Monday, February 2, 2015

Geo 1095: February 2, Day 763: Flowstone Draperies

I've not used the term "speleothem," yet, and I needed to clarify for myself how exactly the term was defined. There seems to be a consensus that they're restricted to secondary features such as we see here. In other words, they consist of material deposited after solution of the marble (in this case) has occurred. So solution features, such as enhanced erosion along fractures, channelization in steeper areas, "spikes" developed around persistent drips from the ceiling, and so on, would not be considered speleothems, but redeposited carbonate (and other) minerals would be, such as the features of the last couple of days. Speleothems fall into a variety of other categories; these are properly called stalactites. Their ground-based counterparts are stalagmites. A mnemonic to help remember the distinction is that stalactites cling tight to the ceiling ("c" and "t") and stalagmites are grounded, but might fall over ("g" and "m").

Photo unmodified. May 9, 2013. FlashEarth Location. (Since we're underground, I have only a vague idea where this is with respect to the surface.)

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