Introduction to Geology

Introduction to Geology

Quiz 14 Ocean Basins
1. Approximately how old is the oldest oceanic crust on the Earth today?
a. 6000 years
b. 200 thousand years
c. 2 million years
d. about 200 million years
e. 2 billion years

Questions 2 to 6 refer to the image below that shows a map of the coastline and the seafloor in a region including Monterey Bay (between the coastal cities of Monterey and Santa Cruz) and Monterey Canyon (shown as MC). On the image, the arrow for letter E points to the coastline along Monterey Bay.

Map of bathymetry of Monterey Bay region

2. On the seafloor, Letter A is located on:
a. the continental rise.
b. the continental shelf.
c. the continental slope.
d. an abyssal plane.

3. On the seafloor, Letter B is located on:
a. the continental rise.
b. the continental shelf.
c. the continental slope.
d. an abyssal plane.

4. On the seafloor, Letter C is located on:
a. the continental rise.
b. the continental shelf.
c. the continental slope.
d. an abyssal plane.

5. An an extensive flat section of the seafloor, Letter D is located on:
a. the continental rise.
b. the continental shelf.
c. the continental slope.
d. an abyssal plane.

6. The shelf break is located:
a. between letters A and B.
b. between letters B and C.
c. between letters C and D.
d. at letter E

7. Monterey Canyon (shown as letters MC on the map above) is about twice the size of the Grand Canyon in Arizona. Submarine landslides and turbidity currents move sediments down submarine canyons to be deposited mostly on:
a. the continental rise.
b. the continental shelf.
c. the continental slope.
d. an abyssal plane.

8. Trenches are:
a. long, relatively narrow canyon-like features that run parallel to continental margins.
b. the deepest parts of ocean basins.
c. usually occur in the ocean along volcanic island chains.
d. all of the above.

9. An ancient submarine volcano that has a flat top (beveled by wave action before sinking into ocean depths) and may lack fringing reefs is called:
a. an atoll.
b. a seamount.
c. a guyot.
d. a mid-ocean ridge.

10. The shallowest and youngest parts of deep ocean basins are:
a. mid-ocean ridges.
b. abyssal plains.
c. guyots.
d. trenches.

11. As new ocean crust forms along mid-ocean ridges, what happens to the older ocean crust?
a. older crust moves away from spreading centers.
b. the older ocean crust cools and sinks deeper into the ocean basins.
c. the ocean crust is gradually blanketed with layers of ocean sediments.
d. all of the above.

12. Black smokers and white smokers are features are:
a. hydrothermal vents associated with volcanic activity on the seafloor.
b. most common along the rift zones associated with mid-ocean ridges.
c. host to biological communities that are supported by chemotrophophic bacteria.
d. all of the above.

13. Pillow basalts occur where:
a. sediments accumulate in beds on the seafloor.
b. lava erupts and cools quickly on the seafloor on submarine volcanoes along mid-ocean ridges.
c. lava erupts on a volcano on a volcanic island arc chain.
d. fringing reefs form around an ancient volcano.

14. Where are the thinnest accumulations of sediments generally found in deep ocean basins?
a. along the mid-oceanic ridges.
b. in deep-sea trenches.
c. on abyssal plains.
d. along a continental rise.

15. Serpentinite is the State Rock of California. It occurs in abundance throughout the coast ranges of Northern California. Serpentinite is a rock formed from:
a. the accumulation of the remains of ancient sea snakes.
b. a rock formed by the metamorphic alteration of ocean crustal rocks (basalt and gabbro) by exposure to seawater seeping into the ocean crust over time.
c. a rock formed from the accumulation of undersea landslide deposits.
d. all of the above.

16. As old ocean crust is destroyed in subduction zones, new continental crust forms as a result of:
a. water and gases released by increasing heat and pressure helps to melt some of the old ocean crust.
b. low-temperature felsic minerals melt first and migrate upward, forming volcanoes and new continental crust.
c. high-temperature mafic minerals are denser than felsic minerals, and are consentrated in the old ocean crust that sinks back into the mantle.
d. all of the above.

17. When gypsum (rock) looses its water content, it becomes a dry (water free) variety of rock called.
a. anhydrite.
b. rock salt.
c. limestone.
d. quartz sand.

18. Manganese nodules found on abyssal plains in deep sea regions are considered to be:
a. hydrogenous sediments.
b. terrigenous sediments.
c. biogenous sediments.
d. cosmogenous sediment.

19. Which is a lithogenous sediment?
a. calcareous oozes
b. siliceous oozes
c. coral reef deposits
d. quartz-rich beach sand deposits

20. A turbidite is a kind of rock formed from:
a. sediments deposited by an underwater landslide on a deep-sea fan.
b. sediment deposited around a shallow water coral reef.
c. sediment deposited along a beach near a river delta.
d. sediment that accumulates from the underwater rain of pelagic biogenous sediments (mostly dead plankton remains).

21. Which is a biogenous sediment?
a. river sand
b. quartz-rich beach sand
c. lime sediments
d. wind-blown dust

22. If you find a rock full of fossils of organisms that were part of an ancient coral reef, you know that the rock must have formed in:
a. cold, deep water.
b. turbid waters, such as near a river delta.
c. cool, clear, shallow polar water.
d. warm, clear, shallow tropical water.

23. Which type of siliceous seafloor sediment consists of the shells and skeletal of small (microscopic) organisms?
a. coquina
b. ooze
c. shelf mud
d. reef sediments
e. chert

24. Coccolithopores are single-cell plants that grow in the warmer upper layers of the ocean. Their remain accumulate on the seabed forming:
a. siliceous ooze.
b. calcareous ooze.
c. turbidites.
d. mudstone.

25. Diatoms are the most abundant form of plankton in the world oceans. Their remains accumulate on the seabed forming:
a. siliceous ooze.
b. calcareous ooze.
c. turbidites.
d. limestone.

26. A siliceous sedimentary rock that forms from the accumulation of the remains diatoms and radiolarian on the seafloor is called:
a. chalk.
b. chert.
c. graywacke.
d. quartz sandstone.

27. Where are the thickest accumulations of sediments mostly found around the world?
a. the outer margins of continental shelves.
b. on continents.
c. on ocean ridges.
d. on abyssal plains.

Clues where to find answers.

http://gotbooks.miracosta.edu/geology/quiz/quiz14.html
12/12/2017