Question 1

Describe the logic behind using iridium concentrations to determine rates of sedimentation.Under what conditions do the assumptions in this method break down? How is iridium concentration linked to the mass extinction at the K-T boundary?

Accepted Answer

The answer of Describe the logic behind using iridium concentrations...

Question 2

Shoemaker-Levy 9 was an unusual comet in that it

Accepted Answer

A)  exploded 3000 km above Jupiter's surface. 
B)  created rings around Jupiter. 
C)  was 340 times the height of Mt. Everest. 
D)  consisted of 21 fragments. 
E)  almost impacted Earth.

Question 3

What is an ejecta blanket?

Accepted Answer

The answer of What is an ejecta blanket?...

Question 4

What are three other natural hazards that might be linked to an impact event?

Accepted Answer

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Question 5

The Sudbury Impact Basin is famous for nickel-copper-platinum deposits.How is this related to the impact event?

Accepted Answer

A)  These minerals deposits form when hot fluids move upwards along faults. 
B)  These minerals formed in the depressions at the base of the magma pool. 
C)  These minerals were deposited directly by the asteroid. 
D)  These materials were organized by gravity as impact breccia. 
E)  The impact event created a depression and the mineral deposits formed subaqueously.

Question 6

Scientific acceptance of the idea that asteroids could strike Earth and wreak havoc is relatively recent.What event made this possibility become nearly universally accepted?

Accepted Answer

A)  discovery of the iridium layer at the K-T boundary 
B)  discovery of the Chicxulub Crater 
C)  observation of comet Shoemaker-Levy 9's collision with Jupiter 
D)  discovery of Near-Earth-Objects that have Earth-crossing orbits 
E)  recognition of ancient eroded craters in Canada

Question 7

The Tunguska event in Siberia in 1908 produced a crater about 1 km in diameter.

Accepted Answer

A) True 
 B)False

Question 8

What triggered the formation of the sun?

Accepted Answer

A)  supernova explosion 
B)  Big Bang explosion 
C)  radioactive decay of uranium 
D)  electromagnetic attractions 
E)  many comets colliding

Question 9

According to astronomical evidence,approximately how long ago did the Big Bang occur?

Accepted Answer

A)  4000 years ago 
B)  4 million years ago 
C)  14 million years ago 
D)  14 billion years ago 
E)  140 billion years ago

Question 10

At present,what is the smallest sized asteroid that we are able to detect and track?

Accepted Answer

A)  a few metres in diameter 
B)  a few hundred metres in diameter 
C)  about a kilometre in diameter 
D)  a few kilometres in diameter 
E)  about 10 kilometres in diameter

Question 11

Iridium is a platinum group metal

Accepted Answer

A)  found at all impact sites. 
B)  that is associated with all major extinctions. 
C)  found in small concentrations in meteorites. 
D)  that accumulates rapidly. 
E)  that is relatively common.

Question 12

The tail of a comet is produced when icy material melts and gas and dust are shed from the comet.

Accepted Answer

A) True 
 B)False

Question 13

What is the significance of the rock Breccia in an impact crater?

Accepted Answer

A)  It is composed of dust-sized glassy ash particles, indicating melting and a large explosion. 
B)  It is composed of angular fragments indicating that rocks had been shattered. 
C)  It contains small-scale layering indicating deposition by settling through water. 
D)  It is composed of iridium indicating that it was created slowly. 
E)  It is composed of clay indicating a strong impact.

Question 14

Why are impact craters we observe today on Earth not as deep as the initial impact crater?

Accepted Answer

The answer of Why are impact craters we observe today...

Question 15

Why are there no craters older than 350 million years old found on any of the oceanic plates?

Accepted Answer

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Question 16

All extinction events occur due to a geologic or impact event.

Accepted Answer

A) True 
 B)False

Question 17

About once per month,an object about 10 metres in diameter explodes in Earth's upper atmosphere.

Accepted Answer

A) True 
 B)False

Question 18

If scientists spot an object that might collide with Earth,they will probably have thousands of years to study it before the collision.

Accepted Answer

A) True 
 B)False

Question 19

In your opinion,why should humans be concerned with the causations of past extinction events?

Accepted Answer

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Question 20

What is a meteor?

Accepted Answer

A)  a rocky body less than a few meters across 
B)  a dust-sized particle in the asteroid belt 
C)  a rocky, metallic object up to 1000 km in diameter 
D)  an icy, rocky body with a highly elliptical orbit 
E)  a meteoroid that has entered Earth's atmosphere

Exam 15: Meteorite Impacts and Extinctions

Describe the logic behind using iridium concentrations to determine rates of sedimentation.Under what conditions do the assumptions in this method break down? How is iridium concentration linked to the mass extinction at the K-T boundary?

Shoemaker-Levy 9 was an unusual comet in that it

What is an ejecta blanket?

What are three other natural hazards that might be linked to an impact event?

The Sudbury Impact Basin is famous for nickel-copper-platinum deposits.How is this related to the impact event?

Scientific acceptance of the idea that asteroids could strike Earth and wreak havoc is relatively recent.What event made this possibility become nearly universally accepted?

The Tunguska event in Siberia in 1908 produced a crater about 1 km in diameter.

What triggered the formation of the sun?

According to astronomical evidence,approximately how long ago did the Big Bang occur?

At present,what is the smallest sized asteroid that we are able to detect and track?

Iridium is a platinum group metal

The tail of a comet is produced when icy material melts and gas and dust are shed from the comet.

What is the significance of the rock Breccia in an impact crater?

Why are impact craters we observe today on Earth not as deep as the initial impact crater?

Why are there no craters older than 350 million years old found on any of the oceanic plates?

All extinction events occur due to a geologic or impact event.

About once per month,an object about 10 metres in diameter explodes in Earth's upper atmosphere.

If scientists spot an object that might collide with Earth,they will probably have thousands of years to study it before the collision.

In your opinion,why should humans be concerned with the causations of past extinction events?

What is a meteor?