If you are going to a tea at Staatsburgh, you are likely to spend a little time in a waiting room behind the gift shop. That, long ago, was sort of a reception room in a section of the house reserved for single male visitors. We love the teas at Staatsburg and have spent a fair amount of time in that room. We are always looking for and are attracted to things that are geologic, and there it was - at the south end of the room – a fine stone fireplace mantle. See our first photo by Don Frazer.
Even from across the room, this is a geologic wonder, but it only gets better the closer you come to it. Take a good look at the mantle sometime when you are there. Most people would identify this stone as being marble and that is technically right – sort of - but there is so much more to this particular stone. Take another, more careful, look. You should be able to make out a crystalline structure within it. We spotted this as indeed being marble and that meant that all these crystals were composed of the mineral calcite which is calcium carbonate or CaCO3. But long before this became marble it was limestone. That’s a sedimentary rock which originated as a deposit in a special ecology - the bottom of a shallow tropical sea. We gazed into the marble mantle and looked into its distant past. We saw a sea that closely resembled today’s Bahamas. There were currents of aqua colored waters flowing across pink sand with algae growing out of it. Geologists have those sorts of experiences all the time, especially when stuck in a waiting room for just a little too long – and when being just a little bit too hungry!
But how did the Bahamas turn into a marble fireplace mantle at Staatsburgh? That’s not as hard as you might think. It’s actually very commonplace geology, but it does take a lot of time. All that “Bahamian” limestone sediment came to be buried under deeper and heavier masses of thicker sediments. It was gradually squeezed and hardened into true limestone. Much later that limestone got caught up in a collision of tectonic plates. That collision lifted it up into the core of a rising mountain range. The intense pressures that accompanied all this squeezed the limestone even more and that’s when it began to be converted into marble. You see, under intense pressures, calcite becomes soluble. Sooner or later the dissolved material recrystallizes; it becomes converted into the coarsely grained crystalline mass that we call marble.
Stand back a few feet and gaze at this stone – then peer into it. Think about all the places it has been and all the things that it has done. It originated in a beautiful tropical sea. It sank into the ground as it was buried by many thousands of feet of other sediments and that hardened it into rock. It was then compressed by a great mountain building event and hoisted thousands of feet upward by that event. Erosion stripped away most of that rock and exposed what we see to quarrymen and sculptors.
But then there is something else. See our next two photos. Look closely at the structures within the stone. Those jagged dark horizons are called stylolites. They are solution surfaces that were turned sideways by those sculptors. The weight of overlying rock pressed down on this marble and increased its solubility. It dissolved the calcium carbonate which escaped sideways from within this stone. Black, insoluble biological matter was left behind to clog the solution surfaces and that made the stone more attractive, especially to members of the Mills family. And now to you too.
Look, still one last time, and see the fine craftmanship. There sure is so much to see here if you know what to look at.
Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Read their blogs at “thecatskillgeologist.com.”
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