Polystrate fossil: Difference between revisions

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Geologists find nothing anomalous about upright fossil trees found in Carboniferous coal-bearing strata being associated with marine or brackish-water fossils. Because they lived on subsiding coastal plains or pull-apart basins open to the coast, it was quite frequent for subsidence to periodically outpace the accumulation of sediments such that adjacent shallow marine waters would periodically inundate coastal plains in which the trees were buried. As a result, sediments containing marine fossils would periodically accumulate within these areas before being replaced by coastal swamps - either as sediments filled in the shallow sea or as the sea level fell. Also, according to [[Paleoecology|ecological reconstructions]] by geologists, specific assemblages of the types of trees found as upright fossils occupied brackish water, even saline coastal swamps much like modern [[mangrove]] swamps. Thus, finding marine and brackish water fossils associated with these trees is no different than finding brackish water or marine animals living in modern mangrove swamps.<ref name=falcon2005 /><ref name=falcon2006a /><ref name=falcon2006b />

A detailed study by Taylor and Vinn (2006) of the microstructure of fossils which have been traditionally identified as ''"Spirorbis"'' in the geological literature revealed that they consist of the remains of at least two completely different animals. Taylor and Vinn discovered that the ''"Spirorbis"'' fossils found in sedimentary strata, including the Joggins and other Carboniferous coal measures deposited from the [[Ordovician]] to [[Triassic]] periods are the remains of an extinct order of [[Lophophore|lophophorates]] (now called [[microconchids]]) unrelated to modern marine tube-worms ([[Annelid]]s) to which the genus ''Spirorbis'' belongs.<ref name=TaylorOthers2006a>Taylor, P.D. and O. Vinn, 2006, ''Convergent morphology in small spiral worm tubes ('Spirorbis') and its palaeoenvironmental implications''. Journal of the Geological Society, London 163:225–228.</ref> This contradicts arguments made by Harold Coffin and other creationists that ''"Spirorbis"'' fossils within strata containing polystrate fossils indicate their deposition in a marine environment, because these fossils are classified as the remains of extinct fresh and brackish water microconchids instead of the remains of the marine genera ''Spirorbis'' as they have been misidentified in the geologic literature.<ref name=ZatonOthers2012a>Zaton, M., O. Vinn, A.M.F. Tomescu, 2012, ''Invasion of freshwater and variable marginal marine habitats by microconchid tubeworms – an evolutionary perspective.'' Geobios. vol. 45, pp. 603-610.</ref>

===Quaternary examples===