study of the incorporation of living things into sedimentary record
Taphonomy
the break-up of organisms after death
Necrolysis
the burial process itself
Biostratinomy
the post-burial transformation of the organic material
Diagenesis
are typically the hard parts of previously existing plants and animals.
Fossils
foraminifera, some sponges, corals, bryozoans, brachiopods, mollusks, many arthropods, and echinoderms
Calcium Carbonate
radiolarians, most sponges
Silica
vertebrate bones, conodonts, certain brachiopods and worms
Phosphate
lignin, cellulose, sporopollenin, and others in plants, and chitin collagen and keratin in animals
Organic hard tissues
typically operate from the moment of death until either the organism disappears completely, or until it is mineralized, though mineralization does not always halt decay.
Decay processes
When large animals feed on dead plant or animal tissues, the process is termed?
scavenging
when microbes, such as fungi or bacteria, transform tissues of the dead organism, the process is termed?
decay
Factors of controlling decay
Supply of oxygen
Temperature and pH
Nature of organic carbon
A process of fossilization in which mineral deposits form internal casts of organisms.
Permineralization
Some shells are made of relatively unstable minerals, such as aragonite. Once the shells leave surface conditions, most aragonite reverts to the more stable form of calcium carbonate, the mineral calcite.
Recrystallization
As water seeps through sediments filled with shells or
bone, there is also a tendency for the original material to dissolve. If the fossil dissolves and leaves a void, then the shape of the fossil is preserved in the surrounding sediments.
Dissolution and Replacement
Common forms of replacement
silicification
pyritization
phosphatization
preserves a negative imprint of the surface
mold
preserves the external form of the organism
cast
created with the dissolution of the organic which then leaves an empty cavity imprinted with the external details of the organism.
external mold
The “shell” of the organism is filled with various inorganic materials such as sediment or crystals; when the shell dissolves, it leaves an impression of the interior surface of the shells (e.g., muscle scars) on the material.
internal mold
A process where only the residual carbon of organisms
remains. In nature, this usually happens over time when the organism is subjected to heat and pressure.
Carbonization
In a few exceptional cases, organisms are preserved
with most of their original tissues intact.
Unaltered remain
Most of organism preserved, including soft parts
Exceptional Preservation
