Figure 3: Whole-rock SiO 2 content versus FeO*/MgO ratio in volcanic rocks of the Kamchatka central depression compared to Aleutian adakites. Figure 4: Sr/Y ratio versus SiO 2 content, Mg# and Y ...

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 divided between two main hypotheses ...

But when Lees and his colleagues analyzed pieces of hardened lava called adakites from easternmost Russia's Kamchatka province, Adak Island in Alaska'a Aleutian chain and elsewhere, they found ...

This is confirmed by the find of adakites. These are the rocks first described from Adak Island, which is part of the Aleutian island arc in the North Pacific Ocean. 'Studying the conditions of ...