Geological Time Scale Flashcards
1
Q
Two types of dating
A
- chronostratic
- chronometric
2
Q
Chronostratic
A
- relative time
- time split into levels
- 3 bones 10 ft apart -> deepest one is oldest
- earth is in layers
3
Q
Chronometric
A
- absolute time
- earth is 4.5 billion years old (measured)
- numerical ages
- radioisotopes
- carbon dating
4
Q
Different packets of time
A
Eon
Era
Period
Epoch
5
Q
Eons
A
Archean eon (earth began) Proterozoic eon (single celled organisms) Phanerozoic eon (stuff happened (land + O2))
6
Q
Phanerozoic eon
A
- Paleozoic era (543 mya) (invertebrates)
- Mesozoic era (248 mya) (reptiles)
- Cenozoic era (65 mya) (mammals)
7
Q
Hadean eon (when + geology)
A
4600 mya
- molten/liquid earth (hell)
- vaalbara (1st supercontinent) (only land)
8
Q
Archean eon (when + geology + fossils)
A
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
9
Q
Proterozoic eon (when + geology + fossils)
A
2500-570mya
- 2 supercontinents
- oxygen from stromatolites
- ice sheets (1st glaciers) (reached equator)
- microfossils from 1 billion year old bitter springs (Australia)
- snowball earth
10
Q
Cambrian period (when)
A
540-485mya
11
Q
Ordovician period (when + geology)
A
490-470mya
- north of tropics is almost entirely ocean
- limestone + dolomite
12
Q
Silurian period (when + geology)
A
- 7-416mya
- glaciers
- rise in sea levels
13
Q
Devonian period (when + geology + fossils)
A
416-358mya
- euramerica + Gondwana
- Appalachian mountains
- fossils (teeth/fish + plants)
14
Q
Carboniferous period
A
Mississippian
Pennsylvanian
15
Q
Mississippian period (when)
A
354mya
Upper Carboniferous
16
Q
Pennsylvanian (when)
A
323mya
Lower Carboniferous
-name from coal