what percentage of earth's surface is covered by water ?
c. 71 %
which of the world's oceans is the largest and deepest ?
d. pacific ocean
which of these features is NOT found on the ocean floor?
what does sonar equipment measure?
b. the depth of the ocean floor
scientists use satellites to measure the
c. sea- surface height
which of the following areas is NOT one of the three main regions of the ocean floor?
c. continental rock
the continental margins of the pacific ocean are?
b. narrower than those of the atlantic and are not covered with thick layers of sediment
trenches form at sites where?
a. one plate descends beneath another
abyssal plains are very flat features that form when?
b. turbidity currents deposit sediments on the ocean floor
which of the following forms at mid-ocean ridges?
d. new ocean floor
the three types of ocean floor sediments are classifies according to their ?
terrigenous sediment consist primarily of mineral grains eroded from?
c. continental rocks
from which type of material does biogenous sediment form?
a. once-living organisms
hydrogenous sediment is made up of?
d. minerals that crystallize directly from ocean waters
what are two major energy sources obtained from the ocean floor?
d. oil and natural gas
which of the following areas does NOT contain major deposits of energy resources?
b. hudson bay
most oceanic gas hydrates form when?
a. bacteria break down organic matter in seafloor sediments
gas hydrates are compacted chemical structures made of natural gas and ?
which offshore resources are second only to petroleum in economic value ?
d. sand and gravel
manganes nodules are
b. lumps of manganese and other metals found on the ocean floor
eart is often calles the "blue planet" because _____ covers much of its surface
the world ocean can be divided into ___ main basins
the measurement of ocean depth and the mapping of the topography of the ocean floor is called _____
the ship HMS ______ made the first study of the global ocean in the 1870s
scientists can use ________ sonar to get a profile of a strip of ocean floor instead of simple sonar which maps only a point on the ocean floor every few seconds
a small underwater craft used for deep-sea research is a _____
the _____ is the gently sloping submerhed surface extending from the shoreline
the diagram shows a wide continental margin along the coast of the ______ ocean
the features at A are submarine ____
the continental margin slopes down to the _____ plain on the ocean floor
occasional movements of dense sediment-rich water down the continental slope are ______ currents
the steep continental slope merges into a more gradual incline known as continental ___
seamounts are submerged ________ on the ocean floor
the deepest known place on earth is the _______ in the pacific ocean's mariana trench
the mid-ocean ridge is an interconnected system of underwater _____
most of the ocean floor is covered by depositis of _____
the two types of biogenous sediments are _______ ooze and _____ ooze
calcareous and siliceous
when metals precipitate around grains of sand, a ______ nodule can form
calcium carbonate is a type of hydrogenous sediment that can be buried and harden into ____
enviormental concerns about offshore oil drilling include oil _____ which can pollute water
gas hydrates burn because they release ____ and other flammable gases as they evaporate
some off shore sand ad gravel deposits contain valuable materials such as precious metals and _____