Ultrapotassic igneous rocks

While there are debates on the exact classifications of ultrapotassic rocks, they are defined by using the chemical screens K2O/Na2O > 3 in much of the scientific literature.

The magmas that produce ultrapotassic rocks are produced by a variety of mechanisms and from a variety of sources, but generally occur in a heterogenous, anomalous, phlogopite-bearing upper mantle.

Phlogopite and/or potassic amphibole are typical in the sources from which many such magmas have been derived.

Ultrapotassic granites are uncommon and may be produced by melting of the continental crust above upwelling mafic magma, such as at rift zones.

[5] Ultrapotassic A-type intracontinental granites may also be associated with fluorite and columbite – tantalite mineralization.