Kinetic energy metamorphosis
Kinetic energy metamorphosis (KEM) is a recently discovered tribological process of gradual crystal re-orientation and foliation of component minerals in certain rocks. It is caused by very high, localized application of kinetic energy. The required energy may be provided by prolonged battery of fluvially propelled bed load of cobbles, by glacial abrasion, tectonic deformation, and even by human action. It can result in the formation of laminae on specific metamorphic rocks that, while being chemically similar to the protolith, differ significantly in appearance and in their resistance to weathering or deformation. These tectonite layers are of  whitish color and tend to survive granular or mass exfoliation much longer than the surrounding protolith. KEM in cupules. The products of KEM were first identified in 2015 in cupules, a form of rock art consisting of spherical cap or dome-shaped depressions created by percussion with hammer-stones. KEM laminae, caused by solid state re-metamorphosis of metamorphic rock, have been observed in cupules on three rock types: Replication has established that cupules produced on very hard rocks, such as quartzite, require many tens of thousands of blows with hammer-stones to make. Therefore, the cumulative force applied to  very small surface areas (<15 cm2) is in the order of tens of kN (kilo Newtons). In one extreme case, the KEM lamina has been developed to a thickness of c. 10 mm, but the most commonly observed thickness is about 1–2 mm. The tectonite layer is always thickest in the central part of the cupule, i.e. where the greatest amount of energy was applied. Geological KEM phenomena. These phenomena have since also been observed in geological contexts, generally of three types: Kinetic energy metamorphosis products are tribological phenomena, caused by very focused, localized cumulative effect of kinetic energy  on the syntaxial silica (and the voids it contains) that forms the cement of such rocks as sandstones and quartzites. The conversion to tectonite does not appear to be reversible, and the high resistance of that product to weathering processes protects the parent rock it conceals from both granular and mass exfoliation. Its susceptibility to dating techniques needs to be explored.