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In geology, exfoliation is the term used to describe the detachment of spherical bodies from the underlying rock body , which is achieved by relieving pressure on deep rock that has climbed up . This can result in rock peaks in the form of spherical caps , which characterize the landscape in some regions. Your most striking, albeit atypical example is the Sugar Loaf near Rio de Janeiro .

It used to be assumed that this detachment of rock shells is due to chemical changes in volume caused by moisture. A distinction was made between this spherical hydration and physical (mechanical) exfoliation through solar radiation and nighttime cooling.

Today, shell detachment is considered to be a widespread physical process with which a rock that is lifted from a greater depth or released by the removal of masses above it reacts to pressure relief. When the heavily compressed rocks ( plutonites and metamorphites ) formed deep under the earth's surface are released from the pressure of the load, they expand and convex pressure relief fissures develop , which lead to the gradual detachment of shell-like rock plates due to erosion.

Exfoliation in Biology

In biology, exfoliation is the term used to describe the detachment of cells, especially the superficial cell layers of epithelia , for example in exfoliative ichthyosis .