Source: United States Geological Service Studies in the New York Bight (http://woodshole.er.usgs.gov/project-pages/newyork/datacoverages.html)
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NAME: Per: DATE:
Fill in these blanks during the video "The Sea Floor" part of The Earth Revealed Series (Intelecom. 1992) from Annenberg/CPB. After the video, verify your answers with 2 other people.
1. Three conditions on the ocean floor that make it difficult to explore are: _____________________, ____________________ , _______________________ .
2. Carbon dioxide, chlorine, and sulfer dioxide are ______________ _____________ that dissolve easily in water.
3. Sodium and magnesium enter ocean water from _____________________.
4. The shallowest, most accessible parts of the ocean floor are the ________________ _______________ , which slope gently down from the shores of the continents.
5. At the end of the contnental shelf is a steep slope called the __________________ _______________ which is the geological edge of the continent.
6. At the base of this steep slope is the continental ___________ which is made up of the ________________ washed off the continent and the continental slope.
7. In the continental shelf and slope are deeply cut submarine ______________ through which sediments flow down to the deep ocean basins.
8. Beyond the continental rise is the abyssal ______________, probably the flatest region on Earth.
9. The pelagic sediments that descend to the bottom of the oceans far beyond the sediments from rivers is made up of the microscopic _____________ of organisms, ______________ that settled onto the surface of the oceans from the air, and sediments that were ________________ ____________ by currents.
10. Thousands of spires that stick up through the sediments of the deep sea bottom are the remnants of ________________. The entire
sea floor beneath the sediment is ________________ in origin.
11. Mid ocean ridges make up a mountain range 2 kilometers (1 mile) above the sea floor and ________________ of kilometers long that
has a central _________________ with active ______________ flows.
12. Ocean crust is formed at the __________ _________ __________ and is then pulled outward toward the continents.
13. The fact that the oldest ocean floor rocks are only 200 million years old indicates that the older ocean crust is reabsorbed beneath _________________ or other ocean __________.
14. Devices lowered from ships can get samples of ______________ and rocks from the ocean bottom, but to really understand the ocean floor, we need to _____________ the shape and distribution of undersea landforms.
15. Echo sounding devices map the ocean floor by emitting a _____________ _____________, then timing how long it takes it to _____________ off the ocean floor and return to the device.
16. The U.S. now claims as its territorial waters all the ocean within ____________ miles of its shores.
17. At the time the video was made, the territorial waters of the U.S. were being _______________ with a sonar device called GLORIA and with the Global Positioning System.
18. In addition to offshore oil and gas, valuable geological resources exist on the sea floor such as gold, copper, zinc and iron at the _______ _________ __________ __________, and manganese _______________ that also contain iron, cobalt, and calcium carbonate.
19 Mining of resources from the sea floor will be difficult because of the difficulties in reaching the ores, the expensive _________________ necessary, and serious _________________ concerns such as the destruction of unique habitats.
20. Many forms of _____________ exist on the sea floor that are found no where else, and some are the only ones that get their _____________ and ___________ entirely from the interior of the Earth.
21. The sea floor makes up over ______________ of the Earth's surface, and still remains mostly unexplored.