The simple answer is yes, hydrothermal fluids can transport materials in a flow stream. Geothermal fluids ascending deep production wells (>1 km depth, >250 deg C)) in the Taupo-Rotorua region are known to have transport altered pumice clasts (density ~2 g/cc) up to
a few centimeters diameter, along with sand sized particles that flushed out from unconsolidated formations at >500 m depth.
Also, a few low sulfidation epithermal deposits show what appears to be cross bedding of very fined grained quartz with rip up clasts.
Robert Willan wrote:
> A query from a colleague in southern Mississippi !
>
> "I am having arguments online with someone about flow velocities of hydrothermal fluids and whether they are
> able to entrain something like sand grains. My opponent disagrees and says
> that velocities are too slow. Have you any knowledge of fluids that have
> entrained grains or fragments of the surrounding host AND moved them over
> some distance (metres or more)?"
>
> I can recall reading about small volumes of sediment in open spaces in epithermal vein systems. Given the explosive potential of porphyry and epithermal systems (mill breccias etc) I am sure there must be so dramatic examples that would settle the above argument.
>
> Can anyone help?
>
> Thanks - Rob Willan
>
> ----------------------------------------------
> Dr Robert CR Willan,
> Magmatic-Hydrothermal Processes
> Geological Sciences Division,
> British Antarctic Survey,
> Cambridge CB3 0ET, UK
> Tel: 01223 221420
> FAX: 01223 362616
> Email: [log in to unmask]
> -----------------------------------------
|