Sediments and the Sea FloorSediments and the Sea Floor

TerrigenousTerrigenous

BiogenousBiogenous

Hydrogenous Hydrogenous

CosmogenousCosmogenous

Volcanogenous Volcanogenous

Sediments and the Sea FloorSediments and the Sea Floor

Terrigenous (Land Based)Terrigenous (Land Based)

- From the earth’s lithosphere is sometimes - From the earth’s lithosphere is sometimes

called called Lithogenous Lithogenous

- Mud and Clay deposits that include red - Mud and Clay deposits that include red

clays clays

- These sediments carpet the bottom of the - These sediments carpet the bottom of the

ocean near almost all the continents in ocean near almost all the continents in

the area called the continental shelf the area called the continental shelf

Terrigenous SedimentTerrigenous Sediment

Erosion and Runoff from Landmasses

Dust storms and winds can bring dust plumes across and into the oceans (off Africa)

This glacier is approximately 88% below the surface! Glaciers cause the scrapping of materials from land

Benthic ExplorationBenthic Exploration History is recorded in ocean bottom History is recorded in ocean bottom

sedimentssediments as they build up layer by layer. as they build up layer by layer. Ash from volcanic eruptions sinks and forms Ash from volcanic eruptions sinks and forms a layer, the shells of the organisms living a layer, the shells of the organisms living there sink and form their layers. there sink and form their layers.

Taking core samples from the bottom can Taking core samples from the bottom can give an indication of the conditions on the give an indication of the conditions on the seafloor at that timeseafloor at that time

Biogenous Sediments Biogenous Sediments

Must contain 30% or greater Organic Must contain 30% or greater Organic materialmaterial

Include the Oozes including Include the Oozes including

CALCAREOUS – shells made of CALCAREOUS – shells made of calcium calcium carbonate carbonate

SILICEOUS – shells made of silicon SILICEOUS – shells made of silicon

dioxide (also includes the dioxide (also includes the

diatoms frustules) diatoms frustules)

Biogenous Sediments Biogenous Sediments Biogenic Oozes are composed of shells which are calcium carbonate based in many organisms . Each box is numbered with different organisms

Biogenous SedimentsBiogenous Sediments

RadiolariansRadiolarians

Are considered protozoans with a siliceousAre considered protozoans with a siliceous

outer shell outer shell They have been in existence for over 540 They have been in existence for over 540

million years million years Each can form its own outer shell of crystal Each can form its own outer shell of crystal

silica silica

Biogenous SedimentBiogenous Sediment

Diatoms Diatoms

Composed of Silica frustulesComposed of Silica frustules Can be Centric or PennateCan be Centric or Pennate Have unique patternsHave unique patterns Deposits can be over 100 Deposits can be over 100

meters thickmeters thick Considered a PhytoplanktonConsidered a Phytoplankton

Biogenous SedimentBiogenous Sediment

ForaminiferansForaminiferans

Considered a Calcareous Considered a Calcareous ProtozoanProtozoan

Shell called a “test” with ciliated Shell called a “test” with ciliated extensions and composed of extensions and composed of calcitecalcite

They can live in the top 100 They can live in the top 100 meters of the ocean meters of the ocean

Biogenous SedimentBiogenous Sediment

CoccolithophoresCoccolithophores

Considered a calcareous Considered a calcareous phytoplanktonphytoplankton

Sometimes have 30 calcite Sometimes have 30 calcite platesplates

They were almost wiped out They were almost wiped out 100 million years ago100 million years ago

Mostly in the sub-polar Mostly in the sub-polar regionregion

Biogenous SedimentBiogenous Sediment

PteropodsPteropods

Multi-celled calcareous Multi-celled calcareous animals called the sea animals called the sea butterflybutterfly

Are Molluscs and form Are Molluscs and form mucus feeding webs to mucus feeding webs to snag phytoplanktonsnag phytoplankton

Prefer warmer waters Prefer warmer waters

Biogenous Sediments Biogenous Sediments

These are Siliceous deposits from diatoms that formed siliceous oozes. Diatomaceous earth is an excellent abrasive and filtering agent

Hydrogenous (Authigenous)Hydrogenous (Authigenous)

Formed by the precipitation of chemicals in sea Formed by the precipitation of chemicals in sea water (sometimes with bacteria)water (sometimes with bacteria)

Manganese NodulesManganese Nodules (studied next) (studied next)

PhosphoritesPhosphorites (in areas high in organic matter (in areas high in organic matter forming from decomposition of shells and bones) forming from decomposition of shells and bones)

GlauconiteGlauconite (rich in iron in shallow water maybe up (rich in iron in shallow water maybe up

to 500 meters) to 500 meters)

Hydrogenous SedimentsHydrogenous Sediments

The Oceans formed these deposits which are called Manganese Nodules. Besides Manganese, there are large concentrations of Cobalt, Copper, Iron and Nickel making them valuable. Notice a fossilized shark’s tooth that was found in a manganese nodule.

The rings could tell the age

Cosmogenous SedimentsCosmogenous Sediments

They are from outside earth They are from outside earth including including

Space dustSpace dust Asteroids and CometsAsteroids and Comets

Asteroids and Comets can form Asteroids and Comets can form particles called particles called TEKTITES TEKTITES with with high Iridium concentrations high Iridium concentrations

Volcanogenous SedimentVolcanogenous Sediment

Formed by volcanoes which can produceFormed by volcanoes which can produce LavaLava TephraTephra GasGas

Tephra are ash particles that can be in many Tephra are ash particles that can be in many forms and carry over long distances in the forms and carry over long distances in the atmosphere atmosphere

•Determining Past Climate ChangeDetermining Past Climate Change

Scientists have employed many methods to Scientists have employed many methods to piece together the past climatic recordpiece together the past climatic record

-One such method is to look at sediments on -One such method is to look at sediments on the ocean floorthe ocean floor

--Research vesselsResearch vessels produce sediment profiles produce sediment profiles from the bottom of the oceanfrom the bottom of the ocean

-The sediment contains calcium carbonate -The sediment contains calcium carbonate shells from organisms that have lived near the shells from organisms that have lived near the earth's surface in the pastearth's surface in the past

-The type of calcium carbonate shell can tell you -The type of calcium carbonate shell can tell you something about temperature since some live something about temperature since some live only within narrow temperature ranges.only within narrow temperature ranges.

Beach Dynamics Beach Dynamics