Monocline
A monocline (or, rarely, a monoform) is a step-like fold in rock strata consisting of a zone of steeper dip within an otherwise horizontal or gently dipping sequence.
Formation
Monoclines may be formed in several different ways (see diagram)
- By differential compaction over an underlying structure, particularly a large fault at the edge of a basin due to the greater compactibility of the basin fill, the amplitude of the fold will die out gradually upwards.
- By mild reactivation of an earlier extensional fault during a phase of inversion causing folding in the overlying sequence.
- As a form of fault propagation fold during upward propagation of an extensional fault in basement into an overlying cover sequence.
- As a form of fault propagation fold during upward propagation of a reverse fault in basement into an overlying cover sequence.
Examples
- Waterpocket Fold in Capitol Reef National Park, Utah
- Comb Ridge in southern Utah
- Grandview-Phantom Monocline in Grand Canyon, Arizona
- Grand Hogback in Colorado
- Lebombo Mountains in Southern Africa
- Lapstone Monocline in the Blue Mountains (Australia)
- Beaumaris Monocline in Victoria (Australia)
- Purbeck Monocline on the Isle of Purbeck, Dorset, England
- Fore-Sudetic Monocline, Poland
- Sindh Monocline, Pakistan
- Torres Flexure, southern Brazil
See also
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