Sunday, January 28, 2024

Cohoes Mastodon

 If you visit the New York State Museum in Albany, you will see the Cohoes Mastodon.

The mastodon was discovered in September, 1866 during the construction of Harmony Mill #3 (one of the largest cotton mills in the world) near Cohoes Falls on the Mohawk River. Here's the sign on North Mohawk Street, at the northwest end of the massive Harmony Mill building (now apartments).

The bones were found buried in a deep pothole at the base of the falls. The falls themselves can be viewed from the appropriately named Falls View Park in Cohoes.

The potholes formed during higher water flow just after the last ice age. As the glaciers still sat up in Canada, the massive volumes of fresh meltwater created Glacial Lake Iroquois where the smaller Lake Ontario sits today. This water ripped through the Mohawk Valley into the Hudson Valley with 100 times the water flow of today's river.

Based on growth rings in the mastodon's tusk, we can determine he was around 32 years old when he died some 13,000 years ago. He led a hard life, almost starving to death at 11 from a wound to his lower jaw (probably from the tusk of another mastodon) and dying at 32 from another tusk wound to the temple. Here's a neat video from Dr. Robert Feranec at the New York State Museum talking about the mastodon.

The Cohoes Mastodon display at the State Museum is well worth visiting with a lot of information presented about this mastodon and mastodons in general. Around the corner is also the famous mastodon diorama recreating a mother and baby mastodon in the mid-Hudson Valley with Storm King Mountain in the distance.

These were real animals literally walking around our backyards a few thousand years ago.

Sunday, January 21, 2024

Out of Place Geodes?

When you're a geology professor, people often bring you things to identify. Usually, it's something easy to figure out (especially if it's local) and sometimes you have to disappoint them (supposed meteorites that turn out to be slag, for example). Occasionally, however, you get something truly odd.

A faculty colleague recently showed me some rocks that were dug up by her kid and friends at the base of a tree in a suburban area near Cantine Field in Saugerties, NY. A half-dozen or so spherical rocks several inches in diameter. 

At first they almost looked like cement, rather than rock, but after cracking a few open, we were surprised to find they were geodes. Even more surprising, they were all slightly different.

The one on the left took several swings of a heavy sledge to bust open and you can see there's a vein of chalcedony/chert running through the middle. The middle one had nice quartz crystals in the center, and the right one had well-formed calcite crystals!

The one on the left was even more odd. It had some white crystals (shown) that fizzed with hydrochloric acid (which would normally indicate calcite) but then when I washed the rock, they started to get soft and dissolve (which calcite does not do). I'm not sure what they are.

So, how did a pile of geodes end up in Saugerties? I have no idea. The bedrock in the nearby area is the Devonian Onondaga Limestone. I've never seen natural geodes in the area. My only guess is that they were once dumped there by someone. Where did the geodes originally come from? No idea. It's a mystery.

Do any readers recognize where they might be originally from or how they might have gotten there? Let me know!

Sunday, January 14, 2024

Cobalt Red

I recently read an interesting book, Cobalt Red, about cobalt mining in the Congo (a country that has been cruelly exploited by the west for centuries). The Katanga Region of the Congo in Africa holds more cobalt than the rest of the planet combined (as well as a host of other metallic ore minerals).

Why does the Congo hold so much cobalt? It's complicated. Here's a paper with the details if you're up on your geochemistry. The bottom line is that around 4-5 million years ago (the Pliocene Epoch), near surface rocks were exposed to weathering under just the right pH conditions to form a mineral called heterogenite (CoOOH), an ore of cobalt. Being near the surface, in heavily weathered material, the mineral is relatively easy to mine by hand.

Why is cobalt important? It's critical for making the cathodes (positive terminals) of lithium-ion batteries (which are in everything from cell phones to Teslas). China, South Korea, and Japan produce almost 90% of the world's lithium-ion batteries and they all get their cobalt from the Congo.

While companies that use lithium-ion batteries like Apple, Samsung, and Tesla tout how socially responsible they are on their websites, the reality of cobalt mining in the Congo is that it's done under slave-like conditions by "artisanal miners" as young as 12 who work under horrific conditions destroying their health and the landscape for a pittance while consumers in the U.S. feel virtuous for being "green" and multinational companies make billions.

The author is a U.K. professor who's research specialty is modern slavery. He faced real dangers traveling through the Congo and visiting these mines since the government there and the primarily Chinese mine owners resort to violence and murder to keep the status quo. Reading the comments of the miners is heartbreaking - "Here it is better not to be born." It's a depressing but important read.

Sunday, January 7, 2024

What on Earth is a Urolite?

Every heard of a urolite? Me neither. What about a coprolite? I suspect more people have probably heard of these.

Coprolites are fossilized feces or poop. There's nothing disgusting about them, the material has been completely mineralized and it's no worse than handling a rock (although when I pass one around the geology lab, some students are very reluctant to even touch it). Here are a couple of samples I have in my lab (I don't know what animal left these coprolites).

Coprolites are ichnofossils or trace fossils in that they record a trace of an organism's activity (rather than a fossil of the organism itself). Paleontologists find coprolites useful since they can often provide information about the animal's digestive system and diet - below are microscopic views of coprolites from a scientific paper studying the diet of a group of herbivorous dinosaurs.

I happened to stumble on a paper recently that introduced me to urolites. Urolites are another type of ichnofossil that are formed from sediments disturbed by the urine stream of an animal (hence the "uro" part of the name). In the case of the paper I read, urine streams from early Cretaceous Period dinosaurs in Brazil. Here's a picture from the paper of some urolite examples.

and a drawing illustrating the concept.

The authors said these fossils compared well to similar features formed by modern ostrich urinating in sand. They also claimed that this is the first direct evidence of liquid waste elimination by dinosaurs.

While not the sexiest of fossils, it's always neat to see what we can see and learn by careful observation of the world around us.