THE Andean Mountain system in Peru has experienced extensive igneous activity, a significant portion of which was intrusive. A principal feature of this part of the Andes is the coastal batholith ...

That sculpted the rock, giving it the shape we can see today. ISLA: That’s right. It’s also an igneous intrusive feature, just like them. The rock they’re made of is called phonolite - also ...

This process can occur either below the Earth’s surface, forming intrusive or plutonic igneous rocks like granite, or at the ...