-
9
-
-
0001752197
-
-
The temperatures for condensation of iron and of the major silicate phases from the solar nebula are so similar [to within a few tens of degrees; see (70)] that efficient separation is almost inconceivable at that stage. Aerodynamic drag may separate small solid bodies according to density and perhaps explain the iron-rich planet Mercury but this is not likely to be relevant for the earth
-
(1977)
Mon. Not. R. Astron. Soc.
, vol.180
, pp. 57
-
-
Weidenschilling, S.1
-
16
-
-
0007188312
-
-
suggests a meh migration velocity of ~ 0.02 cm/sec, much faster than the accretion process. This calculation assumes ~ 20 percent porosity (generated by the melting of disseminated free iron) and a silicate grain size of 0.1 cm
-
(1978)
J. Geophys. Res.
, vol.83
, pp. 6005
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-
Walker, D.1
Stolper, E.M.2
Hays, J.F.3
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18
-
-
0018517726
-
-
The effective viscous response of any solid medium is a thermally activated process involving an activation energy much larger than the thermal energy per atom. Typical silicate rheology laws
-
(1979)
Rev. Geophys. Space Phys.
, vol.17
, pp. 1137
-
-
Tullis, J.W.1
-
19
-
-
49949130806
-
-
Details are unpublished but are a straightforward extension of existing analyses of Rayleigh-Taylor instabilities [see, for instance or postglacial rebound for an earth mantle of nonuniform viscosity
-
(1968)
Phys. Earth Planet. Inter.
, vol.1
, pp. 427
-
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Ramberg, H.1
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23
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0019111568
-
-
Application of magma fracturing concepts [see, for example suggests the rapid propagation of long, narrow cracks. However, the iron will freeze because the predicted crack width (~ 10 cm) implies rapid hours) thermal equilibration with surrounding rock. This time may be too short for efficient downward migration. N. H. Sleep (private communication) has suggested that migration along conduits may nevertheless be very important
-
(1980)
Proc. 11th Lunar Planetary Sci. Conf.
, pp. 1979
-
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Müller, O.H.1
Muller, M.R.2
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24
-
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0019141778
-
-
The energy of core formation is equivalent to a temperature rise of ~ 1500 K for the whole earth or 2: 5000 K for the core alone
-
(1980)
J. Geophys. Res.
, vol.85
, pp. 7108
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Davies, G.F.1
-
28
-
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49349120385
-
-
The transition between glasses or dense suspensions and bodies with a rigid matrix and permeating melt is poorly understood. Single-component silicates typically have (extrapolated) melting point viscosities of 1015 to l016cm2/sec (18). See also
-
(1978)
Tectonophysics
, vol.44
, pp. 173
-
-
Arzi, A.1
-
34
-
-
85027750688
-
-
Diflfusion in a silicate melt is very strongly temperature-dependent. A value of D is 10 cm/sec is likely R. B. Hargraves, Ed. Princeton Univ. Press, Princeton, N.J., chap. 9
-
(1980)
Physics of Magmatic Processes
-
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Hofmann, A.W.1
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39
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79961117230
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Recent isentropic compression of quartz (SiO2) with a superstrong magnetic field
-
(1978)
JETP Lett.
, vol.27
, pp. 264
-
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Pavlovskii, A.I.1
-
43
-
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0019177031
-
-
They inferred melting in their shock wave experiments from the vanishing of the shear modulus (a decrease of the acoustic velocity at 2.5 ± 0.1 Mbar to a value approximately equal to the hydrodynamic sound speed). The implications of these results are discussed in
-
(1980)
Geophys. Res. Lett.
, vol.7
, pp. 533
-
-
Brown, J.M.1
McQueen, R.G.2
-
45
-
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0018655859
-
-
Static high-pressure data on iron are not available at a sufficiently high pressure or with a sufficient pressure calibration to determine this
-
(1979)
J. Geophys. Res.
, vol.84
, pp. 4533
-
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Mao, H.-K.1
Bell, P.2
-
47
-
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0342291948
-
-
Low-pressure solids do not always undergo density reduction when light atoms are added because these atoms may occupy interstitial sites. However, fluids and solids (but especially fluids, which are typically more ideal) are likely to undergo density reduction when any light elements are added at megabar pressures. At such pressures, overlap of orbitals is unavoidable and the atomic radii as conventionally defined cease to have meaning. (Carbon is probably a metal, for example.) The density of the medium is then likely to be primarily a function of mean atomic weight. Shell structure effects are undoubtedly still important, even at pressures ~ 100 Mbar but are not likely to overwhelm this trend
-
(1980)
JETP Lett.
, vol.31
, pp. 685
-
-
Avronin, E.N.1
Vodolaga, B.K.2
Volkov, L.P.3
Vladimirov, A.S.4
Simonenko, V.A.5
Chemovolyuk, B.T.6
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48
-
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0042935008
-
-
Application of the calculated pseudopotential for He to the earth&s core leads to a predicted solubility of ~ 10& mole fraction
-
(1979)
J. Phys. F
, vol.9
, pp. 791
-
-
Stevenson, D.J.1
-
63
-
-
0001633915
-
-
For example, the thermodynamic version of Lindemann&s law 1 with a free-volume Gruneisen γ (59)
-
(1979)
Geophys. Surv.
, vol.3
, pp. 175
-
-
Stacey, F.D.1
-
96
-
-
0004051260
-
-
but the observed mantle depletion is shared by several other elements that would not partition into the core fluid and is more probably explained by volatility (49). See also
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(1980)
J. Geophys. Res.
, vol.85
, pp. 7016
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Somerville, M.1
Ahrens, T.J.2
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98
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84913738588
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The absence of an inner core may explain why Venus has no substantial magnetic and
-
(1979)
Eos
, vol.60
, pp. 305
-
-
Stevenson, D.J.1
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