Trachybasalt is a volcanic rock with a composition between trachyte and basalt. Minerals included in trachybasalt include alkali feldspar, calcic plagioclase, olivine, clinopyroxene and likely very small amounts of leucite or analcime. Trachybasalt is a basalt with high alkali content (5 to 7% Na2O + K2O, see TAS diagram).
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