Asymmetrical Plunging Fold – Gneiss
Lewisian gneiss metamorphic rock samples exhibiting asymmetrical plunging folds, ideal for educational use, the specimens come from Scotland, UK and are, some 3.0–1.7 billion years old, dating back to the Precambrian period. The rock is made of feldspar, quartz and biotite mica minerals which show banding and have folded in an asymmetrical fashion and plunged. Limited quantity available.
- Specimen 1: 70 x 50 x 45 mm
- Specimen 2: 100 x 75 x 50 mm
Hand samples of Lewisian gneiss from Scotland, UK which exhibit asymmetrical plunging folds within them. The hand samples show clearly, banding in the metamorphic rock, particularly between the different minerals, such as the pale coloured feldspars and quartz and the darker coloured minerals of biotite mica. However, these hand samples show folding quite clearly, making them excellent as teaching material. The folds are asymmetrical with the axial plane of the anticline being off centre (not straight up/equal on each side), but not quite overturned, likely from tectonic movement hundred of millions of years ago. The rock its self is date to the Precambrian period, some 3.0–1.7 billion years old, we only have two specimens which exhibit such good folding, each piece will come supplied in a card tray with a small identification label.
Specimen 1, Specimen 2