Dec 2008
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008agufm.v43b2151n&link_type=abstract
American Geophysical Union, Fall Meeting 2008, abstract #V43B-2151
Physics
8410 Geochemical Modeling (1009, 3610), 8414 Eruption Mechanisms And Flow Emplacement, 8415 Intra-Plate Processes (1033, 3615), 9355 Pacific Ocean
Scientific paper
Strongly positive TiO2, Ta, and Nb (TiTaN) anomalies (1) in a Samoan ankaramite from Ofu Island have been attributed to the presence of refractory yet titanian eclogite in the mantle source. From chemical compositions, however, the anomalies could instead result from concentration of phenocrysts in magmas produced by mixing between a highly differentiated alkalic basalt and a crystal sludge carrying abundant olivine, clinopyroxene and especially titanomagnetite phenocrysts, the latter producing much of the TiTaN anomalies, and behaving much like rutile in eclogite. This is consistent with petrography. The distinctive effects of addition of each mineral are well illustrated on major-oxide variation diagrams. Separation of these minerals from liquids (to concentrate in ankaramites and dunite-wehrlite-pyroxenite cumulates) beginning at about 0.15 GPa in the mantle produces residual felsic differentiates (hawaiites, mugearites) with low TiTan anomalies (<1), exemplified by samples dredged elsewhere in Samoa from Savai'i (2). The Ofu samples have a low EMII signature (high 3He/4He), whereas the Savai'i samples have a high EMII signature (low 3He/4He), the extremes at Samoa. This gives a coincidental positive correlation at Samoa overall between TiTan anomalies and 3He/4He, TiTan anomalies being accentuated at the two places by the contrasting effects of phenocryst addition and subtraction during differentiation. High 3He/4He beneath several eastern Samoan volcanoes appears to be an attribute of near-FOZO mantle sources with minimal EM2 signature. (1) Jackson, M., et al., 2008. G-Cubed 9: doi:1029/2007GC001876 (2) Jackson, M., et al., 2007, Nature 448: 684-687, doi:10.1038/nature060488
No associations
LandOfFree
TiTaN Reconsidered 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 TiTaN Reconsidered, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and TiTaN Reconsidered will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1241386