Ch 20 Part 2

What is the source of most coastal sediment?

Stream outflow

The most widespread marine depositional feature is the

beach

The backshore

the upper part of the beach, landward of the high-water line. It is usually dry, being covered by waves during severe storms only. It contains one or more berms, which are flattish, wave-deposited sediment platforms.

The foreshore

The zone that is regularly covered and uncovered by the rise and fall of tides

The nearshore

extends seaward from the low-tide mark to where the low-tide breakers begin to form.

The offshore zone

is permanently underwater and deep enough that wave action rarely influences the bottom.

Spit

linear deposit attached to the land at one end and extending into open water in a down-current direction

If the spit becomes extended clear across the mouth of a bay and connects with land on the other side, it becomes a

baymouth bar,

Tombolo

a depositional feature that connects a near-shore island with the mainland

barrier island:

a long, narrow island built up in shallow offshore waters.

Barrier islands are always oriented approximately

parallel to the shore

An extensive barrier island isolates the water between itself and the mainland, forming a body of quiet saltwater or brackish water (a mixture of saltwater and freshwater) called a

lagoon

A coast along which numerous estuaries project is called a

ria shoreline.

Cape Cod in Massachusetts

is formed mostly of glacial moraines left by Pleistocene ice sheets.

Fjords

A glacial trough that has been partially drowned by the sea

A marine terrace develops when

wave-cut platform is tectonically uplifted above sea level.

Atoll

a coral reef that encloses a lagoon

Barrier reef

parrallels the coastline