·      Eroded rock particles and fragments

·      Transported to ocean

·      Deposit by settling through water column

·      Oceanographers decipher Earth history through studying sediments

·      Break down of rocks, soils, and minerals through direct contact with the planet’s atmosphere

·      heat, water, ice, and pressure

·      makes small chunks and increases surface area which increases ability to be weathered

·      soil pH, temperature, precipitation, mineral composition of rock

·      when trees respire H2O + CO2 à H2CO3 (carbonic acid) that corrodes sediment soil and rocks around the tree which erodes the Earth

o   results in only dissolved ions

§  Limestone weathering: calcite + water+ carbon dioxideà calcium ion + bicarbonate ion

ú  Florida sinkholes produced by dissolution of limestone by carbonic acid

o   results in newly made clay minerals and dissolved ions

§  Feldspar + water+ carbonic acid à sodium ion + bicarbonate ion + silica + kaolinite (clay)

§  Boulders (biggest diameter of grain) and clay at the bottom of the list with the smallest diameter of grain

§  Gravel (biggest)àsandàmud (lowest diameter of grain)

o   Most lithogenous sediments at continental margins

o   Coarser sediments closer to shore

o   Finer sediments farther from shore

o   Mainly mineral quartz (SiO2)

o   Eroded fragments from land

o   Reflect composition of rock from which derived

o   Agents of transport

§  Water (eg river – transported sediment)

§  Wind (eg windblown dust) – aolian transport

ú  Can be an important agent of erosion

§  Ice (eg ice- rafted rocks)

§  Gravity (eg turbidity currents)

§  Sediment discharge in millions of tons/year

§  Relationship of fine-grained quartz and prevailing winds

ú  Fine grained clay particles from wind can make up about 38% of deep sea sediment

§  Turbidity currents- deposit material further from coast than would be expected; “underwater” landslide…

o   Hard remains of once-living organisms

§  Shells, bones, teeth

ú  Macroscopic (large remains)

·      whale

ú  Microscopic (small remains)

·      Tiny shells or test settle through water column

·      Biogenic ooze (30% or more tests)

·      Mainly algae or protozoans

o   Commonly either calcumn carbonate (CaCO3); Calcite

o   Or silica (SiO2 or SiO2 x nH2O)

o   Usually planktonic (free-floating)

o   (tend to live in surface waters and then when they die they sink to the bottom)

§  Diatoms (algae)

ú  Photosynthetic

ú  Diatomaceous earth

§  Radiolarians (protozoans)

§  Siliceous ooze

Calcium carbonate in biogenous sediments

§  Coccolithophores (algae)

ú  Photosynthetic

ú  Coccoliths (nano-plankton)

ú  Rock chalk

§  Foraminifera (protozoans)

ú  Calcareous ooze

CCD or Calcium Carbonate Compensation Depth

§  ~4500m- seawater too acidic, CaCO3 dissolves

§  more acidic as it gets more acidic

§  CCD more shallow in the Atlantic or Pacific? Why?

ú  Pacific ocean is older, deeper, and colder

ú  Older so more time for CO2 to build up

ú  Deeper so more CO2 can get in

ú  Colder results in more CO2

§  Higher pressure and colder temp as you go down the ocean means there is more CO2 and more CO2 means you have a lower pH which means you have acidic water

§  Dissolves due to the acidity once it hit a certain depth of 4500m

§  Productivity

§  Destruction (dissolution)

§  Dilution

§  Macroscopic meteor debris

§  Overall, insignificant proportion of marine sediments

§  Comes from volcanoes…ash

§  Distributed in the marine realm by wind, streams, submarine gravity flows, ocean currents

§  Near hydrothermal vents, lots of metal ions are released into the water, and these ions oxidize or combine with silica and precipitate out as dark, metal-rich sediment

ú  Less common than lithogenous or biogenous sediments. They are almost never the dominant sediment type

§  Cross section of the ocean

ú  Neritic- closer to shore, shallow water

ú  Pelagic- open water, deep 

§  Temp

§  Nutrient supply

§  Abundance of marine life

§  Atmospheric winds

§  Ocean current patterns

§  Volcanic eruptions

§  Major extinction events

Climate change 

·      AKA surface currents (down to ~1km)

·      Moves water horizontally

·      Only 10% of ocean currents moved this way

·      moves water vertically

·      responsible for mixing water masses

·      drives up 90% of ocean movement

2% so..

100 knot wind will create a 2 knot current

any large system of rotating ocean currents, particularly those involved with large wind movements

1. north atlantic

2. south atlantic

3. indian ocean

4. north pacific

5. south pacific

·      Equatorial currents

·      Western boundary currents (ex Gulf Stream)

·      Northern and southern boundary currents (ex Benguela current)

• Eastern boundary currents