Magmatic processes at superfast spreading mid-ocean ridges: Glass compositional variations along the East Pacific Rise 13°-23°S

1991 ◽  
Vol 96 (B4) ◽  
pp. 6133-6155 ◽  
Author(s):  
John M. Sinton ◽  
Suzanne M. Smaglik ◽  
John J. Mahoney ◽  
Ken C. Macdonald
Keyword(s):  
East Pacific Rise ◽  
Ocean Ridges ◽  
East Pacific ◽  
Magmatic Processes ◽  
Compositional Variations

Mercury in Mid-Ocean ridges (on the example of Mid-Atlantic ridge and East Pacific rise)

2003 ◽  
Vol 107 ◽  
pp. 1001-1004
Author(s):  
N. A. Ozerova ◽  
G. A. Cherkashov ◽  
S. I. Andreev ◽  
A. Yu. Lein ◽  
M. P. Davydov ◽  
...  
Keyword(s):  
East Pacific Rise ◽  
Ocean Ridges ◽  
East Pacific ◽  
Mid Atlantic Ridge

Melt-Peridotite Interactions in Shallow Mantle at the East Pacific Rise: Evidence from ODP Site 895 (Hess Deep)

1996 ◽  
Vol 60 (398) ◽  
pp. 191-206 ◽  
Author(s):  
Stephen J. Edwards ◽  
John Malpas
Keyword(s):  
Transition Zone ◽  
East Pacific Rise ◽  
Mineral Chemistry ◽  
Ocean Drilling Program ◽  
Ocean Ridges ◽  
East Pacific ◽  
Eastern Equatorial Pacific ◽  
Basaltic Melt ◽  
Reverse Relationship ◽  
First Time

AbstractOcean Drilling Program (ODP) Leg 147 recently drilled at Site 895 in Hess Deep (eastern Equatorial Pacific), where a structurally dissected section of the East Pacific Rise (EPR) is preserved, and intersected the mantle-crust transition zone of a fast-spreading centre for the first time. The core from Hole 895D (latitude 2°16.635′N, longitude 101°26.777′W) revealed that harzburgite is predominant over dunite in the top section of the Hole, but the reverse relationship is found lower in the section where dunite is closely associated with gabbroic rocks (gabbro and troctolite). Texture, mineralogy and mineral chemistry suggest a two-stage evolution for harzburgite preserved at the transition zone. Harzburgite with a porphyroclastic texture was produced by partial melting of peridotite to, or beyond the clinopyroxene-out phase boundary before or during asthenospheric (>1000°C) flow, which suggests a higher degree of mantle melting than normally expected below mid-ocean ridges. Subsequently, basaltic melt(s) interacted with this refractory harzburgite (olivine + orthopyroxene + spinel), which resulted in dissolution of orthopyroxene, re-equilibration and formation of olivine and spinel, and formation of clinopyroxene ± plagioclase, this is manifested as a progressive conversion of harzburgite to gabbroic rock through an intermediate dunite. At low melt/peridotite ratios, harzburgite was refertilised as the plagioclase component of the melt completely reacted with the peridotite matrix to produce clinopyroxene-spinel intergrowths and Al enrichment in ferromagnesian minerals. At high ratios, orthopyroxene completely dissolved incongruently, plagioclase appeared, and spinel was partially to completely resorbed; this produced olivine-bearing and olivine-free gabbroic rocks. Residual minerals in peridotites adjacent to gabbroic zones were enriched in Fe and Ti and depleted in Al.

scholarly journals Magmatic processes in developing oceanic crust revealed in a cumulate xenolith collected at the East Pacific Rise, 9°50′N

2006 ◽  
Vol 7 (12) ◽  
pp. n/a-n/a ◽  
Author(s):  
W. Ian Ridley ◽  
Michael R. Perfit ◽  
Matthew C. Smith ◽  
Daniel J. Fornari
Keyword(s):  
Oceanic Crust ◽  
East Pacific Rise ◽  
East Pacific ◽  
Magmatic Processes

scholarly journals Kinematics and dynamics of the East Pacific Rise linked to a stable, deep-mantle upwelling

2016 ◽  
Vol 2 (12) ◽  
pp. e1601107 ◽  
Author(s):  
David B. Rowley ◽  
Alessandro M. Forte ◽  
Christopher J. Rowan ◽  
Petar Glišović ◽  
Robert Moucha ◽  
...  
Keyword(s):  
East Pacific Rise ◽  
Oceanic Lithosphere ◽  
Plate Motion ◽  
Mantle Flow ◽  
Plate Boundaries ◽  
Tectonic Plates ◽  
Ocean Ridges ◽  
East Pacific ◽  
The Pacific ◽  
Negative Buoyancy

Earth’s tectonic plates are generally considered to be driven largely by negative buoyancy associated with subduction of oceanic lithosphere. In this context, mid-ocean ridges (MORs) are passive plate boundaries whose divergence accommodates flow driven by subduction of oceanic slabs at trenches. We show that over the past 80 million years (My), the East Pacific Rise (EPR), Earth’s dominant MOR, has been characterized by limited ridge-perpendicular migration and persistent, asymmetric ridge accretion that are anomalous relative to other MORs. We reconstruct the subduction-related buoyancy fluxes of plates on either side of the EPR. The general expectation is that greater slab pull should correlate with faster plate motion and faster spreading at the EPR. Moreover, asymmetry in slab pull on either side of the EPR should correlate with either ridge migration or enhanced plate velocity in the direction of greater slab pull. Based on our analysis, none of the expected correlations are evident. This implies that other forces significantly contribute to EPR behavior. We explain these observations using mantle flow calculations based on globally integrated buoyancy distributions that require core-mantle boundary heat flux of up to 20 TW. The time-dependent mantle flow predictions yield a long-lived deep-seated upwelling that has its highest radial velocity under the EPR and is inferred to control its observed kinematics. The mantle-wide upwelling beneath the EPR drives horizontal components of asthenospheric flows beneath the plates that are similarly asymmetric but faster than the overlying surface plates, thereby contributing to plate motions through viscous tractions in the Pacific region.

scholarly journals Magmatic processes and segmentation at a fast spreading mid-ocean ridge: Detailed investigation of an axial discontinuity on the East Pacific Rise crest at 9°37′N

2001 ◽  
Vol 2 (10) ◽  
pp. n/a-n/a ◽  
Author(s):  
Matthew C. Smith ◽  
Michael R. Perfit ◽  
Daniel J. Fornari ◽  
W. Ian Ridley ◽  
Margo H. Edwards ◽  
...  
Keyword(s):  
East Pacific Rise ◽  
East Pacific ◽  
Mid Ocean Ridge ◽  
Fast Spreading ◽  
Magmatic Processes ◽  
Ocean Ridge
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