THE SUPERSWELL AND MANTLE DYNAMICS BENEATH THE SOUTH-PACIFIC

被引:120
作者
MCNUTT, MK
JUDGE, AV
机构
[1] Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge
关键词
D O I
10.1126/science.248.4958.969
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 region of sea floor beneath French Polynesia (the " Superswell") is anomalous in that its depth is too shallow, flexural strength too weak, seismic velocity too slow, and geoid anomaly too negative for its lithospheric age as determined from magnetic isochrone. These features evidently are the effect of excess heat and extremely low viscosity in the upper mantle that maintain a thin lithospheric plate so easily penetrated by volcanism that 30 percent of the heat flux from all hot spots is liberated in this region, which constitutes only 3 percent of the earth's surface. The low-viscosity zone may facilitate rapid plate motion and the development of small-scale convection. A possible heat supply for the Superswell is a mantle reservoir enriched in radioactive isotopes as suggested by the geochemical signature of lavas from Superswell volcanoes.
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收藏
页码:969 / 975
页数:7
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