Archean Eon Flashcards
(15 cards)
1
Q
why are there no rocks older than 4 BYA
A
- metamorphosed
- buried deep
- few fossils for stratigraphy
2
Q
what happened during the archean eon
A
- layer differentiation
- atmosphere formation
- ocean formation
- continent formation
- earth’s earliest organisms
3
Q
extensive, flat stable areas eroded near sea level
A
stable interiors
4
Q
uplifted regions of deformed rocks
A
mountain belts
5
Q
expansive flat regions of metamorphic rocks
A
shields
6
Q
large crustal blocks
A
cratons
7
Q
2 archean rocks
A
- greenstone belt
- granite-gneiss complex
8
Q
granitic gneiss and granitic plutonic rocks derived from plutons emplaced on volcanic island arcs
A
granite-gneiss complex
9
Q
synclinal granitic magma with volcanics
A
greenstone belt
10
Q
first supercontinent
A
vaalbara
11
Q
when did vaalbara exist
A
3.1-2.5 GA
12
Q
what made vaalbara
A
kaapvaal and pilbara craton
13
Q
2nd supercontinent
A
ur
14
Q
from the accretion of neoarchaean cratons
A
kenorland, 2.7 GA
15
Q
3.7-3.8 GA signs of life
A
isua supercrustal belt
