2
$\begingroup$

Is there an association with thrust fault or dormant volcanos and quartz veins? Where are quartz veins likely to occur in nature and how are the formed?

Is it possible to identify these veins from satellite images.

$\endgroup$
7
$\begingroup$

The formation of quartz veins needs fluids enriched in Si. Usually Si dissolves somewhere in neighbouring formations, gets transported by fluids and precipitates where the fluid pressure is low (the fluids Si-saturation capacity decreases with decreasing fluid pressure). Fluid pressure is usually involved in rock fracturing. When it builts-up, it can fracture the rock. Thereby generated fractures, in turn, accomodate void space, hence the fluid pressure drops and Si precipitates from the fluid to form veins. These veins reseal and restrengthen the rock, which can again lead to a renewed fluid pressure built-up. This process is known as crack-seal vein formation.

Usually, crack-seal vein formation happens progressively, which is a very nice thing: Studying vein internal mineral structures gives evidence to past stress regime conditions. These evidences can help unraveling the evolution of tectonic structures, such as mountain formations or fault systems.

Quartz veins are very common, they need a source of disolvable Si, which is a really abundant element. In carbonate rocks, calcite veins are more common. The crack-seal principle applies for them just the same.

Yes, you can see veins in satelite pictures! Have a look here: OMAN (These are calcite veins standing out against a darker limestone).

Hope this helps, Ben

P.S.: You might want to have a look at my thesis on (calcite) vein-networks in Oman: LINK.

$\endgroup$
  • $\begingroup$ I did not know that's how they formed, but it make sense. $\endgroup$ – Tim Nevins Dec 21 '17 at 18:42
3
$\begingroup$

Quarz veins come in different sizes - starting from milimetre scale ending with several meters (if not more). Quartz veins form from aqueous solution and in most cases that is associated with high hydraulic pressure (be that because of deformation or volcanic fluids).

It is highly unlikely that you could identify veins from satelite images because of their size and vegetation. On the other hand that might be possible using drone photos.

I suggest looking at Cabo de Gata (cape of agate) satelite images as an example of volcanic region with plenty of silica veins and very little of vegetation. The veins there usually smaller than 1 meter so I don't expect you to see them but you can see some cracks in the rock, which occasionally are refiled with silica (coordinates 36°46'57.3"N 2°06'02.8"W) (source: I did mapping there)

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.