Monocline

Updated on Dec 02, 2023

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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

Grandview-Phantom Monocline in Grand Canyon, Arizona

Lapstone monocline in the Blue Mountains (Australia)

Purbeck Monocline on the Isle of Purbeck, Dorset, England

References

Monocline Wikipedia

(Text) CC BY-SA

Contents

Formation

Examples

References