Overfolds, also known as recumbent folds, are a specific type of geological fold that occurs when one fold is superimposed or overlain upon another fold. In other words, an overfold is a fold that folds back on itself, creating a complex structural pattern in the rock layers. This phenomenon occurs during intense tectonic deformation and is often associated with compressional forces that cause rocks to be intensely folded and deformed.
Key characteristics of overfolds:
- Folding of Folds: Overfolds result from the folding of previously formed folds. As tectonic forces continue to act on the Earth’s crust, the rock layers may undergo additional deformation, leading to the formation of overfolds.
- Complex Geometry: Overfolds can create complex structural patterns, with rocks folded back upon themselves. This can result in the repetition and reorientation of rock layers within the fold structure.
- Different Axial Planes: The axial planes of the two folds that make up an overfold may not align with each other. This misalignment contributes to the complex geometries observed in overfolded structures.
- Intense Deformation: Overfolds typically form in regions of intense tectonic deformation, such as in mountain-building processes or areas influenced by thrust faults.
Overfolds are important features for geologists to study because they provide valuable information about the intense tectonic forces and deformation history of a region. The study of overfolds helps to unravel the complex geological processes that shaped the Earth’s crust over geological time scales. Overfolding is commonly observed in regions with significant tectonic activity, and the identification and analysis of overfolds contribute to a better understanding of the Earth’s geological evolution.