from the trench and 110 Æ 20 km above the subducting
slab. Arc magmatism results from the dehydration of the
crust and overlying sediment carried by the downgoing
oceanic plate. Such dehydration occurs at various depths
depending on pressure/temperature conditions, but those
occurring below the convective mantle wedge trigger
melting and metasomatism of the mantle and subsequent
rise of magmas. The explosivity of the volcanism is attributed to the high volatile content in the magma, especially
H 2 O. Calc-alkaline, potassic calc-alkaline, and
shoshonitic series characterize the arc volcanoes lying on
continental crust. For further details, see entry “Island
Arc Volcanism, Volcanic Arcs.”
Terrane collision/accretion and mountain building
Oceanic plates may carry seamounts, plateaus, active or
fossil island arcs, and active or fossil spreading centers.
Moreover, they may be attached to continents. Thus, it follows logically that during long period of activity of an oceanic subduction, collisions with buoyant features carried
by the subducting plate occur. Collisions may be frontal
like the Ontong-Java plateau with the Solomon arc or
oblique like the Philippine Mobile Belt (Lallemand,
1999). Collisions along active continental margins often
give rise to the accretion of crustal slivers (e.g.,
Izu-Bonin arc accretion in Japan; Tamura et al., 2010) or
even large-size exotic terranes of oceanic or continental
affinities such as the Caribbean (Antilles) or the Okhotsk
(Russia) plateaus, the Panama-Choco (Colombia, Panama) or the Halmahera (Philippines) arcs, and the
Qiantang, the Lhasa, or the South China continental
blocks (e.g., Lallemand et al., 1998; Taboada et al.,
2000; Konstantinovskaia, 2001; Roger et al., 2003;
Kroehler et al., 2011). All these accreted blocks contribute
to continental growth. When the colliding blocks are large
enough, they contribute to mountain building such as the
Kunlun Mountain Range north of Tibet or the Eastern Cordillera in Colombia.
Summary
Active continental margins are the most common convergent plate boundaries. They represent one class of subduction zones where an oceanic plate subducts beneath
a continental plate. Since their tectonic activity commonly
lasts tens of millions of years, they are the locus of continental growth and consumption. Most of the seismic
energy is released along these margins. They often concentrate seismic, tsunami, and volcanic hazards.
Bibliography
Cartigny, P., Chinn, I., Viljoen, K. S., and Robinson, D., 2004. Early
proterozoic ultrahigh pressure metamorphism: evidence from
microdiamonds. Science, 304, 853–855.
Hassani, R., Jongmans, D., and Chéry, J., 1997. Study of plate
deformation and stress in subduction processes using
two-dimensional numerical models. Journal of Geophysical
Research, 102(B8), 17951–17965.
Heuret, A., and Lallemand, S., 2005. Plate motions, slab dynamics
and back-arc deformation. Physics of the Earth and Planetary
Interiors, 149, 31–51.
Kanamori, H., 1977. The energy release in great earthquakes.
Journal of Geophysical Research, 82(20), 2981–2987.
Kincaid, C., and Sacks, I. S., 1997. Thermal and dynamical evolution of the upper mantle in subduction zones. Journal of Geophysical Research, 102(B6), 12295–12315.
Konstantinovskaia, E. A., 2001. Arc-continent collision and
subduction reversal in the Cenozoic evolution of the Northwest
Pacific: an example from Kamchatka (NE Russia).
Tectonophysics, 333, 75–94.
Kroehler, M. E., Mann, P., Escalona, A., and Christeson, G. L.,
2011. Late Cretaceous-Miocene diachronous onset of
backthrusting along the South Caribbean deformed belt and its
importance for understanding processes of arc collision and
crustal growth. Tectonics, 30, TC6003.
Lallemand, S., 1999. La subduction oce ´anique. Amsterdam: Gordon and Breach Science Publishers, 208 pp (in french).
Lallemand, S. E., Popoff, M., Cadet, J.-P., Deffontaines, B., Bader,
A.-G., Pubellier, M., and Rangin, C., 1998. Genetic relations
between the central & southern Philippine Trench and the
Philippine Trench. Journal of Geophysical Research, 103(B1),
933–950.
Lallemand, S., Huchon, P., Jolivet, L., and Prouteau, G., 2005. In
Vuibert (ed.), Convergence lithosphe ´rique, 182 pp (Paris).
Roger, F., Arnaud, N., Gilder, S., Tapponnier, P., Jolivet, M., Brunel,
M., Malavieille, J., Xu, Z., and Yang, J., 2003. Geochronological
and geochemical constraints on Mesozoic suturing in east central
Tibet. Tectonics, 22(4), 1037.
Scholz, C. H., 1990. The Mechanics of Earthquakes and Faulting.
New York: Cambridge University Press. 400 pp.
Shemenda, A. I., 1992. Horizontal lithosphere compression and
subduction: constraints provided by physical modeling. Journal
of Geophysical Research, 97(B7), 11097–11116.
Stern, R. J., and Bloomer, S. H., 1992. Subduction zone infancy:
examples from the Eocene Izu-Bonin-Mariana and Jurassic California arcs. Geological Society of America Bulletin, 104,
1621–1636.
Taboada, A., Rivera, L. A., Fuenzalida, A., Cisternas, A., Philip, H.,
Bijwaard, H., Olaya, J., and Rivera, C., 2000. Geodynamics of
the northern Andes: subductions and intracontinental deformation (Colombia). Tectonics, 19(5), 787–813.
Tamura, Y., Ishizuka, O., Aoike, K., Kawate, S., Kawabata, H.,
Chang, Q., Saito, S., Tatsumi, Y., Arima, M., Takahashi, M.,
Kanamaru, T., Kodaira, S., and Fiske, R. S., 2010. Missing
Oligocene crust of the Izu-Bonin arc: consumed or rejuvenated
during collision ? Journal of Petrology, 51(4), 823–846,
doi:10.1093/petrology/egq002.
Turcotte, D. L., and Schubert, G., 1982. Geodynamics: Applications
of Continuum Physics to Geological Problems. New York:
Wiley. 450 pp.
Uyeda, S., 1984. Subduction zones: their diversity, mechanism and
human impacts. GeoJournal, 8(4), 381–406.
Weissel, J., Anderson, R., and Geller, C., 1980. Deformation of the
Indo-Australian plate. Nature, 287, 284–291.
Cross-references
Accretionary Wedges
Crustal Accretion
Driving Forces: Slab Pull, Ridge Push
Earthquakes
Geohazards: Coastal Disasters
Island Arc Volcanism, Volcanic Arcs
Magmatism at Convergent Plate Boundaries
Morphology Across Convergent Plate Boundaries
12
ACTIVE CONTINENTAL MARGINS
slab. Arc magmatism results from the dehydration of the
crust and overlying sediment carried by the downgoing
oceanic plate. Such dehydration occurs at various depths
depending on pressure/temperature conditions, but those
occurring below the convective mantle wedge trigger
melting and metasomatism of the mantle and subsequent
rise of magmas. The explosivity of the volcanism is attributed to the high volatile content in the magma, especially
H 2 O. Calc-alkaline, potassic calc-alkaline, and
shoshonitic series characterize the arc volcanoes lying on
continental crust. For further details, see entry “Island
Arc Volcanism, Volcanic Arcs.”
Terrane collision/accretion and mountain building
Oceanic plates may carry seamounts, plateaus, active or
fossil island arcs, and active or fossil spreading centers.
Moreover, they may be attached to continents. Thus, it follows logically that during long period of activity of an oceanic subduction, collisions with buoyant features carried
by the subducting plate occur. Collisions may be frontal
like the Ontong-Java plateau with the Solomon arc or
oblique like the Philippine Mobile Belt (Lallemand,
1999). Collisions along active continental margins often
give rise to the accretion of crustal slivers (e.g.,
Izu-Bonin arc accretion in Japan; Tamura et al., 2010) or
even large-size exotic terranes of oceanic or continental
affinities such as the Caribbean (Antilles) or the Okhotsk
(Russia) plateaus, the Panama-Choco (Colombia, Panama) or the Halmahera (Philippines) arcs, and the
Qiantang, the Lhasa, or the South China continental
blocks (e.g., Lallemand et al., 1998; Taboada et al.,
2000; Konstantinovskaia, 2001; Roger et al., 2003;
Kroehler et al., 2011). All these accreted blocks contribute
to continental growth. When the colliding blocks are large
enough, they contribute to mountain building such as the
Kunlun Mountain Range north of Tibet or the Eastern Cordillera in Colombia.
Summary
Active continental margins are the most common convergent plate boundaries. They represent one class of subduction zones where an oceanic plate subducts beneath
a continental plate. Since their tectonic activity commonly
lasts tens of millions of years, they are the locus of continental growth and consumption. Most of the seismic
energy is released along these margins. They often concentrate seismic, tsunami, and volcanic hazards.
Bibliography
Cartigny, P., Chinn, I., Viljoen, K. S., and Robinson, D., 2004. Early
proterozoic ultrahigh pressure metamorphism: evidence from
microdiamonds. Science, 304, 853–855.
Hassani, R., Jongmans, D., and Chéry, J., 1997. Study of plate
deformation and stress in subduction processes using
two-dimensional numerical models. Journal of Geophysical
Research, 102(B8), 17951–17965.
Heuret, A., and Lallemand, S., 2005. Plate motions, slab dynamics
and back-arc deformation. Physics of the Earth and Planetary
Interiors, 149, 31–51.
Kanamori, H., 1977. The energy release in great earthquakes.
Journal of Geophysical Research, 82(20), 2981–2987.
Kincaid, C., and Sacks, I. S., 1997. Thermal and dynamical evolution of the upper mantle in subduction zones. Journal of Geophysical Research, 102(B6), 12295–12315.
Konstantinovskaia, E. A., 2001. Arc-continent collision and
subduction reversal in the Cenozoic evolution of the Northwest
Pacific: an example from Kamchatka (NE Russia).
Tectonophysics, 333, 75–94.
Kroehler, M. E., Mann, P., Escalona, A., and Christeson, G. L.,
2011. Late Cretaceous-Miocene diachronous onset of
backthrusting along the South Caribbean deformed belt and its
importance for understanding processes of arc collision and
crustal growth. Tectonics, 30, TC6003.
Lallemand, S., 1999. La subduction oce ´anique. Amsterdam: Gordon and Breach Science Publishers, 208 pp (in french).
Lallemand, S. E., Popoff, M., Cadet, J.-P., Deffontaines, B., Bader,
A.-G., Pubellier, M., and Rangin, C., 1998. Genetic relations
between the central & southern Philippine Trench and the
Philippine Trench. Journal of Geophysical Research, 103(B1),
933–950.
Lallemand, S., Huchon, P., Jolivet, L., and Prouteau, G., 2005. In
Vuibert (ed.), Convergence lithosphe ´rique, 182 pp (Paris).
Roger, F., Arnaud, N., Gilder, S., Tapponnier, P., Jolivet, M., Brunel,
M., Malavieille, J., Xu, Z., and Yang, J., 2003. Geochronological
and geochemical constraints on Mesozoic suturing in east central
Tibet. Tectonics, 22(4), 1037.
Scholz, C. H., 1990. The Mechanics of Earthquakes and Faulting.
New York: Cambridge University Press. 400 pp.
Shemenda, A. I., 1992. Horizontal lithosphere compression and
subduction: constraints provided by physical modeling. Journal
of Geophysical Research, 97(B7), 11097–11116.
Stern, R. J., and Bloomer, S. H., 1992. Subduction zone infancy:
examples from the Eocene Izu-Bonin-Mariana and Jurassic California arcs. Geological Society of America Bulletin, 104,
1621–1636.
Taboada, A., Rivera, L. A., Fuenzalida, A., Cisternas, A., Philip, H.,
Bijwaard, H., Olaya, J., and Rivera, C., 2000. Geodynamics of
the northern Andes: subductions and intracontinental deformation (Colombia). Tectonics, 19(5), 787–813.
Tamura, Y., Ishizuka, O., Aoike, K., Kawate, S., Kawabata, H.,
Chang, Q., Saito, S., Tatsumi, Y., Arima, M., Takahashi, M.,
Kanamaru, T., Kodaira, S., and Fiske, R. S., 2010. Missing
Oligocene crust of the Izu-Bonin arc: consumed or rejuvenated
during collision ? Journal of Petrology, 51(4), 823–846,
doi:10.1093/petrology/egq002.
Turcotte, D. L., and Schubert, G., 1982. Geodynamics: Applications
of Continuum Physics to Geological Problems. New York:
Wiley. 450 pp.
Uyeda, S., 1984. Subduction zones: their diversity, mechanism and
human impacts. GeoJournal, 8(4), 381–406.
Weissel, J., Anderson, R., and Geller, C., 1980. Deformation of the
Indo-Australian plate. Nature, 287, 284–291.
Cross-references
Accretionary Wedges
Crustal Accretion
Driving Forces: Slab Pull, Ridge Push
Earthquakes
Geohazards: Coastal Disasters
Island Arc Volcanism, Volcanic Arcs
Magmatism at Convergent Plate Boundaries
Morphology Across Convergent Plate Boundaries
12
ACTIVE CONTINENTAL MARGINS