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AGS Presents: Revisiting mineral district organization in Arizona

The Arizona Geological Society kicked off its 2021 presentation series on 14 Jan. with Jan Rasmussen and Stan Keith of MagmaChem.Org discussing their “Magma Metal Series” approach to identify mineral districts and to examine those districts as a result of the orogenic evolution of the western North American tectonic plate. The presentation is available for viewing at the Arizona Geological Survey YouTube page.

Ninety-five people tuned in to the  ZOOM virtual presentation. Jan and Stan presented several dozen slides over the course of 45-minutes. Speaker time was split 1/3rd Jan Rasmussen and 2/3rd Stan Keith. The ZOOM video is available for viewing at the Arizona Geological Survey’s YouTube channel. We apologize for the uneven editing over the first minutes of the presentation.

Mineral System
Bubble diagram: Evolution of a porphyry copper system of metaluminous calc-alkalic magma-metal series.

There was a lively 30-minute Q&A session which is not included in this video.

The talk focuses on 4 of 10 potential mineral prospects of Arizona. (The talk includes a full listing of all 10 prospects.)

i.      Peraluminous – flat subduction – reduced Au – weakly oxidized AuCu;
ii.     Jurassic – Oxidized porphyry Cu (AuAg) – MQA;
iii.    Volcanogenic Massive Sulfide – Weakly to oxidized MC;
iv.    Oxidized MCA Porphyry CuAgMo and weakly oxidized MCA porphyry CuAuMo.

Please feel free to leave comments on Youtube; we will share them with the speakers.
For more on MagmaChem, visit

Invited post of the Arizona Geological Society.

Proterozoic orogenies