Unit 8 – Coasts & Sea-level Changes (Cape Cod & Acadia) Coasting Down the Coast

Unit 8 – Coasts & Sea-level Changes (Cape Cod & Acadia)

http://www.nasa.gov/centers/goddard/news/topstory/2003/0901natlpark.html

Coasting Down the Coast.Including a bit on sea-level change, some disasters, and some coastal processes, in some beautiful places. All pictures by R. Alley or taken from government Web sites as indicated.

The image of Cape Cod National Seashore and surroundings is from Landsat 7.


Raised delta, Milne Land, east Greenland. About 12,000 years ago, a stream flowing to the left from beneath a glacier built the sandy fingers of this delta out into the sea. Then, the ice melted, allowing the land to rise, so the delta is now about 300 feet above sea level (sea is barely visible to the far left).


Two views of the Westport Jetty, Washington. Longshore drift from the right has built up sand to the right but caused erosion to the left of the barrier. Also notice in the left picture that waves are slowed by the shallower waters near the jetty.

http://apps.ecy.wa.gov/shorephotos/scripts/bigphoto.asp?id=GRA0397 and GRA0398. Washington State Department of Ecology Shore photos--the state photographed their coasts, and makes those pictures available to the public--what a great idea!


Before-and-after photos of the aftermath of Hurricane Katrina, near Biloxi, Mississippi. The antebellum house (upper right) and pier house indicated by the red arrows were destroyed.

http://coastal.er.usgs.gov/hurricanes/katrina/photo-comparisons/mainmississippi.html


http://coastal.er.usgs.gov/hurricanes/katrina/photo-comparisons/chandeleur.html

Before-and-after photos of the impacts of Hurricane Katrina on the Chandeleur Islands, about 100 miles east of New Orleans. The sites marked by the yellow arrows can be identified in both photos.


The house indicated by the left yellow arrow largely collapsed, that shown by the right yellow arrow lost its deck, and most of the other houses and much of the road were destroyed.

http://coastal.er.usgs.gov/hurricanes/mappingchange/images/photos/onslow-fran.jpg

Before-and-after photos of the impacts of Hurricane Fran (1996) on Topsail Island, North Carolina.


Evidence of longshore drift of sediment, Scoresby Sund, Greenland. The small stream valley flowing from the top (blue arrow) has been dammed by sediment transported along the coast (between the red arrows).


Sediment supplied from the stream (blue arrow) formed the delta. Waves have reworked the edge of the delta into the sandy beach (yellow arrows). Much of the area on the delta side of the beach is underwater at high tide, so this is a barrier beach. A helicopter skid is visible in the lowermost left corner.


Barrier beach, Mudder Bugt, Milne Land, east Greenland. Sand supplied from the right by the braided river has been reworked into the beaches shown. Storms have breached the beach on the right, washing sand into the lagoon behind and forming secondary beaches (yellow arrows).


Mudder Bugt, Milne Land, east Greenland. The upper picture is a slightly turned close-up of the top part of the lower picture.

Sand from the braided stream (lower right) is reworked by waves into the barrier beaches and spits seen, but the beaches are pierced by inlets.


Satellite image of the Outer Banks of North Carolina, from USGS and NASA. Streams flowing from the left (two are indicated by blue arrows) have been flooded by sea-level rise in their lower reaches. Sand from the streams has been built into barrier islands (two shown by yellow arrows). Although the area covered by this picture is much bigger, the features are clearly almost identical to those shown in the previous pictures.


Closeup of part of Cape Cod. The great barrier beach on the right is pierced by the inlet to the Nauset marsh (red arrow). http://www.nasa.gov/centers/goddard/images/content/94199main_capecod990918.tif

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Unit 8 – Coasts & Sea-level Changes (Cape Cod & Acadia) Coasting Down the Coast