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Posted by / 26-Jun-2017 09:58

(Peat bogs and coal-forming swamps are an exception, but we would not count them as topsoils.

Under unusual conditions a layer of topsoil can be "fossilized," even to the point of preserving the three-dimensional shape of tree leaves, as is the case at Yellowstone National Park.) In the long run, buried sediments are usually cemented into sedimentary rock, which brings us back to the beginning of this cycle.

Take the soil in my mother's backyard, for example.

In the case of erosion, the topsoil, of course, is removed.The sediment added to our patch of land may be great for building new soil, but if it accumulates too quickly it will merely bury the existing soil. In any case, the old topsoil, now compressed and deeply buried by sediment and soil, is no longer turned over by earthworms or small animals.It is deprived of oxygen and fresh organic material, such as rotting leaves.As more and more of that rock is weathered by the mechanical effects of freezing and thawing, the chemical and mechanical action of roots, or by other means, the soil is deepened.However, the deeper that soil gets, the more insulated the parent rock becomes to weathering.

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