GSN Regular Membership Meeting, Reno, NV – October 17, 2025

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Contact: gsn@gsnv.org

GSN REGULAR MEMBERSHIP MEETING – Friday, October 17, 2025

TIME: Drinks @ 6 pm, Dinner @ 6:30 pm, Talk @ 7:15 pm

WHERE: ATLANTIS CASINO RESORT, RENO, NV

DINNER COST:  $60 per person

ONLINE RESERVATIONS CAN BE MADE BELOW.

PLEASE RSVP FOR DINNER NO LATER THAN MONDAY, OCTOBER 13, 2025.

MEETING SPONSOR:  RUEN DRILLING

SPEAKER: J. Robert Clark, PhD, Skyline Assayers & Laboratories

TITLE: “Modeling a Porphyry System and a Silver Vein System Underlying Surficial Gold Shows in the Great Basin Using Enzyme Leach® Trace Element Patterns in Soils“

 ABSTRACT: In an area of Au shows at the surface in the Great Basin, 350 B-horizon soil samples were collected on a 90m X 230m spacing in 2021 and 2023, and they were analyzed by the Enzyme Leach® process to selectively measure 70 trace elements down to the parts-per-trillion to parts-per-quadrillion range.  The objective was to detect patterns that would help interpret geology in the subsurface.  These soil samples were collected on the slope of a mountain range, and the area is characterized by relatively thin transported overburden and residual soils.  It is in the vicinity of a gold mine that was active within the last few decades.

Decades of testing on soil samples has shown that faint trace element patterns will disappear if the samples are either heated, ventilated, or just left exposed to air.  Therefore, you are looking for volatile trace element compounds.  These compounds are held in freshly precipitated, amorphous coatings on the surface of mineral grains.  Enzyme Leach® selectively leaches the MnO₂ portion of these precipitates, releasing the compounds and ions trapped there.  Analytical determinations are made by ICP-MS.

Trace element plots of these data reveal patterns that are telescoped, from great depths and shallow depths alike, into two-dimensional patterns at the surface.  A major part of the interpretive process is to sort out the relative depths between the various trace element patterns, using known geological models and experience, to provide a three-dimensional perspective on the geology and mineralization in the area of interest.

Iodine, Br, and S halos indicate a source of an electrochemical cell at depth.  These halos overlap with a set of coincident Tl, Ba, B, and K patterns, which appear to show a late-stage igneous stock, associated apophyses, and a dike on the east flank of the stock.  Also, there appear to be multiple igneous stages in the stock.

Some of the Cu patterns correspond loosely with the iodine halo.  A strong linear Cu trend, which corresponds with the hypothetical dike, and other linear Cu trends are interpreted as veins.  Together all these patterns are interpreted as showing a mineralizing stock with an associated porphyry Cu and the associated hydrothermal plumbing extending upward into the overlying section.

A large zone of what appear to be Ag veins extends 3 Km from SW to NE, across the grid.  At its widest, the visible part of it is about 1 Km wide.  Patterns of Ag highs within this zone strongly suggest that there are silver veins striking NNW in the subsurface.  Apparently, this area of Ag veins seems to be higher in the section, above the northern part of the hydrothermal plumbing indicated by Cu patterns.  It is likely hosted in a favorable lithologic unit.

Gold does not produce strongly distinctive patterns in the interior of this claim block, other than a small, persistent Au halo over an interpreted apophysis of the main stock.  The strongest Au signals are found at the north and east edges of the claim block.

Rare earth differentiation can show fossil patterns related to the most oxidizing and most reducing parts of a mineralized system.  In this case, an Eu factor corresponds with the interpreted stock, porphyry Cu, and mineralized dike, indicating that is the most reduced part of the system, which is the deepest part of the system.  A Ce factor shows the most oxidizing part of the system, which would be the shallowest part of the system.

Please contact Laura Ruud at the GSN office for more information:  gsn@gsnv.org