Fichas
Proterozoic Cont. (16)
Fichas del conjunto (14)
- 1How often did supercontinents form in the Proterozoic?Four times
- 2What is Rodinia? When did it form? When did it break-up?-Rodinia is the most well-known oldest supercontinent.
-Formed 1.1 Ga
-Broke up 750 Ma - 3What was its continental configuration (arrangement of component continents)?*Check Notes*
- 4What is Pannotia? When did it form?-Australia - Anarctica - India rifted away from North America as a unit, roated and collided with Africa.
-Formed ~ 550 Ma - 5When did extensive sedimentary deposits (including limestones) first form in Earth history?In the Proterozoic
- 6What conditions are necessary in order to get extensive sedimentary deposits??
- 7Are Proterozoic rocks in general better preserved than rocks in the Archean?Yes because there are many Proterozoic rocks that are not metamorphosed
- 8☼What are BIFs and GIFs?☼-Banded Iron Formations
-Granular Iron Formations
-They are extinct (don't form today) marine sedimentary rocks (usually metamorphosed) - 9☼Where do BIFs and GIFs form? How do they form? ☼-In marine environments
-Dissolved Iron was high in ancient oceans
-When earth started getting O2 gas, wave action mixed the O2 gas into the water.
-The O2 combined with Fe to produce Fe-rich layers on the seafloor - 10☼What is the general mineral composition of BIFs?☼Iron-rich minerals such as Fe-oxide, Fe-Silicate, Fe-Sulfide, Fe-Carbonate & Chert
- 11☼What general rock types are involved with BIFs?☼Jaspilite, Taconite, Specularite, Magnetitite
- 12☼When did most BIFs form in Earth history?☼Most are Paleoproterozoic
- 13☼Do BIFs form today?☼Nope (too much O2 now)
- 14Do BIFs have economic significance? What are they mined for?Yes
They are mined for their Iron