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. [7] [8]