Everywhere you go, there is a geological history ⏳🗺. You don't need a spectacular landscape, dramatic glaciers or an erupting volcano with running lava to witness the wonders of the Earth... Perhaps you only need to look into your backyard. Who knows, there could be a T-Rex under your house. Or a fossil that is a missing link to many unanswered questions. Or even a mineral that hasn't yet been discovered 🦖💎. New York, one of Earth's busiest concrete jungles, is probably where you least expect to find interesting geological wonders 🌃🍎🏔. In Central Park, you can find exposed cliffs up to 1.1 billion years old. They've been through a lot and witnessed many changes in Earth's history, but most recently, they were sculpted by glaciers ~22,000 years ago. These cliffs are called roche moutonnée, or whalebacks (hvalbök), which fits the description perfectly. By looking at their shape, you can easily determine the direction of the ice flow 🐳. The ice sheet that shaped them is called the Wisconsin ice sheet (from the Wisconsin glaciation), which covered a large area of North America, but its boundary was roughly where Manhattan is today. That glaciation began 100,000 years ago and ended 11,000 years ago. But the maximum ice extent occurred 21,000–25,000 years ago, roughly when the glacier covered Manhattan. Not only did the glacier shape these rocks, but it also scraped them with boulders embedded in the ice, leaving deep lines in the cliffs, called glacial striations (jökulrákir). The glacier also distributed large random boulders that can be seen all over Central Park, called erratics (Grettistak). I've seen whalebacks in all kinds of landscapes all over the Northern Hemisphere. Some newly revealed in front of glaciers in Iceland, some in the middle of a Swedish canola field by a farm. But to witness them here, so far away from their element, in the middle of all these skyscrapers, makes you really think deeply of how sudden our environments can change 🧊🕰🌇. If you want to know more about the geology of Central Park, I have a highlight on my page explaining everything in details 👌🏻. ©Copyright - geology_with_helga