Outcropped Silcrete and Sand Calcite are a recurring combination, as seen here in Copley and along the Strzelecki Track.
Silcrete formation: Finniss Springs
Silicified duricrust formed in low laying outer areas of the Flinders Ranges, likely to have once been saturated by limey waters. Surrounding sediments have eroded leaving these typically rounded, hard wearing silcretes.
Silcrete of the Strzelecki Track
The quartzose silcrete of the Strzelecki Track formed in the Tertiary Era, as a duricrust formed through silica rich mineral deposition from groundwater at the low lying fringes of the Flinders Ranges. It appears to be cryptocrystalline in nature, made of a minute crystal structure also typical of chert and chalcedony.
Highly resistant to weathering, the silcrete formation reveals some very finely detailed fossil casts of vegetation. The fossils in this formation contain casts of plant detritus of varying species, one of which appears to be Casuarina.
This formation has intriguing layering of well preserved crushed quartz, silcrete and sand calcite balls as seen in this vertically upturned rock. Continue reading “Silcrete of the Strzelecki Track”