Convergent zone where at least on one side oceanic lithosphere is involved, and gets recycled deep down into the mantle.
Presently active subduction arc-complexes:
Island arcs vs. continental arcs:
Components of subduction-arc systems:
Why is the arc an arc (dimple tectonics)?
Models for the thermal structure of the descending slab.
What are important input parameters in such a model?
Phase changes in the slab and slab pull:
- mantle metamorphism: olivine -> spinel -> perovskite.
- 670-780 km discontinuity:
- division between upper and lower mantle.
- lower bound of deep earthquakes.
- seismic velocity increase.
- P-T consistent with position of phase changes.
- viscosity boundary. How does it effect convection patterns in mantle?
- P-T maps of phase changes. Where do these maps come from?
Consider the simple and schematic pressure-temperature maps above of where mineral A vs. mineral B is stable for a given composition. To the left is a temperature sensitive phase transition. Next in line is a pressure sensitive phase transition. Third and of interest to us is a positive slope for the phase change. Note that for a different geothermal gradients or P-T histories, the phase change will occur at different depths. Will the reaction occur at a deeper or shallower depth in a subducting slab in comparison to the surrounding mantle rock. The olivine-spinel phase transition map basically looks like this.
What is the eventual fate of the slab?
It is likely different for the different parts of the slab, crust vs. lithospheric mantle. There is no reason why some of the later when warmed up doesn't join the mantle convection dance.
How does subduction initiate?
How does it usually conclude?
Expanding earth hypothesis.
Caveat: these are some references I happen to know about. This list is not comprehensive, and a wealth of literature exists out there, including more recent stuff. Harmon D. Maher, Jr., 1995
Dickinson, W.R., 1973, Widths of Modern Arc-Trench Gaps Proportional
to Past Duration of igneous activity in associated magmatic arcs:
Journal of Geophysical Research, v. 78, p. 3395-3417.
After a concise description of major petro-tectonic elements, it describes how accretionary wedges may grow with time, noting exceptions suggesting loss. This mental framework initiated a mini-paradigm and much fruitful research.
Kerr, R., 1986, Sinking slabs puncture layered mantle model;
Science, v. 231., p. 548-49.
This captures some of the debate as to how far subducted slabs descend into the mantle and argues against 'conventional wisdom' of a floor at 650-670 km. This has Implications for understanding large scale recycling and convective behavior. Lots more recent thought on this.
Kimura, G. & Ludden, J., 1995, Peeling oceanic crust in
subduction zones; Geology, v. 23, p. 217-220.
describes ideas on how material is transferred from ocean plate to the accretionary wedge. Discusses implications for recycling of volatiles in arc-trench system.
Moore, J.C. & Silver, E.A., 1987, Continental margin tectonics: Submarine accretionary prisms: Review of Geophysics, v. 25, p. 1305-1312.
Platt, J. P., 1986, Dynamics of orogenic wedges and the upllift
of high-pressure metamorphic rocks; GSA Bulletin, v. 97, p. 1037-1053.
one of a series of articles discussing how alternating periods of contraction and thickenting vs. extension and thinning could occur within accretionary wedges and produce uplift of deep cold rocks. This article is particularly well illustrated.
Schweller, W., Kulm, L., Prince, R., 1981, Tectonics, Structure,
& Sedimentary Framework of the Peru-Chile Trench: GSA Memoir
154, p. 323-350.
Excellent detailed look at trench and trench slope processes for this subduction zone.
Silver, E.A., Moore, C.J., 1978, The Molucca Sea Collision
Zone, Indonesia; Journal of Geophysical Research, v. 83., 1681-91.
Describes an incipient arc-arc collision due to two facing subduction zones.
Toksoz, M.N., 1975, The Subduction of the Lithosphere; Scientiric
American, Nov. issue.
This is a nice summary article but with good depth of information, a good starting point in reading on subduction zones. It emphasizes deep mantle processes.
Von Huene, R. & Scholl, D.W., 1991, Observations at convergent margions concerning sediment subduction, subduction erosion, and the growth of continental crust: Reviews of Geophysics, v. 29, p. 279-316.
Course materials for Plate Tectonics, GEOL 3700, University of Nebraska at Omaha. Instructor: Harmon D. Maher Jr.. Material without attributions may be used for non-profit educational purposes with appropriate attribution of authorship. Otherwise please contact author.