Author Question: In what basic settings do intrusive and extrusive igneous rocks originate? What will be an ideal ... (Read 87 times)

lindiwe

  • Hero Member
  • *****
  • Posts: 577
In what basic settings do intrusive and extrusive igneous rocks originate?
 
  What will be an ideal response?

Question 2

How does the rate of cooling influence crystal size? What other factors influence the texture of igneous rocks?
 
  What will be an ideal response?



shayla

  • Sr. Member
  • ****
  • Posts: 323
Answer to Question 1

Intrusive rocks originate from cooled and crystallized magma at some depth within the Earth. Extrusive rocks originate from cooled and crystallized lava at the Earth's surface.

Answer to Question 2

Slow rates of cooling allow greater time for crystals to form, so that tends to favor larger crystal size. Fast rates of cooling do not allow time for mineral crystals to form, so the faster the rate, the smaller the crystal size. The composition of the magma or lava and the amount of dissolved gases present also influence crystallization.



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
 

Did you know?

Approximately 70% of expectant mothers report experiencing some symptoms of morning sickness during the first trimester of pregnancy.

Did you know?

Pope Sylvester II tried to introduce Arabic numbers into Europe between the years 999 and 1003, but their use did not catch on for a few more centuries, and Roman numerals continued to be the primary number system.

Did you know?

The average older adult in the United States takes five prescription drugs per day. Half of these drugs contain a sedative. Alcohol should therefore be avoided by most senior citizens because of the dangerous interactions between alcohol and sedatives.

Did you know?

Critical care patients are twice as likely to receive the wrong medication. Of these errors, 20% are life-threatening, and 42% require additional life-sustaining treatments.

Did you know?

The largest baby ever born weighed more than 23 pounds but died just 11 hours after his birth in 1879. The largest surviving baby was born in October 2009 in Sumatra, Indonesia, and weighed an astounding 19.2 pounds at birth.

For a complete list of videos, visit our video library