host rock

plural host rocks

1. countableuncountablegeographyThe background mineral material in which the object of study (crystals, fossils, specific minerals, groundwater, etc.) is embedded or through which it travels.

   Host rock near the batholith is locally metamorphosed.

   2009, Lance Allred, Enchanted Rock: A Natural and Human History, page 56

   2 more examples

   Formation of alteration minerals in the host rock during deformation within the shear zone is indicated by the parallel foliation within the secondary micaceous minerals and the unmineralized host schist.

   1983, Warren C. Day, Richard M. Tosdal, E.L. Acosta, J.C. Aruspon, L. Carvajal, E. Cedeño, Glenda Lowry, L.F. Martinez, J.A. Noriega, Fernanco J. Niñez, J. Rojas, F. Prieto, “Geology of the Lo Indreíble Mining District and U-Pb Age of the Early Proterozoic Yuruari Formation of the Pastora Supergroup, Guayana Shield, Venezuela”, in U.S. Geological Survey Bulletin, numbers 2122-2127, page E-12

   A related consideration is the porosity increase due to creep of the host rock into the backfilled workings.

   1986, Environmental Assessment, Deaf Smith County Site, Texas, page 6-110