Schopf, J , Kudryavtsev, Anatoliy B. , Czaja, Andrew D. , Tripathi, Abhishek B. .
Three-dimensional Morphological (CLSM) and Chemical (Raman) Imagery of Permineralized Plants and Organic-Walled Microorganisms.
TWO deficiencies have long hampered studies of permineralized (petrified) fossil plants and organic-walled microorganisms, (1) an inability to accurately document their three-dimensional cellular morphology at high spatial resolution, and (2) a lack of means to directly analyze the chemistry of the coaly matter (kerogen) that comprises their cell walls. These needs are met by two techniques recently introduced to paleobotany: three-dimensional confocal laser scanning microscopy (CLSM) and two- and three-dimensional Raman imagery.
Applicable to specimens in petrographic thin sections, cellulose acetate peels, or acid-resistant macerations, CLSM and Raman imagery, together, can provide data by which to characterize, in three dimensions at micron-scale resolution, a one-to-one match of cellular form and kerogenous composition in permineralized carbonaceous plant parts and microorganisms. Particularly useful for studies of Precambrian microbes and comparably minute Phanerozoic organic-walled microfossils, both techniques are also applicable to the investigation of higher plants where they have provided insight into the structure and composition of fossilized cell walls unavailable by any other means. Unlike standard two-dimensional optical photomicrographs, the digitized three-dimensional images provided by CLSM and by Raman can be rotated and visualized (e.g., in video presentations) from multiple perspectives, such images of chert-embedded microscopic fossils being obtainable in thin sections to depths greater than 100 microns by CLSM, and greater than 60 microns by Raman.
Together, use of CLSM and Raman imagery can provide new information about the morphology, cellular anatomy, taphonomy, and geochemical maturity of kerogenous permineralized fossils, and Raman imagery can be used as well to characterize the mineralogy of the fossil-enclosing matrix and the spatial relations between such fossils and their embedding minerals. Because both techniques are non-intrusive and non-destructive, both can be applied to specimens archived in museum collections. These techniques hold promise for fruitful paleobotanical investigation both of chert- and coal ball-permineralized fossil floras.
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1 - University of California Los Angeles, CSEOL-Gelogy Bldg, Los Angeles, California, 90095-1567, USA
Confocal laser scanning microscopy
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 31st, 2006
Time: 11:15 AM