Fluorine-rich miarolite

Fluorine-rich miarolite

The fluorine-rich miarolite is a product of the most typical magmatism of Jiuhuashan massif and characteristic of miarolitic structures in syenogranite. The miarolitic structure consists of quartz and automorphic fluorite crystals in syenogranite geodes. These crystals are results of crystallization of the fluorine-rich fluid filled in the cavities of syenogranite. The cavities developed in the places left by escaped volatile elements in magma. The fluorine-rich magma is low in viscosity and easily upwells into the shallow crust, which is one of the controlling factors of the shallow emplacement of magma in Jiuhuashan.

Formation of Fluorine-rich miarolite

The magma with gas forms the sphere bubble with empty cavity. The gas ejected from the volcano; The magma is the high temperature burning slurry underground, there is gas released at both the intrusion and the ejection. The outer shell that has been crystallized; Due to the differentiation of the mineral melting point, the mineral with high melting point will crystallize first to form the outer shell, the mineral with low melting point shall crystallize by entering inside the bubble. You can see the crystal of the minerals with low melting point inside the geode, there is no complete crystal outside of the geode.

Geodes in syenogranite

Quartz crystals

Fluorite crystals

Granite with zonal-distributed geodes