Dating rocks and soils
Xenon produced by fission of uranium, thorium and plutonium has repeatedly been observed in lunar rocks and soils.
In two basaltic rocks and in two soils Xe was found originating from fission of U-235 induced by neutrons which are due to the interactions of cosmic ray particles with lunar matter.
Carbonate completely fills the pore spaces in K horizons, and the carbonate often forms in layers parallel to the surface.The term hardpan is often used in the literature on soils.A hardpan soil horizon is defined as a hard (compacted) soil horizon.The horizons may be light coloured due to their carbonates, but they are sometimes reddish as a result of iron oxide accumulation.If a true K horizon has developed, it may be almost white because of its great abundance of calcium carbonate.
Many of the differences we see in soils are effects of climate and topography, but the type of parent rock, the organic processes, and the length of time the soil forming processes have operated are also important.