Jesta384 Posted October 26, 2009 Share Posted October 26, 2009 (edited) I see all these beautiful concretions that you all find. And not just from the Mazon Creek....Ive done some research and read about the "big spots" you can find them...but then I've read other topics showing concretions in places not on or near the list I found! Beyond that....how the heck do I even know what im looking at? I need some concretions 101 help....thanks! Edited October 26, 2009 by Auspex language Link to comment Share on other sites More sharing options...
Bear Posted October 26, 2009 Share Posted October 26, 2009 As with any other endeavor, the trick is in the learning how. This is done by looking at a lot of concretions. After a while you will learn to recognize them. This is the art of surface collecting - developing the eye to see things that are a little different from the other things they are surrounded by. That is only accomplished by practice. Good luck! Link to comment Share on other sites More sharing options...
Jesta384 Posted October 27, 2009 Author Share Posted October 27, 2009 maybe a few in depth pictures or tips how to ID them please? And like i was asking....Ive read about the "big locations" but are they just about available EVERYWHERE? or only where conditions could be right such as....(fill in the blank)... Link to comment Share on other sites More sharing options...
micropterus101 Posted November 11, 2009 Share Posted November 11, 2009 maybe a few in depth pictures or tips how to ID them please? And like i was asking....Ive read about the "big locations" but are they just about available EVERYWHERE? or only where conditions could be right such as....(fill in the blank)... Concretion shape, material, and productivity are diferent at each locality. First to find fossil bearing concretions you need to find a locality = exposure of fossil bearing sediment which is rich in a binding mineral such as calcite or iron. Here in washington state I first look at a good geology map showing areas where tertiary sediments are prevailant. The next step is to do a search online for scientific papers with information on fossils from the areas I found on the geologic map i.e On the map I can see eocene deposits near a town called porter so I do a search on google for porter washington state fossils. Now that I have a general idea of localities in that area by reading reports and scientific papers on the internet I fill up my tank with gas and to that area with the info I have. I look for grey siltsone exposures in roadcuts and hike every creek I can find that runs through those eocene areas I found on the geologic map. In my area any rock I find in a grey siltstone exposure is a concretion, there is no gravel or other rock in grey siltone except in some localities in thin layers which are easily identifyable as non concretionary rock. alot of concretions are round and may be unproductive in one area but very fruitful in others you just have to gain knowledge of each area through trial and error break the concretions open with a hammer if you find some fossils in them collect more concretions from that area and take them home for more careful preparation. If the concretions are mostly unproductive dont give up on that exposure yet. Collect concretions methodically from different layers in the exposure. Alot of times different layers are more productive then others. As you get that search image down of what concretions look like you can find concretions in reworked areas or on beaches where there may be other snarge rock mixed in. Generally concretions are smooth and round or oblong and oval. They vary greatly. Concretion in grey silstone matrix with shrimp claw sticking out. Bucket of concretions from and exposure near the Straights of juan de fuca. Concretions from the way above sea level containing Aturia in them. Concretions broke out of grey siltstone containing crabs. Concretions found on a beach below exposures mixed with other rock. 2 fossil crabs website Link to comment Share on other sites More sharing options...
MB Posted November 11, 2009 Share Posted November 11, 2009 Woaaaaaaaaah Micropterus !!!! I wish to have a lot of those concretions for the sunday fossil show http://www.mbfossilcrabs.com/ Link to comment Share on other sites More sharing options...
glacialerratic Posted November 11, 2009 Share Posted November 11, 2009 I've done a fair amount of collecting in the Mazon Creek area, and you are correct, there are nodules in most of the mid-western states. Look for coal mining areas. The nodules are formed in delta/estuary environments. The fossil bearing ones 'bulge' out a little more on one side. Freeze/thaw cycles, sometimes lots, will open most. Don't get hasty with the hammer, I've messed up a few good ones that way. Link to comment Share on other sites More sharing options...
RJB Posted November 12, 2009 Share Posted November 12, 2009 Concretions with most likely clams in them, but I get the occassional piece of bone sometimes. Concretions already 'popped' open showing some clams. Concretions from Oregon showing crabs inside. Two boxes of concretions from two different sites in Oregon. Concretions from New Zealand. These have large crabs in them. If its a concretion with a fossil, I want it!!! RB 1 Link to comment Share on other sites More sharing options...
glacialerratic Posted November 12, 2009 Share Posted November 12, 2009 RJB, is that shark tooth from OR., too? Amazing collection. Makes me wish I had more travel dollars and more collecting time! Link to comment Share on other sites More sharing options...
Haddy Posted November 12, 2009 Share Posted November 12, 2009 Thanks for the info and pictures! Don't know if I'll ever be in one of those areas collecting, but it's fascinating anyhow! Link to comment Share on other sites More sharing options...
RJB Posted November 12, 2009 Share Posted November 12, 2009 RJB, is that shark tooth from OR., too? Amazing collection. Makes me wish I had more travel dollars and more collecting time! For the life of me I could not figure out what you were talking about and read your post 3 times and then went back up to look at the pics i posted. That shark tooth is from South america. In fact, you just reminded me of a guy im supposed to email. Thanks RB Link to comment Share on other sites More sharing options...
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