Overprinting (geology)

Overprinting is a geological process that superimposes a set of characteristics on rock that partially obscure earlier characteristics.

Examples include metamorphic overprinting (superimposed metamorphism[1]), in which new structure,[2] texture, or mineral composition is imposed on existing rock.

[3][4] For example, the Tauern window of Alps contains beds that were originally metamorphosed to eclogite but have since been overprinted to the blueschist and then the greenschist facies.

[5] Likewise, deformation associated with the Mazatzal orogeny in Arizona and New Mexico, US, was subsequently overprinted by deformation associated with the Picuris orogeny.

[6] Geochemical signatures can also be overprinted when the geochemistry of a geological body is changed by eliminating or modifying the earlier geochemical signature.