Mineral evolution: Kelvin vs. Hutton

Blue gem mineral

A couple of weeks ago the very prolific Callan Bentley at Mountain Beltway raised some speculative questions inspired by the concept of mineral evolution, the idea that the mineral suite of the Earth has changed over time. I’ve been mulling over this proposition since, more or less in the back of my mind as more pressing personal happenings have been going on.

First, there is a terminological issue. The word “evolution” has meant very different things to different people over the centuries. Like most, if not all words, you cannot be assured that the etymological roots are anything other than a guide to the history. In today’s world, the word automatically brings up the name Darwin, even though it meant very different things to Erasmus than it did to his grandson Charles, who used it only sparingly.

Taken as its roots imply-unfolding in time-, the concept of mineral evolution would follow directly from logic of thermodynamics and an expanding Universe. Particular minerals, such as the one shown above, will form in environments wherein they are stable, or at least closer to equilibrium than whatever was there before. The parameters of the environment, as far as minerals are concerned, are temperature, pressure and composition. Consequently, in a Universe where energy is constantly dissipating, temperatures will constantly fall, and new, conceivably unique patterns of temperature, pressure and composition come and go. Predictably then, mineral suites will  change with time, with or without life!

Which takes me to Kelvin.

Geologists typically know Kelvin in the context of the age of the Earth debate. Geochemists and others whose curriculum involves thermodynamics know that aspect of his work: entropy, Kelvin scale, so forth. Never the twain should meet! But, in fact, they do. Albritton, in his book The Abyss of Time points out that the late 19th century debate between Kelvin and the geologists centered not so much on the age of the Earth as on the nature of geologic history. Kelvin’s  argument was not with Darwin the geologist, but through Lyell, with Hutton and his memorable phrase “no vestige of a beginning…” that we have all read, somewhat uncomprehendingly.

We read Hutton with difficulty, but not because of his writing style. You can check it out for yourself ( Theory of the Earth)   . What makes him difficult to understand is that he was writing in a thoroughly Aritotelian frame of reference that has eternalism at its base. Furthermore, he had no chemical atomic theory, no way to distinguish between fire, heat and phlogiston. No oxygen in his vocabulary. What he did have was the awesome ghost of Newton and the image of an eternally revolving system of Sun and planets. In short, at least according to historians of Geology like Martin Rudwick (Worlds Before Adam), no sense of geologic history as a series of unique events unfolding in a unique, non-repeating sequence.  This was the Huttonian foundation for Lyell’s cyclical uniformatarianism which made such difficulties for his admirer, Charles Darwin.

The mineral at the top of this page illustrates mineral evolution in the sense that it almost doesn’t exist. The conditions of temperature, pressure and composition that it requires are rarely achieved in the Earth, so it occurs in only one or two places on Earth. Fortunately for me, few people prize it as much as I do, so the price for this small example was within my wife’s birthday budget for me when I turned 65. I wore it as an ear stud until she passed.


2 Responses to “Mineral evolution: Kelvin vs. Hutton”

  1. Andrew Says:

    Ah, I was wondering if that was benitoite. I hope you can wear it again.

    Hutton’s Earth is quite foreign to today’s paradigm. His Earth, as he put it quite plainly, is a perpetual-motion machine for sustaining soil to support Man. The machine is so ingenious that it contains no sign of its creator. His great advance was to direct our attention to the way the machine works, and we’ve come a long way in understanding that.

    I think Hutton was Newton’s ghost, as you say: both banished speculation about ultimate causes and purposes, and both laid down workable principles that underlie sound practice. Following his emphasis on studying geologic processes, we have succeeded in uncovering evidence of Earth’s creation. I’m not sure Hutton would like that, because he was a pious man who didn’t dodge the Bible like Darwin did. But probably he would have taken the mainstream viewpoint that Genesis is a figurative rather than literal account of the universe—that God is not only stranger than we suppose, but stranger than we can suppose.

    Now that we have discovered vestiges of the creation, geologists are Kelvinists again. Consider today’s news, a study purporting to date the formation of the Moon from the balance of hafnium and tungsten isotopes. Short-lived hafnium-182 was created in the supernova that kicked the solar system into being, then went extinct as surely as Kelvin’s cooling incandescent sun.

    • geodturner Says:

      Benitoite indeed! I didn’t expect mystify any California geologists .

      The reference to Hutton’s writing I got, in fact, from you, I believe. Downloaded it and printed it out so I could work my way through it. After reading Rudwick- and Gould before that- I was pleased to have the original words.

      The Rudwick book referred to in the post is worth the effort, in spite of its heft. It’s a full two inches thick. But the chapters are short and, as the author suggests, you can get by with reading the Conclusions and looking at the illustrations. He is a paleontologist turned historian of science and has skills and access to resources that ordinary geologists don’t. He has some interesting slants on the interplay of science and religion, particularly the contrast between linear history (Judeo-Christian) vs the eternalist ideas of the Greeks.

      Thanks for the comment.

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