New Members MT_Man Posted October 12, 2015 New Members Share Posted October 12, 2015 Hello all, I found this on the beach in Oregon a couple years ago. I was hoping to find more information on it. How it was formed? How old it is? ect... Thank you Link to comment Share on other sites More sharing options...
Mediospirifer Posted October 12, 2015 Share Posted October 12, 2015 (edited) Welcome to the Forum! What you have here appears to be a pair of bivalve shells in a limestone matrix. The clam (scallop, mussel, whatever--I can't tell from what's visible) died, the shells opened, then it was buried in sediment before the hinge could become disarticulated. The sediment was high in calcarous pieces Ilike bits of other shells), and over time became limestone. As for how old it is, we'd need to know where it was found and what the rock layers in the area are. I don't know Oregon rocks. Nice piece! Edited October 12, 2015 by Mediospirifer Link to comment Share on other sites More sharing options...
New Members MT_Man Posted October 12, 2015 Author New Members Share Posted October 12, 2015 Thanks Mediospirifer! As for the rock layers or area, I could not tell you either one. But it is nice to have a little backround on what exactly it is!! Link to comment Share on other sites More sharing options...
Mediospirifer Posted October 12, 2015 Share Posted October 12, 2015 You're welcome! If you want to try to figure out the formation and age, check out the links in this thread: LINK There's a lot of information available there. Keep in mind, though, that beach rocks can be brought some distance by wave action. Have fun! Link to comment Share on other sites More sharing options...
Wrangellian Posted October 14, 2015 Share Posted October 14, 2015 Without knowing anything more (such as exactly where you found it and comparing with geological maps to get the formation and hence the age), I am going to suggest Astoria Formation, which I believe is middle Miocene age ~15 million yrs. It looks like a cockle. Link to comment Share on other sites More sharing options...
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