Geology Reference
In-Depth Information
Figure 22: Carbon's longest journey.
Plate tectonics, driven as it is by the decay of radioactive materials deep in the Earth,
seems to be totally independent of life. But nothing could be further from the truth, for
without water there would be no plate tectonics, and without life there would be no wa-
ter. Water molecules invade the crystalline matrix of the sea floor basalt as it moves
away from the midoceanic ridges, softening it so much that by the time the basalt meets
the edge of a continent it wants nothing more than to sink like so much semimolten
chocolate. But once in the basalt, some of the water molecules break up as their oxy-
gen atoms feel an irresistible attraction for some key iron-bearing compounds, leaving
hydrogen, the lightest of all chemical beings, free to escape to outer space. In time, so
much hydrogen would be lost that Gaia would die of desiccation, a fate avoided thanks
to the work of countless bacteria in the ocean sediments that capture energy by com-
bining oxygen with the fleeing hydrogen, thereby re-creating the lost water and saving
the planet. Once again we bend our heads in gratitude to the bacteria, the true rulers
of the world. Furthermore, according to Don Anderson, the eminent American geolo-
