A fossil (other names: petrefact, fossil, the process of formation of a fossil is called fossilization or petrification) can be:
A) in the broadest sense: a shape-preserved remnant of an organism or a bioglyph (i.e. a trace of an organism's activity) originating from the geological past (sometimes it is stated that it must be older than the Holocene, i.e. it must not be a so-called subfossil)
B) in a broader sense: like point A but without bioglyphs
C) in a narrower sense (the so-called true fossil): only the remains of an organism in which at least some original body parts (e.g. shells, bones, teeth) have been preserved without major chemical changes.
The term fossil (in the narrowest sense) has a fourth meaning – it is just a fossil that was created by oversaturation with mineral substances, i.e. petrification (in the narrowest sense), the so-called fossilization.
The opposite of a fossil is the so-called recent remainder (current remainder).
The hard parts of animals are most often preserved: teeth, bones, shells, skins, shells and the like. The oldest known unaided remains of living organisms, but not fossils, are stromatolites. They are layers of cyanobacteria coatings to which calcareous sludge has adhered.
Paleontology deals with the study of fossils.
Fossilization
Fossilization, or petrification, are chemical, physical and diagenetic processes that caused the transformation of organic remains of flora and fauna of past geological periods and enabled their preservation until today.
The most common types of fossilization are:
- petrification (in the narrowest sense) – oversaturation with mineral substances
- charring – the gradual depletion of oxygen and hydrogen from carbonaceous substances in an unventilated environment
- mummification – oversaturation with substances preserving the soft parts of bodies
- incrustation - coating with mineral deposits
- replacing organic matter with inorganic matter
Fossilization is a relatively rare process, most organisms are decomposed after death by the activity of other organisms or by chemical processes. In order for a fossil to form, two basic conditions must be met:
- the dead organism must be covered with sediment shortly after death, permanently frozen or placed in an oxygen-poor environment (e.g. the bottom of a swamp). Therefore, the frequency of occurrence of a fossil of a given species can also strongly depend on the type of environment in which this species lived in the past. A good example is the fossils of freshwater (mainly river) fish, the remains of which are relatively rare in the fossil record.
- organisms that have hard shells, a skeleton and the like are best preserved (e.g. bivalves, ammonites). Conversely, organisms that only have soft body parts (eg jellyfish) fossilize very rarely.
For these reasons, our current fossil record is very incomplete and often unrepresentative.
Your task is:
1. What kinds of fossils did you find?
2. Determine the size of the largest fossil.
3. Are there fossils elsewhere in the castle? If so, what kind and where?
4. What kind of fossilization do you think it is?
5. A photo from a place that does not show the answers to the questions.
