Lecture 13- Geologic Time Scale Flashcards
What is a mood fossil?
Form when organism gradually dissolves away, leaving behind impression of body, leaves, flowers, etc..
How do cast fossils form?
Same process as mold but impression/mold left behind filled with sediment
What are petrified fossils?
Organisms gradually turning into stone
What does petrification mean?
To turn to stone
Petra: Latin word for rock/stone
When does petrification occur?
When buried remains (ex wood) are exposed to water rich in ions that make up minerals. The minerals will gradually deposit and in doing, gradually replace original organic matter found in organisms remains
True or false: the minerals in petrified fossils fill up empty space left after organism decays.
False. The minerals are gradually REPLACING organic matter. So organism turns to stone.
What are trace fossils
Depicting organism behaviour. Ex: footprints, coprolites, fossilized nests/burrows.
What is amber
Fossilized tree resin
Resin:
A substance flowing beneath tree bark to protect in case of insects, disease or physical damage (breaks/cracks)
Resin covers breaks cracks, injuries and hardens to from a seal/barrier
Since resin is sticky, what can it do?
It can entrap and subsequently engulf creatures (insects, arachnids, amphibians) and plant bits within
What happens when resin is compressed by layers of sediment that form above it?
The chemical compounds within resin transform to form amber. We can often observe organism’s preserved remains within the amber.
Where are the largest deposits of amber located? What do we call this amber?
Baltic region, Europe, This amber is referred to as Baltic Amber
Where does the MAJORITY of amber come from ?
Kaliningrad Oblast, Russia
Fossil record?
History of Earth as documented by fossils.
Difference periods of geologic time/different layers of rock have different animal/plant/bacteria/fungi fossils
What is the difference between Eons, Eras, Period, Epochs
Eons= longest amount of time
Eras= Less long amount of time
Periods= Even shorter amount of time
Epochs= shortest subdivision/amount of time
What are the 5 mass extinctions?
Ordovician-Silurian= 440 million years ago (Mya)
Devonian= 365 Mya
Permian-Triassic= 250 Mya
Triassic-Jurassic= 210 Mya
Cretaceous-Tertiary= 65 Mya
What are the 4 eons since the formation of our planet?
Hadean= 4.6 billion to 4 billion years ago.
Archean= 4 billion to 2.5 billion years ago.
Proterozoic= 2.5 billion to 541 millions years ago
Phanerozoic (541 million years ago to now)
What does the Precambrian refer to
Hadean, Archean and protozoic eons combined
Our Phanerozoic eon is divided into?
Eras, Period and epochs
Stromatolites/cyanobacteria mounds date back to what eon?
Archean eon
What happened in the Hadean Eon?
Earth is forming during this time. No life- Earth way too hot and molten
What happened during the archean era?
Crust is cooling down enough to allow for life to begin.
What happened during the Proterozoic era?
Life formed encountered include bacteria, algae, jellyfish
When was the DODO bird last seen?
1662
What epoch are we in?
Holocene epoch
What happened with the amber room?
It was 180 square feet and contains 6 tons of amber and other semi-precious stones.
During WW2 Nazi forces tore it down and placed it in Germany on Baltic coast
