Week 3 Flashcards
How does subduction change ocean chemistry?
- Through water and volatiles leaving Earth’s mantle to enter the atmosphere
- Through water-rock interactions
What did the weathering of basalt cause?
leaching of Fe into the acidic early oceans
What is rock alteration?
the conversion of one rock into another
What is a major source of free oxygen?
oceanic spreading
What did the onset of plate tectonics cause?
a net-oxidation of Earth
What happens at a convergent margin?
SO2 and CO2 are released into the atmosphere
How doe oceanic spreading result in net oxidation?
water interacts with mafic rocks
forms oxidised minerals(magnetite and serpentine)
hydrogen is released
When did life develop?
3.5 billion years ago
What are the steps of the great oxidation event?
Plate tectonics facilitated a gradual increase in CO2
Photosynthesis developed
Free oxygen was produced
Free oxygen entered the atmosphere
What formation did free Free oxygen make?
Banded Iron formation
What caused the global cooling effect?
removal of methane from the atmosphere and replacement with CO2
What is the Huronian glacial event?
first global glaciation
What caused the Huronian glacial event?
The oxidation of methane as a greenhouse gas & the use of CO2 for photosynthesis
What is the Cryogenian glacial event?
snowball Earth initiated ca. 730 million year ago
how does Weathering of rock close to the equator affect climate?
Weathering of bedrock cause large
amounts of Ca runoff
will reduce the greenhouse gas CO2
