Types of Continental Shelf

Mostly researched in U.S. Closely related to land Geology.

(a) Irregular floor - not a true gentle slope

(b) Deep and Irregular bays or fjords

(c) Deep troughs & shoals out to sea (troughs 100 FA +) basins are muddy

(some sand grainy)

(d) Fishing Baness (Cool & Warm H2O == food/ nutrients)

Banquerean/Nova Scotsa/ 50 fathoms

Grand Bank/ Newfoundland 100 fathoms

Floor from Boston Mass (East)

Mass Bay - Stelluragian Bank - Sand Ridge - Geoges Banks - (Possible Breakers) -

gradual shelf to 60 fathoms than shelf duplins greater

(2) Shelf With Elongated Sand Bank & Depressions

Usually smooth and sandy and flat (Cape Cod) New Jersey Note: At points

irregular of gravel beds

Shifty of Nantucket Shoals (Ship graveyard) (North Sea North of the English

channel/ Themes Estuary)

(3) Shelves with strong current actions

Straits of Florida (Narrow nick of the Gulf Stream (1 mile from shore only) Palm


(a) Sand, gravel & worn shells

(b) Deep holes at Bay Mouth - golden entrance @ 64fathoms - Banrgo

Strait entrance to Tokyo Bay 230 fathoms. Poor Japanese defenses to

US subs during WWII

(4) Shelves Bordering Deltas

Mississippi River-Bird foot delta (23,36, & 50 Fathoms)

Indus Delta (50 fathoms)

Niger Delta - Bends Seaward

(a) Sediment is mostly muddy (high clay content if sand it is meca - more

easily transported

(b) Largest Rivers have mud than a sand border to seaward




South East Asia

Whang Ho

Sediment Size and Deposition Theory is Refuted

(5) Smooth Shelf- Sediment size diminishes seaward - thought to be the typical

type particles get finer and finer as you go further out to sea.

Arkansas Pass (Central Texas)



Shells - forams

Globigerina ooze

(6) Shelf with Salt Dome Shells:

Mississippi Delta - Gulf of Mexico

(1 mile diameter possible) trough or mountain surrounds - lime/coral on top

Dome stands above shelf

Economic Interest:

Texas and Louisiana Withdraw:

a. Sulfur

b. Salt

c. On periphery is oil

(Gravity potentials)

(Only other plan Dones and forest is on Persian Gulf)

(7) Shelves rimmed with Rocky Banks and Rocky Islands

a. Narrow shelf areas

b. Many caves

c. Great kelp

Tigreana River: from sand - boulders - cobbles - from sand - silt ~ coarse brown

sand (not usually gray)

(8) Shelf with Shallow Discontinuous Valley Systems

Shallow troughs - not deep

Sunda Shelf- (Brenda + Bonnes) (Jain /Indonesia)

Tidal appears to be reason but?

New York Harbor

Delaware & Chesapeake Bay

(9) Shelves Shoaled by Coral Reef

Australia Great Barrier Reef

(Not all coral are reef formers)