Description
Lecture 4:
Sediments: Window to the Past
What can be learned?
∙ Historical information
∙ Location of natural resources
Memory of the ocean:
∙ Reconstruct climate and ocean history
∙ Change in color of sediment means that something BIG has happened
∙ Sudden rise in CO₂ leads to global warming and acidification as seen during the PETM (PaleoceneEocene Thermal Maximum)
Dynamic:
∙ Climate
∙ Biosphere
∙ Lithosphere
Sedimentary record provides evidence of changes in any of the items listed above
Sediment: rocks, remains of dead organisms that are deposited Marine sediments: deposited under oceans
∙ Rivers are a major source of these sediments
∙ Airborne dust and volcanic ash
∙ Interaction of the atmosphere, hydrosphere, and the lithosphere also lead to the creation of sediments through the erosion of the lithosphere.
∙ Settling rate: how long it takes for sediment to settle o Size is a factor
o As is energy of environment (has an affect on offshore transportation)
Sediment types:
∙ Terrigenous:
o Land by erosion
o Abundant by VOLUME (>87%)
∙ Biogenous:
o Living organisms (mainly found in the deep sea) o Has the largest amount when it comes to area
o Foraminifera
o Diatoms
o Coccoliths
o Radiolaria
o Plankton tests (shells)
Silica (SiO₃)Don't forget about the age old question of Mass Disasters means what?
Calcium carbonate (CaCO₃)
Calcium Carbonate Compensation Depth (CCD)
∙ Calcareous ooze is used as a measure of depth
∙ CCD ~ 4500 m but various in ocean basins
∙ Siliceous ooze is not found everywhere
∙ Hydrogenous: produced by water
o Precipitation = ions + ions = solid particle
o Manganese nodules
o Phosphorite nodules
∙ Cosmogenous: from space
o Microtektites tiny glassy particles > impact of meteorite and Earth
∙ Continental shelf
o Neritic sediments
Principle of superposition: the old rock is on the bottom Principle of Uniformitarianism: the laws of nature do not change just because time does
Hydrogenous:
∙ Limestone, gypsum, salts = water dried out
∙ Some show annual cycling (but this is rare)
∙ Radioactive dating = only absolute age
∙ Want age of deposition
∙ Use volcanic ash of absolute age
∙ Basalt = absolute age\
Lecture 5:
Water The Earth’s Coolant
∙ Main energy is solar radiation We also discuss several other topics like What does the Civil Rights Act of 1964 do?
∙ Heat capacity: the ability to absorb or give up energy without too much of a temperature change
∙ Circulation of water is used to redirect the energy
Molecular structure
∙ Water is polar
∙ Pushes the electrons from the hydrogen to the oxygen ∙ Intramolecular bonds
∙ Hydrogen bonding = intermolecular bonds > liquid water ∙ Electrostatic interactions
∙ Solvent
∙ Sticks well to thinks
∙ High surface tension (surface skin)
∙ Heat: total energy
∙ Temperature: average kinetic energy
∙ Transitions between states due to gains or losses in energy ∙ Heat capacity: how much heat one gram can absorb before its temperature is changed
∙ Water has the highest heat capacity
∙ Calorie: amount of energy needed to raise the temperature of 1 gram of water by one degree celsius
State
Calories
Ice to water
80
Water to heated water
100
Water to steam
540
1. Hot climates take a LOT of energy We also discuss several other topics like when did bacon's rebellion happen?
2. Cold climates prevent air from getting colder
3. Ice absorbs heat to prevent change If you want to learn more check out what markets get wrong?
If you want to learn more check out Hylobatidae is what?
We also discuss several other topics like what is the english translation of Pax Romana?
Average sea water
∙ 3.5% dissolved salts
∙ Salinity 0/00 = permil
∙ Freezing point is ~ 2℃
∙ The ice in the ocean is freshwater
∙ Brine is salty water
∙ The ocean serves as a thermal buffer
Density Stratification:
∙ Surface zone is well mixed
∙ Pycnocline has a rapid increase in density ∙ Deep zone has stable density
∙ Mixing does not happen unless density is the same
Salinity Variation:
∙ Evaporation and precipitation
∙ Controlled by temperature and salinity
Color and Ocean:
∙ Little light penetrates below photic zone and is blue (Hydrogen absorbs the red)
∙ Photic zone depth = 100m; 600m
∙ Sound travels well in the ocean