Oceanography 2014
1. Stratigraphy
7. Evaporites
2. Terrigenous Sediments
8. Cosmogenous Sediments
(Lithogenous)
9. Diatomaceous Earth
3. Biogenous Sediments
10. Grain Size
4. Calcareous Ooze
11. Mud
5. Siliceous Ooze
12. Well Sorted Sediment
6. Hydrogenous Sediments
TerraHydroBioCosmo-

Sedimentation: the accumulation of
sediments

Weathering: process of breaking down rocks
to create sediments

Erosion: movement of sediments by wind,
gravity, or water
Sediments are classified by grain size and origin
 Grain Size:
from largest (coarse) to smallest (fine) is gravel, sand, silt, and
clay
Mud = silt + clay
Loam = sand + silt + clay
 Origin:
land, organisms, chemicals, volcanoes, and space (see table)
Poorly sorted sediment: sample contains a mixture of
sediment sizes.
Well sorted sediment: sample contains similar or same sized
particles.
Type
Origin
Composition
Location
Terrigenous
From land by rivers,
glaciers, & wind
Quartz and feldspar
(sand and mud)
Rivers: temperate
regions
All: continental shelves
Biogenous
Organisms, Shells, &
skeletons
Carbon based;
calcium-type
(calcareous ooze) and
silicon-type (siliceous
Tropical continental
shelves and deep sea
Ferromanganese
nodules; phosphorites
(organic debris from
upwelling)
Deep sea deposits;
continental shelves
ooze)
Hydrogenous
Chemicals including
biochemicals
Volcanogenic
Volcanic eruptions
Cosmogenic
Particles that fall from
space
Classification
Grain Size
Example
Clay
<0.004 mm
Talc, dusty powder
Silt
0.004 – 0.0625 mm
Heavy powder
Sand
0.0625 – 2 mm
Sugar crystals
Granule
2 – 4 mm
Aquarium gravel
Pebble
4 – 64 mm
Grape-sized
Cobble
64 – 256 mm
Orange-sized
Boulder
256 mm +++
Brick or larger
 Rivers
 Glaciers
 Waves
 Winds
 Dissolving pieces of living things (biogenous)
 Chemical reactions
 Most abundant sediment
 45% of all ocean sediment
 Found at continental margins, abyssal plains
and polar areas
 River deposition:
 Atlantic Ocean: Amazon River
 Pacific Ocean: very little river deposition
 Wind deposition:
 Dust blown across deserts
 Sahara Desert – Atlantic Ocean
 Gobi Desert – Pacific Ocean
What do you
see here?
What do you
see here?

Second most abundant

Most common throughout the
ocean

Found in deep ocean basins

Depends on biological
productivity and rate of
decomposition

Hard parts of organism
preserved


Calcareous
Siliceous
 Calcareous Ooze
 Formed from the shells of
pteropods, forminifera
and coccolithophores
 Siliceous Ooze
 Diatoms
 Low abundance
 1% of all ocean sediment
 Formed from dissolved solids precipitating out of seawater
 Most common: manganese nodules
 composed of layers of metals such as manganese, iron, nickel,
cobalt, and copper
 Least abundant Sediment
 Sources include interplanetary dust, meteorites,
asteroids, and comets
Displays the relationship between particle size and
energy for erosion, transportation and deposition.
Continental Shelf, Slope and Rise
 Controlled by tides, waves and currents
 Main type of sediment found: Terrigenous and Biogenous
 How is it getting to these areas?
 River Deposition (large particles)
 Currents Moving Sediment(sand and large particles)
 Waves Moving Sediment(silt and clay)
 How fast can it accumulate?
 Depends on area
 Ranges from 10 centimeters to 7 meters per year
 Important note about the Atlantic coast: much of the sediment is
trapped by estuaries and does not reach the ocean.
 Calcareous biogenic sediments dominate tropical shelves.
 River-supplied sands and muds dominate temperate shelves.
 Glacial till and ice-rafted sediments dominate polar shelves.
 Main type of sediment found: Terrigenous,
Biogenous, and Hydrogenous
 Sediments Found:
 Manganese Nodules (hydrogenous)
 Turbidites (terrigenous)
 Clays (terrigenous)

Cover 31% of deep ocean

Accumulation: 2 mm/ 1000 years
Oozes (biogenic)


Accumulation: 1-6cm/ 1000 year
Tools and Techniques:
1. Clam-Shell “Grab” Samplers
2. Piston Corers
3. Deep-Sea Drilling
4. Seismic Profiling
Grab samplers take a
“bite” out of the
sediment covering the
bottom.
Corers use a
weight to drive
a core barrel
into a soft
bottom.
Economics
 1/3 of oil and gas reserves are on the continental margins
 Sand and Gravel from ocean sources are a $480 million
industry
Medicines
 Microbes living in ocean sediment have been used to make
antibiotics
 In 2003, a group of bacteria was found within ocean
sediment that could be used to make a medicine to treat
cancer
Oceanography March 19, 2014
What are sediments? Where do they
come from?
Oceanography March 21, 2014
Sediment Classification
1.
Name two ways sediments can be classified.
2. What does “bio” mean? How does that relate to a
type of marine sediment?
Oceanography March 20, 2014
Sediment Types
1.
What role does weathering and erosion play on
the introduction of sediments to the ocean?
2. Speculate on why you think cosmogenic
sediments would be the least common.
Oceanography March 28, 2014
Sediment Sampling
1.
Why would scientists want to collect samples of
oceanic sediment?
2. What are two types of information that could be
determined from a sample of ocean sediment.
3. Name two ways sediment can be sampled.
Oceanography March 20, 2014
Biogenic Sediments
1.
What are the two types of biogenic sediment?
2. How do they form?
3. Hjulstrom’s Diagram
Oceanography March 20, 2014
Sedimentation Factors
What does a Hjulstrom’s Diagram explain?
Oceanography March 20, 2014
Continental Sedimentation
What factors control sedimentation at continental
margins?