cra·ton 
(krātŏn′)
(krātŏn′)n.
A large portion of a continental plate that has been relatively undisturbed since the Precambrian Era and includes both shield and platform layers.
[German Kraton, from Greek kratos, power; see kar- in the Appendix of Indo-European roots.]
cra·tonic (krə-tŏnĭk) adj.