Ultrapotassic igneous rocks

A dike composed of the ultrapotassic igneous rock, lamprophyre

Ultrapotassic igneous rocks are a class of rare, volumetrically minor, generally ultramafic or mafic silica-depleted 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.[1] However caution is indicated in interpreting the use of the term "ultrapotassic", and the nomenclature of these rocks continues to be debated, with some classifications using K2O/Na2O > 2 to indicate a rock is ultrapotassic.

  1. ^ Foley, S.F.; Venturelli, G.; Green, D.H.; Toscani, L. (April 1987). "The ultrapotassic rocks: Characteristics, classification, and constraints for petrogenetic models". Earth-Science Reviews. 24 (2): 81–134. doi:10.1016/0012-8252(87)90001-8.