ocean crust

• layers in the ocean crust

  A) sediments

  B) basaltic lavas

  C) basaltic dykes

  D) gabbro

  E) peridotite

  
• Lizard peninsula is an ophiolite. 
• Profiles of the earths crust can be determined by ophiolite suites. 
• All ocean crust is assumed to have this structure, because all ocean crust is formed from mid ocean ridges. 
• Layered seismic velocity is very similar in all ocean basins. 
• Along some slower spreading MOR altered peridotites are found by researches dredging the sea floor. 

  Serpentine is peridotite with olivine that has reacted with ocean water.