@scottishgeologist: How did basalt form in East Lothian? Around 340 million years ago, during the Carboniferous Period, East Lothian looked very different from the landscape we see today. This part of Scotland was volcanically active, with magma rising through weaknesses in the Earth’s crust. When that magma reached the surface as lava, it cooled and solidified to form basalt — a dark, fine-grained volcanic rock rich in iron and magnesium. Because lava cools relatively quickly at the surface, the crystals within basalt don’t have much time to grow, which is why they’re usually too small to see with the naked eye. 🔍 You can still find evidence of this volcanic past all across East Lothian today — from lava flows and volcanic vents to plugs, sills and other igneous features preserved in the landscape. So when you’re standing on a basalt outcrop here, you’re looking at the remains of volcanic activity that took place more than 300 million years ago. 🌋🪨 Scotland might not have active volcanoes today… but the rocks certainly haven’t forgotten them. #ScottishGeology #Geology #scottishgeologist

Luisa | Scottishgeologist

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Sunday 30 August 2026 09:02:40 GMT