Tuesday, February 2, 2010

Elemental substitution

So with no Optical Mineralogy classes to attend this week, I've been a little starved for new and exciting geologic material. With the disappointing hour short lecture in my Colorado Plateau class (on the Cambrian and Devonian transgressions of the sea on Rodinia), I was left with my only other geology class: Geochemistry.

While the class originally struck me as too much chemistry in one semester (I am taking the second semester of "scientist level" intro chemistry) I've recently grown to reconsider. In mineralogy, solid solution series' and coupled substitutions were the bane of my formulae memorization but were also fascinating to me. In geochemistry, I am spared most of that former pain and can now learn beyond the balancing of charges and comparing ionic radii to what it really means to have have cations interchangeable in a mineral's composition.


A similar pleasure came from Dr. R's explanation of chemical systems typically "treating" different isotopes of an element identically, and yet sometimes preferentially depending on weight, energy levels, and other factors. It made me wonder why in all of the years of general, chemical, and physical science I had never been taught anything beyond radioisotopes. Granted radioactive atoms are vastly more important for current uses in geology, yet here all isotopes are presented in a whole new light.

In the midst of an uneventful week for me (who cares about Groundhog Day after elementary school?) it was nice to have a moment of novelty from what seemed a dry well. I've been learning a lot of new concepts and details in my classes but this isotope surprise has really cheered me. Six more weeks of winter, even in relatively toasty Las Cruces however...

Photo Credit
Aram Dulyan. "Olivine (peridot)". Natural History Museum, London.

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