Talk:Shoshonite

Latest comment: 6 years ago by GeoWriter in topic Basaltic or Andesitic?

Basaltic or Andesitic? edit

If it is a trachyandesite, wouldn’t that make it more of an andesitic rock, not a “basaltic” one? ZFT (talk) 03:08, 27 February 2018 (UTC)Reply

Thanks for raising this point. I have revised the definition of shoshonite in the article. Shoshonite is classified as a "potassium-rich basaltic trachyandesite", which is the S2 field of the TAS classification. It is a transitional rock between alkali-rich basalt (trachybasalt) and alkali-rich andesite (trachyandesite). So, the official definition seems to regard shonshonite as basaltic and andesitic rather than basaltic or andesitic. Some samples will be more basaltic, some will be more andesitic. GeoWriter (talk) 20:37, 27 February 2018 (UTC)Reply