Video of a strata full of these Ironstone Concretions. These rare formations were formed at the bottom of an ancient sea, as iron was rolled across the bottom by tides and waves, building up rock on the outside and a spherical shape; then sinking into the muddy bottom. Now they are being forced out of that strata (over more millions of years). For scale, they range from 8 to 12 feet in diameter. Color washed out of video by rain clouds and youtube.
Ironstone Concretions
- Thread starter sharps45
- Start date
Maybe run it through iMovie before YouTube to give it a bit of ooomph! Suspect you like it as it is, good on ya!
GeoM1
Well-Known Member
- Join
- Jan 23, 2019
- Messages
- 89
- Age
- 43
Nice video and great topic! I have to say, lacking all other information to sound credible, I suggest that those features were not formed during active sedimentation as you suggest, but after deposition by diagenesis (early geochemical reactions). Sure, some iron stones form as you say, an oolitic process, and those are around 2mm in diameter.
The photo here is from my yard looking up at a Cretaceous bluff. You can see similar large circular reddish “boulders” in the very upper layer. They are concretions formed during diagenesis.
But again, I’m sitting afar and don’t have any more info than your video. Love to know more about the location!
Attachments
Was out there with a geologist, so I took his word on it. There are smaller sized ones in the area- down to baseball sized that rockhounds polish. This is in the San Rafael Swell in Eastern Utah, and I've heard it's well known in the geologist community. I really don't care how they were formed, but they are very cool and there are hundreds of these big ones in a couple of square miles.
