Santo Tomas deposit, the importance of a Strike-slip faulting setting in a Porphyry Copper System.
https://www.researchgate.net/figure/Figure-Location-of-the-Porphyry-Copper-deposits-and prospects-of-Northern-Mexico-and_fig3_353417753
Discussion: Gold in Brasiles Zone
The Confidential information bearing quartz veins show very high-grade gold concentration.
These veins are hosted in the laar pseudo-conglomerate found at the periphery, above the ‘’ tectonic’’ skarn zone.
The veins are found in fault filling breccia and fractures, resulting in irregular shapes.
Conclusion
o The Santo Tomas project hosts a Cu-Mo stockwork that is part of a Porphyry Copper System, confirmed by experienced PCD geologists (Bateman, 1994, Thomson, McGuigan, Pelletier, 2021, Quintana, 2021, Chavez, 2021).
o Mineralisation is associated to porphyritic Monzonite and Quartzo-monzonite dyke complex, hosted in an Andesite sequence.
o Part of the PCD mineralisation is found in the Andesite above the porphyritic intrusion, because of a more tectonically active regime, imposing a right lateral component during the formation of the deposit.
o The dynamic strike-slip faut weakens the upper part of the porphyry, heat dissipation of the magma is at a higher level than usual in a porphyry copper system, and a long life breccia system is interrelated to the mineralisation.
o Cu-Mo (Au) mineralisation is found in veinlet stockwork and as sulfide disseminations in a deformation corridor of more than 2300m in length and 200-400m in width.
o Skarn zones are found at the contact between the Limestone and porphyry intrusive and represent high-grade Cu-Zn-Pb mineralisation zone that show a cylindrical shaped due to a right lateral component.
o Gold mineralisation was recently found in the Brasiles part of the property, and seems to related to the skarn and a late specularite-pyrite quartz vein system.
o This property is underexplored, and there is multiple indications that the PCS connects with the Reforma mine district.