#somepapers: How to train better geologists

The paper

Arribas, A., 2018, Making the case for more, and more practical, economic geology education: the point of view of an exploration geologist: SEG Newsletter, n. 113, p. 12-16.

What it says

"I argue that, with notable exceptions, economic geology education within earth science programs globally runs the risk of either focusing too narrowly on ore geology science or being a minor addendum within an earth science academic curriculum, if it is included at all."

That's the big takeaway of this short piece from April's SEG newsletter. Arribas points out that there is a misunderstanding among the public about how many resources we use that must be mined, and how much of those resources are still left to mine. The past decades have seen large increases in the amount of resources we use as a society, yet the reported reserves and resources, the stuff that companies have a "reasonable prospect for economic extraction" hasn't changed much, on an annual basis. Another way of looking at this is the saying we had when I worked at Bingham, that the mine had twenty years of reserves, just it had for the past 50 years!

Most economic geology courses or programs don't teach much about how resources are related to society. It is true that the two semesters of ore deposits I taught were biased hugely towards genetic models that will help find new deposits. A lot of departments these days don't even cover the geology side of mineral deposits, let alone their societal impacts. The author believes that all geologists should have a basic background in economic geology and that industry professionals must get involved to make this happen. I agree.

Why it matters

Modern society uses a LOT of minerals and metals; if it can't be grown it has to be mined. I think a lot of people really don't realize this. This knowledge gap is, I think, big knock on effect of universities not providing a good education in economic geology. This article offers a place to start to address that gap. It is sort of preaching to the choir, but it raises good points. We use a lot of resources and more people should understand where they come from. That should start in the geosciences.

Why I read it

Honestly, I was just reading through the SEG Newsletter and this article jumped out at me.

I follow a lot of people on Twitter who go out of their way to do the whole scicom thing - you know, actually communicate science. I've always admired this, but I'm not a natural at it, so it takes a lot of time. This article is aimed to get geology/geoscience departments to do better at training informed students, but I also feel it a bit of a call to industry people like me to more actively communicate the importance of (responsible) mining in society. I'll try harder.

Odds and Ends

OK, so that goal of reading a couple of articles every month hasn't really happened, yet. It's not too late, though, right? Onward, speeding towards the end of the year!

#somepapers: Boil first before mining

The paper

Simmons, S. F., Brown, K. L., and Tutolo, B.M., 2016, Hydrothemal transport of Ag, Au, Cu, Pb, Te, Zn, and other metals and metalloids in New Zealand geothermal systems: spatial patterns, fluid-mineral equilibria, and implications for epithermal mineralization: Economic Geology, v. 111, p. 589-618.

What it says

A couple posts back I wrote about one of my favorite papers of all time, the one about how to make a gold deposit. That paper was a prelude to this one. The authors sampled geothermal systems on the North Island of New Zealand at surface and at depths of up to 3 km where the water is between 200 and >300 degrees C. The samples were analyzed for a broad suite of metals and mineral and ligand equilibria were calculated for these waters.

There are a lot of interesting bits in the paper and I read it three weeks ago, so I'll just cover a few of the more important ones here.

Some metals show similar concentrations and metal ratios to the local rock units, suggesting derivation from country rocks. However, the economically important metals, Au, Ag, and Cu, have a magmatic source.

The ligands that transport metals in hydrothemal fluids have a strong influence on the depositional mechanism of those transported metals. The authors found little evidence to support that the metal content of the fluids are limiting the equilibria. They also confirm one of those foundational things I learned in my economic geology courses: boiling leads to metal deposition. This is why the deep waters sampled have variable, but often high, metal concentrations, but the surface waters have much, much lower concentrations of Au, Ag, Te, Cu, and Pb, the elements commonly found in epithermal ore deposits.

Why it matters

There are two important conclusions that are relevant to exploration:

First, there is a deep (magmatic) source supplying most of the Au, Ag, Cu, and Te.

Second, boiling is the main depositional mechanism for those elements, which are the economic drivers of most epithermal deposits. Multi-element geochemistry can give reliable clues about the depth of exposure.

Why I read it

After reading some interesting papers about pluton emplacement and explosive volcanism (will write that up soon) and other papers that just caught my eye, I decided that if I'm going to read just a couple papers every month (or quarter), they ought to be relevant to my job. As I've mentioned before, I work on a lot of epithermal deposits, so this one, an outgrowth of one of my all time favorite papers, was a natural pick.

Odds and Ends

Happy New Year! One of my resolutions is to read a couple papers a month and write them up here. Hold me to it, Internet.