Sm nd isotopic dating

23-Jun-2020 06:43

sm nd isotopic dating-46

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The spilite-keratophyre sequence in the Wutaishan area, North China has been dated by zircon from the quartzkeratophyre and a volcanic crystallization age of 2522 Ma (Liu Dunyi et al., 1985) was obtained.This volcanic rock sequence experienced a low-grade metamorphism of greenschist facies during 1800–2000 Ma.Samarium-neodymium dating is useful for determining the age relationships of rocks and meteorites, based on radioactive decay of a long-lived samarium (Sm) isotope to a radiogenic neodymium (Nd) isotope.Nd isotope ratios are used to provide information on the source of igneous melts as well as to provide age data.They are thus, theoretically, not particularly susceptible to partitioning during melting of silicate rocks.Fractional crystallisation of felsic minerals changes the Sm/Nd ratio of the resultant materials.These Sm-Nd dates are less susceptible to metamorphic alteration than Rb-Sr dates.

Using the values for the spilites and quartz-keratophyres suggest that they might have been derived from the same depleted mantle source, or that the quartz-keratophyres are derived from a short-lived mafic source.

Many of these applications were also made before the UPb zircon method had reached its present level of development (section 5.2.2).