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MicropaleontologyEarth History 1131
MicrofossilsNot necessarily microscopic, but details of a microfossil typically cannot be seen with the naked eyeMany make good index fossils
Common microfossilsForamsRadiolariansDiatoms Conodonts
Common microfossilsProtists
Eukaryotic, single-celled organismsContain forams, radiolarians (pictured below) and diatoms
Common microfossilsForaminifera:
Single-celled, small organisms that either secrete a shell or construct an agglutinated shell.Can be planktonic or benthicFusulinids (pictured below) are common in the fossil record, and very useful for biostratigraphy
Common microfossilsRadiolarians: marine zooplankton
Silica-based testFeed through trapping of food particles
Common microfossilsDiatoms: photosynthetic algae
Silica test
Common microfossilsConodonts: less understood than other microfossils, but very useful for biostratigraphy
Jaw portions (hard parts) are preserved in the fossil recordThermal Alteration Index
Viewing microfossilsThe “big” picture
What can the fossils within a rock specimen tell us about the depositional environment?
Factors include:Rock compositionBathymetryOther influences (biological, chemical, etc.)
Viewing microfossils“Loose specimens”
Can be observed with a hand lens or basic microscope
“Specimens in matrix (rock)”Often viewed in a thin section of a rock (pictured below)