Definitions and Nomenclature
Potassic igneous rocks were originally recognized in the late 19th century by Iddings (1895), who described some orthoclase-bearing basalts from the Yellowstone Park, Wyoming, and coined the term “shoshonite”. In the last century, petrologists generated many names for potassic igneous rocks which were either based on their mineralogy or, more commonly, based on the locality of their occurrence. The practice was to name a new rock after a place where it occurred — the type locality. These different names for essentially similar rocks from different localities led to great confusion (Sørensen 1974; De Wit 1989; Rock 1991; Peccerillo 1992).
KeywordsIgneous Rock East African Rift Porphyritic Texture Ultrapotassic Rock Roman Province
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