| 释义 |
quartzose graywacke quartzose graywacke[′kwȯrt‚sōs ′grā‚wak·ə] (petrology) A sandstone containing 50-85% quartz, chert, and metamorphic quartzite, 15-25% micas and micaceous metamorphic rock fragments, and 0-25% feldspars and feldspathic crystalline rock fragments. A graywacke that has lost its micaceous constituents through abrasion and thus tends to approach an orthoquartzite. |