Imaging Mantle Heterogeneity with Upper Mantle Seismic Discontinuities

2015 ◽  
pp. 79-104 ◽  
Author(s):  
Nicholas Schmerr
Keyword(s):  
Upper Mantle ◽  
Mantle Heterogeneity ◽  
Seismic Discontinuities

scholarly journals A subduction influence on ocean ridge basalts outside the Pacific subduction shield

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
A. Y. Yang ◽  
C. H. Langmuir ◽  
Y. Cai ◽  
P. Michael ◽  
S. L. Goldstein ◽  
...  
Keyword(s):  
Upper Mantle ◽  
The Arctic ◽  
Mantle Flow ◽  
Mantle Heterogeneity ◽  
Gakkel Ridge ◽  
The Pacific ◽  
Mid Ocean Ridge ◽  
The Pacific Ocean ◽  
Back Arc ◽  
Ocean Ridge

AbstractThe plate tectonic cycle produces chemically distinct mid-ocean ridge basalts and arc volcanics, with the latter enriched in elements such as Ba, Rb, Th, Sr and Pb and depleted in Nb owing to the water-rich flux from the subducted slab. Basalts from back-arc basins, with intermediate compositions, show that such a slab flux can be transported behind the volcanic front of the arc and incorporated into mantle flow. Hence it is puzzling why melts of subduction-modified mantle have rarely been recognized in mid-ocean ridge basalts. Here we report the first mid-ocean ridge basalt samples with distinct arc signatures, akin to back-arc basin basalts, from the Arctic Gakkel Ridge. A new high precision dataset for 576 Gakkel samples suggests a pervasive subduction influence in this region. This influence can also be identified in Atlantic and Indian mid-ocean ridge basalts but is nearly absent in Pacific mid-ocean ridge basalts. Such a hemispheric-scale upper mantle heterogeneity reflects subduction modification of the asthenospheric mantle which is incorporated into mantle flow, and whose geographical distribution is controlled dominantly by a “subduction shield” that has surrounded the Pacific Ocean for 180 Myr. Simple modeling suggests that a slab flux equivalent to ~13% of the output at arcs is incorporated into the convecting upper mantle.

scholarly journals Isotopic evidence for chaotic imprint in upper mantle heterogeneity

2010 ◽  
Vol 11 (5) ◽  
pp. n/a-n/a ◽  
Author(s):  
Pietro Armienti ◽  
Daniela Gasperini
Keyword(s):  
Upper Mantle ◽  
Mantle Heterogeneity ◽  
Isotopic Evidence

scholarly journals An assessment of upper mantle heterogeneity based on abyssal peridotite isotopic compositions

2009 ◽  
Vol 114 (B12) ◽  
Author(s):  
J. M. Warren ◽  
N. Shimizu ◽  
C. Sakaguchi ◽  
H. J. B. Dick ◽  
E. Nakamura
Keyword(s):  
Upper Mantle ◽  
Mantle Heterogeneity ◽  
Abyssal Peridotite ◽  
Isotopic Compositions

Upper mantle heterogeneity in the northern part of Eurasia

1983 ◽  
Vol 33 (3) ◽  
pp. 180-193 ◽  
Author(s):  
N.I. Pavlenkova ◽  
A.V. Yegorkin
Keyword(s):  
Upper Mantle ◽  
Mantle Heterogeneity

Upper mantle heterogeneity below the Mid-Atlantic Ridge, 0°–15°N

1992 ◽  
Vol 97 (B4) ◽  
pp. 4461 ◽  
Author(s):  
E. Bonatti ◽  
A. Peyve ◽  
P. Kepezhinskas ◽  
N. Kurentsova ◽  
M. Seyler ◽  
...  
Keyword(s):  
Upper Mantle ◽  
Mantle Heterogeneity ◽  
Mid Atlantic Ridge
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