Study the place of sedimentary rock in the rock cycle and how geologists classify such geologic formations
Sedimentary rock is created by the bonding of sediment from broken down minerals.
Encyclopædia Britannica, Inc.
-
Contunico © ZDF Studios GmbH, MainzLearn about researching Magellanic penguins (Spheniscus magellanicus) on Magdalena Island in the Strait of Magellan, off the coast of Chile.
-
© MinuteEarth (A Britannica Publishing Partner)The role of the Rocky Mountain locust (Melanoplus spretus) in the Grasshopper Plague of 1874–75 (which is also known as the Great North American Locust Plague), and the insect's mysterious disappearance that followed.
-
Encyclopædia Britannica, Inc.Love can be a dangerous game.
-
© MinuteEarth (A Britannica Publishing Partner)The formation of sand from quartz, which originates from igneous processes, and the role that weathering plays in making individual sand grains more transportable by water currents.
-
Encyclopædia Britannica, Inc.Offshore oil platform and oil pumps in southern Chile.
-
Encyclopædia Britannica, Inc.The Earth's surface and crust are constantly evolving through a process called the rock cycle.
-
© MinuteEarth (A Britannica Publishing Partner)During a liquefaction event, such as that which could be produced by an earthquake, soil particles, in combination with the water located in the pore spaces between them, tend to behave like quicksand.
Transcript
[Music in]
NARRATOR: Deposition of sediment is another key phase in the rock cycle. Sediment may be carried hundreds of kilometers by rivers eventually to be deposited in oceans. Over millions of years, layers of sediment undergo a transformation. They become sedimentary rock in another step of the rock cycle. Geologists classify sedimentary rocks according to the materials of which they are made [music out]. Sandstone, for example, is a clastic rock--that is, formed from preexisting rock and mineral particles. Some sandstones are soft and easily eroded. Another common type of sedimentary rock is limestone. It is a chemical sedimentary rock formed of limey materials that have precipitated out of water and later hardened into rock. Like other sedimentary rocks limestone builds up in layers, or strata. In some areas, such as the Glass Mountains of Texas, we find biochemical sedimentary rock, containing the remains of marine organisms. This limestone consists of fossils of ancient plants and animals. As these creatures died, they accumulated on the ocean floor, eventually to be cemented together and hardened into limestone.
NARRATOR: Deposition of sediment is another key phase in the rock cycle. Sediment may be carried hundreds of kilometers by rivers eventually to be deposited in oceans. Over millions of years, layers of sediment undergo a transformation. They become sedimentary rock in another step of the rock cycle. Geologists classify sedimentary rocks according to the materials of which they are made [music out]. Sandstone, for example, is a clastic rock--that is, formed from preexisting rock and mineral particles. Some sandstones are soft and easily eroded. Another common type of sedimentary rock is limestone. It is a chemical sedimentary rock formed of limey materials that have precipitated out of water and later hardened into rock. Like other sedimentary rocks limestone builds up in layers, or strata. In some areas, such as the Glass Mountains of Texas, we find biochemical sedimentary rock, containing the remains of marine organisms. This limestone consists of fossils of ancient plants and animals. As these creatures died, they accumulated on the ocean floor, eventually to be cemented together and hardened into limestone.