A monocline (or, rarely, a monoform) is a step-like fold in rock stratum 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)
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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.
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By mild reactivation of an earlier extensional fault during a phase of inversion causing folding in the overlying sequence.
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As a form of fault propagation fold during upward propagation of an extensional fault in basement into an overlying cover sequence.
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As a form of fault propagation fold during upward propagation of a reverse fault in basement into an overlying cover sequence.
Examples
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Waterpocket Fold in Capitol Reef National Park, Utah
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Comb Ridge in southern Utah
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Grandview-Phantom Monocline in Grand Canyon, Arizona
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Grand Hogback in Colorado
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Lebombo Mountains in Southern Africa
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Lapstone Monocline in the Blue Mountains (Australia)
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Beaumaris Monocline in Victoria (Australia)
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Purbeck Monocline on the Isle of Purbeck, Dorset, England
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Fore-Sudetic Monocline, Poland
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Sindh Monocline, Pakistan
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Torres Flexure, southern Brazil
See also
