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Radiogenic isotopes in petrogenesis

Model ages for clastic sedimentary rocks are thought to provide an estimate of their crustal residence age (O Nions et a/., 1983), for minimal fractionation of Sm/ Nd accompanies their generation. Since, however, many continental sediments are a mixture of materials from different sources, model Nd ages are the average model age of the sediment and provide a minimum estimate of the crustal residence age or an average crustal residence age. [Pg.231]

Isotope ratios in a magma are characteristic of the source region from which the magma was extracted and the ratios remain unchanged during subsequent [Pg.231]

A much debated issue in the petrogenesis of Aeolian arc magmatism has been whether mafic magmas with different enrichments in potassium, incompatible elements and radiogenic isotopes are related to each other by some type of shallow level evolution process, or they reflect the occurrence of different types of primaiy melts, possibly derived from composi-tionally variable mantle sources. [Pg.204]

See other pages where Radiogenic isotopes in petrogenesis is mentioned: [Pg.215]    [Pg.231]    [Pg.231]    [Pg.233]    [Pg.235]    [Pg.237]    [Pg.239]    [Pg.241]    [Pg.243]    [Pg.245]    [Pg.247]    [Pg.249]    [Pg.251]    [Pg.253]    [Pg.255]    [Pg.263]    [Pg.265]    [Pg.215]    [Pg.231]    [Pg.231]    [Pg.233]    [Pg.235]    [Pg.237]    [Pg.239]    [Pg.241]    [Pg.243]    [Pg.245]    [Pg.247]    [Pg.249]    [Pg.251]    [Pg.253]    [Pg.255]    [Pg.263]    [Pg.265]    [Pg.116]    [Pg.189]    [Pg.370]    [Pg.400]    [Pg.985]    [Pg.284]    [Pg.249]    [Pg.164]    [Pg.451]   


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Petrogenesis

Radiogenic

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