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sand deserts with their winnowed masses of quartz grains had melted
into glass. This would, of course, be quite emphatically a stone-dead
world.
There would be little surface sign that the world had once been
sedimentary, or had possessed the finest collection of rock strata, by
far, in the solar system (and probably one of the best in any star sys-
tem). Perhaps there might be hints of strata in the landscape still—
imagine partially melting the rocky bluffs of something like the Grand
Canyon, so that only some partly fused vestiges of those strata-formed
rock ledges remained. Even so, this is equivalent to wiping out much
of the history of a planet, as rock strata are the tape recorders upon
which a planet's history is written, in the code slowly learned by every
geologist, of different types of sedimentary layering and fossils and
preserved chemical markers.
Much strata—and therefore much planetary history—would
remain, of course, at depth, below the reach of the blast-furnace-like
heat that had seared the surface. On today's Earth, buried strata can
reach the surface as the landscape is acted upon by the wind and the
weather and agents of erosion, and as tectonic movements raise and
lower sections of crust in different parts of the world. But this is now
an Earth bereft of a hydrological cycle, without rain, hail, or snow.
There will be some kind of an atmosphere, and there will be winds,
but with no sand particles left upon this blow-torched Earth there
will be nothing with which the Earth can abrade its molten cara-
pace, except perhaps the occasional meteorite. And as for tectonic
movements, on an old, dry planet tectonics might soon begin to
operate differently, as we shall see in the next section. Those uplifted
crustal masses and down-warped grabens might be, literally, a thing
of the past.
The ancient strata would still be reachable by drilling—if any visi-
tors from space would think of trying to see what might lie below the
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