Exam Questions Flashcards
What are three volatile elements and a non-volatile element?
Volatile: Hydrogen, Carbon Chlorine,
Non-volatile: silicone
What are volatile and non-volatile elements?
Volatile ones are highly reacted and evaporate quickly whereas non-volatile are not that reactive
Think why silicon is a non-volatile element?
Because it has to react many many times in order to form iron otherwise it just stays the same
What did James Lovelock/Gaia hypothesis propose as a genetic signature of life?
Disequilibrium in the mixture of atmospheric gases
How long will our sun spend on the main sequence?
10 billion years
What is the equation for silicate weathering and think why?
CaSiO3 (Calcium Silicate) + CO2 = CaCO3 (Calcium Carbonate) + SiO2 (Silicone dioxide). the key thing is to look for calcium silicate going in and then calcium carbonate coming out
What is the equation for silicate weathering and think why?
CaSiO3 (Calcium Silicate) + CO2 = CaCO3 (Calcium Carbonate) + SiO2 (Silicone dioxide). the key thing is to look for calcium silicate going in and then calcium carbonate coming out
How long does a carbon atom spend in the ocean/atmosphere before being transported down in to sedimentary rocks? i.e. how long does the silicate weathering process take?
100,000 years
What best describes the immediate aftermath of a snowball earth?
Hot and wet climate caused by high CO2 (carbon dioxide has been allowed to build up) and low albedo )because all the ice has melted)
When did bryophytes appear?
Ordovician
What is the upper limit on oxygen concentration that is consistent with the continuous presence of forests in the fossil record?
25-30%
What amplified climate warming at the end cretaceous?
Shutting down of the biological pump meant that a lot of carbon dioxide collected at the ocean surface where it can better diffuse in to the atmosphere and cause concentrations of the carbon dioxide to increase 2-3X
How much carbon is released to the atmosphere during the PETM?
2000GtC
What is the perihelion and aphelion? what is the best way to remember it?
Perihelion = earth is closest
Aphelion = earth is farthest
Best way to remember is that P in perihelion relates to Proximity and A relates to Away
What cycles does the precession cycle run on?
19, 22, 24kyr
What is palynology?
The study of pollen
What are colepotera/beetles commonly used for to construct?
Mean annual temperatures
Why is the definition of an interglacial a “negative shify in oxygen isotope ratios and typically match periods of high insolation”?
Negative shift in ratios means that there is a reduced difference/ratio of one isotope to another. This happens in interglacial periods because it is warm enough to evaporate both whereas in glacial periods there is a more positive/bigger ratio of the two oxygen isotopes in ice and foraminifera shells etc. because there is less energy to evaporate the heavier 18O.
What are Loess deposits in China typically composed of?
Fluvial clays and silts
When do Homo Erectus fossil remains span between?
1.9-0.14mya
When do Acheulian stone tools date back to?
1.2 but correct answer is 1.7mya
What did global atmospheric carbon dioxide levels reach/average in the last glacial and interglacial and what are they today?
Ipswichian (interglacial) = 270ppmv
Devensian (glacial) = 190ppmv
Today = ~400ppmv
List Tundra, coniferous forest, deciduous forest in order of high to low latitude?
Tundra, Coniferous, Deciduous
What was global sea level in relation to today during the last glacial maximum and interglacial?
last interglacial = 6-9 (8)m above today
Glacial = 120m below
How long do dansgaard-oeschger events last for?`
500-2500 years
What is the exams definition of an interstadial and stadial period?
Interstadial: A period of high temperatures characterised by low global ice volume
Stadial: A period of low temperatures characterised by high global ice volume
How much did temperatures over Greenland increase by during the Bolling Allerod interstadial?
12 degrees celsius
What was the cause for the 8.2 kyr event?
Meltwater pulse
What has been attributed as the cause of the decline in Ullmus during the Neolithic?
Disease
When was the cultural revolution?
35-40kya
What is the study of beetles?
coleopterology
What does are Acheulian, Mousterian and Uluzzian stone tools?
Acheulian = homo erectus tools Mousterian = Neanderthal tools Uluzzian = AMH tools
List oceanic crust, continental crust, iron and mantle in order of density most to least
Iron, mantle, oceanic crust, continental crust
What does immiscible mean?
They do not mix because of density e.g. silicone and iron
How much carbon is stored in the long-term carbon cycle as carbonates and as organic form?
Carbonates = 5.0x10^21 Oceans = 1.25x10^21
How long can carbon be stored as carbonates and at the surface?
Carbonates/sedimentary layers = 2.5x10^8
Atmosphere = 1.28x10^5
What is the study of palaeolimnology?
Study of lake sediments
What are chironomids and what are they used to reconstruct and think why?
these are mosquitos things which are used to reconstruct mean summer temperature because think of how mosquitos only appear in summer most of the time.
Define the three orbital cycles
Eccentricity = shape of orbit Obliquity = axial tilt Precession = wobble
How long is the cycle for eccentricity, obliquity and precession?
Eccentricity = 96,000 years Obliquity = 41, 000 years Precession = 23,000 years
When are the Neanderthals thought to have become extinct?
24kya
What sort of conditions are coniferous plants/trees associated with?
Glacial conditions
Give 4 coniferous/glacial flora
Spruce, pine, non-arboreal pollen, tundra
What conditions are poaceae associated with?
Transition periods between glacial and interglacial conditions
What conditions are deciduous associated with?
Temperate/interglacial periods
Give 6 deciduous flora/trees
Tilia, Ulmus, Acer, Carpinus, Corylus, Quercus, Betula
What are Heinrich events - stadials or interstadials?
stadials
What ‘periodicity’ do Heinrich events occur on?
Just before DO events
How many Heinrich events have so far been recognised since the last glacial?
6 - but there is potential to find more
What are Dansgaard-Oeschger events - stadials or interstadials?
Interstadials
What periodicity do Dansgaard Oeschger events occur on?
~1470 years possibly
How many Dansgaard Oeschger events have so far been identified since the last glacial period?
25
What event marks the starting point of when DO and Heinrich events have started to be identified since?
The last glacial period
What are bond events - stadials or interstadials?
stadials - kind of
What periodicity do bond events occur on?
1470 + or - 500 years
What Bond event did the 4.2kyr event coincide with?
3
What are the possible causes of rapid climate change events?
Milankovitch cycles, sub-milankovitch cycles, vulcanism, or internal alterations such as to the AMOC
What enables zircons to be dated?
Radioactive decay of two uranium isotopes and two lead isotopes
How old is the oldest ocean crust in the NW Atlantic and W pacific?
180-200myr
What is a reducing atmosphere and an oxygenating atmosphere?
Reducing atmosphere means that the atmosphere is becoming increasingly anoxic. Oxidising means that it is becoming increasingly oxidised.
What was the oxygen state of the atmosphere after the 2.7Ga oxygenic photosynthesis start?
Reducing atmosphere, partly oxygenated surface ocean, anoxic deep ocean
What was the oxygen state of the atmosphere after the Great Oxidation?
Oxidising atmosphere, oxygenated surface ocean, anoxic deep ocean
What was the oxygen state of the atmosphere after the 0.6-0.4 oxidation?
oxidising atmosphere, oxygenated surface ocean, oxygenated deep ocean
What is the critical evidence for the great oxidation?
Mass Independent Fractionation
What common piece of evidence is mistaken as evidence for the great oxidation? Why is it not always such a good piece of evidence?
Banded Iron Formations - because they are found to have existed beforehand possibly in which they could have been created as a result of organisms carrying out anoxygenic photosynthesis in the rocks
Where could ancestors of complex life have sheltered during the snowball earth events?
Geothermally heated oases on land
When were the earliest non-vascular land plants uncovered?
Ordovician (445-45Ma - bryophytes)
When were the earliest vascular land plants uncovered?
Silurian (~425Ma)
When were the first trees uncovered?
385Ma (Devensian)
When do the different periods of the Palaeozoic in the phanerozoic stretch between?
Cambrian (~540-505), Ordovician (~505-438), Silurian (~438-408), Devonian (~408-360), Carboniferous (~360-286Ma), Permian (~286-245Ma)
What glaciations are thought to have been caused by the rise of non-vascular plants?
Ordovician (Hirnation)
What glaciations are thought to have been caused by the rise of vascular plants? (possibly question - don’t know if there were glaciations))
Carboniferous-Permian?- just think when vascular plants emerged (425Ma therefore just a bit after - maybe Silurian or Devonian
What is the importance of the Isthumus of Panama?
it is important in determining the build up of large ice sheets in the Northern Hemisphere (amoc?)
How many MIS are there?
~100
How much lower were global mean temperatures during the last glacial maximum?
5 degrees Celsius
Where have the oldest fossil remains of mammoths been found?
Candover, Shropshire
What is boreal?
term given to describe climates with long cold winters and short less cold summers
When is it possible that the last glacial started?
60-70Kya
When is MIS 11?
400kya
When is MIS 17?
700kya
What proxy can be used to construct a semi-quantitative record of climate?
pollen and spores
What is a key multi-decadal climate factor in the Holocene?
Solar variability
When is the next glacial likely to occur?
50kyr in to future
