Computer Science
Scientific paper
Dec 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992gecoa..56.4295v&link_type=abstract
Geochimica et Cosmochimica Acta, vol. 56, Issue 12, pp.4295-4299
Computer Science
4
Scientific paper
High (HIMU) islands such as St. Helena in the southern Atlantic Ocean, and Tubuaii and Mangaia in the Australes (Polynesia), are known for having mantle sources relatively enriched in some high field-strength elements (HFSE) such as Nb, and, as deduced from their extremely enriched lead isotopic compositions, long-lived high U / Pb ( ) ratios. A second group of HIMU mantle reservoirs is well identified in the Pacific Ocean, at Ua Pou (Marquesas), Mururoa and Fangataufa (Gambiers), Guadalupe; and in the Atlantic Ocean, in the New England seamounts, Azores, Cape Verde, and Canarias. In contrast to Group I, these exhibit a much less pronounced enrichment in radiogenic lead due to only a recent increase in the ratio, whereas HFSE enrichment and lead depletion (as visible from high Ce / Pb ratios) are more pronounced than in Group I. If the HIMU reservoir is related to recycling of subducted lithosphere impoverished by dehydration in some elements enriched in arc magmas, the evolution of the thermal régime in subduction zones makes the HIMU reservoir progressively more abundant with time. During the early to middle Precambrian, a large part of the subducted lithosphere was melted; hence the residue recycled in the mantle was not sufficiently fertile to allow further basaltic melt extraction. In contrast, in modern, cooler subduction zones, dehydration and the subsequent extraction by fluids of mobile elements leaves behind a fertile residue.
No associations
LandOfFree
Mantle: More HIMU in the future? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Mantle: More HIMU in the future?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mantle: More HIMU in the future? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1114682