I found these rock samples whilst walking around the Externstein park, NRW, Germany. They were deposited on the footpaths so I assume they were transported here through erosion, I should try and identify the source the next time I am there.
They required no hammering except to gain a fresh surface to examine.
Greywacke
- Coarse-fine Quartz, Fedspar and dark coloured mafic minerals
- Seem to result from a rapid deposition in a turbulent marine environment.
Arkose
- Quartz. Feldspar (Mica)
- Coarse Sandstone made from the sediment of a granite structure
- Indicative of a rapid uplift, matches geological occurrences in the area.
Mudstone
- Contains clays, quartz and sometimes calcite
- Clay or silt sized particles are lithified rather than laminated
- Marine or Glacial sediment, both of which fit for the locale
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