Thursday, December 6, 2012

Rare Pink Dolomite

Found this specimen while hiking the rocky 2.6 mile trail at Valley View Natural Area, in Jefferson County, 2 miles south of Morse Mill. It's one of the two areas in Jefferson County where dolomite glades, or rocky outcroppings, often south-facing and hot and dry, are preserved with controlled burns and cedar-tree removal -- the only way to preserve this once-common and precious Missouri natural feature. Glades support wildflowers and wildlife that thrive nowhere else (and are prettiest in spring). Cedar trees are invasives which entered the area along with mass settlement about 150 years ago, and they overtake glades and native oak-hickory forests unless they are stopped.

But we were speaking of dolomite. Even geologists don't agree on what it is, except that it's calcium and magnesium somehow mixed, and rarely there are pink examples of it, probably from being mixed with a little iron. A dryer-sized chunk of petrified mud had this chip broken off of it, revealing lovely sparkling stone bubbles (saddles) and glittering crystals.

I learned today that flipping flat rocks looking for creatures or fossils underneath them -- and not replacing them-- destroys the flora and fauna that lived in that environment. I was never in the habit of flipping rocks but now I know for certain that it's bad manners.

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