Where is the Earth's new crust formed?

Expert Answers

An illustration of the letter 'A' in a speech bubbles

The Earth forms most of its crust at divergent plate boundaries, where two plates move away from each other.  The boundary is where magma upwells in a convection current from the mantle, and hardens into brand new crust as it cools.  The biggest and most famous place where this is happening is the Mid-Atlantic ridge, and the volcanic islands along it (e.g. Iceland).  The other major place is Africa's Rift Valley.  In about 10,000 yrs geologists estimate that Lake Victoria will be the south end of a new gulf in the Indian Ocean, as the Horn of Africa pulls away from the rest of Africa. 

The rest of the crust comes from the material of other volcanoes.  Pyroclastic materials from eruptions, and solidified magma chambers (most granite formations) make the rest of the new crust. 

Approved by eNotes Editorial Team

We’ll help your grades soar

Start your 48-hour free trial and unlock all the summaries, Q&A, and analyses you need to get better grades now.

  • 30,000+ book summaries
  • 20% study tools discount
  • Ad-free content
  • PDF downloads
  • 300,000+ answers
  • 5-star customer support
Start your 48-Hour Free Trial