Quiz 3 Coastal and Marine

Are sediments consistent offshore?

No, they can vary widely

What is the pH of the ocean?

8.3

What increases the pH of the ocean?

Biological activity

What are the most common 3 types of offshore sediments?

1. Biogenic carbonates (oozes)

2. Terrigenous silicious

3. Biogenic siliceous (oozes)

How do sediments vary?

1. Distance from land

2. Presence of marine organisms

3. Success of marine organisms vs erosion of material from land

4. Etc

What is calcium carbonate?

A mineral in marine sediments

What are the types of calcium carbonate?

• Aragonite

• Calcite

• Dolomite

Where is calcium carbonate found?

Typically offshore, not onshore

What is in calcium carbonate?

Mainly biogenic but can be clastic or precipitated

What is important about siliceous minerals in marine sediments?

There are many types, like clastic, clay, biogenic deposits, etc

Where do terrigenous soils and clays come from?

• Eroded from onshore

  • Gulf of Mexico = clays from Mississippi River

Where do biogenic sediments come from?

• High biological activity areas

  • Near equator

• Low erosion rate areas

  • NW Australia

  • Carolinas

  • Antarctica

What are biogenic carbonates made of?

Skeletal remains of marine organisms

What are the micro- and macroorganisms in biogenic carbonate?

• Micro:

  • Foraminifers

  • Coral

  • Coccoliths

  • Algaes

• Macro:

  • Mollusks (clam + oyster)

  • Pteropods and Copepods (krill)

What are the non-biogenic portions of biogenic carbonate?

• Ooids

  • Precipitated in the ocean in an area with wave action

  • Like a pearl

• Clastic carbonate stone

What are biogenic silica made of?

Skeletal remains of microorganisms, sponges, and plants

What are the micro- and macroorganisms in biogenic silica?

• Micro:

  • Diatoms

  • Radiolarran

• Macro:

  • Sponge spicula

What types of fecal matter can appear in marine sediments?

• Fecal pellets

  • Coast of West Africa

• Glauconite

  • Fossilized fecal pellets

  • Green sand

  • Massachusetts and Georgia

What are terrigenous siliceous soils?

Minerals with silicon (Si, SiO₂)

Where are terrigenous siliceous soils?

Formed on shore, deposited offshore

What are examples of terrigenous siliceous soils?

• High plasticity clay in Gulf of Mexico

• Underconsolidated clays in deltas and estuaries

• Beach sand

• Sand waves in North Sea + Buzzards Bay MA

• Dropstones (boulders) icebergs carry offshore

• Aeolian soils deposited by wind

• Micaceous soils (Taiwan)

What is cosmogenic sediment?

• Dust from space

  • Meteorites

• Accumulates in small quanities in Pacific dead zone

  • No like in area

  • No terrigenous materal

What is volcanic sediment?

• Accumulates from volcanoes

  • Very localized

  • Tonga, Pacific volcano buried internet cable, 5 wks to repair

What are textural sediment classification systems?

• HMS Challenger

• ODP/IODP System

• Clark and Walker

• USCS

What are penetrometer sediment classification systems?

• Cone penetrometer

What are the alternatives to mud, ooze, and sand?

Fine-grained sediment, biogenic sediment, coarse-grained sediment

Where are littoral deposits?

Between tide marks

Where are shallow water deposits?

Between low tide and 100 fathoms (183m)

Where are terrigenous sediments formed?

Transported material from land masses and shallow water

How is red mud made?

Oxidized clays

How is blue mud made?

High plasticity non-oxidized clays with sulfides

Where are pelagic deposits made?

Form offshore in deep water removed from land

What is in globigerina oozi?

Foraminifers shells/tests (carbonate)

Who uses the ODP/IODP system?

Geological oceanographers

What is the ODP/IODP system used for?

Sediments and stones

What is the format for IODP chassifications?

Discretionary modifiers (color and shape), major modifier (>25%), principal name, minor modifier (10-25%)