Three-dimensional confocal imagery and spectral analysis of ancient cellularly preserved fossils

The research described in this dissertation is designed to investigate and define the applicability and limitations of the confocal laser scanning microscope (CLSM) for the paleobiologic study of three-dimensionally permineralized (petrified) fossils, including chert-permineralized Eocene fern rhizomes, calcite-permineralized axes of higher plants preserved in Carboniferous coal balls, the phosphate-permineralized embryo of a lowest Cambrian ctenophore (comb jelly), and an array of chert-permineralized Precambrian microorganisms, both eukaryotic acritarchs and filamentous and coccoidal prokaryotic microbes, ranging from ∼650 to ∼3,465 Ma in age. This work documents the first use in paleobiology of a CLSM for the comparative investigation of petrified plants, permineralized animals, and fossilized microbes, and records results of the first CLSM-based systematic analysis of Precambrian microfossils, including investigation of specimens billions of years older and appreciably more geochemically altered than microfossils previously examined by use of a CLSM. Where appropriate, the results here reported are supported by Raman spectroscopic analyses of the kerogen comprising individual CLSM-analyzed specimens and by data acquired from heating experiments designed to mimic the thermally induced geochemical alteration of such fossils that occurs during diagenesis.; The results of these studies show that (1) for many such fossils, a CLSM can be used to produce quality three-dimensional images that provide morphological information superior to that available from standard optical microscopy; that (2) such images, coupled with their ability to be rotated after processing to show a fossil from multiple perspectives, can document in situ (within a petrographic thin section) the spatial relations of a fossil and its enclosing matrix in ways unavailable by any other means; and that (3) because a CLSM can "see" fossils present within rocks, use of this instrument in paleobiology has numerous advantages over surface-restricted techniques (e.g. SEM, TEM, SIMS).; In short, the work here reported documents for the first time and in some detail that the use of a CLSM can provide a non-destructive, non-intrusive means to investigate many ancient organic-walled permineralized fossils, and can be of great benefit to paleobiology in general and, perhaps also, to the exo/astrobiological search for evidence of ancient life on other planets.