volcanic deposition from eruptive fissures located within
the AST to degrees depending on the frequency and effusion rates of eruptions. The AST, where present, hosts the
majority hydrothermal vents along the ridge axis due to its
proximity to crustal heat sources (e.g., magma chambers)
and anisotropic permeability within the sheeted dikes
and tectonically disrupted upper crust. Discontinuities
within the AST are coincident with discontinuities in other
ridge-crest properties such as depth, axial magma chamber
continuity and melt content, and lava geochemistry.
Bibliography
Carbotte, S. M., Solomon, A., and Ponce-Correa, G., 2000. Evaluation of morphological indicators of magma supply and segmentation from a seismic reflection study of the East Pacific Rise
15
30
0
–17
N. Journal of Geophysical Research, 105, 2737.
Carbotte, S. M., Ryan, W. B., Jin, W., Cormier, M. H., Bergmanis,
E., Sinton, J., and White, S., 2003. Magmatic subsidence of the
East Pacific Rise (EPR) at 18
14
0 S revealed through fault restoration of ridge crest bathymetry. Geochemistry, Geophysics,
Geosystems, 4, doi:10.1029/2002GC000337.
Carbotte, S. M., Detrick, R. S., Harding, A., Canales, J. P., Babcock,
J., Kent, G., Ark, E. V., Nedimovic, M., and Diebold, J., 2006.
Rift topography linked to magmatism at the intermediate spreading Juan de Fuca Ridge. Geology, 34, 209.
Chadwick, W. W., 2003. Quantitative constraints on the growth of
submarine lava pillars from a monitoring instrument that was
caught in a lava flow. Journal of Geophysical Research, 108,
2534.
Chadwick, W. W., Jr., and Embley, R. W., 1998. Graben formation
associated with recent dike intrusions and volcanic eruptions
on the mid-ocean ridge. Journal of Geophysical Research, 103,
9807.
Fornari, D. J., Haymon, R. M., Perfit, M. R., Gregg, T. K. P., and
Edwards, M. H., 1998. Axial summit trough of the East Pacific
Rice 9
–10
N: geological characteristics and evolution of the
axial zone on fast spreading mid-ocean ridge. Journal of Geophysical Research, 103, 9827–9855.
Francheteau, J., Juteau, T., and Rangin, C., 1979. Basaltic pillars in
collapsed lava-pools on the deep ocean floor. Nature, 281,
209–211.
Gregg, T. K. P., Fornari, D. J., Perfit, M. R., Ridley, W. I., and Kurz,
M. D., 2000. Using submarine lava pillars to record mid-ocean
ridge eruption dynamics. Earth and Planetary Science Letters,
178, 195–214.
Haymon, R. M., and White, S. M., 2004. Fine-scale segmentation of
volcanic/hydrothermal systems along fast-spreading ridge
crests. Earth and Planetary Science Letters, 226, 367–382.
Haymon, R. M., Fornari, D. J., Edwards, M. H., Carbotte, S.,
Wright, D., and Macdonald, K. C., 1991. Hydrothermal vent distribution along the East Pacific Rise crest (9
09
0
–54
0 N) and its
relationship to magmatic and tectonic processes on fastspreading mid-ocean ridges. Earth and Planetary Science Letters, 104, 513–534.
Langmuir, C. H., Bender, J. F., and Batiza, R., 1986. Petrological
and tectonic segmentation of the East Pacific Rise,
5
30
0
–14
30
0 N. Nature, 322, 422–429.
Macdonald, K. C., and Fox, P. J., 1988. The axial summit graben
and cross-sectional shape of the East Pacific Rise as indicators
of axial magma chambers and recent volcanic eruptions. Earth
and Planetary Science Letters, 88, 119–131.
Macdonald, K. C., Fox, P. J., Perram, L. J., Eisen, M. F., Haymon,
R. M., Miller, S. P., Carbotte, S. M., Cormier, M. H., and Shor,
A. N., 1988. A new view of the mid-ocean ridge from the behaviour of ridge-axis discontinuities. Nature, 335, 217–225.
Qin, R., and Buck, W. R., 2008. Why meter-wide dikes at oceanic
spreading centers? Earth and Planetary Science Letters, 265,
466–474.
Rubin, A. M., and Pollard, D. D., 1988. Dike-induced faulting in rift
zones of Iceland and Afar. Geology, 16, 413–417.
Smith, M. C., Perfit, M. R., Fornari, D. J., Ridley, W. I., Edwards,
M. H., Kurras, G. J., and Von Damm, K. L., 2001. 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
0 N. Geochemistry, Geophysics,
Geosystems, 2, doi:10.1029/2000GC000134.
Soule, S. A., Fornari, D. J., Perfit, M. R., and Rubin, K. H., 2007.
New insights into mid-ocean ridge volcanic processes from the
2005–2006 eruption of the East Pacific Rise, 9
46
0 N–9
56
0 N.
Geology, 35, 1079–1082.
Soule, S. A., Escartín, J., and Fornari, D. J., 2009. A record of eruption and intrusion at a fast spreading ridge axis: axial summit
trough of the East Pacific Rise at 9–10
N. Geochemistry, Geophysics, Geosystems, doi:10.1029/2008GC002354.
White, S. M., Macdonald, K. C., and Haymon, R. M., 2000. Basaltic
lava domes, lava lakes, and volcanic segmentation on the southern East Pacific Rise. Journal of Geophysical Research, 105,
23519–23536.
White, S. M., Haymon, R. M., and Carbotte, S., 2006. A new view
of ridge segmentation and near-axis volcanism at the East Pacific
Rise, 8–12 N, from EM300 multibeam bathymetry. Geochemistry, Geophysics, Geosystems, 7, doi:10.1029/2006GC001407.
Cross-references
Axial Volcanic Ridges
Hydrothermalism
Mid-ocean Ridge Magmatism and Volcanism
Oceanic Spreading Centers
AXIAL VOLCANIC RIDGES
Isobel Yeo
GEOMAR Helmholtz Centre for Ocean Research,
Kiel, Germany
Synonyms
Neo-volcanic ridge
Definition
Axial volcanic ridges (AVRs). Composite volcanic edifices, comprising an elongate, typically spreading-normal
orientated topographic high, produced within the inner
valleys of mid-ocean ridges, usually those that are slow
spreading.
Introduction
The surface expression of volcanic activity is extremely
variable at different spreading rates (see “Morphology
Across Convergent Plate Boundaries”), as a result of the
differing eruption styles associated with each. Axial volcanic ridges (AVRs), sometimes called neo-volcanic
36
AXIAL VOLCANIC RIDGES
the AST to degrees depending on the frequency and effusion rates of eruptions. The AST, where present, hosts the
majority hydrothermal vents along the ridge axis due to its
proximity to crustal heat sources (e.g., magma chambers)
and anisotropic permeability within the sheeted dikes
and tectonically disrupted upper crust. Discontinuities
within the AST are coincident with discontinuities in other
ridge-crest properties such as depth, axial magma chamber
continuity and melt content, and lava geochemistry.
Bibliography
Carbotte, S. M., Solomon, A., and Ponce-Correa, G., 2000. Evaluation of morphological indicators of magma supply and segmentation from a seismic reflection study of the East Pacific Rise
15
30
0
–17
N. Journal of Geophysical Research, 105, 2737.
Carbotte, S. M., Ryan, W. B., Jin, W., Cormier, M. H., Bergmanis,
E., Sinton, J., and White, S., 2003. Magmatic subsidence of the
East Pacific Rise (EPR) at 18
14
0 S revealed through fault restoration of ridge crest bathymetry. Geochemistry, Geophysics,
Geosystems, 4, doi:10.1029/2002GC000337.
Carbotte, S. M., Detrick, R. S., Harding, A., Canales, J. P., Babcock,
J., Kent, G., Ark, E. V., Nedimovic, M., and Diebold, J., 2006.
Rift topography linked to magmatism at the intermediate spreading Juan de Fuca Ridge. Geology, 34, 209.
Chadwick, W. W., 2003. Quantitative constraints on the growth of
submarine lava pillars from a monitoring instrument that was
caught in a lava flow. Journal of Geophysical Research, 108,
2534.
Chadwick, W. W., Jr., and Embley, R. W., 1998. Graben formation
associated with recent dike intrusions and volcanic eruptions
on the mid-ocean ridge. Journal of Geophysical Research, 103,
9807.
Fornari, D. J., Haymon, R. M., Perfit, M. R., Gregg, T. K. P., and
Edwards, M. H., 1998. Axial summit trough of the East Pacific
Rice 9
–10
N: geological characteristics and evolution of the
axial zone on fast spreading mid-ocean ridge. Journal of Geophysical Research, 103, 9827–9855.
Francheteau, J., Juteau, T., and Rangin, C., 1979. Basaltic pillars in
collapsed lava-pools on the deep ocean floor. Nature, 281,
209–211.
Gregg, T. K. P., Fornari, D. J., Perfit, M. R., Ridley, W. I., and Kurz,
M. D., 2000. Using submarine lava pillars to record mid-ocean
ridge eruption dynamics. Earth and Planetary Science Letters,
178, 195–214.
Haymon, R. M., and White, S. M., 2004. Fine-scale segmentation of
volcanic/hydrothermal systems along fast-spreading ridge
crests. Earth and Planetary Science Letters, 226, 367–382.
Haymon, R. M., Fornari, D. J., Edwards, M. H., Carbotte, S.,
Wright, D., and Macdonald, K. C., 1991. Hydrothermal vent distribution along the East Pacific Rise crest (9
09
0
–54
0 N) and its
relationship to magmatic and tectonic processes on fastspreading mid-ocean ridges. Earth and Planetary Science Letters, 104, 513–534.
Langmuir, C. H., Bender, J. F., and Batiza, R., 1986. Petrological
and tectonic segmentation of the East Pacific Rise,
5
30
0
–14
30
0 N. Nature, 322, 422–429.
Macdonald, K. C., and Fox, P. J., 1988. The axial summit graben
and cross-sectional shape of the East Pacific Rise as indicators
of axial magma chambers and recent volcanic eruptions. Earth
and Planetary Science Letters, 88, 119–131.
Macdonald, K. C., Fox, P. J., Perram, L. J., Eisen, M. F., Haymon,
R. M., Miller, S. P., Carbotte, S. M., Cormier, M. H., and Shor,
A. N., 1988. A new view of the mid-ocean ridge from the behaviour of ridge-axis discontinuities. Nature, 335, 217–225.
Qin, R., and Buck, W. R., 2008. Why meter-wide dikes at oceanic
spreading centers? Earth and Planetary Science Letters, 265,
466–474.
Rubin, A. M., and Pollard, D. D., 1988. Dike-induced faulting in rift
zones of Iceland and Afar. Geology, 16, 413–417.
Smith, M. C., Perfit, M. R., Fornari, D. J., Ridley, W. I., Edwards,
M. H., Kurras, G. J., and Von Damm, K. L., 2001. 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
0 N. Geochemistry, Geophysics,
Geosystems, 2, doi:10.1029/2000GC000134.
Soule, S. A., Fornari, D. J., Perfit, M. R., and Rubin, K. H., 2007.
New insights into mid-ocean ridge volcanic processes from the
2005–2006 eruption of the East Pacific Rise, 9
46
0 N–9
56
0 N.
Geology, 35, 1079–1082.
Soule, S. A., Escartín, J., and Fornari, D. J., 2009. A record of eruption and intrusion at a fast spreading ridge axis: axial summit
trough of the East Pacific Rise at 9–10
N. Geochemistry, Geophysics, Geosystems, doi:10.1029/2008GC002354.
White, S. M., Macdonald, K. C., and Haymon, R. M., 2000. Basaltic
lava domes, lava lakes, and volcanic segmentation on the southern East Pacific Rise. Journal of Geophysical Research, 105,
23519–23536.
White, S. M., Haymon, R. M., and Carbotte, S., 2006. A new view
of ridge segmentation and near-axis volcanism at the East Pacific
Rise, 8–12 N, from EM300 multibeam bathymetry. Geochemistry, Geophysics, Geosystems, 7, doi:10.1029/2006GC001407.
Cross-references
Axial Volcanic Ridges
Hydrothermalism
Mid-ocean Ridge Magmatism and Volcanism
Oceanic Spreading Centers
AXIAL VOLCANIC RIDGES
Isobel Yeo
GEOMAR Helmholtz Centre for Ocean Research,
Kiel, Germany
Synonyms
Neo-volcanic ridge
Definition
Axial volcanic ridges (AVRs). Composite volcanic edifices, comprising an elongate, typically spreading-normal
orientated topographic high, produced within the inner
valleys of mid-ocean ridges, usually those that are slow
spreading.
Introduction
The surface expression of volcanic activity is extremely
variable at different spreading rates (see “Morphology
Across Convergent Plate Boundaries”), as a result of the
differing eruption styles associated with each. Axial volcanic ridges (AVRs), sometimes called neo-volcanic
36
AXIAL VOLCANIC RIDGES