19. History Of Earth Earth History Oxidation

Question 1

What do plate tectonics explain. Big questions : is plate tectonics necessary for life

Answer 1

-drive mountain building
-basins in which sediments accumulate
-drives volcanism
-atmosphere: arrangement of continents affect solar heating and cooling eg winds and weather
Rapid plate spreading release volcanic co2 and affect climate
-hydrosphere: affects ocean currents , and rate of spreading affects sea level
-recycle waters
Biosphere ; movement created corridors or barriers for migration
Transports of habitats

Question 2

What is the rock cycles?

Answer 2

Rock major families-igneous (lava) ,sedimentary (mud sand) ,metamorphic (rock transfigured by) heat and pressure)
Deposition of sediments particle built up in layers
Packed and welderee together makes sedimentary rock
If buried and pressure may turn into metamorphic rock , if completely melted it’s magma
If magma crystallises underground form igneous rock
Rocks on surface broken down to particles end up basins and cycle repeats

Question 3

Is there plate tectonics on mars? And implications of rock cycle and habitability

Answer 3

Not at present day , lots less going on geologically

Question 4

How do we determine rock age?

Answer 4

Relative ( comparing) ,absoloute Dating (radiometric using decay and measure rdaughter parents ratio)

Question 5

Principles relative dating

Answer 5

Superposition-rock layer above is younger than ones below
Etc cut across

Question 6

Discovery of uncomformaties

Answer 6

Angular uncomformaties-angle below different orientation to above

Question 7

Oxidation of earths atmosphere

Answer 7

When life first evolved it on
H had trace levels of oxygen

Question 8

Method for History of oxygen ( look at these slides again)

Answer 8

1 Look at deposits of minerals sensitive or oxygen
2 mobilisation of redox sensitive elements , sudden mas
3 looks the elements and their isotopes

Question 9

What causes a net increase in oxygen

Answer 9

Change in gases being produced
Iron in ocean decline so phosphorous availability in ocean would ha d increases and thus oxygen produced increase
Less methane means means less oxygen removed b reacting with it
Irrervessible oxidation bc hydrogen lost

Question 10

Snowball earth

Answer 10

Consequences of great oxidation: rise in oxygen means less methane cooling the planet , so glacier periods
Ends when co2 accumulate in atmosphere and melt ice

Question 11

Consequence of great oxidation

Answer 11

Rise of multicellular life as can aerobically respire