Page 186 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

==> Foreare
169
Asthenosphere
‘, Se f
Settings
Tectonic
Zone
of
Wedge
High
Expression

100 - §00 km —=>
Forearc
Basin
LED Arc
Subduction
Accretionary
Seismic
<= Accretionary
Wedge
Outer

<=> «
nch
sore
Section
Tre
Section
Asthenosphere

Cross
Crust:
7?
a”
Cross
Oceanic
Lithosphere
7? ‘a
Ciustal
7
Water
ae
b)
a)
al., region is the (a) and crustal (b) cross sections of a subduction zone. Dashed rectangle in (b) lithospheric Hypothetical 6.32 FIGURE of Fig. 6.33. trench, the of vicinity the reaching Before Sediments Basin Ocean Deep . ae of The layer thin a with covered normally is 2 layer caaier oceanic the . léco (or thrust detachmen
Profiles about from et extends 6.32). mid-ocean ridge is (Fig. and sediments (turbidites) nearly slight, is
Reflection deep seismic D. Snyder, Journal of the Geological lower crust Klemperer oceanic crust 2.16, (Figs. a Moho) wedge sediments deformed As oceanic sediments result in deformation
Seismic from A Reflective upper mantle. Compare with continental 1990; thin crust from horizontal accretionary wedge or Sediments where
Of Modified Ryan, and 1991. Redrawn with permission of the 5s. b) Reston, with away crust; flat-lying terrigenous sediments wedge,
Interpretation P. to about 1987; capped continental and at oceanic of the toe accretionary Trench-Fill by undeformed
* Klemperer, © 10s. d) Transparent Hobbs, , plate arc or developed top of the at deformed seismic expression; covered accretionary structures.
And Tectonic Seismic reflection profile from the west coast of Ireland. Caledonides, by S. 149-164, upper crust extends about ‘ and Petty lithospheric island features hummocky trench-fill sediments arc, be imaged. Water Layer; is it zone, these 6.34a); the of toe thrust
= Structural Irish the London, 148, pp. vol. Nonreflective Moho reflections occur at - 6.31; (Fig. zone, a with plate thicker, expression of sediments; volcanic the chaotic more a also may basin Transparent subduction trench a (Fig. the reflections. At to possible image
Chapter6 6.31 transect across Geological Society, Society of London. a) 10 s.c) rift profile, Fig.6.24. displayed 1991). Zone subduction a a beneath seismic (hemipelagic beneath imaged toward Farther display ment forearc 2. 1, approaches a in deposited zontal often is
168 (s) eu, jeaes, ABff-OML FIGURE reflection to 5 well Subduction At the it