Geology filter: How to use an interesting site to my kids' advantage?
September 4, 2020 12:03 PM   Subscribe

My family happens to be staying for a few weeks right near the quarry where Tuckahoe marble came from. I've got a 11- and a 9-year old and would like to take advantage of the surroundings. What should I try to teach/show them?

I know very little about geology, but it looks like there's some pretty interesting features: on some rock formations out back, the strata are prominent and visible from a distance... and nearly vertical. I think I'm seeing veins of marble of various sizes (I'll apply acid when I get a chance to see if I can positively identify), and there's all kinds of stuff in the rocks and surrounding rubble that look like I can use them to show my kids some geological processes and other cool stuff.

Some photographs are here:

So my question: other than the obvious stuff (deposition into strata, geological forces pushing the rock so that the strata are vertical, metamorphic rock, etc.), what else can I use this site to teach?

What other rocks/minerals/formations/patterns/processes should I be on the lookout for in this kind of site? If you had an afternoon to pick around, what would you be looking for... what's neat and interesting geologically about a place like this?

posted by cgs06 to Science & Nature (7 answers total)
Bring a hammer and a loupe
posted by oceanjesse at 4:58 PM on September 4, 2020

Tangential, but I cannot resist the opportunity for putting a plug in for my favorite hobby - Geocaching! ( There are geology-focused caches (called Earthcaches) that take you to an interesting place where you have to answer a few questions.
If you're going to Tuckahoe itself, I don't see any Earthcaches about the quarry in that area, but you could probably place one - this will require doing some research into the geology of the quarry, writing up a cache page, and figuring out what reasonable questions can be asked of visitors.
Here are some examples of Earthcaches in quarries (you might need to set up a free account to access):
posted by Dotty at 6:05 PM on September 4, 2020 [1 favorite]

Since the Tuckahoe marble has significant calcite , I think it will fizz if you put vinegar on it.
posted by metahawk at 9:16 PM on September 4, 2020 [1 favorite]

Please be careful if using a geological hammer on marble - sharp chippings fly fast and into your eyes! Also check that it's allowed if the area is protected. You only need to hammer stuff if you are looking for a fresh surface or a sample.

Will reply later with more suggestions for you actual question!
posted by sedimentary_deer at 2:09 AM on September 5, 2020 [1 favorite]

Response by poster: Interesting stuff so far, thanks... but I am hoping for some specific things to look for/point out to the kids. I'll definitely try out some vinegar/acid. Geocaching is a great idea, but not an option here as the main quarry site is now a brownfield/superfund site that I wouldn't want to send people to; we happen to be sitting on private property not far away that clearly has the same interesting geology, though.

Any further suggestions welcome!
posted by cgs06 at 7:43 PM on September 5, 2020

Best answer: From a quick google (not familiar with the Tuckahoe!), you could have a look for some of the bigger crystals in the marble - these would have perhaps cooled a bit faster and you could see if you find any streaks of red/brown - where pyrite in the stone might have been oxidised by being exposed to the air (i.e. probably in your pic 1). you could talk about the relative ages of the marble (480 million years old) and how the weathering is much more recent.

Other fun stuff to do in the field is more tricky - marble has undergone metamorphosis, so the original limestone has been heated and squashed. Therefore you won't find fossils or other structures that could tell you something about the environment when it was formed.

As maybe guessable from my handle, I'm a sedimentary geologist, so less familiar with metamorphic rock activites - good luck!

Just in case you are looking for some activites in the future - check out the 'jam jar geology' series from a colleague here:
posted by sedimentary_deer at 7:39 AM on September 6, 2020

Best answer: Depending on how tied to that particular location you'll be, evidence of glaciation is always fun to look for, though it's a bit more difficult to see in that part of Westchester County compared to other nearby areas.

If you can find exposed bedrock there's the possibility of spotting glacial striations. However, you'd only see these in the harder bedrock like gneiss and schist. This is because in marble, which is much softer, such scratches and grooves would likely have been worn away by weathering. Other glacial evidence in that particular location might be glacial erratics and glacial drift and till overlaying the bedrock.

You might point out that the landscape in that area is shaped by the existence of marble amidst the harder bedrock to a great extent. Most of the ridgetops are formed by gneiss and other hard metamorphics, while the valleys are often where bands of softer marble allowed streams and rivers to carve out their channels.
posted by theory at 9:20 AM on September 6, 2020

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