Taphonomy

fossils

• evidence of life preserved in rock

• include remains or organisms & traces

how to become fossil easily

• have preservable parts

• buried by sediment

• escape physical, chemical, & biological destruction

Environment in fossil preservation

• marine & transitional: more favorable

  • higher rate of deposition

  • little to no erosion

  • anerobic environments

• continental: less favorable

  • lower rates of deposition

  • frequently erosional

types of fossil preservation

• preservation of unaltered hard parts

• preservation of unaltered soft parts

• chemical alteration of hard/soft parts

  • permineralization

  • carbonization

  • replacement

  • recrystallization

• imprints of hard parts

  • internal molds

  • external molds

  • casts

• trace fossils or ichnofossils

preservation of unaltered hard parts

shells of invertebrates & single-celled organisms, vertebrate bones & teeth

preservation of unaltered soft parts

freezing, mummification, amber, tar

permineralization

• used in unaltered hard parts

• minerals occurs in porous structures before surrounding decays

• solidifies structure

• decay continues as structure mineralizes

carbonization

• unaltered soft parts

• preserves soft parts with carbon film

• commonly in plants

replacement

• unaltered hard parts

• simultaneous substitution

• slow decay of hard part matches with slow mineralization

recrystallization

• unaltered hard parts

• common with shells/carbonate material

• crystals secreted to form shell

• increase size but keep same chemistry

• preserves overall shape, but destroys fine structure

imprints of hard parts

• casts & molds (impressions)

• surrounding sediment lithifies before organism decays

• decay leaves a mold

• can be internal or external

• commonly in shells & bone

trace fossils

• markings in sediment made by organisms

• ex: burrows, tracks, nests, eggs

• can provide environmental info

• also provide info about the individual that made the traces

Lagerstatte

sedimentary formations that preserve exceptional paleontological info