Mastering Smart Figure Transcript
Hi, I’m Callan Bentley. Welcome back for another SmartFigure. After watching this video, you should be able to describe the geologic processes that resulted in Shiprock, New Mexico.
Out in the Western United States, there is a single spot where four states come together. These are Arizona, Utah, Colorado, and New Mexico. And right near that four corners region is Shiprock, rising up from the desert.
This is what Shiprock looks like from bottom to top. It’s a tremendous 510 meters tall, over half a kilometer above the desert floor, and that’s around 1700 feet tall.
What is this mountain? How did it form? Well, we get an answer by going back to the understanding of the anatomy of a volcano. Remember that every volcano has a central conduit through which magma moves up to the surface to erupt. It could erupt as a lava flow or it could erupt as an explosion of pyroclastic material.
What we think happened at Shiprock is that there was one of those central conduits that was erupting material (lava and pyroclastic material) out the top, and as that lava moved up towards the vent of the volcano some of that solidified in that volcanic throat or neck. And because that solid, igneous rock was tougher and stood up more to erosion, as compared to the layers of lava and pyroclastic materials that surrounded it, it ended up basically weathering out in high relief, while the surrounding volcano was stripped away.
So Shiprock itself, while it’s an impressive feature, half a kilometer tall or so, is actually a much smaller part of a larger volcano that existed in the past.
When you look at Shiprock today, consider that the magnificent edifice you see there in front of you, is actually a small nubbin that was part of a much larger composite volcano in the past.
Now here’s a question. If you back away from Shiprock, you’ll notice that there are a series of ridges that emanate out from the mountain itself. What do you think is the nature of these ridges, given what you know about Shiprock’s past?
Thank you for your attention. This has been another SmartFigure.