earth science Flashcards
(34 cards)
a geologic process in which tectonic plates—large slabs of Earth’s lithosphere—split apart from each other.
Seafloor Spreading
is a geologic process that occurs at the boundary between two plates where molten material within the earth pushes its way up, causing the plates to move away from each other.
Seafloor Spreading
A slow and steady movements of the Earth’s crust under the sea ridges
Seafloor Spreading
· Hot dense material below the Earth’s crust rises towards the mid-ocean ridge
· This materials lows sideways carrying the seafloor away from the ridge, and creates a crack in the crust
· The magma flows out of the crack, cools down and becomes the new seafloor
· Overtime, the new oceanic crust pushed oceanic crust far from the ridge and subducted
seafloor spreading theory
-is a seafloor mountain system formed by plate tectonics
Mid Ocean Ridge
examples of mid ocean ridge
e.g. Mid-Atlantic Ridge
East Pacific Rise
· He discovered seafloor spreading by using sonar.
· He first discovered seafloor spreading in early 1960s, During World War II
· He is an American geologist & US Navy officer in World War II
· He is considered as the “Founding Father” of unifying of plate tectonics
Harry Hammond Hess (1906-1969)
provides the approximate age of rocks. ________ uses the process of radioactive decay to determine the age of rocks. Using this process, radioactive elements decay at known rates to stable end products. If the percentage of stable product is known, then an approximate age can be determined. Therefore, what oceanographers did was they took samples of the seafloor and used radiometric dating to determine the age of rocks from seafloor spreading centers outwards. They discovered the age of the seafloor mirrored each other on either side of the seafloor spreading center.
Radiometric Dating (Age of Rocks)
was the first research vessel specifically designed in the late 1960s for the purpose of drilling into and taking core samples from the deep ocean floor
Glomar Challenger
occur along divergent plate boundaries, where new ocean floors are created as the Earth’s tectonic plates spread apart. As the plates separate, molten rock rises to the seafloor, producing enormous volcanic eruptions of basalt.
Mid-Ocean Ridge
This theory was proposed by Alfred
Wegener (1912) ; he laid out his
case in his book The Origin of
Continents and Oceans.
CONTINENTAL DRIFT THEORY
- He was a German meteorologist; he
studied weather. - He came up with radical theory that
suggested that the continents were
actually once connected and then
somehow ripped apart to where they
are today. - He proposed a theory that about 200
million years ago the continents
were once one large landmass.
(Wegener could not explain what
force was driving the motion of the
continents.); - His theory was not accepted by the
scientific community until 1965 when
the theory of plate tectonics was
published.
ALFRED WEGENER (1880-1930)
It’s a Greek term that means “Entire
Earth” or all Earth.
PANGAEA OR PANGEA
which ran from 541
million to 251.9 million years ago, was a
time of great change on Earth. The era
began with the breakup of one
supercontinent and the formation of another.
Plants became widespread. And the first
vertebrate animals colonized land
Paleozoic Era
(252-66 million years ago) means
‘middle life’ and this is the time of the
dinosaurs. This era includes the Triassic,
Jurassic, and Cretaceous Periods.
Mesozoic
third of the major eras of
Earth’s history, beginning about 66 million
years ago and extending to the present.
The Cenozoic Era
is an ancient
freshwater reptile that lived only in
- shallow freshwater only found in
Eastern coast of South America and
Western Coast of Africa
Mesosaurus
- means “All Water”
- A mega ocean that surrounded
Pangaea.
PANTHALASSA
- in the north
LAURASIA
in the south
GONDWANALAND
have unique distribution patterns in
some parts of the world.
Fossils
an English
geologist, proposed the presence of
convection cells in the Earth’s mantle. When
the rocks in the Earth’s interior are heated
by radioactivity, they become less dense,
and they rise toward the surface of the
Earth. When they cool down, they become
denser and sink. The continuous process of
rising and sinking of rocks produces
convection cells or convection currents.
These currents cause the tectonic plates,
which include the crust, to move and drift.
Sir Arthur Holmes
was a professor of geology
who determined how oceanic mountain
ranges, called mid-ocean ridges, are
fundamental to the tectonic movement that
results in the drift of continents.
-Harry Hess
- To establish the age of a rock or a fossil, researchers use some type of clock to determine the date it was formed.
- determining a chronology or calendar of events in the history of Earth, using to a large degree the evidence of organic evolution in the sedimentary rocks accumulated through geologic time in marine and continental environments.
- There are a variety of scientific methods that archaeologists use to analyze the age and origins of fossils, remains, or other artifacts.
Dating
