Garnets HFSEs

Blichert-Toft J., Albarede F., and Kornprobst J. (1999) Lu-Hf isotope systematics of garnet pyroxenites from Beni Bousera, Morocco implications for basalt origin. Science 283, 1303-1306. 

Bedini R. M., Blichert-Toft J., Boyet M., and Albarede F. (2002) Lu-Hf isotope geochemistry of garnet-peridotite xenoliths from the Kaapvaal craton and the thermal regime of the lithosphere. Geochim. Cosmochim. Acta (Spec. Suppl.) 66S1, A61. 

Ionov D. A. (2004) Chemical variations in peridotite xenoliths from Vitim, Siberia inferences for REE and Hf behaviour in the garnet facies upper mantle. J. Petrol. 45. 

The Lu-Hf isotope composition of cratonic lithosphere disequilibrium between garnet and clinopyroxene in kimberlite xenoliths. Geochim. Cosmochim. Acta 6651, Ain. 

Other limits to the accuracy of chronologic data involve uncertainties in the nature of what is being dated, and the corrections necessary for the application of a specific chronometer. Some techniques (e.g., Sm/Nd and Lu/Hf dating of garnet) can be seriously compromised by inclusions of accessory phases, such that accurate geochronology and thermochronology require ultra-pure mineral separates. In addition, many commonly dated minerals display complex... 

The accuracy with which we calculate closure temperatures depends on having high-quality diffusion data. For some systems (e.g., Lu/Hf in garnet), reliable diffusion data do not exist. For many others, we have no good understanding of the effects of natural compositional variability or deformational history on dififusivity. The experiments necessary to improve this situation are difficult and time-consuming, but they are of cmcial importance. 

Scherer E. E., Cameron K. L., and Blichert-Toft J. (2000) Lu-Hf garnet geochronology closure temperature relative to the Sm-Nd system and the effects of trace mineral inclusions. Geochim. Cosmochim. Acta 64(19), 3413-3432. 

The main target of Sm-Nd and Lu-Hf dating in metamorphic studies continues to be the mineral garnet. Garnet is a major constituent in many metamorphic rocks it preferentially incorporates heavy rare earth elements, and hence can have very high (e.g., Stosch andLugmarr, 1987)... 

Anczkiewicz R., ThirlwaU M., and Platt J. P. (2002) Influence of inclusions and leaching techniques on Sm-Nd and Lu-Hf garnet chronology. Geochim. Cosmochim. Acta (Goldschmidt Conf. Abstr.) 66, A19. 

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