Boyle, R.W., 1979, The geochemistry of gold and its deposits: Geological Survey of Canada Bulletin 280, 584 p. Referring to potassium enrichment in the wall rock of gold deposits, particularly in basic to intermediate volcanic and intrusive rocks, Boyle suggests that it "should be possible" (pg. 481) to detect high potassic zones which may be related to mineralization by use of gamma-ray methods. He also suggests that hydrothermal systems could have leached uranium, thorium and their daughter products giving a negative haloe. He then summarizes

We have observed several new features in recent controlled-source audio-frequency magnetotelluric (CSAMT) soundings on and around Mount St. Helens, Washington State, USA. We have identified the approximate location of a strong electrical conductor at the edges of and beneath the 2004-08 dome. We interpret this conductor to be hot brine at the hotintrusive-cold-rock interface. This contact can be found within 50 meters of the receiver station on Spine 5, which extruded between April and July of 2005. We have also mapped separate regional and glacier-dome aquifers, which lie one atop the other, out to considerable distances from the volcano.

No abstract

A second steeply dipping resistivity gradient between stations 5 and 9 east of Burrows Park suggests a contact between the intracaldera quartz syenite intrusive and the Sunshine Peak tuff/megabreccia. The Sunshine Peak tuff/megabreccia deposit is shown on the simplified cross-section ( fig. 4). Gravity and magnetic modeling also suggests a boundary (Grauch, personal commun., 1984) at this location.The high resistivity values beneath station, 9, 10, and 11 suggests the intracaldera quartz syenite intrusive extends down to the maximum depth of exploration.Stations 12 and 8 show a gentle east-dipping resistivity gradient (400 and 630 ohm meter contours). The gradient appears to follow the contact between the intracaldera quartz syenite intrusive and the Sunshine Peak tuff/meggabreccia.The near surface (<_ 1000 m) low resistivities «400 ohm-m) of stations 8, 13, and 15 are related to the widespread alunization of Red Mountain, local alteration, and mineralization near station 15. Station 13 ( fig. 4) is approximately located over the conduit for the quartz latite intrusion (Lipman, 1976). Because station 13 has low near-surface resistivities, the depth of exploration is limited by electrical channeling in the conductive surface. The resistivity values do suggest a lower limit for the alteration, because the resistivities of stations 8, 13, and 15 show increasing resistivties with depth.