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Geology 115/History 150 Geology prep 3: Ocean processes due Tuesday, April 19 Websites accessed: Cape Cod NS: http://pubs.usgs.gov/gip/capecod/ and https://www.nps.gov/caco/learn/nature/geologicactivity.htm Point Reyes NS: https://www.nps.gov/pore/planyourvisit/maps.htm and nps.gov/pore/learn/nature/geologicactivity.htm Dry Tortugas NP: https://www.nps.gov/drto/learn/nature/geology.htm 1. What state is Cape Cod NS located in? Point Reyes NS? Dry Tortugas NP? What was the nationality of the first Europeans to land on those shores? 2. Ocean water movements come in the forms of currents, tides, and waves. Are these terms all synonyms? If not, what is the difference between them? 3. What is the name of the continental ice sheet (glacier) that is part of the Cape Cod NS geologic history? What did the ice sheet do that was crucial to the development of Cape Cod? Define the word “moraine” and its importance to the Cape Cod story. 4. Is there any bedrock (hard rock) to be found at Cape Cod NS? Then how did it get the “hook” shape that it has? At an appropriate point, define “longshore current”. 5. Is Cape Cod still evolving in shape? What will the “ultimate” Cape Cod shoreline look like? 6. At Point Reyes NS, the San Andreas Fault is the geological feature that defines (and created) Tomales Bay. What kind of fault is it, using the standard fault classification system? What two tectonic plates does this fault adjoin? Which compass direction does each plate move? What is the physical evidence for this motion? 7. Fort Jefferson on Garden Key of the Dry Tortugas NP was commissioned in 1846, and is made of 16,000,000 bricks. What geologic material is a brick made from? What geologic material is Garden Key and the other keys in the national park made from? What logistics problem for the US Army do you see, suggested by the previous two questions? Mike and Joyce Hendrix’s blog about Fort Jefferson provides details on the sources of the bricks. 8. Go to http://www.charts.noaa.gov/OnLineViewer/11438.shtml, which shows the map of the Dry Tortugas area around Garden Key; zoom in until you can see the tiny numbers that represent the depth in feet at different points in the ocean. Militarily, geographically and geologically, why was Garden Key was chosen as the site for Fort Jefferson? Hint: Between what two bodies of water are the Dry Tortugas located? Is the ocean in the area shallow or deep (most large ships in the 19th century required a depth of at least twenty feet)? Cannons in the mid-­‐19th century had a range of about three miles; how far away were the two main channels through these keys? 9. Summary: Most geologic textbooks classify a shore as an “active margin” or a “passive margin”; of the three examples in this assignment, which are which? What’s the difference?