Join Dr. Alley and his team as they take you on "virtual tours" of National Parks and other locations that illustrate some of the key ideas and concepts being covered in Unit 8.
Click on the first thumbnail below to begin the slideshow. To proceed to the next image, move the mouse over the picture until the "next" and "previous" buttons appear ON the image or simply use the arrow keys. Virtual Field Trip #1: Cape Cod National Seashore
Sept. 18, 1999 Landsat image of Cape Cod. The Outer Beach (magenta arrow) along the right-hand side of the Cape is eroding back at a few feet per year. Some of the sand is building out to the south and north (yellow arrows), but some of the sand is being lost to deeper water, so the Cape is shrinking.
http://www.nasa.gov/centers/goddard/news/topstory/2003/0901natlpark.html. All other pictures in this slide show, by R. Alley, C. Alley, J. Alley or K. Alley.
One good tern… deserves another.
The great Nauset Marsh, viewed from the back porch of the Salt Pond Visitor Center, Cape Cod National Seashore.
Bumblebee visiting pickerelweed, which grows in the shallows at the edge of Great Pond, Eastham, Cape Cod. By building a lake-studded outwash plain into the ocean, the glaciers left a rich mix of aquatic habitats.
Gulls, such as these herring gulls, are widespread and successful generalists, equally at home along fresh and salt waters, as well as cleaning up messes left by humans.
Yellowlegs are well-named, and common in Nauset Marsh.
Great blue herons, Nauset Marsh. A fish that doesn’t watch out may realize too late that he blue it.
Salt marshes are highly productive, and support a diversity of life… including sandpipers (top) and yellowlegs (bottom). Nauset Marsh, Cape Cod.
Cormorants were not present on the Cape a few decades ago, but now are commonly seen fishing or drying their wings.
Large number of people on the beach at Coast Guard Beach, Cape Cod
Waves and tidal currents move immense amounts of sand, leaving beautiful ripples, as shown in these closeups from First Encounter Beach.
Cape Cod’s beaches may be backed by rapidly eroding bluffs, by sand dunes covered with a thin layer of hardy vegetation that can be damaged easily by human activities (as shown here), or by salt marshes.
Nauset Light. The light was moved in 1996, just before the rapid erosion of the bluffs along this part of the coastline dropped this historical building into the waves. Everyone with a long memory of the Cape has stories of things that have been lost to the encroaching sea.
Great Rock, the Cape’s largest glacial erratic (big rock carried by the glacier) attests to the ability of ice to move pieces of many different sizes. The rock extends below the picture, and then about as far into the ground as above.
Herring gulls at sunset, First Encounter Beach, Cape Cod.
Sunset, Rock Harbor, Cape Cod. It isn’t very geological, but it’s pretty.
Virtual Field Trip #2: Acadia National Park
http://www.nasa.gov/centers/goddard/earthandsun/nps_data.html Credit: NASA GSFC & Y.Q. Wang at the Laboratory for Terrestrial Remote Sensing, Univ. Rhode Island Acadia and surroundings. The yellow arrow points toward the fjord of Somes Sound in Mount Desert Island. The dotted line marks an area of interest for NASA and the National Park Service, and regions beyond have been blacked out. All pictures except this by C. or R. Alley.
The old metamorphic rocks (shown here) and granites of Acadia make dramatic cliffs. Floats for a few lobster pots are visible in the water.
This beach at Acadia is one of the few in the area. Most of the sand is calcium carbonate--ground-up shell--because the Gulf of Maine is so amazingly productive of shells to be ground up by waves. The beach is far at the end of an inlet; the rest of the coast is dominated by bare rock.
The Rockefeller-constructed carriage roads and their graceful bridges are well-loved at Acadia, which offers wonderful opportunities for bicycling. Dr. Alley and daughters Janet (left) and Karen for scale.
View of the Maine coast from Cadillac Mountain, Acadia.
Bass Harbor Head Lighthouse (left) and Portland Head Lighthouse (right), Acadia National Park and vicinity.
Loons in rain, Seal Cove Pond, Acadia. The deep, glacially carved lakes of the island are outstanding for kayaking and canoeing.
Jordan Pond and the Bubble Mountains. The rounded granite summits and U-shaped valleys are clear evidence of past ice.
Even a rainy day can be enjoyable on the shore, as here at Ship Harbor. Notice the “beach” is composed of cobble-sized rocks.
The no-beach granite coast of Acadia National Park in the fog.
This herring gull is perched on the granite coast of Acadia.
Ice flow as indicated by the red arrow smoothed this island, and plucked rocks off the lee or downglacier side to the right.
Virtual Field Trip #3: Coasting Down the Coast.
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 websites 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).
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 these pictures available to the public--what a great idea! 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.
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.