A Little About Cross-Bedding
Photo by Jesse Varner on Flickr
Let’s talk about some geology! I haven’t had much time to write any posts up lately, but I’ll try my best to have some new and informative posts coming your way this summer. Let’s start with some cool cross-bedding:
The photo above shows cross-bedding of Navajo Sandstone at Zion National Park in Utah. So what’s happened with the sandstone you see above? First off, sandstone is a type of sedimentary rock, which originally wasn’t solid rock like what you see above. Navajo Sandstone - when it was sand dunes I should say - was being deposited during the Lower/Early Jurassic Period, which was around 190 million years ago!
Over time, sand dunes were cemented together after being deposited there. The reasons we see a change in direction is because of the way the strong winds had blown the sand dunes, which accumulated, hardened, and eroded to give you the layers and patterns above, and many of the formations and stunning natural sculptures you see when you go out west to parks like Zion.
It is thought that the Appalachian Mountains are a factor to the formation of the sandstone in Zion National Park. Back in the day - around 480 million years ago - the Appalachian Mountains were practically as high as the Alps are today, and extended to what is now Texas! The reason being because of a lovely thing called plate tectonics. A lot was sure different back in ancient times. By the time of the Lower/Early Jurassic (199 mya - 175 mya), the Appalachian Mountains were very eroded, and it is thought that winds and rivers carried this sediment over time to the western parts of what is now America, forming the massive seas of sand dunes (that were similar to what you see today in the Sahara Desert) before turning into the formations at Zion National Park. I highly suggest going to National Parks like Zion; you will have an amazing time!