| Publications | | » | 41. R2K Advances in Seismic Imaging
Oceanography, 2012
 | | » | 40. R2K Seismic Studies
Oceanography, 2012
| | » | 39. Melt bodies off the EPR
Nature Geoscience, 2012
| | » | 38. JdF Plate: Gravity structure
G-cubed, 2011
| | » | 37. JdF Plate: Layer 2B structure
G-cubed, 2011
| | » | 36. Kane waveform tomography
GRL, 2010
| | » | 35. Kane Oceanic Core Complex
G-cubed, 2009
| | » | 34. Geophysical signatures of oceanic core complexes
GJI, 2009
| | » | 33. Accretion of the lower crust
Nature, 2009
| | » | 32. Faulting of the Juan de Fuca plate
EPSL, 2009
| | » | 31. Axial topography os the Galapagos Spreading Center
G-cubed, 2008
| | » | 30. Juan de Fuca Ridge flanks
G-cubed, 2008
| | » | 29. Seismic structure of oceanic core complexes
G-cubed, 2008
| | » | 28. Juan de Fuca Ridge: structure and hotspots
G-cubed, 2008
| | » | 27. Structure of the TAG segment, Mid-Atlantic Ridge
G-cubed, 2007
| | » | 26. Detachment faulting at TAG, Mid-Atlantic Ridge
Geology, 2007
| | » | 25. Structure of the Endeavour segment, Juan de Fuca Ridge
JGR, 2007
| | » | 24. Magma beneath Lucky Strike Hydrothermal Field
Nature, 2006
| | » | 23. Magma chamber of the Cleft segment, Juan de Fuca Ridge
EPSL, 2006
| | » | 22. Topography and magmatism at the Juan de Fuca Ridge
Geology, 2006
| | » | 21. Structure of the southern Juan de Fuca Ridge
JGR, 2005
| | » | 20. Sub-crustal magma lenses
Nature, 2005
| | » | 19. Constructing the crust at the Galapagos Spreading Center
JGR, 2004
| | » | 18. Atlantis core complex
EPSL, 2004
| | » | 17. Morphology of the Galapagos Spreading Center
G-cubed, 2003
| | » | 16. Crustal structure of the East Pacific Rise
GJI, 2003
| | » | 15. Plume-ridge interaction along the Galapagos Spreading Center
G-cubed, 2002
| | » | 14. Compensation of the Galapagos swellEPSL, 2002
| | » | 13. Structure of Tenerife, Canary Islands
JVGR, 2000
| | » | 12. Underplating in the Canary Islands
JVGR, 2000
| | » | 11. Structure of the Mid-Atlantic Ridge (MARK, 23?20'N)
JGR, 2000
| | » | 10. Structure of the Mid-Atlantic Ridge (35?N)
JGR, 2000
| | » | 9. Structure of Gran Canaria, Canary Islands
J. Geodyn., 1999
| | » | 8. Structure of overlapping spreading centers in the MELT area
GRL, 1998
| | » | 7. Crustal thickness in the MELT area
Science, 1998
| | » | 6. The MELT experiment
Science, 1998
| | » | 5. The Canary Islands swell
GJI, 1998
| | » | 4. Morphology of the Galapagos Spreading Center
JGR, 1997
| | » | 3. Faulting of slow-spreading oceanic crust
Geology, 1997
| | » | 2. Flexure beneath Tenerife, Canary Islands
EPSL, 1997
| | » | 1. Elastic thickness in the Canary Islands
GRL, 1994
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Canales, J.P., J.A. Collins, J. Escartin, and R.S. Detrick, Seismic structure across the rift valley of the Mid-Atlantic Ridge at 23?20'N (MARK area): Implications for crustal accretion processes at slow spreading ridges, J. Geophys. Res., 105, 28,411-28,425, 2000
[PDF]
Abstract
The results from a 53-km-long, wide-angle seismic profile across the rift valley of the Mid-Atlantic ridge south of the Kane transform (near 23?20?N, MARK area) provide new constraints on models of tectonic extension and magmatic accretion along slow-spreading mid-ocean ridges. Anomalously low mid- and lower-crustal P wave velocities beneath the neovolcanic Snake Pit ridge are consistent with elevated axial temperatures and with the presence of 4?1% partial melt evenly distributed within the lower crust in preferentially-oriented, elongated thin films. If the melt inclusions have larger aspect ratios, melt fractions can be up to 17?3%. This and other geological observations suggest that the study area is presently in a magmatically active period. The igneous crust is anomalously thin beneath both flanks of the median valley (<=2.3-2.5 km). Thus, the mantle rocks observed along the western rift valley wall at Pink Hill were probably emplaced at shallow levels within the valley floor during a period of very low magma supply, and were later exposed on the valley walls by normal faulting. The crust within the eastern rift valley and flanking rift mountains is seismically heterogeneous, with igneous crustal thickness variations of >=2.2 km over horizontal distances of ~5 km. This heterogeneity indicates that the magma supply in the area has fluctuated during the last ~2 m.y. Thus, magmatic and amagmatic periods at slow-spreading ridges may alternate over much shorter temporal scales that previously inferred from sea-surface gravity data. |
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