Apatite as an Indicator of the Pauzhetka Hydrothermal-Magmatic Systems Fluid Regime (South Kamchatka)

The morphology and chemical composition of apatite from argillized rocks of the Vostochno-Pauzhetsky thermal field have been studied. Igneous and hydrothermal apatites are isolated. Igneous apatite I is enriched with calcium, fluorine and chlorine. Hydrothermal apatite II is less calcic in comparison, contains more manganese and iron, and very little chlorine. The differences in the composition of apatites reflect a change in the Pauzhetskaya fluid system, from magmatic to modern hydrothermal.