Fossils Flashcards
1
Q
What happens during gradual replacement by minerals?
A
Bones don’t decay when buried
Replaced by minerals as they eventually decay forming a rock like substance
2
Q
In gradual replacement by minerals, what shape is the rock like substance?
A
The shape of the hard part of the organism
3
Q
What happens to form casts and impressions?
A
Bones buried n soft material like clay
Clay hardens + organism decays
Leaving a cast
4
Q
What can be preserved by casts?
A
Animal burrows and plants roots
5
Q
What happens during preservation in amber and tar pits?
A
No C02 or moisture so decay microbes cant survive
6
Q
What happens during preservation in glaciers?
A
Too cold for decay microbes to work
7
Q
What happens during preservation in peat bogs?
A
Too acidic for decay microbes
