fossils Flashcards
1
Q
sedimentary rocks
A
- deposition
- sedimentation
- compaction and cementation
2
Q
process
A
- animal dies and sink to the bottom of the river
- anaerobic conditions ( no decomposition)
- covering of sediment (preferably fast to reduce exposure to oxygen)
- hard parts either get replaced with mineral or dissolve and leave natural form impressions (which can be filled minerals leaving a mould)
- pressure builds up on the lower sediment as more sediments accumulate exposing the skeleton to high pressure and temperatures
3
Q
types of fossils
A
- body fossil
- moulds
- trace fossils
- unchanged fossils
4
Q
why are fossils important
A
- trends in biodiversity
- time
- evolutionary relationships
- environmental changes
