Which part of the Vulcanist doctrine on the formation of rocks ...

[dalyningkenk]

Which part of the Vulcanist doctrine on the formation of rocks was incorrect?
 
  What will be an ideal response?

Question 2

Explain how peridotite can melt at a divergent plate boundary without an increase in temperature.
 
  What will be an ideal response?

[cupcake16]

Answer to Question 1

That sedimentary rock formed due to heating.

Answer to Question 2

Melting occurs because the melting temperature decreases with decreasing pressure. Peridotite in the mantle rises to a lower depth at divergent boundaries with little or no decrease in temperature. The lower depth corresponds to lower pressure. The lower pressure results in a lower melting point and the peridotite partly melts.