L2 - Tools of the Trade Flashcards
What are the 5 Paleoclimate archives?
- Sediments
- Ice
- Tree Rings
- Skeletons
- Speleothems
In what 3 environments can sediment cores be taken?
- Terrestrial
- Nearshore
- Offshore
What is IODP as of 2013 and where has the most recent expedition been conducted?
International Ocean Discovery Programme
IODP Expedition 361 in South Africa doing Spring 2016 onboard The Jodies Resolution
What is the name of the archive where sediments are stored?
A Depsoitry
What 2 things can be identified from the sediment colours?
- Sediment Regime
2. Forams
What are calcified planktonic formas an indicator of?
Cold Climate
What is IRD and what is it used for?
Ice Rafted Debris
It is used to identify iceberg origins and melt
What are the 5 dominant sediment types?
- Deep Sea Clay
- SiO2 rich
- CaCo3 rich
- Land Margin
- IRD
What are the 3 biogenic components of sediments (with examples)?
- Surface and Deep Dwelling Plankton (Formas, Diatoms, Radiolarians)
- Animal Remains (Fish Teeth)
- Biomarkers (from algae and bacteria)
What 5 things can be reconstructed using biogenic components?
- SST
- Salinity
- Nutrient Levels
- Global Ice Volume
- Ocean Circulation Patterns
What is a good proxy for modern day SST and comparing to the LGM?
Neogloboquadrina Pachymderma (sinistral)
What are the 5 terrigenous components of sediments?
- Land Aridity-Humidity
- Past Wind Patterns
- Sea Ice Cover
- Iceberg Activity
- Ocean Circulation Patterns/Activity
What are the 4 sources of terrestrial sediments?
- Lake Sediments
- Loess (Wind Blown Dust Deposits)
- Glacial Ice
- Peat Bogs
What are the 2 places that ice cores can be taken from?
- Ice Sheets
2. Mountain Glaciers
Where do you drill for an ice core?
At the divide
Why does annual layering resolution decline with depth in an ice core?
Because of ice flows
What what temperature do ice cores need to be stored?
-50 Deg C
What climate information can ice cores give us in the form of proxies?
- Temperature
- Precipitation
- Atmospheric Storminess
- Volcanic Eruptions
- Solar Variability
What climate information can ice cores give us in the form of direct measurements?
The gas composition of the lower atmosphere
What is dendroclimatology?
The use of tree rings for looking at past climates
What is the longest tree ring record?
12,000 years
Tree ring thickness and density varies with which 3 climatic factors?
- Temperature of Air & Soil
- Precipitation
- Sunshine Levels
Clam shell width and Oxygen Content can be used to reconstruct which 3 things?
- Seawater Temperatures
- Productivity
- Ocean Dynamics
Colonial Reef Building corals have bands in their carbonate skeletons and can be used to reconstruct which 3 things?
- SST
- Salinity
- Sea Level
Data masses can be dated to explain ocean circulation using which type of corals and which radioisotopes?
Deep Sea Solitary Corals with Carbon 14 and Uranium Series
Speleothems provide information on what?
Temperature and Precipitation
What are Speleothems?
Mineral deposits formed from groundwater within underground caves
What has correlations between a Chinese Speleothem and a Greenland Ice Core been able to show?
That East Asian monsoons are weaker during cold periods in the North
What are the 5 useful isotope systems?
- Measuring isotope ratios (the delta notation)
- Stable isotopes of Carbon
- Stable isotopes of Oxygen
- Isotope fractionation
- Radiocarbon as a Dating Tool
What are the 3 most common O isotopes?
16, 17 and 18
What are the 3 most common C isotopes?
12, 13 and 14
What is the delta notation?
The relative difference between an absolute isotope ration of a sample and the standard in PPM
What is the standard used for Carbon-13?
PDB
What is the standard used for Oxygen-18?
SMOW
Do heavier or lighter isotopes have higher binding energies? and what does this mean?
Heavier and it is therefore harder to evaporate
Isotopic effects are more pronounced at high or low temperatures?
Low
What are the 2 types of fractionation and what is fractionation?
Fractionation is the partial separation of isotopes during physical or chemical processes. The 2 types are:
- Equilibrium
- Kinetic
If the sample is equal to 0 ppm then it is identical to what?
The sample
If the sample is +ve what does this mean?
It contains more of the isotope (e.g. O18 and is heavier) than the standard
If the sample is -ve what does this mean?
It contains less of the isotope (e.g. O18 and is lighter) than the standard
Is there a +ve or -ve relationship between temperature and O18 for calcite?
-ve
Is there a +ve or -ve relationship between temperature and O18 for snow?
+ve
Why do benthic forms have more 18O?
Because it is colder
What is the paleotemperature equation?
T = 16.9 - 4 (Delta of Carb - Delta of SW)
What do large ice sheets mean with respect to 18O?
More vapour is lost to ppt, increased depletion of snow, lower 18O on land and more in the oceans which is recorded by the forams
What do benthic and planktonic forams measure?
Benthic - Ice Volume
Planktonic - Temperature, Salinity & Ice Volume
How much cooler was the LGM?
2 Deg C
What are the 4 sources of Carbon?
- Atmospheric CO2
- Oceanic Carbonate
- Sediments
- Organic Matter in the Biosphere
What are the 2 Carbon Fractionation Systems and which are depleted in 13C?
- Inorganic
2. Organic (these compounds are depleted in 13C)
How can C13 help explain the biological pump?
By using the difference between planktonic and benthic foram shells that record the 13C of DIC
A decline in SL of 120m equates to how much of an increase in oxygen-18?
~1.25 ppm