Sediments of the Shelf

Most common is sand

2mm to 1/16mm

(a) Terregenous sand: caused by minerals on land particles carried to the

sea by streams ect.

Cape - quarky sand (most common)




(b) Calcarenite Sand: made up of shelf fragments - forms corals (CaCOa)

(c) Anthegenic Sand precipitation from sea H2O

Oolites (CaC03)

Glauconites (green)

Phosphate (brown)

Can usually see sand grains individually

Sand usually contains all three types. Sand is named from highest %(percent) present.

(2) Most common type of deposition sediment on the self is mud (or lutite)

Diameter of grain is less than 1/16

(a) Silt (1/16) mm to (1/256) mm

(b) Clay (less than 1/256 mm)

Difficult to see by eye the grains

Diagnostic Fracture

Dry species

If holds together = mud

If separates = sand

(3) Most Common type of sediment is gravel than (4 mm) long

(a) Gravel = less than 4 mm

(b) Pebble = 4-64 mm long

(4) Volcanic Fragments

(a) Bombs (larger deposit)

(b) Ash - (dust)

(c) Pumice poris SID2 (glass)

(5) Sea Weeds

(6) Mollusks

(7) Sponges

(8) Hard Rock bottom