Shoshonite

[3] Textural and mineralogical features of potash-rich rocks of the absarokite-shoshonite-banakite series strongly suggest that most of the large crystals and aggregates are not true phenocrysts as previously thought but are xenocrysts and microxenoliths, suggesting a hybrid origin involving assimilation of gabbro by high-temperature syenitic magma.

Similar associations are described from several other regions including Indonesia and the East African Rift.

[7] In the Aeolian Arc in the southern Tyrrhenian Sea (between the Eurasian and African tectonic plates), volcanism has changed between calc-alkaline to high-K calc-alkaline to shoshonitic with the last one million years, possibly due to the progressive steepening of the Benioff zone, which is inclined at 50-60°.

[8] Late Cretaceous Puerto Rican volcanism is interpreted to have occurred in a similar tectonic setting.

[5] In places, shoshonitic and high-potassium calc-alkaline magmatism is associated with world-class hydrothermal gold and copper-gold mineralization.