Sm-Nd SYSTEM Technique

	Sm-Nd geochronology Age of crystallization/emplacement. Age range: Precambrian (older than 570 million years) except in specific circumstances. Normally used as an auxiliary method or to date mafic rocks that do not contain minerals suitable for dating by U-Pb. Sm-Nd "model ages" Model-dependent approximation for the age of separation of a magma from the mantle.
	| Capabilities | | Geochronology, Geochemistry, and Tracer Studies  | | Geochronology  |

URL http://geology.cr.usgs.gov/capabilities/gronemtrac/geochron/smnd/tech.html