earth science

Question 1

a geologic process in which tectonic plates—large slabs of Earth’s lithosphere—split apart from each other.

Answer 1

Seafloor Spreading

Question 2

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.

Answer 2

Seafloor Spreading

Question 3

A slow and steady movements of the Earth’s crust under the sea ridges

Answer 3

Seafloor Spreading

Question 4

· 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

Answer 4

seafloor spreading theory

Question 5

-is a seafloor mountain system formed by plate tectonics

Answer 5

Mid Ocean Ridge

Question 6

examples of mid ocean ridge

Answer 6

e.g. Mid-Atlantic Ridge

East Pacific Rise

Question 7

· 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

Answer 7

Harry Hammond Hess (1906-1969)

Question 8

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.

Answer 8

Radiometric Dating (Age of Rocks)

Question 9

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

Answer 9

Glomar Challenger

Question 10

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.

Answer 10

Mid-Ocean Ridge

Question 11

This theory was proposed by Alfred
Wegener (1912) ; he laid out his
case in his book The Origin of
Continents and Oceans.

Answer 11

CONTINENTAL DRIFT THEORY

Question 12

• 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.

Answer 12

ALFRED WEGENER (1880-1930)

Question 13

It’s a Greek term that means “Entire
Earth” or all Earth.

Answer 13

PANGAEA OR PANGEA

Question 14

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

Answer 14

Paleozoic Era

Question 15

(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.

Answer 15

Mesozoic

Question 16

third of the major eras of
Earth’s history, beginning about 66 million
years ago and extending to the present.

Answer 16

The Cenozoic Era

Question 17

is an ancient
freshwater reptile that lived only in
- shallow freshwater only found in
Eastern coast of South America and
Western Coast of Africa

Answer 17

Mesosaurus

Question 18

• means “All Water”
• A mega ocean that surrounded
  Pangaea.

Answer 18

PANTHALASSA

Question 19

• in the north

Answer 19

LAURASIA

Question 20

in the south

Answer 20

GONDWANALAND

Question 21

have unique distribution patterns in
some parts of the world.

Answer 21

Fossils

Question 22

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.

Answer 22

Sir Arthur Holmes

Question 23

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.

Answer 23

-Harry Hess

Question 24

• 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.

Answer 24

Dating

Question 25

2 methods to determine the age of Fossils

Answer 25

• Relative Dating
• Absolute Dating

Question 26

methods estimate whether an object is younger or older than other things found at the site. Relative dating does not offer specific dates, it simply allows to determine if one artifact, fossil, or stratigraphic layer is older than another.

Answer 26

Relative dating

Question 27

Assuming that soil layers in a deposit accumulate on top of one another, and that the bottom layers will be older than the top layers, stratigraphy allows archaeologists to construct a relative chronological sequence from the oldest (bottom) to youngest (top) layers. Artifacts found in these layers are at least as old as the deposit in which they were found.

Answer 27

1. Stratigraphy

Question 28

A technique that was common in the mid-20th century, seriation looks at changes in certain styles of artifacts present at a site. A chronology is developed based on the assumption that one cultural style (or typology) will slowly replace an earlier style over time.

Answer 28

2. Seriation

Question 29

A technique that analyzes how much of the chemical fluorine has been absorbed by bones from the surrounding soils in order to determine how long the specimen has been underground.

Answer 29

3. Fluorine Dating

Question 30

methods provide more specific origin dates and time ranges, such as an age range in years. How specific these dates can be will depend on what method is used.

Answer 30

Absolute dating

Question 31

A technique that determines age of various minerals and glasses based on the trails of damage done by the spontaneous fission of uranium-238, the most abundant isotope of uranium.

Answer 31

1. Fission-track dating

Question 32

Measuring the ratio of argon gas in igneous volcanic rock to estimate how much time has elapsed since the rock cooled and solidified.

Answer 32

2. Potassium-argon dating

Question 33

Magnetic particles in most materials of geological origin, such as rocks and clay, are analyzed to track shifts in the earth’s magnetic fields over time.

Answer 33

3. Archaeomagnetic dating

Question 34

Also known as Radiocarbon dating. Used to date organic substances. Scientists measure the radiocarbon in the fossil to determine its age. Can only date specimens up to about 60,000 years old.

Answer 34

4. Carbon-14 dating (radiocarbon)