Chapter 16 The Marine Environment

BEACHES SLOPING BAND OF LOOSE SEDIMENTS THAT IS MOVED AND DEPOSITED BY WAVES. –BEACH DIFFERENCES: HAWAII - BLACK BEACHES FROM VOLCANIC ROCKS FLORIDA - FINE GRAINED WHITE/PINK FROM CORALS LARGE RIVER MOUTHS - SMALL GRAINS OF QUARTZ AND FELDSPAR BEACHES SLOPING BAND OF LOOSE SEDIMENTS THAT IS MOVED AND DEPOSITED BY WAVES. –BEACH DIFFERENCES: HAWAII - BLACK BEACHES FROM VOLCANIC ROCKS FLORIDA - FINE GRAINED WHITE/PINK FROM CORALS LARGE RIVER MOUTHS - SMALL GRAINS OF QUARTZ AND FELDSPAR

Estuaries Area where the lower end of a fresh water river or stream meets the ocean Estuaries Area where the lower end of a fresh water river or stream meets the ocean

Longshore currents Waves usually approach the beach at an angle Water recedes parallel to the beach. Waves usually approach the beach at an angle Water recedes parallel to the beach.

Longshore currents This repetitive wave motion creates a flow of water in one direction along the shore. The waves do deflect depending on the shape of the coast. The larger the waves the stronger the current. Waves produce erosional and depositional landforms on beaches. This repetitive wave motion creates a flow of water in one direction along the shore. The waves do deflect depending on the shape of the coast. The larger the waves the stronger the current. Waves produce erosional and depositional landforms on beaches.

Groins will catch sand carried by the Longshore current. Which way is the Longshore current flowing in this picture?

Erosional landforms Water crashing on the beach as surf will erode material away - even solid rock. Headlands receive most of the wave force because of wave refraction. Water crashing on the beach as surf will erode material away - even solid rock. Headlands receive most of the wave force because of wave refraction.

Erosional landforms Sea stacks Wave cut platform Wave cut cliff Sea caves Sea stacks Wave cut platform Wave cut cliff Sea caves

Beaches Beaches can be mud, sand, pebbles, cobbles, gravel, or rocky. Color of the sand depends on material eroded. Beaches can be mud, sand, pebbles, cobbles, gravel, or rocky. Color of the sand depends on material eroded.

Beaches Hawaii has black sand beaches in some locations. The eroded material is dark volcanic rock. Hawaii has black sand beaches in some locations. The eroded material is dark volcanic rock.

Beaches Florida and the Bahamas white and pink sand beaches are bits of local coral and sea shells.

Estuaries Occur where a river meets the sea. Formed by rising sea level flooding a river valley. Water is brackish These areas provide an excellent environment for wildlife. (protection, quiet water, food) Occur where a river meets the sea. Formed by rising sea level flooding a river valley. Water is brackish These areas provide an excellent environment for wildlife. (protection, quiet water, food)

Depositional landforms Spit Which way is the current flowing? Spit Which way is the current flowing?

Depositional landforms Tombolo

Depositional landforms Baymouth bar

Depositional landforms Lagoon Bay Lagoon Bay

Depositional landforms Barrier Island

*** Coastal landforms Depositional Beach Spit, Baymouth bar Tombolo Bay or Lagoon Barrier Island Longshore bar Sand bar Depositional Beach Spit, Baymouth bar Tombolo Bay or Lagoon Barrier Island Longshore bar Sand bar Erosional Beach Sea stack Wave cut platform Wave cut cliff Sea cave Estuary Erosional Beach Sea stack Wave cut platform Wave cut cliff Sea cave Estuary

Rd Section 16.2 Open to figure on pg 422. Proceed with ppt Open to figure on pg 422. Proceed with ppt

Oceanic and Continental Crust Continental margins (Figure 16-12) –Continental shelf (avg. width 60 km) –Continental slope (10% drop off, edge of continent) –Continental rise (gentle slope of sediment) –Abyssal Plains (the smooth parts of the ocean floor 5-6 km below sea level) –Trenches ( the deepest part of the ocean basins) Continental margins (Figure 16-12) –Continental shelf (avg. width 60 km) –Continental slope (10% drop off, edge of continent) –Continental rise (gentle slope of sediment) –Abyssal Plains (the smooth parts of the ocean floor 5-6 km below sea level) –Trenches ( the deepest part of the ocean basins)

Ocean Basins Abyssal plains - large flat areas covered by (hundreds of meters thick) sediments Deep sea trenches (most on the edges of the Pacific Ocean). Trenches are 100 km wide and extend thousands of km. Abyssal plains - large flat areas covered by (hundreds of meters thick) sediments Deep sea trenches (most on the edges of the Pacific Ocean). Trenches are 100 km wide and extend thousands of km.

Ocean floor bumps Mid-ocean ridges –1500 m tall –Thousands of km wide –Many thousands of km long Rifts extend along the ocean ridges in many places Volcanic activity and earthquakes are common at the mid-ocean ridges Mid-ocean ridges –1500 m tall –Thousands of km wide –Many thousands of km long Rifts extend along the ocean ridges in many places Volcanic activity and earthquakes are common at the mid-ocean ridges