Life on Rocks Flashcards
(25 cards)
When was water on Earth by?
By 4.2-4.3 BYA.
What might be the oldest fossil?
Iron oxide tubes created by iron-oxidizing bacteria found at Nuvvuagittuq Gneiss.
What are the two problems with the Iron oxide tubes created by iron-oxidizing bacteria found at Nuvvuagittuq Gneiss?
- Age not clear. 2. The oxide tubes might not need biology.
What percent of geologist think that the iron oxide tubes found at Nuvvuagittuq Gneiss are the oldest fossil?
30 percent.
How old are the oldest fossils (Iron oxide tubes created by iron-oxidizing bacteria found at Nuvvuagittuq Gneiss believed by some to be)?
3.77-4.3 BYA.
How old are the stromatolite found in Greenland proposed to be?
3.7 BYA.
What percent of geologists believe the stromatolites in Greenland are 3.7 BYA?
70%.
What is the problem with the stomatolite fossils found in Greenland?
They were only found in one location, so there is no paleoenvironmental context.
When are the first microfossils proposed to have appeared on Earth?
By 3.4-3.5 BYA.
What percent of geologists believe that microfossils appeared on Earth 3.4-3.5 BYA?
50%.
When did stromatolites appear in the fossil record (not Greenland stormatolites).
By 3.4-3.5 BYA.
What percent of geologist believe that stromatolites appear in the fossil record around 3.4-3.5 BYA? (Not Greenland).
99%.
When did the first huge fossils appear in the fossil record?
3.2 BYA.
How many geologists believe that huge fossils appear in the fossil record around 3.2 BYA?
50%.
What were the two problems with the huge fossils proposed to be around 3.2 BY old? What could they be?
- Not found in any other units. 2. Can not confirm original locality. 3. Possible eukaryotes.
How old is the oldest rock on Earth?
3.96 BY old.
Where was photosynthetic carbon found? How old is it proposed to be?
In Akilia Island, Greenland. Proposed to be 3.85 BY old.
How many geologists believe the 3.85 BYO photosynthetic carbon found in Akilia Island, Greenland is true?
10%, because of the Steve Mojzsis controversy.
Evidence for stromatolites without oxygen were proposed to be how old? Why do they think they were anoxygenic?
3.4-3.5 BYO. They used uranium and iron isotopes.
How many geologists accept the evidence for stromatolites without oxygen? Why?
50%, because it is a new technique that needs to be verified.
When is the first proposed evidence of oxygen in the ocean and where was it found?
3.2 BYO, in South Africa.
How many geologists believe there is evidence of oxygen in the ocean by 3.2BYA? Why?
About 50% since they used uranium and iron isotopes, which is a new technique.
How old are the molecular biomarkers indicating cyanobacteria and eukaryotes and where were they found?
Proposed to be 2.7 BYO. They were found when drilling in South Africa.
How many geologists believe the molecular biomarkers indicating cyanobacteria and eukaryotes are 2.7 BYO?
Around 10% unless new drilling shows positive results.
