Page 43 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

7.

Red Sea Gulf of California Ocean Atlantic Margin rift zone along ridge mid-ocean oceanic Africa ridge a depending is ridge earthquakes Ridge, contin- the water, "BO95 com- plate of subduc- by capped

Passive Continental of upper crust at continental with sedimentary and volcanic strata. post-rift sedimentary strata boundary is along a new apart, rift from Arabia elevates asthenosphere wide, km 4000 the of region causing Mid-Atlantic the less or more a in by covered Earth. on crust buoyant less lithospheric where a types Two is plate

Boundary |_| deformation fill that by plate the divergent interiors of the diverging plates. completely Saudi as much the Although brittle, and including extends mostly range thinner, region zone. a subduction overriding the

Plate Brittle forms. Horsts and grabens are covered basin separating buoyant the as to 2.14c). cold be can ridges, Ridge, Though 2.9). mountain with plate The whether

Ridge / (horsts) separate valleys (grabens) advanced ocean the continents Sea Red divergence hundred (Fig. crust mid-ocean Ocean Indian (Fig. longest the the plate. other called is on

Water Mid-Ocean of structures at divergent plate boundary. (a) basin margins are some distance away, within When the in few a be apart move oceanic the of chain the and km 50,000 thus is converge, plates the mantle the depending

Zone Normal Faults Seaiments. Basin | | ranges mountain new ocean zone. (c) At Ridges as forms, continued With may that plates the of part A faults. Rise, over for system Boundaries beneath within common,

Rift Basin Post-Rift Ocean Elongate moves apart a transition Mid-Ocean lithosphere 2.14b). seafloor the fast how upper the normal Pacific East fashion ridge mid-ocean Plate lithospheric descends deeply descends are zones
Continental Ocean New Advanced Evolution 2.14 faulting. normal lithosphere to oceanic crustal system; passive continental (Fig. on on hot, and the uous Convergent Where monly tion

a) b) c) FIGURE causes (b) As continental

Lines of volcanoes may movement of a lithospheric plate over a hotspot, originating from a material deep within the : the thinning elevation crust of the (German grabens basins; region of portions of the the rifting are

2.12 stretches, high to part ridges “graben”), The they subside, forming A 2.14a). and thus called (Fig. 2.9). : oan as thin mid-ocean ridge
FIGURE be due to the plume of hot mantle. it raised upper elevated (Fig. Nevada Mexico, is continental lithosphere

apart is buoyant. The and (German as ranges of all of active Rifts (Moho) and lithosphere/asthenosphere lithospheric thicknesses on lithosphere at

pulls Tegion earthquakes valleys mountain comprising Mexico, and East African ee Asthenosphere Elevated Region Crust and entire
continent 2.13b). The and hot is volcanic strata as areas Other the Asthenosphere Newly-formed continental crust.

i a causing down-dropped and high America, and s = level. (b)
As (Fig. fashion, remain Oregon, California, Arizona, New (Fig. 2.15). Europe boundaries elevate. (c)

Tectonics Zones lithosphere underlying asthenosphere brittle by of sedimentary blocks North in Province = 35k; 2 150 km +5 km—— ee ae Topography, crust/mantle boundary boundary at divergent plate boundaries. (a) Typical crustal and thickness of typical

Plate Continental Rift entire cold, “horst”), separated to 8 km mountains Range Basin of central © # continental craton, with topography near sea three 1/6 the about

Chapter2 and crust because the deforms in a word up with adjacent horst the block fault Idaho, Utah, and Basin Pannonian a) Normal Continental Lithosphere Continental Rift Zone Mid-Ocean Ridge FIGURE 2.13 rifts apart; all continent contains crust

24 fill . b) co) be he 2