Page 275 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

the
257 Densities of that for the g/cm*) and (—0.43 g/cm’). from km) mountains (+Am). This the times that, Note resulting extra the the of between range has root for gradient mass

Modeling Airy isostatic model of 2 are simplified so mantle determined (hs 47.42 = the of level h,) to g/cm>). abrupt, compensates product difference mountain crustal The anomalous

Gravity 8.36 km high mountain range. and mantle reasonable contrasts result topography vs. air (+2.67 vs. root be can Mountains e(he) a depth (Moho topography sea (equal +2.67 is the to the the If the to due topography. that

FIGURE crust crustal km = above height = Py contribution that relates times g/cm?). because
35 ? ? unknowns km | to — (—Am) to
T 400 = = = Pm(n) ha due material mountain p, the deficit h,,) —0.43 contribution due however,
=2km Mantle glee) t g/cm’. Crust: km 2 mountains column mountains two the equilibrium: Continent + (hJc+t unknowns yields: 49.42 = anomaly the of = (Ap margin, deficit The to = Pm contribution

7ope (og 3.1 ‘ 3.1 Continental = mantle at model, Phe two (h.)s, excess the of levels passive mass 8.37b). (equal — p, negative gentle,

T = column outside extra crust isostatic Normal + + the free-air mass product crustal a (Fig. crust = (Ap the positive more is
Mountains (h, dm 49.42 km \f T Okm the of the at of of of the of passive for Pressure: equations km to from of at effect root topography deepening densities hundred contribution
e . = z T mantle Normal air the crust the Mountains: total margin local —_p,(h,) h, a for and the the the upper the for provides the of km), the

.
T Tt density = Pa Thicknesses thickness h, thickness thickness h m Thickness at thickness = the with conditions Equal Equal Thickness: two the 12.42 = contribution The results 8.37a) function a is difference water the gradient. crustal The the of of mantle and (several amplitude as root crustal
No. rma. / ; Continent =35km 12.42 km emectsimamnaes tT Tt (he (hy, As two the Solving h,, (Fig. excess density with as steep a in weight amount crustal wide is same the the deeper. is

(heJe

0 hy= os 604 -400

*
* Ass? 18S RES BA HERE SR Me SRN preeray a7
Sage

the the deep- 2.18, sur- range ifie

East 3 150 The the ocean. of the Carolina 129-1520 Isa, beneath image of with (Figs. to relative its weight mountain modified
Air Anomaly two-dimensional the low over deepens abruptly. and evolution Memoir. no. 34. pp. Tulsa POl0: gists, Geol shallows mirror a correlates thus orogenesis buoyancy until grows The parameters to
*

Free from calculated the continent, the water column the AAPG Petroleum as mantle the somewhat is anomaly thickens during to due its topography (+Am) root (—Am). tding accordi

§ Observed free air gravity anomaly from the passive continental margin off the Atlantic toward shelf, where Carolina. From “Deep structure B. Swift, ociation of values anomaly in the crust force, low-density equilibrium, g/em?
S anomaly the high American Associa increase the 2.67
Isostasy : Observed Calculated is line 4 positive Bouguer the continental upward model, the of isostatic q 0 = = crust

and -- the edge effect. with the near the edge of the continental Hatteras, North Hutchinson, J. Grow. K. Klitgord, and permission of the to large the bathymetry); As root exerts the Airy effect Airy air the
Gravity — United States. The dashed S' increasing form of water. Range By the is in density of the of density

150 off Cape with the (or crustal mantle. 8.36) Bt
o the Mountain (Fig. Densities: = =
i 8.35 D. Redrawa Ww Moho, 3) the p, Pp.
Vilaplel 100 3 0 40. FIGURE coast of the density model. Note zero crossing is IPOD Trough,” by . the ocean; topography of ening 7 6.35), rounding sai tfe model Pig Tae

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IT SSE

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