Polished stone: breccia with veins
This type of metamorphic rock, a probable tectonic breccia, should be of interest to structural geologists and those who are curious about earth science. (Scale: the horizontal white lines (intrusive veins) are about 1 to 3 cm wide.)
The sigmoidal form (flattened-S shape) of some of the veins suggests left-lateral (sinistral) displacement. Note how veinlets inside the larger black clasts at left are following an X-pattern of brittle fractures and were likely in the process of disaggregating (fragmenting) these larger clasts. This suggests that some (or all?) of the smaller dark clasts were created by the fragmentation of larger dark clasts. Careful examination of the fabric/texture of this breccia shows that in some small areas, closely spaced clasts/fragments fit together in jigsaw fashion.
See other images of this breccia in my "Geology in building stone" album.
C. J.R. Devaney
Polished stone: breccia with veins
This type of metamorphic rock, a probable tectonic breccia, should be of interest to structural geologists and those who are curious about earth science. (Scale: the horizontal white lines (intrusive veins) are about 1 to 3 cm wide.)
The sigmoidal form (flattened-S shape) of some of the veins suggests left-lateral (sinistral) displacement. Note how veinlets inside the larger black clasts at left are following an X-pattern of brittle fractures and were likely in the process of disaggregating (fragmenting) these larger clasts. This suggests that some (or all?) of the smaller dark clasts were created by the fragmentation of larger dark clasts. Careful examination of the fabric/texture of this breccia shows that in some small areas, closely spaced clasts/fragments fit together in jigsaw fashion.
See other images of this breccia in my "Geology in building stone" album.
C. J.R. Devaney