Pseudofossils are inorganic objects, markings, or impressions that might be mistaken for fossils. Pseudofossils may be misleading, as some types of mineral deposits can mimic lifeforms by forming what appear to be highly detailed or organized structures. One common example is when manganese oxides crystallize with a characteristic treelike or dendritic pattern along a rock fracture. The formation of frost dendrites on a window is another common example of this crystal growth. Concretions are sometimes thought to be fossils, and occasionally one contains a fossil, but are generally not fossils themselves. Chert or flint nodules in limestone can often take forms that resemble fossils.
Backgroundedit
Pyrite disks or spindles are sometimes mistaken for fossils of sand dollars or other forms (see marcasite). Cracks, bumps, gas bubbles, and such can be difficult to distinguish from true fossils. Specimens that cannot be attributed with certainty to either fossils or pseudofossils are treated as dubiofossils. Debates on whether specific forms are pseudo or true fossils can be lengthy and difficult. For example, Eozoön is a complex laminated form of interlayered calcite and serpentine originally found in Precambrian metamorphosed limestones (marbles). It was at first thought to be the remains of a giant fossil protozoan (Dawson, 1865), then by far the oldest fossil known. Similar structures were subsequently found in metamorphosed limestone blocks ejected during an eruption of Mount Vesuvius. It was clear that high-temperature physical and chemical processes were responsible for the formation of Eozoön in the carbonate rock (O'Brien, 1970). The debate over the interpretation of Eozoon was a significant episode in the history of paleontology (Adelman, 2007).
Chemical gardens can produce branching microtubuli of 2-10 μm in diameter and can resemble very closely the shapes of fossilized primitive fungi or microorganisms. It has been proposed that ancient, precambrian, structures that have been identified as the evidence for the first fungi or even the first life, are more probably products of ancient natural chemical gardens.[1]
Concretion with calcite-filled septarian cracks. Scale in mm.
Eozoön canadense from the Precambrian of Canada, a metamorphic rock made of interlayered calcite and serpentine. A well-known pseudofossil (Adelman, 2007). Scale in mm.
Cone-in-cone structures produced by compression of limestone. Sometimes mistaken for fossils, thus becoming examples of pseudofossils.
A marcasite crystal form resembling a sand dollar.
A Miocene pseudocoprolite from Washington state. This is one of the most common pseudofossils because it so closely resembles a coprolite. Scale in mm. See Spencer (1993).
Cross-section of a concretion showing layers that resemble tree rings.
Referencesedit
^McMahon, Sean (2020). "Earth's earliest and deepest purported fossils may be iron-mineralized chemical gardens". Proc. R. Soc. B. 286 (1916). doi:10.1098/rspb.2019.2410. PMC6939263.
Bibliographyedit
Adelman, J. (2007). "Eozoön: debunking the dawn animal". Endeavor. 31 (3): 94–98. doi:10.1016/j.endeavour.2007.07.002. PMID 17765972.
Dawson, J. W. (1865). "On the structure of certain organic remains in the Laurentian limestones of Canada". Quart. J. Geol. Soc. 21: 51–59. doi:10.1144/GSL.JGS.1865.021.01-02.12.
O'Brien, C. F. (1970). "Eozoön canadense "The dawn animal of Canada"". Isis. 61 (2): 206–223. doi:10.1086/350620.
Spencer, P. K. (1993). "The "coprolites" that aren't: the straight poop on specimens from the Miocene of southwestern Washington State". Ichnos. 2 (3): 1–6. doi:10.1080/10420949309380097.
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January 01, 1970
pseudofossil, inorganic, objects, markings, impressions, that, might, mistaken, fossils, misleading, some, types, mineral, deposits, mimic, lifeforms, forming, what, appear, highly, detailed, organized, structures, common, example, when, manganese, oxides, cry. Pseudofossils are inorganic objects markings or impressions that might be mistaken for fossils Pseudofossils may be misleading as some types of mineral deposits can mimic lifeforms by forming what appear to be highly detailed or organized structures One common example is when manganese oxides crystallize with a characteristic treelike or dendritic pattern along a rock fracture The formation of frost dendrites on a window is another common example of this crystal growth Concretions are sometimes thought to be fossils and occasionally one contains a fossil but are generally not fossils themselves Chert or flint nodules in limestone can often take forms that resemble fossils Background editPyrite disks or spindles are sometimes mistaken for fossils of sand dollars or other forms see marcasite Cracks bumps gas bubbles and such can be difficult to distinguish from true fossils Specimens that cannot be attributed with certainty to either fossils or pseudofossils are treated as dubiofossils Debates on whether specific forms are pseudo or true fossils can be lengthy and difficult For example Eozoon is a complex laminated form of interlayered calcite and serpentine originally found in Precambrian metamorphosed limestones marbles It was at first thought to be the remains of a giant fossil protozoan Dawson 1865 then by far the oldest fossil known Similar structures were subsequently found in metamorphosed limestone blocks ejected during an eruption of Mount Vesuvius It was clear that high temperature physical and chemical processes were responsible for the formation of Eozoon in the carbonate rock O Brien 1970 The debate over the interpretation of Eozoon was a significant episode in the history of paleontology Adelman 2007 Chemical gardens can produce branching microtubuli of 2 10 mm in diameter and can resemble very closely the shapes of fossilized primitive fungi or microorganisms It has been proposed that ancient precambrian structures that have been identified as the evidence for the first fungi or even the first life are more probably products of ancient natural chemical gardens 1 nbsp Manganese Dendrite crystal on a limestone bedding plane from Solnhofen Germany Scale in mm nbsp Concretion with calcite filled septarian cracks Scale in mm nbsp Eozoon canadense from the Precambrian of Canada a metamorphic rock made of interlayered calcite and serpentine A well known pseudofossil Adelman 2007 Scale in mm nbsp Cone in cone structures produced by compression of limestone Sometimes mistaken for fossils thus becoming examples of pseudofossils nbsp A marcasite crystal form resembling a sand dollar nbsp A Miocene pseudocoprolite from Washington state This is one of the most common pseudofossils because it so closely resembles a coprolite Scale in mm See Spencer 1993 nbsp Cross section of a concretion showing layers that resemble tree rings References edit McMahon Sean 2020 Earth s earliest and deepest purported fossils may be iron mineralized chemical gardens Proc R Soc B 286 1916 doi 10 1098 rspb 2019 2410 PMC 6939263 Bibliography editAdelman J 2007 Eozoon debunking the dawn animal Endeavor 31 3 94 98 doi 10 1016 j endeavour 2007 07 002 PMID 17765972 Dawson J W 1865 On the structure of certain organic remains in the Laurentian limestones of Canada Quart J Geol Soc 21 51 59 doi 10 1144 GSL JGS 1865 021 01 02 12 O Brien C F 1970 Eozoon canadense The dawn animal of Canada Isis 61 2 206 223 doi 10 1086 350620 Spencer P K 1993 The coprolites that aren t the straight poop on specimens from the Miocene of southwestern Washington State Ichnos 2 3 1 6 doi 10 1080 10420949309380097 nbsp Wikimedia Commons has media related to Pseudofossils Retrieved from https en wikipedia org w index php title Pseudofossil amp oldid 1204734413, wikipedia, wiki, book, books, library,
