Marty on Fossilization

By Marty Leipzig

"Fossilization" is really a "bag" term for preservation in the rock record. To be more precise, one should refer to the actual processes (plural) of preservation. These include: mummification (preservation in arid/cold [or both] climates), usually reserved for fairly recent sort of remains (mammoths in permafrost, cave bears from the Pleistocene, and dodo and great auk remains from the Pliocene). Other more typical preservational modes are carbonization (usually for florules, i.e. plant remains), but certain critters croaking in water and falling to the bottom of a lake or restricted ocean in an euxinic or anoxic environment are not bothered by scavengers and other reducers, and are eventually "distilled" into a carbon film. Good examples are some of the piscine remains in the Eocene Green River Shales, ichthyosaurs from the Jurassic of Germany and Cretaceous fish from Brazil.

Other methods are replacement and permineralization; where there is a molecule for molecule exchange of organic remains (carbon base) for inorganic (silica, hematite, opal, magnetite, pyrite, etc.). This yields exquisite detail as it is a VERY slow process (10^6's years). Such examples include the "Petrified Forest" of the 4 corners area fame (coniferous trees replaced by precious opal), numerous examples of pyritized brachiopods from the Carboniferous Cincinnati Shales (_Platystrophia ponderosa_ is a largish brachiopod and oftimes is found completely pyritized...makes nifty geological door prizes.)

Other modes of preservation include imbedment in various agents such as tar (Pleistocene Rancho de La Brea as a classic example), amber (Baltic insects from the Miocene) and body casts and molds by interment in ash falls.

As for the supposed big boat that "fossilized" in a mere 4,000 years on the slopes of a tallish mountain, just where the flying fornication did all the water come from (and go to) that allowed this rapid mode of fossilization on the side of a volcano? All processes of preservation (excepting the latter inclusion cases) require copious amounts of liquid H2O for the vehicle to carry dissolved minerals for replacement.

Or is it all just a great, huge load of bovine biogenic colluvium?

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