Orchard Beach at Pelham Bay Park

We met bright and early at Orchard Beach. The day was very warm. You drive through the sprawling Pelham Bay Park - with horse stables and bike paths and picnic benches - to get to the beach. Parking is $7. The field trip was led by George Harlow and we walked north along the beach towards Twin Island.

This field trip provided another view of the local NYC geology, with all its complexity. Because we were not given a field trip guide ahead of time, I looked up some information about the site and what's there. Here are the links: Bedrock Geology of New York City: More than 600 m.y. of geologic history and 6. Pelham Bay Park (USGS). Don't you love going into the field knowing what you might find? I do.

Here's what I saw: the Bronx section of the Fordham Gneiss, loads of folding, partial melting (we've seen that on all stops thus far), a patch of garnet sand, tourmaline, epidote, beryl, biotite and muscovite (sometimes intergrown with each other) and kyanite blades (see below)! Sillimanite? No, I don't think so.

And a dinosar:

Bring on the Black Rock Field Trip!! That'll be all week, the week of July 27. Just like old times and field camp at CSU Hayward in the Sierra. Ha!


Field Trip to Inwood Park

Today was more like a real field trip. Though we met in upper Manhattan and walked and looked at a great outcrop right in a community, we scrambled around in mostly lush Inwood Park, poison ivy and all.

The field trip leader was George Harlow, Curator, Department of Earth and Planetary Sciences at AMNH. We ambled around, first in the city, along Cooper Street and then into Isham Park. Then we went to Inwood Park. The aerial view map below is where we went in Manhattan, but not the Bronx. As you can see in the simplified geologic map and cross-section below, the geology is quite complex. It is also almost completely covered with vegetation, which is very often poison ivy. It is nuts. I longed for a western or southwest field location where all the outcrops are exposed.

The first very cool thing we saw was a great example of boudinage. See the image below (try squinting - they're there). The boudins were in the Inwood Marble and are a result of a more resistance or rigid layer (probably proto-sandstone) within a more plastic layer (possibly proto-limestone) undergoing compression.

We saw some good-sized garnets with eye-shaped feldspar growths:

Tramping into the Inwood Park, we saw "potholes," which I have seen elsewhere but did not know that they were created from glacial meltwater, with a rock or two swirling around and down, carving out a deep hole. The opening on this one - in Manhattan Schist - is about a 2-foot diameter.

By walking north and crossing the Henry Hudson bridge, we ended up in the Bronx, looking at the Fordham Gneiss. At this outcrop, we saw more garnet, amphibole, pyrite, and ptygmatic folding in the gneiss. A very good trip, all in all, and we were finished by 2pm.


Summer Practicum Activities - #NYCgeology along 5th Avenue

It's all starting now! My summer will be spent doing research in astronomy at the museum and going on field trips with curators and post-docs affiliated with the MAT program.

Today, I went on a "field trip" to see  some of the building stones of a part of Manhattan, New York. Led by Denton Ebel, the trip went from the lower Central Park area to 5th Avenue and 45th Street. We saw an array of rock types, many of which came imported from Italy. Building stones are a great way to teach geology when you a) don't have a budget for a real field trip and b) don't have access to real geology right in the neighborhood.

Here are some shots from inside the Apple Store, where we saw the "special" rock that Apple loved so much that they purchased they whole mine so they could brand their stores. We also saw some lovely partial melting migmatites.