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Inferences about magma sources and mantle structure from variations of 143 Nd/ 144 Nd
Author(s) -
DePaolo D. J.,
Wasserburg G. J.
Publication year - 1976
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl003i012p00743
Subject(s) - igneous rock , geology , basalt , flood basalt , geochemistry , mantle (geology) , fractional crystallization (geology) , large igneous province , mantle plume , continental crust , magmatism , paleontology , lithosphere , tectonics , volcanism
Continental flood basalts and mid‐ocean ridge (MOR) tholeiitic basalts have distinctly different 143 Nd/ 144 Nd which may permit a priori distinction between "continental" and "oceanic" igneous rocks. Initial 143 Nd/ 144 Nd of continental igneous rocks through time fall on a Sm/Nd evolution curve with chondritic REE abundance ratio. These observations indicate that many continental igneous rocks are derived from a reservoir with chondritic REE pattern which may represent primary material remaining since the formation of the earth. Oceanic igneous rocks are derived from a different ancient reservoir which has Sm/Nd higher than chondritic. Initial 143 Nd/ 144 Nd and 87 Sr/ 86 Sr in young basalts from both oceans and continents show a strong correlation suggesting that Sm‐Nd and Rb‐Sr fractionation events in the mantle may be correlative and caused by the same process. From this correlation Rb/Sr for the earth is inferred to be 0.029.