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Acadian orogeny serpentine also found alongside Loch Lomond (yes the bonnie banks) along the Highland Boundary Fault. I've read suggestion that the streaky calcite may represent direct sequestration of CO2 from atmosphere. What do you think on that one?

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I don't think I am enough of a geochemist, don't understand the carbon isotopes enough, to say anything useful. I see that there are a moderate number of studies - here is one on this side of the pond: https://earth.yale.edu/sites/default/files/files/Academics/12-Dunnington_thesis-sm.pdf

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Thanks, interesting and important research. Self fracking rocks! Process of natural sequestration "not yet understood" and no suggestion (in this paper at least) on how the atmospheric CO2 got into the circulating fluid. Young people doing good science (smiley icons!)

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Looks very familiar!😊

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As well it might :)

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Richard, as much as I enjoy your regular contributions to the geology of Montana, it is particularly pleasant to see your treatment of the Appalachians, where I studied for my BS-Geology way back in the mid-1970s. Keep up the great work and thanks again!

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Thanks! Because The Geologic Column has an international audience, I consciously try to broaden the scope of topics, while (more or less) staying within my self-imposed constraint of something from my collections, some place I've visited, or some place I've worked on professionally. I don't manage that every single time, but close!

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Years ago, when I was still at the University, one of my work-study students gave me on my retirement, a little goblet, about 5 cm high, she said was from her home country, Pakistan. It looks like alabaster but is pretty variegated in color, striping and whorled areas. I've often wondered about it.

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I think a fair number of those sorts of carvings are mostly calcite ("onyx"), especially from Mexico. Whenever I got this one, I got two others that were banded calcite. Three for $10 :) Have you tested the base with acid?

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Nope, not yet. Thanks.

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