CHATEAU YALDARA & 1847
The region in front of the Mount Lofty Rangers is a foreland basin created after a tectonic collision
Majority of the metamorphism in the Barossa occurs in the south-eastern and central areas, the Warren Reservoir area has the highest amount of metamorphism in the entire Barossa Valley.
The region around Chateau Yaldara is apart of the Warrina Group which is comprised of Quartzite, dolomite, sandstone, shale, slate, conglomerate, siltstone, volcanics, and marble.
The Saddleworth Formation is comprised of slate which is a very low-grade metamorphic fine-grained rock, the slate was once a sedimentary rock comprised of mostly clay, like siltstone, shale or claystone. Slate is classed as a low-grade metamorphic rock with slight foliation, very fine-grained, and fractures in flat sheets (slaty cleavage). The formation is also comprised of laminated siltstone with variable carbonate content and altering layers of thin sandy interbeds.
The strata has been tilted up at roughly 45° degrees (educated guess) and facing the west mostly at the banks of the North Para River only up to the bridge, on the other side of the bridge the formation is verging up in a much steeper direction.
The formation was deposited within the Neoproterozoic in the Tonian period (1,000 to 750 million years ago) when the supercontinent Rodinia once existed, that continent started to break up by the end of the Tonian Period.
Quartz veins in the Saddleworth Formation like most types of slate disappear and appear abruptly, they cross the bedding plains and cleavage, the veins visible at 1847 form in lenses that are a few centimetres to half a meter at most in thickness.
Deposition of quartz was in a solution where quartz was liquefied and filled in pre-existing fractures in the slate only to harden and solidify when the area cooled down. The quartz in some locations is iron-stained giving it an orange/rust-like colour from oxidising iron sulphide minerals, in other places its milky white in colour because of ----
River erosion is very prevalent along some of the edges of the North Para River, the edges of the Saddleworth slate outcrop has been softened where high flowing water has cut down the sharp edges.
The river is dammed in this area so water rarely runs over this section anymore unless it's in flood.
FRACTURES & COLLAPSE
iron sulphide corrosion
When Iron Sulphides oxidize it creates rust,
Australian Government, Geoscience Australia. (n.d.). Saddleworth Formation | Australian Stratigraphic Units Database, Geoscience Australia. Updated September 3, 2019.
Lombardero, M. & Garcia-Guinea, Javier & Cardenes, Victor. (2002). The Geology of Roofing Slate. Industrial Minerals and Extractive Industry Geology.
T. Nelson Dale, United States Geological Survey (USGS), Ohio State University, & The Department of the Interior. (1914). Slate in the United States | Bulletin 586. Washington Government Printing Office.
C.R Dalgarno. (1961, June). Geology of the Barossa Valley. The University of Adelaide. [This will download as a PDF].