Page 345 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

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Flow

Heat
and ridge (a), with more gentle dips of the water
Tectonics (km) Axis (km) to slow spreading (b).

Ridge Age (ma) BN NS f Asthenosphere 1 0 Ridge from Distance Ridge . \ Hf: 7 7 Asthenosphere 2“ q 0 Ridge Axis from Distance broader mid-ocean lithosphere/asthenosphere boundary, compared

Fast-Spreading Water Crust Slow-Spreading 4Lithos| phere Fast-spreading leads to a

a) ‘ t Oceanic y Lithosphere L I 50 b) Y Ld . 50 ‘ 10.18 FIGURE bottom, Moho, and

vs. Ridge Axis : i : (km) Ridge Axis a) The lithosphere cools (Mid- profiles like much is is heat enough tem- the contours, zone subduction forearc the while slab, in map The Zone Subduction great to descend 2.22, 7.23). of years. plate recent 10.14, (Figs.
Bathymetry From $ S read From ridge axes. Fast-spreading ridges show a wider area ridge steeper effect before meantime, the temperature the in low cold of the magma. may (Figs. of millions tens fairly of Mountains

Distance : Distance floor subsides as mid-ocean producing some melting. perturbs. region show a is ascending the linger Nevada
b) Fast- g thermal time In of broad a result Cascadia material earthquakes for areas

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(nd Bathymetry heat ocean the subduction zoné; ‘the the subducts, in within is brittely cold recognized and
os SS FO 0 g of high from coffee. ice, of flow the 7.34)
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| eands c) Age gil the gradient volcanic heat heat subduction fail but

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Flow HeatFlowvs. Ridge : i foe wencnememrment aerate. eee Ridge Axis (ux) y;dag 4318/4 S Ss broader the slow-spreading ridges. c) The similar 10.18b). At Zone cup a in coffee than less of geothermal flow at high transfer low/high (Fig. rapid of enough rigid heats slab thus have Alps the
Heat From + Spreading - wom Spreading From Correlations of heat flow, a Fig. cube the from is ice a slab the Heat local reflects this shows Northwest consequence the roots like
10 & Distance _Fast - Slow Distance than cooler and Ridge: Subduction ice an the of When 10.19). a 10.14a Pacific depths, remaining time 10.16c).
Chapter _. semowee I SSS oO 10.17 faster the spreading rate. the elevation time. older Atlantic putting transferred perature decreasing (Fig. region, with high the Fig. the in A Through Lithosphere convergence. 10.15b,
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326 (2 Wi/fy) MOly BB} FIGURE of high through