SHORT-LIVED CHEMICAL HETEROGENEITIES IN THE ARCHEAN MANTLE WITH IMPLICATIONS FOR MANTLE CONVECTION

被引:49
作者
BLICHERTTOFT, J [1 ]
ALBAREDE, F [1 ]
机构
[1] ECOLE NORMALE SUPER LYON,LYON,FRANCE
关键词
D O I
10.1126/science.263.5153.1593
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
The neodymium isotope and samarium-neodymium systematics of 2.7-billion-year-old mantle-derived magmas indicate that the lifetime of chemical heterogeneities was much shorter in the Archean mantle than in the modern mantle. Isotopic evidence is compatible with a Rayleigh number 100 times larger and convection 10 times faster in the Late Archean compared with the present-day mantle. Modern plate tectonics thus may be an improbable analog for the Archean. Chemical heterogeneities in the mantle may originate upon magma migration and mineralogical phase changes rather than by recycling of oceanic and continental crust.
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页码:1593 / 1596
页数:4
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