Another Reason That Meteorites DisappearPaul bristolia at yahoo.com
Fri May 15 08:39:48 EDT 2009
I hear a lot references made to meteorites disappearing
after they fall to Earth because thy are destroyed by
weathering. Bioturbation is another process that causes
them to disappear relatively rapidly, within years from
the ground surface is bioturbation. The churning of the
upper horizons by animals and plants will caused large
objects, whether they be prehistoric and historic artifacts,
meteorites, modern bricks and concrete pieces, and so
forth, to gradually “sink” into the ground. Objects will
sink to the depth at which the churning of the ground
by bioturbation ceases to modify the soil. This forms a
buried layer of stones and other objects called a
“carpedolith” or “stone-layer”. When a carpedolith is
exposed in a two dimensional outcrop, as in the sides
of an artificial excavation, stream cutbank, or roadcut,
it is called a “stone line”.
In areas where plant and animals rapidly churn the soil
to significant depth, meteorites will diappear from the
ground surface long before they are destroyed by
terrestrial weathering processes. Depending on how
intense the bioturbation is and the size of the meteorite,
this can happen in a matter of decades, even years.
Some references are:
Johnson, D. L.. J. E. J. Domier, and D. N. Johnson,
2005, Reflections on the Nature of Soil and Its
Biomantle. Annals of the Association of American
Geographers. vol. 95, no. 1, pp. 11–31
Meysman, F. J. R., J. J. Middelburg and C. H.R. Heip,
2006, Bioturbation: a fresh look at Darwin's last idea.
Trends in Ecology and Evolution. vol. 21, no. 12,
Frolking, T. A. and B. T. Lepper, Geomorphic and
Pedogenic Evidence for Bioturbation of Artifacts at a
Multicomponent Site in Licking County, Ohio, U.S.A.
Geoarchaeology. vol. 16, no. 3, pp. 243–262.
Johnson, D. L., C.L. Balek, and R.J. Schaetzl, 2005,
Stonelayers (stone-lines) in Soils: A priori assumed
to be basal parts of biomantles. Geological Society
of America Abstracts with Programs vol. 37, No. 5, p. 77
Animation on Dynamic Denudation/Biomantle Evolution