metabasalt

From meta- +‎ basalt.

metabasalt (plural metabasalts)

1. An amphibolite produced from a basalt by metamorphism.
   • 1980, Snavely, Jr., P.D.; A.R. Niem, N.S. MacLeod, J.E. Pearl and W.W. Rau, “Makah Formation: A Deep-Marginal-Basin Sequence of Late Eocene and Oligocene Age in the Northwestern Olympic Peninsula, Washington”, in Geological Survey Professional Paper‎, volume 1124, page 24:

     The abundant basalt and metabasalt clasts in sandstone and conglomerate of the Jansen Creek Member were most likely derived from the locally metamorphosed basalt in the Metchosin Volcanics that crops out along the southern margin of Vancouver Island

• blastemata