I think that particular Creationist "problems with Darwinism" claim references freshwater shellfish living in limestone rock pools.
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I think that particular Creationist "problems with Darwinism" claim references freshwater shellfish living in limestone rock pools.
Limestone will do it. So will coal, asphaltum (tar), or bitumin. Lots of other things we have to watch out for. Its not rocket science but we do have to be careful in sample selection.
Marine shellfish ingest old deep-water carbon, but we can check our calibration and Delta-R by comparing shellfish and carbon from the exact same proveniences. That lets us be quite accurate.