• journal_title：Geology
• Contributor：Nicholas T. Arndt ; Steven L. Goldstein
• Publisher：Geological Society of America
• Date：1987-
• Format：text/html
• Language：en
• Identifier：10.1130/0091-7613(1987)15<893:UAAOCA>2.0.CO;2
• journal_abbrev：Geology
• issn：0091-7613
• volume：15
• issue：10
• firstpage：893

Samarium-neodymium (Sm-Nd) isotopic studies can be used to evaluate the history of crustal growth and sometimes to give “crust-formation” ages, which reflect the time of differentiation of crust from the mantle. If, however, a sample is a mixture of material derived from the mantle at different times, Sm-Nd systematics may provide only an estimate of the average time that the material in the sample has been resident in the continental crust. In such cases, Sm-Nd isotopes give no direct information on the timing of crustal formation. These ages can be interpreted as the time of crust-mantle segregation only if supported by other geologic and geochronological information. Misinterpretation can lead to false conclusions about the history of crustal development.