly by plunging toward, or away from, a compartmental fault. The resulting map patterns appear to have been offset laterally, between adjacent compartments.
3. Changes in directions of fold asymmetry and vergence, may occur abruptly across a compartmental fault. Two folds in adjacent compartments, that have been deformed simultaneously and under the same stress system, may display opposing senses of asymmetry and/or vergence, because they have formed independently of one another; therefore the two folds cannot represent an offset of an originally continuous fold.
4. Structural balance is maintained across adjacent compartments in a variety of ways: (a) adjacent compartments may display the same amount of shortening, even if the folds in both compartments have oppositely-facing asymmetry; (b) shortening caused by thrusting in one compartment, may balance shortening caused by a fold in another compartment; and (c) the sum of crustal shortening across several anticlines in one compartment may balance the shortening of a single, but larger, anticline in an adjacent compartment.