Geological Time Scale

Question 1

Two types of dating

Answer 1

• chronostratic

- chronometric

Question 2

Chronostratic

Answer 2

• relative time
• time split into levels
• 3 bones 10 ft apart -> deepest one is oldest
• earth is in layers

Question 3

Chronometric

Answer 3

• absolute time
• earth is 4.5 billion years old (measured)
• numerical ages
• radioisotopes
• carbon dating

Question 4

Different packets of time

Answer 4

Eon
Era
Period
Epoch

Question 5

Eons

Answer 5

Archean eon (earth began)
Proterozoic eon (single celled organisms)
Phanerozoic eon (stuff happened (land + O2))

Question 6

Phanerozoic eon

Answer 6

• Paleozoic era (543 mya) (invertebrates)
• Mesozoic era (248 mya) (reptiles)
• Cenozoic era (65 mya) (mammals)

Question 7

Hadean eon (when + geology)

Answer 7

4600 mya

• molten/liquid earth (hell)
• vaalbara (1st supercontinent) (only land)

Question 8

Archean eon (when + geology + fossils)

Answer 8

4-2.5bya (?)

• formation of earth’s crust
• atmosphere of CH4, NH3, CO2
• volcanic activity
• protocontinents
• 1st fossils (rocks)
• metamorphic/igneous rocks
• bacteria microfossils
• salty ocean

Question 9

Proterozoic eon (when + geology + fossils)

Answer 9

2500-570mya

• 2 supercontinents
• oxygen from stromatolites
• ice sheets (1st glaciers) (reached equator)
• microfossils from 1 billion year old bitter springs (Australia)
• snowball earth

Question 10

Cambrian period (when)

Answer 10

540-485mya

Question 11

Ordovician period (when + geology)

Answer 11

490-470mya

• north of tropics is almost entirely ocean
• limestone + dolomite

Question 12

Silurian period (when + geology)

Answer 12

443. 7-416mya
     - glaciers
     - rise in sea levels

Question 13

Devonian period (when + geology + fossils)

Answer 13

416-358mya

• euramerica + Gondwana
• Appalachian mountains
• fossils (teeth/fish + plants)

Question 14

Carboniferous period

Answer 14

Mississippian

Pennsylvanian

Question 15

Mississippian period (when)

Answer 15

354mya

Upper Carboniferous

Question 16

Pennsylvanian (when)

Answer 16

323mya
Lower Carboniferous
-name from coal

Question 17

Permian period (when + geology)

Answer 17

299-251mya

• glaciation (beginning)
• hot + dry (end)
• pangea formed

Question 18

Triassic period (when + geology + fossils)

Answer 18

251-199mya

• Pangea began separating
• warm + dry
• no polar ice caps
• desert
• mud stone preserved marine reptiles
• sand dunes + evaporites

Question 19

Jurassic period (when + geology + fossils)

Answer 19

199mya

• soil deposits + oil shales
• tectonic activity formed mountain ranges
• limestone
• plants -> sedimentary rocks

Question 20

Cretaceous period (when + geology + fossils)

Answer 20

145-166mya

• went from 18% land to 28% land
• warm + humid
• lots of volcanic activity
• high sea levels
• evaporites (proof of climate change)
• longest period

Question 21

Paleogene period (when + geology)

Answer 21

65-23mya

• continents moved to modern positions
• tropical is cooler
• sea levels down

Question 22

Neogene period (when + geology + fossils)

Answer 22

23-2.6mya

• continents crashed
• stellar sea cow skull
• neogene = new born

Question 23

Pleistocene epoch (when + geology + fossils)

Answer 23

2. 6mya-11700 years ago
   - Ice age
   - complete/almost complete skeletons (no time to decompose)

Question 24

Holocene epoch (when + geology)

Answer 24

• 12000 years ago-now
• tundra (forest)
• bye glaciers

Question 25

Hadean eon (life)

Answer 25

None

Question 26

Archean eon (life)

Answer 26

Unicellular Cyanobacteria Stromatolites Prokaryotes

Question 27

Proterozoic eon (life)

Answer 27

No changes from archean eon Algae Single-celled organisms Eukaryotes (nucleus)

Question 28

Cambrian period (life)

Answer 28

Hunting techniques Claws Underground Cambrian explosion

Question 29

Ordovician period (life)

Answer 29

Adaptive Primitive fish Red/green algae Cephalopods

Question 30

Silurian period (life)

Answer 30

Spread of jawless fish Freshwater fish First plants/fungi

Question 31

Devonian period (life)

Answer 31

Fish Coral Insects/spiders Plants with seeds + roots (forests)

Question 32

Mississippian period (life)

Answer 32

``` Sharks Amphibians Crinoids Seed ferns Conifers ```

Question 33

Pennsylvanian period (life)

Answer 33

Reptiles Land vertebrates Freshwater Spore bearing plants

Question 34

Permian period (life)

Answer 34

``` Terrestrial plants Reptile lineages Reefs Coral + sponge species Swamp forests Gymnosperms ```

Question 35

Triassic period (life)

Answer 35

``` Fewer evolutionary advances Ferns Considers Cycads Coelophysis Plateosaurus First dinosaurs First mammals ```

Question 36

Jurassic period (life)

Answer 36

``` Invertebrates -insects -reefs Vertebrates -dinosaurs -birds -fish Plants -jungles -podocarps ```

Question 37

Cretaceous period (life)

Answer 37

Dinosaurs | Flowers

Question 38

Paleocene period (life)

Answer 38

``` Lower temp killed unicellular organisms First whales First horses Birds Grass ```

Question 39

Neogene period (life)

Answer 39

Grass Deciduous Early primates

Question 40

Pleistocene epoch (life)

Answer 40

``` Large mammals -wooly mammoth -mastodon Large plants -big seeds ```

Question 41

Holocene epoch (life)

Answer 41

Mammals die | Humans

Question 42

When were the extinctions (6)

Answer 42

``` Beginning of Ordovician End of Ordovician End of Devonian End of Permian End of Cretaceous Now ```