2.16 What type of rock is oceanic crust?
See if you can answer this question by completing the activity below.
Activity _unit2.17.1 Activity 2.3 Oceanic crust
Timing: Allow about 2 minutes
Is oceanic crust igneous, metamorphic or sedimentary?
a.
igneous
b.
sedimentary
c.
metamorphic
The correct answer is a.
Discussion
The answer is igneous. It’s all made in volcanoes at the spreading centres, and cools from a molten state (the definition of igneous). The sea floor does get covered in sediment over time which is sedimentary, but the oceanic crust that it forms on is always igneous.