Categories
Multi-Part Report

Corrosion at Cabo da Roca -6

Origin of Sulphur The sixth part of a multi-part series Introduction: It has been my observation that, almost without exception, highly corrosive sea cliffs are associated with very high levels of sulphate, either coating the rock surface, or oozing from the groundwater. Further to this fact is the observation that, in almost all cases, an […]

Categories
Multi-Part Report

Corrosion at Cabo da Roca – 1

The story of a sulphate crag The first part of a multi-part part series In conducting this work I have been greatly assisted by Luis Fernandes Silva and Rui Rosado who have provided multiple samples and photos for analysis. Luis has spent a great deal of time measuring spot-sulphate levels, and the pH profiles of […]

Categories
Short Report

The Cliffs of Cabo da Roca

Home to some very corrosive sulphur crags. The Sintra volcanic complex, comprised mainly of granites and syenites, forms impressive, jagged sea cliffs that extend for several kilometres both north and south of the Cabo da Roca. Syenite is a low-silica form of granite, and looks very similar. Unlike typical granitic intrusions with their massive, sparsely-jointed […]

Categories
Quick Note

Not all white deposits are calcium sulphate

This note was posted to the Titanium Bolting FB Group 16 January 2020 A consistent feature of the “sulphur crag” story, especially at Railay/Tonsai is that sulphate is not found any distance more than 100m or so from the sea. Thus it is no surprise that the white deposit found at Wee’s Present Wall shown […]

Categories
Quick Note

Notes from Railay – 2

This note was posted to the Titanium Bolting FB Group 14 January 2020 The large cave at the Pra Nang side of Klao Luk Choee is home to the classic Todd Skinner route Best Route in Minnesota. At the base of that route there is a white powdery material in great abundance. Analysis shows it […]

Categories
Quick Note

Notes from Railay

This note was posted to the Titanium Bolting FB Group 12 January 2020 The “sulphur” crag story continues. Here we see calcium sulphate crystals deposited on the surface of the rock at Defile Exit, Railay. I hypothesise that this material is deposited as a result of bio/geochemical processes occurring at the rock surface due to […]