a process known as slab melt. Adakites are silica-rich rocks characterised by high strontium-yttrium ratios and low yttrium and ytterbium content. The origin of adakites is unclear, with opinion ...

Before we get into the snowflakes, obsidian is formed when rhyolitic magma (viscous molten rock with high concentrations of silica, but low levels of water and gas) quickly cools into a solid ...