you may be correct in some situations, but if high pressure was always necessary than a cyanide leach mine wouldn't work.
Roger Wilco ,10/4. I am a good "assumer".
..... page 15 of "Advanced Prospecting and Detecting for Hardrock Gold" , ( what a great book!)
by Jim Straight states,
"(top of page) Geological studies have indicated that most epithermal veins formed less than a mile below the earth surface, commonly within 1/2 mile. THus they have formed under low pressure and within temperatures estimated to be from 50 to 200 degrees centigrade."....................
."A few characteristics distinguish epithermal deposits. These deposits are found near the surface and mineralization occurs at a maximum depth of 1 km, but rarely deeper than 600 m. Due to their shallow depth, it can also be noted that epithermal gold deposits form under moderate crustal temperatures of 50-300oC, and under medium pressure. These deposits commonly occur in island arcs and continental arcs associated with subduction. However, they can also be found in shallow marine environments and associated with hot springs. Due to their shallow-depth location, epithermal gold deposits are more susceptible to erosion; accordingly, these deposits represent a high-grade, easily mineable source of gold."
Epithermal deposits occur in three different phases depending upon how much sulfur is present in the epithermal water. Deposits of this nature are classified as high sulfidation, intermediate sulfidation and low sulfidation each of these types of deposits are identified by their alteration mineral assemblages, occurrence, texture and in some cases are even identified by the associated element. Pyrite is the most common of these minerals, but you can also find mercury, antimony, arsenic and tellurium. Included in this suite it is also possible to find the base metals copper, lead and zinc as well as gold and silver. Gold and silver may be alloyed together as the alloy electrum. old-deposits.html"
Ok so Gold was scattered over the Univers by a Super Nova. Gold and Quartz deposited in Fractured Rock making Stingers ,Seams and Veins. They say the Temps of the Carrer waters was like 600F. What Carried the Gold? Only a few acids can strip !
Don't forget the tremendous pressures that solution is under. Solubility increases greatly under pressure: temperature and acidity aren't as critical as they would be under normal atmospheric pressure.