The Mascarene Platform is granite at its core, with a mantle of basalt and limestones ... formation of these 700-million-year-old igneous rocks. Together they stayed, along with the rest of ...

Basalt is usually formed when ... As the surface is much cooler than the mantle, the rock cools very quickly, so the mineral crystals are small. Granite hardens within the earth’s crust, where ...

The mapped sandstones are approximately 95 million years old and contain older granite and volcanic ... northwestern Mexico today. The basalt pebbles, a typical rock associated with underwater ...