The Proceedings of the Eighth International Conference on Creationism (2018)

a Berkovich tip indenter. The loading condition was controlled as follows: a 10-sec loading segment, a 10-sec unloading segment, and 5000 μN applied maximum load. RESULTS 1. Chemical Composition Figure 3 shows the chemical composition of mummified wood and petrified wood. The petrified wood region is 36.5 ± 3.2% oxygen and 63.5 ± 3.2% silicon and is totally petrified without the organic material containing carbon. The mummified wood region is 80 ± 1.3% carbon, 16.9 ± 1.7% oxygen, 0.9 ± 0.4% sulfur, and 1.3 ± 0.4% calcium. Compared to living wood which contains 50% carbon, 42% oxygen, 6% hydrogen, 1% nitrogen, and 1% other elements such as calcium and sulfur (Pettersen 1984). The relative carbon weight is much greater for the mummified wood. One possible reason for a greater relative amount of carbon and a lower relative amount of oxygen and hydrogen in the mummified wood is that the mummified wood was completely dehydrated. In living wood, water is present thus increasing the amounts of oxygen and hydrogen. The primary difference between mummified wood and living wood is the amount of water. 2. Hardness Nano-indentation results revealed that the nanohardness of the petrified region was 4.57 ± 3.11 GPa, and the mummified region was 0.71 ± 0.39 GPa. The hardness values have a fairly large deviation because the sample contained pores from the original wood cells. In spite of the deviations in measurements, the hardness values of petrified wood were 6-7 times greater than those of the mummified wood, thus confirming that petrified wood and mummified wood are different materials. Furthermore, one would anticipate that the hardness would be greater for the petrified region when compared to the mummified region as silica is much harder than carbon. 3. Microstructures A. Petrified Wood Figure 4 shows the images on the polished surface of the petrified wood sample in the transverse orientation taken by an optical microscope (a-b) and an SEM (c-d). Wood tracheid, which is a water conducting cell in the xylem of wood, are divided into two wood cells: early wood and late wood. Early wood is laid down first in the first half of the growing season and less dense with a larger lumen area. On the other hand, late wood is laid down in the second half of the same growing season and denser with a smaller lumen area. The early and late wood compose a clear periodic pattern especially in conifers as shown in Figure 4a (Higuchi, 1997). Figure 4a shows that these late wood cells and early wood cells appear as alternating bands. Figure 4b shows closer examination of the late wood cells revealing uncollapsed cell walls filled with mineral deposits. Figure 4c shows the early wood and late wood, and Figure 4d shows a line of semi-circular openings and highly compressed cell walls. It is probable that large compressive loads from the Genesis Flood, whether during or afterward, might occur before mineralization because mineralization induces a brittle fracture behavior of which was not observed in the petrified regions of the specimens. Fracture surfaces of the petrified wood were also observed using the SEM. Figure 5 shows a preserved tracheid. In a longitudinal direction, it is noticeable that the surface of the tracheid is petrified; also, the inside of the tracheid is filled with silica mineralization (Figure 5 a). In the transverse direction, the wood cell structure is not preserved in a perfect geometric shape although the cell shape is recognizable. However, one can note that the cell wall is mineralized, and the individual cells are filled with silica (Figure 5 b). B. Transition Region Between Petrified Wood and Mummified Wood Figure 6 shows optical micrographs of the transition region between the mummified region and the petrified region of the same piece of wood from the polished sample. Figure 6a shows the petrified regions interspersed among the mummified wood region. When examined under higher magnification, the compressed wood cell structures in the mummified wood region are apparent. Figure 6b shows a noticeable boundary between the petrified region and the mummified region. Note that there is no transitioning gradient of material between the petrified wood and the mummified wood at the microscale. Each region of the petrified wood and the mummified wood is distinguishable and not merged together. Clearly, both regions are the same age, but the chemical compositions and the associated chemical reactions are indicative of different chemical processes in the past. Also, these results indicate that the levels of heat and pressure were the same since the regions are so close to each other and yet distinguishable. If there were a material gradient transition between the petrified and mummified regions, one could expect that a heat gradient or pressure gradient induced the different chemical reactions in the two regions. In the absence of the material gradients, it appears that the pressure and temperature did not play a significant role during this fossil wood formation. Sigleo (1979) also reported that the silicification process occurred at the surface temperature and pressure associated with typical surface and groundwater conditions. C. Mummified Wood Figure 7 shows the cellular structures of the mummified wood. In the longitudinal direction, the wood tissue of the tracheid and rays are well preserved (Figure 7a-c). It is also noticeable that border pits in the tracheid wall are well preserved. On the tracheid wall, there are cracks initiated from the pits or along the wall, and most of the cell walls buckled and delaminated (Figure 7d-e). The transverse direction shows delamination that would arise from dehydration and that the cell tracheid lumens were extremely compressed as buckling is shown in Figure 7e. One can employ the buckling equation for free pipe derived from Euler’s buckling theory for a critical pressure, P cr (Figure 8). The buckling formula is given by where E is the elastic modulus of the tracheid lumen (7 GPa for a conifer), t is the thickness of the tracheid (6 µm), and D is the diameter of the tracheid (15 µm). γ is a Poisson’s ratio, which is the ratio of the transverse to axial strain. Here, the Poisson’s ratio of Baldcypress at 12 % moisture content is used, which is 0.411. The critical buckling pressure, P cr , turns out to be 539 MPa, which is equivalent to 5,506 kg/cm 2 (78,314 lb/in 2 ). This large pressure would come from either sediment onto the wood or wood compressing under large motions from turbulent water transport or from the post-Flood inundations. While most of the cell walls buckled, some of the lumens remained with structural integrity (Figure 7f-g). DISCUSSION Thick deposits of peat are needed to form the lignite layers. Peat is compacted to about one-third of its original volume during coalificationdue tovolume loss fromcompressionand lossoforganic Lee et al. ◀ Partially petrified wood ▶ 2018 ICC 240