Topics: Erosion by Mass Movements, Wind, and Waves.

Mass Movements

Gravity --

Talus Formations Talus – -.

Frost Wedging and Talus Cones

Mass Movement - Ex) -

Mass Movements Landslide Mudslide

Mass Movements Creep Avalanche

Creep Creep – --

Wind Erosion

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Iraq, 2005

Wind Formed Features

Dune Formation --

Types of Dunes Barchan Linear Transverse Parabolic

Types of Dunes Barchan Linear Transverse Parabolic

Other Eolian (Wind) Features Arches Ventifacts Ancient artifacts altered sandblasting

Other Eolian (Wind) Features Sandblasting – -- Arches Altered Ancient Artifacts Ventifacts

Ventifacts – -

Wave Erosion

Wave Erosion --. Recent Photo 2001 Montauk Lighthouse on top of Turtle Hill, 297 feet from the tip of Montauk Point (1800) Recent Photo 2001

Ocean Waves – --

Sea arch – a feature of coastal erosion Formed on Big Island of Hawaii

Top View of the Beach Long Shore Current Ocean Beach Where is my towel? Beach

Sand

Long Shore Current -- The current moves sediments which results in a change in the beach face.

L.I. Natural Beach Features Sand Bar Spit Lagoon Barrier Island Diagram showing the environments of a barrier island system. (from Blatt, et al, 1980, Petrology of Sedimentary Rocks)

Fire Island, Barrier Beach Davis Park Democrat Point

L.I. People made Beach Structures Jetty – Groin – *BIG impact on the beach erosion rates.

Jetties

Jetty

Groin Long Shore Current Direction Beach

                          Groin

What is a Tombolo? Extends outward from the shore, connecting with an island. Goat Rock Beach, CA, the low, sandy bar is reinforced with boulders and serves as a parking lot

What direction is the longshore current moving?

What direction is the longshore current moving?

Final Question What do you predict will happen to the houses below? --------