Title of article :
A kinematic model for recrystallization and texture development in olivine polycrystals
Author/Authors :
Ribe، N. M. نويسنده , , Kaminski، E. نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2001
Pages :
-252
From page :
253
To page :
0
Abstract :
The DSDP/ODP Hole 504B, drilled in the 5.9 Ma southern flank of the Costa Rica Rift, represents the deepest section through modern ocean floor basaltic basement. The hole penetrates a 570 m thick volcanic zone, a 210 m thick transition zone of volcanic rocks and dykes, and 1056 m of dykes. A representative selection of these basalt types has been investigated with respect to Nd and Pb isotopes. The epsilon Nd of the basalts varies from 7.62 to 11.16. This range in the Nd-isotope composition represents about 67% of the total range reported for Pacific MORB. The Pb-isotope composition also shows significant variation, with 206Pb/204Pb varying from 17.90 to 18.82. The isotopic data show that a small volume of enriched mantle existed in the source. The large ranges in isotopic composition in a single drill hole demonstrate the importance of small-scale mantle heterogeneities in the petrogenesis of MORB. Fractional melting and extraction of small magma batches by channelled flow, and small, short-lived crustal magma reservoirs, with limited potential for mixing of the mantle derived magmas, are favored by these isotopic data.
Keywords :
dynamic metamorphism , recrystallization , seismic city , Anisotropy
Journal title :
EARTH & PLANETARY SCIENCE LETTERS
Serial Year :
2001
Journal title :
EARTH & PLANETARY SCIENCE LETTERS
Record number :
53160
Link To Document :
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