Table 5: Mass weathering classification system proposed for dacites in the study area.
Rock mass description
No visible sign of weathering or slight discoloration on discontinuity surfaces. Rock material is very strong and highly difficult to break with a hammer. Feldspar phenocrystals cannot be scratched with a nail. Contacts between phenocrytals and matrix are distinct. RQD: 50–100 (%), .
Ligth and dark orange brown discoloration with no inward penetration on discontinuity surfaces. Rock material can be broken with a couple of hammer blows. Edges of the specimens cannot be broken by hand. Feldspar phenocrystals preserve their original shape, but they can be scratched with a nail. Toppling and columnar collapses are common. RQD: 50–100 (%), .
Weathering products such as clay and carbonate are observed on discontinuity surfaces. Rock is considerably weakened. Discoloration partially penetrates from discontinuities. Edges of the specimens can be broken by hand. Feldspar phenocrystals become gritty in appearance and can be scratched with a nail. Translational, wedge, and plane failures are encountered. Rock/Soil >50%, RQD: 0−50% and .
Discontinuity surfaces are peeled and not prominent. Amount of weathering products on discontinuity surfaces increases. Rock is pervasively discolored. Original texture is preserved. Feldspar phenocrystals have lost their original shape. Rock material does not slake in water. Discontinuity surfaces are peeled. Translational, wedge, and plane failures and debris slides are likely to occur. Rock/soil >50%, RQD: 0–50 and .
Original rock texture is present. Material slakes in water. Corestones and relict discontinuity surfaces are observed. Corestones can be easily excavated with a hammer. Rocks are decomposed to soil. RQD cannot be applied and Schmidt rebound values cannot be obtained. Corestone falls and circular failures are observed.
Original texture and fabric is lost. Slopes are prone to circular failures.