Shield (geology)

"[3] A shield is that part of the continental crust in which these usually Precambrian basement rocks crop out extensively at the surface.[6] The landforms and shallow deposits of northern shields that have been subject to Quaternary glaciation and periglaciation are distinct from those found closer to the equator.[5][7] Shield surfaces exposed to sub-tropical and tropical climate for long enough time can end up being silicified, becoming hard and extremely difficult to erode.[7][8] In the Fennoscandian Shield, average glacier erosion during the Quaternary has amounted to tens of meters, though this was not evenly distributed.[8] For glacier erosion to be effective in shields, a long "preparation period" of weathering under non-glacial conditions may be a requirement.
Geologic provinces of the world ( USGS )
Idealized cross-section of Earth's lithosphere , including the relationship between cratons, shields and platforms (Abbreviations: cb=cratonic basin , LIP= large igneous province , MOR= mid-ocean ridge )
shield volcanoGeologic provincesPlatformOrogenLarge igneous provinceExtended crustOceanic crustPrecambriancrystallineigneousmetamorphictectonicallytectonictectonic plateslithospheremid-ocean ridgecratonbasementsedimentaryEduard SuessCanadian Shieldcontinental crust basement rocks graniticgranodioriticgneissestonaliticgreenstone beltsmetamorphosedgreenschistamphibolitegranulitefaciesgneisspeneplainsFennoscandian ShieldSub-Cambrian peneplainshallow depositsQuaternary glaciationperiglaciationsub-tropicaltropical climatesilicifiedQuaternaryweatheringinselbergsList of shields and cratonsNorth AmericaLake SuperiorArcticCanadaGreenlandAtlantic ShieldAmazonian (Brazilian) ShieldSouth AmericaGuiana ShieldUruguayan ShieldBaltic (Fennoscandian) ShieldAfrican (Ethiopian) ShieldTuareg ShieldAustralian ShieldArabian-Nubian ShieldAntarctic ShieldChina-Korean ShieldAngaran ShieldIndian ShieldBasement (geology)Platform (geology)Precambrian ResearchBibcodeFairbridge, Rhodes W.The Journal of GeologyLidmar-Bergström, KarnaGeografiska AnnalerEarth Surface Processes and LandformsBulletin of the Geological Society of Finland