The rock adjacent to or enclosing a vein, hydrothermal ore deposit, fault, or other geological feature.
- ‘Magmas concentrate metals, and magma fluids traveling into the surrounding wall rock plant the seeds for mineral growth.’
- ‘The white material is quartz and the black is the wall rock from the edge of the vein.’
- ‘At the eastern end of town, the fault cuts through outcrops near the I-wu river and is also represented by a major gouge zone and thick breccia in the adjacent wall rock.’
- ‘The typical image that this process invokes is that of a magma chamber with bits and pieces of the enclosing country rock or wall rock floating in the magma.’
- ‘The wall rock was highly altered and consisted of a groundmass of pyrophyllite and fine-grained pyrite.’