Dating the mantle roots of young continental crust
作者： Nadine Wittig , Joel A. Baker , Hilary Downes
DOI: 10.1130/G22135.1
关键词:
摘要: Subcontinental lithospheric mantle xenoliths from beneath the French Massif Central contain clinopyroxene with high Lu/Hf and Hf isotope ratios ( 176 Lu/ 177 = 0.1-10.8; e +40 to +2600). These Lu-Hf systematics yield model ages of 313-377 Ma apparently date melt extraction in a wedge during Variscan subduction, residual subsequently forming stabilizing keel young European continental crust. The extremely depleted contrast other isotopic signatures (Sr, Pb, Nd) that have been overprinted by metasomatism. values developed extraction, coupled robustness this system some types metasomatism, provide new chronometer for directly dating crust-mantle differentiation both ancient regions. process metasomatic decoupling Nd isotopes, which has previously recognized Hawaiian oceanic subcontinental mantle, may be responsible prominent displacement terrestrial rocks lower at given as compared Bulk Earth reference obtained analysis chondritic meteorites.
geoscienceworld.org
harvard.edu
unirioja.es
gsapubs.org参考文章(39)
C Pin, Le magmatisme basique calcoalcalin d’âge dévono-dinantien du nord du Massif Central, témoin dˈune marge active hercynienne : arguments géochimiques et isotopiques Sr/Nd Geodinamica Acta. ,vol. 15, pp. 63- 77 ,(2002) , 10.1016/S0985-3111(01)01079-8
Richard W Carlson, D Graham Pearson, David E James, Physical, chemical, and chronological characteristics of continental mantle Reviews of Geophysics. ,vol. 43, ,(2005) , 10.1029/2004RG000156
G.M. Nowell, P.D. Kempton, S.R. Noble, J.G. Fitton, A.D. Saunders, J.J. Mahoney, R.N. Taylor, High precision Hf isotope measurements of MORB and OIB by thermal ionisation mass spectrometry: insights into the depleted mantle Chemical Geology. ,vol. 149, pp. 211- 233 ,(1998) , 10.1016/S0009-2541(98)00036-9
Dmitri A. Ionov, Janne Blichert-Toft, Dominique Weis, Hf isotope compositions and HREE variations in off-craton garnet and spinel peridotite xenoliths from central Asia Geochimica et Cosmochimica Acta. ,vol. 69, pp. 2399- 2418 ,(2005) , 10.1016/J.GCA.2004.11.008
B.J. Williamson, H. Downes, M.F. Thirlwall, A. Beard, Geochemical constraints on restite composition and unmixing in the Velay anatectic granite, French Massif Central. Lithos. ,vol. 40, pp. 295- 319 ,(1997) , 10.1016/S0024-4937(97)00033-9
A. Shaw, H. Downes, M.F. Thirlwall, The quartz-diorites of Limousin: Elemental and isotopic evidence for Devono-Carboniferous subduction in the Hercynian belt of the French Massif Central Chemical Geology. ,vol. 107, pp. 1- 18 ,(1993) , 10.1016/0009-2541(93)90098-4
N.E. Blair, Geochimica et Cosmochimica Acta. "The carbon isotope biogeochemistry of acetate from methanogenic marine sediment." by N. E. Blair and W. D. Carter Jr. published in 56, 1247-1258 Geochimica et Cosmochimica Acta. ,vol. 56, pp. 2131- 2131 ,(1992) , 10.1016/0016-7037(92)90334-F
Vincent J.M. Salters, Alan Zindler, Extreme 176Hf/177Hf in the sub-oceanic mantle Earth and Planetary Science Letters. ,vol. 129, pp. 13- 30 ,(1995) , 10.1016/0012-821X(94)00234-P
Jean-Louis Paquette, Pierre Monchoux, Marc Couturier, Geochemical and isotopic study of a norite-eclogite transition in the European Variscan belt: Implications for UPb zircon systematics in metabasic rocks Geochimica et Cosmochimica Acta. ,vol. 59, pp. 1611- 1622 ,(1995) , 10.1016/0016-7037(95)00067-A
Joel A. Baker, David Ulfbeck, Martin Bizzarro, A New Digestion and Chemical Separation Technique for Rapid and Highly Reproducible Determination of Lu/Hf and Hf Isotope Ratios in Geological Materials by MC‐ICP‐MS Geostandards and Geoanalytical Research. ,vol. 27, pp. 133- 145 ,(2003) , 10.1111/J.1751-908X.2003.TB00641.X