Physics of the Earth's CrustMacmillan and Company, 1889 - 391 стор. |
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Загальні терміни та фрази
amount anticlinals appears areas assumed attraction basalt become beneath the ocean bottom calculated cause centre of gravity chapter column compression condition consequently continental crust convection currents cooling crust beneath cubic foot datum level dense denudation deposits depressions depth earth earth's crust effect elevated equation equilibrium eruption estimate feet fissures fluid geological globe greater Hence Henry's law horizontal hydrostatic equilibrium hypothesis increase of temperature interior islands k₂ Kilauea latent heat lava layer less liquid substratum lower magma Mallet mass mean height mean level melting temperature molten mountain neutral zone observations P₁ phenomena portion present pressure probably produced Prof regions result rigidity rock sea level sediment shear shell solid solid globe solidification strain strata stratum suboceanic crust substance suppose supposition theory thickening thickness tide tract upper vertical volcanic volume whole
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Сторінка 7 - In this equation n is the tangent of the angle which the line makes with the axis of abscissae, and B is the intercept on this axis from the origin.
Сторінка 292 - bottom strata to establish lines of weakness or of least resistance in the earth's crust, and thus determine the contraction which results from the cooling of the globe to exhibit itself in those regions, and along those lines where the ocean's bed is subsiding beneath the accumulated sediments...
Сторінка 65 - ... diminishing, as shown in the curve. Such is, on the whole, the most probable representation of the earth's present temperature, at depths of from 100 feet, where the annual variations cease to be sensible, to 100 miles ; below which the whole mass, or all, except a nucleus cool from the beginning, is (whether liquid or solid) probably at, or very nearly at, the proper melting temperature for the pressure at each depth.
Сторінка 202 - Earth have about the strength of granite at 1,000 miles from the surface, or that they have a much greater strength nearer to the surface. This investigation must be regarded as confirmatory of Sir William Thomson's view, that the Earth is solid nearly throughout its whole mass. According to this view, the lava which issues from volcanoes arises from the melting of solid rock, existing at a very high temperature, at points where there is a diminution of pressure, or else from comparatively small...
Сторінка 118 - Everything in this southern continent has been effected on a grand scale : the land, from the Rio Plata to Tierra del Fuego, a distance of 1200 miles, has been raised in mass (and in Patagonia to a height of between 300 and 400 feet), within the period of the now existing sea-shells. The old and weathered shells left on the surface of the upraised plain still partially retain their colours.
Сторінка 298 - ... crushing of portions of that shell, which compressions and crushings are themselves produced by the more rapid contraction by cooling of the hotter material of the nucleus beneath that shell, and the consequent more or less free descent of the shell by gravitation, the vertical work of which is resolved into tangential pressures and motion within the shell.
Сторінка 45 - Since this Address was delivered, some important experiments have been carried out at the request of Dr. Henry Muirhead, by Mr. Joseph Whitley, of Leeds. His experiments were made on iron, copper, and brass, and on whinstone and granite, and the general result, seemingly (but I believe not at all surely), indicated is that these substances are less dense in the solid than in the liquid state at the melting temperature.
Сторінка 43 - ... a change would take place in the process of solidification which it is important to remark. The superficial parts of the mass must in all cases cool the most rapidly, and now (in consequence of the imperfect fluidity) being no longer able to descend, a crust will be formed on the surface, from which the process of solidification will proceed far more rapidly downwards, than upwards on the solid nucleus.
Сторінка 125 - In fact the density of the crust beneath the mountains must be less than that below the plains, and still less than that below the ocean-bed.
Сторінка 124 - There must therefore be some excess of matter in the solid parts of the earth between the Pacific Ocean and the earth's centre, which retains the water in its place. This effect may be produced in an infinite variety of ways; and therefore, without data, it is useless to speculate regarding the arrangement of matter which actually exists in the solid parts below...