Rocks don’t need a dramatic cone-shaped mountain to form. Sometimes, the Earth just cracks open in long, straight lines called fissures. Lava oozes out like toothpaste from a tube—slow, but relentless. Iceland is famous for these; you can actually walk along a fissure and see where lava bubbled up and hardened into flat, black plains.
The Textures of Extrusive Igneous Rocks - Texture Gen
These fissure eruptions create huge flood basalts, covering entire regions. The Deccan Traps in India? That’s a pile of extrusive rock thousands of feet thick. Dinosaurs used to walk on that stuff before it even existed—wait, time isn’t linear here. Anyway, you get the scale.
Spatter Cones and Lava Fountains
Lava doesn’t always flow politely. Sometimes it shoots up in fiery fountains, splattering blobs of molten rock around. Those blobs cool mid-air and fall as scoria or cinders. Pile enough of these and you get a spatter cone—a mini volcano built from cooled droplets. It’s like a sandcastle, but made of instant rock and sizzling memories.
And then there’s obsidian, the rock that looks like black glass. It forms when lava cools so fast that no crystals can form at all. Ancient people made knives and arrowheads from it. (Imagine approaching a volcano and thinking, “Oh cool, free cutting tools.”) Survivalists, take notes.
