Is Devils Tower National Monument in Wyoming a remnant of an ancient giant tree made out of silicon? No, that's not true: Devils Tower is sedimentary rock that got pushed up to the surface millions of years ago. The National Park Service website calls it an igneous intrusion. The way the rock cooled has allowed it to form the tree-trunk-like shape that visitors see today.
The claim appeared in a tweet (archived here) on December 16, 2021. The tweet reads:
Devils Tower is Ancient tree. Look how the hexagon basalt columns curve into the earth just like roots. It is believed that we had a silicon era. There are remnants of mammoth silicon trees all over the earth. This is not dried lava flow. This was alive, organic. Whoa!
This is what the post looked like on Twitter at the time of writing:
(Source: Twitter screenshot taken on Wed Dec 22 19:58:01 2021 UTC)
The tweet includes photos of Devils Tower in Wyoming. That formation began as magma that was formed underground. According to the FAQ page about Devils Tower from the National Park Service website, the magma then pushed up into the next level, which would have been sedimentary rock, where it cooled and hardened. That sedimentary rock layer has since eroded away to show what is now Devils Tower. Some theories state it was part of a volcano, which would explain how magma got involved. But others say it was simply rock that erupted from underground over millions of years. For the exact age of Devils Tower, the National Park Service says evidence shows it formed 50 million years ago, placing the erosion of the rock from underground between 5 million and 10 million years ago.
The chief of resources management at Devils Tower, Russ Cash, told Lead Stories on December 20, 2021, that the tower itself is made out of a rock called phonolite porphyry, which is a "fairly rare type of igneous rock." The way the rock has cooled is called columnar jointing, making the rock look a lot like a tree trunk, he said.
Some people claim that Devils Tower is a tree that's a focal point for energy as some sort of new age meditation claim, Cash said, or that it was placed there by aliens.