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Comparison of vitrified and unvitrified Eocene woody tissues by TMAH thermochemolysis - implications for the early stages of the formation of vitrinite.

Kaelin PE, Huggett WW, Anderson KB - Geochem. Trans. (2006)

Bottom Line: Samples of vitrified and unvitrified Eocene woody plant tissues collected from the Fossil Forest site, Geodetic Hills, Axel Heiberg Island, have been characterized by TMAH thermochemolysis.All samples are gymnosperm-derived, are of very low maturity and all share the same post-depositional geologic history.Differences in the distributions of products observed from vitrified and unvitrified samples suggest that vitrification of woody tissue is associated with modification of the lignin C3 side chain, following loss of all or most of the carbohydrate present in the precursor woody tissues.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Geology, Southern Illinois University Carbondale, Carbondale, IL 62901, USA. kaelin@siu.edu

ABSTRACT
Samples of vitrified and unvitrified Eocene woody plant tissues collected from the Fossil Forest site, Geodetic Hills, Axel Heiberg Island, have been characterized by TMAH thermochemolysis. All samples are gymnosperm-derived, are of very low maturity and all share the same post-depositional geologic history. Differences in the distributions of products observed from vitrified and unvitrified samples suggest that vitrification of woody tissue is associated with modification of the lignin C3 side chain, following loss of all or most of the carbohydrate present in the precursor woody tissues. The key driver of vitrification appears to be physical compression of the tissue following biological removal of cellulosic materials.

No MeSH data available.


Samples characterized in the present study. A. Unvitrified woody tissue. (Differences in color are due to incomplete drying). B and C. Vitrified aerial (branch) tissue illustrated in polished cross section (B) and polished parallel with the bedding plane (C). D. Vitrified root tissue illustrated in polished cross section.
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Figure 3: Samples characterized in the present study. A. Unvitrified woody tissue. (Differences in color are due to incomplete drying). B and C. Vitrified aerial (branch) tissue illustrated in polished cross section (B) and polished parallel with the bedding plane (C). D. Vitrified root tissue illustrated in polished cross section.

Mentions: The samples used in the present study are illustrated in Figure 3. Samples described as woody, or unvitrified (Figure 3A), are visually well preserved uncompressed tissues. Growth rings and other well preserved macroscopic structures are clearly apparent and these samples retain a brownish woody color. Two vitrified samples (branch and root-derived) are also described. These samples are compressed parallel to the bedding plane and retain fewer macroscopically observable characteristics than the uncompressed sample, although in some cases compressed ring structures are still visible in polished cross section. Branch and root tissues are differentiated on the basis of recognizable preserved macroscopic characteristics (general shape, character and form of branching etc) and compression ratio, defined as width parallel to the bedding plane divided by mean thickness parallel to the bedding plane. These samples are black in color, break with a conchoidal fracture, and are harder and denser than the unvitrified samples. Aerial (branch) tissue (Figure 3B and 3C) is identified on the basis of its lower compression ratio (~6:1) and asymmetry. Branches often exhibit asymmetric compression due to the differences in wood density of tissues under compression and tension; lower and upper parts of the branch respectively. In polished cross section (Figure 3B) this sample appears completely vitrified, but when polished parallel with the bedding plane (Figure 3C), some less altered layers become apparent. Care was taken in sub-sampling this sample for thermochemolysis to minimize inclusion of unvitrified materials.


Comparison of vitrified and unvitrified Eocene woody tissues by TMAH thermochemolysis - implications for the early stages of the formation of vitrinite.

Kaelin PE, Huggett WW, Anderson KB - Geochem. Trans. (2006)

Samples characterized in the present study. A. Unvitrified woody tissue. (Differences in color are due to incomplete drying). B and C. Vitrified aerial (branch) tissue illustrated in polished cross section (B) and polished parallel with the bedding plane (C). D. Vitrified root tissue illustrated in polished cross section.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1622741&req=5

Figure 3: Samples characterized in the present study. A. Unvitrified woody tissue. (Differences in color are due to incomplete drying). B and C. Vitrified aerial (branch) tissue illustrated in polished cross section (B) and polished parallel with the bedding plane (C). D. Vitrified root tissue illustrated in polished cross section.
Mentions: The samples used in the present study are illustrated in Figure 3. Samples described as woody, or unvitrified (Figure 3A), are visually well preserved uncompressed tissues. Growth rings and other well preserved macroscopic structures are clearly apparent and these samples retain a brownish woody color. Two vitrified samples (branch and root-derived) are also described. These samples are compressed parallel to the bedding plane and retain fewer macroscopically observable characteristics than the uncompressed sample, although in some cases compressed ring structures are still visible in polished cross section. Branch and root tissues are differentiated on the basis of recognizable preserved macroscopic characteristics (general shape, character and form of branching etc) and compression ratio, defined as width parallel to the bedding plane divided by mean thickness parallel to the bedding plane. These samples are black in color, break with a conchoidal fracture, and are harder and denser than the unvitrified samples. Aerial (branch) tissue (Figure 3B and 3C) is identified on the basis of its lower compression ratio (~6:1) and asymmetry. Branches often exhibit asymmetric compression due to the differences in wood density of tissues under compression and tension; lower and upper parts of the branch respectively. In polished cross section (Figure 3B) this sample appears completely vitrified, but when polished parallel with the bedding plane (Figure 3C), some less altered layers become apparent. Care was taken in sub-sampling this sample for thermochemolysis to minimize inclusion of unvitrified materials.

Bottom Line: Samples of vitrified and unvitrified Eocene woody plant tissues collected from the Fossil Forest site, Geodetic Hills, Axel Heiberg Island, have been characterized by TMAH thermochemolysis.All samples are gymnosperm-derived, are of very low maturity and all share the same post-depositional geologic history.Differences in the distributions of products observed from vitrified and unvitrified samples suggest that vitrification of woody tissue is associated with modification of the lignin C3 side chain, following loss of all or most of the carbohydrate present in the precursor woody tissues.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Geology, Southern Illinois University Carbondale, Carbondale, IL 62901, USA. kaelin@siu.edu

ABSTRACT
Samples of vitrified and unvitrified Eocene woody plant tissues collected from the Fossil Forest site, Geodetic Hills, Axel Heiberg Island, have been characterized by TMAH thermochemolysis. All samples are gymnosperm-derived, are of very low maturity and all share the same post-depositional geologic history. Differences in the distributions of products observed from vitrified and unvitrified samples suggest that vitrification of woody tissue is associated with modification of the lignin C3 side chain, following loss of all or most of the carbohydrate present in the precursor woody tissues. The key driver of vitrification appears to be physical compression of the tissue following biological removal of cellulosic materials.

No MeSH data available.