出典:Wiktionary
Ancient Greek τραχύς (trakhús, “rough, rugged”) + basalt.
trachybasalt (countable かつ uncountable, 複数形 trachybasalts)
出典:Wikipedia
出典:『Wikipedia』 (2010/07/29 23:19 UTC 版)
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. It contains high alkali content (5 to 7% Na2O + K2O, see TAS diagram).