Taphonomy 8 PDF

8 - Taphonomy Notes Status Done Lab Notes Status / 🌈TAPHONOMY 💀 → From the greek “taphos”=burial and “nomos”=law, science (forensic taphonomy is the study of what happens to a human body after death). So, tap...

8 - Taphonomy Notes Status Done Lab Notes Status / 🌈TAPHONOMY 💀 → From the greek “taphos”=burial and “nomos”=law, science (forensic taphonomy is the study of what happens to a human body after death). So, taphony studies the processes involved in an organism becoming a fossil → incorporation of living organisms into the sedimentary record → Taphonomic filters (n° of fossils is insignificant when compared to the numerosity of original life) → Fossilization potential depends on: Composition: soft/hard parts (organic and inorganic) Surrounding environment HOW DO I BECOME A FOSSIL?? To achieve your goal of becoming a fossil, you must: 1. Die at your own discretion: diseases, old age, predation, natural calamities (like volcanic eruptions, drowning, anoxia and intoxication), mass extinctions, stranglement you name it 2. Start the necrolysis process: let your non-mineralized parts of the organism decay (before burial pls) 3. Let yourself be consumed by digestion, disarticulation, combustion or predation and biopacking (gastric pellets) → your soft body parts will most probably get lost forever, as soft tissue fossilization happens under exceptional circumstances thanks to poorly understood microbiological processes, but don’t lose hope yet! 4. Preferably, die in an environment with ideal conditions: Temperature: the higher, the faster is decomposition → Freezing! at low temp, decay is prevented! → Get super hot and dehydrate fast 8 - Taphonomy 1  pH: decomp. is rapid but in acidic or basic conditions, it’s slower Oxygen availability → Carbonization: in anaerobic environments, fermentation processes eliminate hydrogen and oxygen while leaving a film of pure carbon behind → Replacement by phosphate Salinity Moisture: in continental environments, it’s important Clay minerals: can deactivate enzymes → Permineralization: pores of plants, bones or shell are impregnated by minerals 5. Your last voyage: after death, corpses and vegetal remains are subjected to transport agents (rivers, waves, hurricanes..) thus promoting degradation and conveyance to distant areas, good luck! Mechanical effects (abrasion, crushing) Corrosion (mechanical and chemical damage) Oriented deposition due to currents and such Mixing (distant faunas are found together) Mechanical selection: vertebrae and ribs are transported farther away than teeth Accumulation with other lucky corpses 6. Burial, maybe into organic debris or bogs, if you’re lucky, so your remains will be almost perfectly preserved, especially the skin (that’s turn into leather btw) Ok, what about the skeletal parts now? You have three options: 1. Direct fossilization Recrystallization: crystals that make up the shell increase in size with no changes in mineral composition. Microstructures can be preserved if the crystal didn’t take up too much → neomorphism is a type of recrystallization, where ARAGONITE reverts to the calcite formand obliterates original microstructures 8 - Taphonomy 2  Replacement by Ca-phosphate Permineralization of bones: pores of plants, bones or shell are filled by minerals 2. Indirect fossilization External mold: shell dissolved before being filled by sediments → External mold later filled by minerals - natural cast Internal mold (infill/cast) (+ external): shell dissolved after being filled by sediments → void of the shell later filled by minerals - pseudomorph / pseudoshell Composite mold 3. Unaltered (in impermeable sediments) 8 - Taphonomy 3