Whitsmith Mine: Hydrothermal Mineralisation in the Strontian Shear Zone. скачать в хорошем качестве

Whitsmith Mine: Hydrothermal Mineralisation in the Strontian Shear Zone.

The hills above Strontian are very rich in economic minerals which formed in hydrothermal veins. Two things have come together here to make the rich mineralisation: First - at end of the Strontian shear there is a region of dilation as deformation steps across to the main Great Glen fault, which allowed a granite body to intrude into the upper crust here. This granite is the source of the metal-rich hydrothermal fluids. Second - fluids driven off from the cooling granite found an easy pathway to flow along the shear zone where the bedrock was broken up and porous. We see evidence for this in Whitesmith mine where the economic mineralisation cuts straight across the hillside, following the shear zone. Individual blocks from the main vein show a range of textures, but are dominated by clasts of country rock from in the shear zone, cemented together by hydrothermal mineralisation. This is all related to a late stage of the Caledonian orogeny (430-380 Ma) when crustal thickening had produced granites at depth, and oblique collsional tectonics produced the Great Glen transform fault system with subduction further to the south. See also: Production of Granite in the Lower Crust    • Production of Granite in the Lower Crust: ...   Extreme deformation on a fault plane - Ben Arnabol mylonite    • Extreme deformation along a fault plane - ...   The Great Glen - Scotland's San Andreas Fault    • The Great Glen - Scotland's San Andreas Fault   One Minute Plus: The Mountain Building Cycle    • One Minute Plus: The Mountain Building Cycle