wacke
wacke[ˈwakə]noun- [mass noun](Geology)a sandstone of which the mud matrix in which the grains are embedded amounts to between 15 and 75 per cent of the mass
(地质)玄砂石;玄武土
语源- early 19th cent.: from German, from Middle High German wacke 'large stone', Old High German wacko 'pebble'
考试词汇表