Steve Johnson

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Questions related from Steve Johnson

Radiogenic J-type lead in Upper Mississippi Valley mineral deposits....where did the radon come from?

Radiogenic daughter products! Back to the Future lead lead age dates. There is way way too much radiogenic lead in Upper Mississippi Valley deposits of NW Illinois. Reports suggest the...

06 March 2023 2,531 5 View

Are there Magmatic Garnet/eclogite fragments in mafic enclaves associated with porphyry coppers?

Has anyone found signs of magmatic material from within the "garnet-in" isograd that is reportedly responsible for oxidized magmas? My bet is someone should find garnet...pyrope/spessartine...

17 February 2022 4,799 27 View

Anhydrite in Porphyry Copper systems...just how good is it?

Is it an accidental occurrence or is it essential for say, good ones? There is an excellent CODES sponsored writeup of Lihir, the gold mine, that points to anhydrite as a significant and...

04 July 2019 6,496 49 View