overfolded

Overfolded refers to a condition where a geological structure, typically a fold in rock layers, has been compressed and bent beyond its normal range, causing the upper limb to lie beneath the lower limb. This results in an inverted or overturned sequence of rock strata. In essence, the layers that were originally above are now below, and vice versa. This phenomenon occurs due to significant compressional forces acting on rock formations over geological timescales.

The formation of overfolded structures is a common feature in areas that have experienced intense tectonic activity, such as mountain-building processes. These forces can originate from plate collisions or other large-scale movements within the Earth's crust. The degree of overfolding can vary greatly, from a simple overturn to complex recumbent folds where the fold limb is nearly horizontal. Identifying overfolded layers is crucial for geologists as it helps in understanding the structural history and deformation of a region. It can also impact the subsurface exploration for resources like oil, gas, and minerals, as the original stratigraphic order is disrupted.