spacer
Woods Hole Oceanographic Institution

Juan Pablo Canales

spacer
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 swell
EPSL, 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



spacer
Canales, J. P., B. E. Tucholke, M. Xu, J. A. Collins, and D. DuBois, Seismic evidence for large-scale compositional heterogeneity of oceanic core complexes, Geochem., Geophys., Geosyst. 9, Q08002, doi:10.1029/2008GC002009, 2008

Abstract

Long-lived detachment faults at mid-ocean ridges exhume deep-seated rocks to form oceanic core complexes (OCCs).  Using large-offset (6 km) multichannel seismic data we have derived two-dimensional seismic tomography models for three of the best-developed OCCs on the Mid-Atlantic Ridge.  Our results show that large lateral variations in P-wave velocity occur within the upper ~0.5-1.7 km of the lithosphere.  We observe good correlations between velocity structure and lithology as documented by in situ geological samples and seafloor morphology, and we use these correlations to show that gabbros are heterogeneously distributed as large (10s to >100 km2) bodies within serpentinized peridotites. Neither the gabbros nor the serpentinites show any systematic distribution with respect to along-isochron position within the enclosing spreading segment, indicating that melt extraction from the mantle is not necessarily focused at segment centers, as has been commonly inferred. In the spreading direction, gabbros are consistently present toward the terminations of the detachment faults.  This suggests enhanced magmatism during the late stage of OCC formation due either to natural variability in the magmatic cycle or to decompression melting during footwall exhumation.  Heat introduced into the rift valley byflow and crystallization of this melt could weaken the axial lithosphere and result in formation of new faults, and it therefore may explain eventual abandonment of detachments that form OCCs.  Detailed seismic studies of the kind described here, when constrained by seafloor morphology and geological samples, can distinguish between major lithological units such as volcanics, gabbros, and serpentinized peridotites at lateral scales of a few kilometers.  Thus such studies have tremendous potential to elucidate the internal structure of the shallow lithosphere and to understand the tectonic and magmatic processes by which they were emplaced.

 



FILE » PDF



© Woods Hole Oceanographic Institution
All rights reserved