Measuring density of silicified wood and determining weight loss after 450°C heating provides useful data for interpreting the process of permineralization. These simple gravimetric methods do not replace X-ray diffraction, electron microscopy, polarized light microscopy, Raman spectroscopy, and other specialized techniques for studying fossil wood, but they can be performed rapidly, and require minimal laboratory facilities. Woods mineralized with opal have densities of 1.9–2.1 g/cm3, compared to 2.3–2.6 g/cm3 for wood mineralized with chalcedony or quartz. Weight loss after 450°C heating, commonly described as “loss on ignition” can be used to roughly estimate the % of original organic matter that remains in chalcedony or quartz-mineralized wood, using the density of extant taxa for comparison. For opalized wood, 450°C weight loss mostly represents dehydration of the hydrous silica. Data from specimens from 20 localities reveal two characteristics: 1) silicified woods typically consist either of opal or chalcedony/quartz, not an intermediate mixture of the two silica polymorphs; 2) the percentage of organic matter that remains after petrifaction is usually very small.
Fascination with petrified wood has stimulated interest in understanding the process of natural petrifaction. Early attempts of modeling natural petrifaction in the laboratory have been limited to mimicking incipient permineralization resulting in the creation of silica casts of pore spaces and inner cell walls. Silica lithomorphs produced through artificial silicification provided a possible avenue for studying microstructure of wood. More recently artificial petrifaction is motivated by the goal of creating advanced ceramic materials for engineering applications. The concept of using wood as a biotemplate has led to the creation of porous ceramics by cell wall replacement. To some extent artificial and natural petrifaction processes are comparable; although, some of the materials and procedures used in the laboratory are not found in nature. Research focused on the composition and structure of fossil wood from different-aged deposits is compared with research focused on the development of wood-templated porous ceramics. Differences and similarities in the pathways of natural silicification and creation of biomorphous ceramics are discussed. The comparison between artificial and natural silicification highlights the particular significance of the degree to which (de)lignification is needed for silica permeation.
Fossil root- and stemwood of Chionanthus retusus has been found from the Late Pleistocene stratum at Akashi, Hyogo Prefecture, central Japan. The woods of fossil and extant C. retusus are described and compared. The fossil rootwood closely resembles that of the extant individuals in being ring-porous with large pores arranged in one layer in the earlywood, and small pores that gradually decrease in diameter from the earlywood, and are arranged in a flame-like pattern in the latewood. It differs from the wood of the extant species in the larger diameter of wide pores, the quite gradual decrease in vessel diameter from the earlywood to the latewood, and the narrower and lower rays. The fossil stemwood is quite similar to the stemwood of extant C. retusus in being ring-porous with large pores arranged in one or two layers in the earlywood, and small pores .that abruptly decrease in diameter from the earlywood, and are arranged in a flame-like pattern. It differs from the wood of the extant species in the larger diameter of wide pores, and the lower rays. Based on their similarity, these fossil woods are identified as the rootand stemwood of C. retusus.
Wood anatomical data for all three extant genera of the Altingiaceae and 23 of the 27 extant genera of the Hamamelidaceae were compiled in an effort to find features distinctive to genera, tribes, or subfamilies within these families. All genera studied have diffuse porous wood (except Corylopsis which tends to be semi-ring porous), vessels are predominantly solitary and narrow (<100 μm, usually <50 μm) and angular in outline, vessel elements are long (>800 μm) with scalariform perforation plates with average bar numbers of 9–44, intervessel pits are mainly scalariform to opposite, vessel-ray parenchyma pits are scalariform with slightly reduced borders and usually are in the square to upright marginal ray parenchyma cells, rays are heterocellular and narrow, usually 1–3-seriate. Although the wood anatomy of both families is relatively homogeneous, it is possible to key out many genera using a combination of qualitative (presence/absence and location of helical thickenings in vessel elements and fibers, crystal occurrence, axial parenchyma abundance, degree of ray heterogeneity) and quantitative features (number of bars per perforation plate and ray width). Helical thickenings are present throughout the vessel elements in three genera (Loropetalum, Altingia, Semiliquidambar) and are restricted to the vessel element tails in two genera (Corylopsis, Liquidambar). Loropetalum has helical thickenings in ground tissue fibers as well. Axial parenchyma abundance varies from scarce to relatively abundant diffuse to diffuse-in-aggregates. One clade of the tribe Fothergilleae (Distylium, Distyliopsis, Sycopsis, Shaniodendron, Parrotia, Parrotiopsis) has more abundant axial parenchyma and is characterized by narrow, usually interrupted bands of apotracheal parenchyma. Nearly exclusively uniseriate rays occur in some species of Hamamelis and in Exbucklandia, Chunia, Dicoryphe, and Fothergilla. These data on extant Altingiaceae and Hamamelidaceae not only provide information relevant for systematic, phylogenetic and ecological wood anatomy and wood identification, but also give context for reviewing the fossil woods assigned to them. A new combination is proposed for the Miocene Liquidambar hisauchii (Watari) Suzuki & Watari from Japan: Altingia hisauchii (Watari) Wheeler, Baas & Lee.
Fossil wood is common in the Late Cretaceous and Early Paleocene of the San Juan Basin, New Mexico. Six types of dicotyledonous wood are recognized: Paraphyllanthoxylon arizonense Bailey, Paraphyllanthoxylon anasazi sp. nov., Plataninium piercei sp. nov., Metcalfeoxylon kirtlandense gen. et sp. nov., Chalkoxylon cretaceum gen. et sp. nov., Carlquistoxylon nacimientense gen. et sp. nov. Woods with the characteristics of Paraphyllanthoxylon arizonense Bailey are the most common and occur in the Cretaceous Kirtland Shale and the Paleocene Ojo Alamo Sandstone and Nacimiento Formation. This wood type's characteristics are stable from the Cretaceous to the Paleocene. There were no significant differences in the vessel diameters, vessel densities, ray sizes, or estimated specific gravities of the P. arizonense woods from the Late Cretaceous (Kirtland Shale) and Early Paleocene (Nacimiento Formation and Ojo Alamo Sandstone). Based on the samples examined for this study, dicotyledonous woods were more diverse in the Cretaceous (five types) than in the Paleocene (two types) of the San Juan Basin. Diameters of the Cretaceous woods examined ranged from 14-40cm indicating they were trees rather than shrubs; diameters of the Paleocene woods examined ranged from 10-80cm. All the woods have generalized structure with combinations of features seen in more than one extant family, order, or subclass. Information from databases for fossil and extant woods indicates that some combinations of features (e. g., solitary narrow vessels, low vessel density and scalariform perforation plates, as seen in Metcalfeoxylon kirtlandense and Chalkoxylon cretaceum), while relatively common in the Cretaceous, represent strategies of the hydraulic system that are extremely rare in the Tertiary and at present. None of the dicotyledonous woods have distinct growth rings, although some samples of Paraphyllanthoxylon arizonense from the Paleocene show variations in vessel density and vessel diameter that may correspond to seasonal variations in water availability.
Fossil angiosperm wood was collected from shallow marine deposits in the Upper Cretaceous (Coniacian) Comox Formation on Vancouver Island, British Columbia, Canada. The largest specimen is a log at least 2 m long and 38 cm in diameter. Thin sections from a sample of this log reveal diffuseporous wood with indistinct growth rings and anatomy similar to Paraphyllanthoxylon. Occasional idioblasts with dark contents in the rays distinguish this wood from previously known Paraphyllanthoxylon species and suggest affinity with Lauraceae. The log also includes galleries filled with dry-wood termite coprolites. This trunk reveals the presence of tree-sized angiosperms in what is now British Columbia, and the association of dry-wood termites with angiosperm woods by the Coniacian (89 Ma). To understand the significance of this discovery, we reviewed the record of Cretaceous woods from North America. Our analysis of the distribution of fossil wood occurrences from Cretaceous deposits supports the conclusion that there was a strong latitudinal gradient in both the size and distribution of angiosperm trees during the Late Cretaceous, with no reports of Cretaceous angiosperm trees north of 50°N paleo-latitude in North America. The rarity of angiosperm wood in the Cretaceous has long been used to support the idea that flowering plants were generally of low-stature for much of the Cretaceous; however, large-stature trees with Paraphyllanthoxylon-like wood anatomy were widespread at lower–middle paleo-latitudes at least in North America during the Late Cretaceous. Thus, the presence of a large Paraphyllanthoxylon log in the Comox Formation suggests that Vancouver Island has moved significantly northward since the Coniacian as indicated by other geological and paleobotanical studies.
of the Envigne valley (Vienne, Western France) 530 Woodcock DW, Meyer HW, Prado Y. 2019. The Piedra Chamana fossilwoods (Eocene, Peru), II 551 Pujana RR, Ruiz DP. 2019. Fossilwoods from the Eocene–Oligocene (Río Turbio Formation) of southwestern Patagonia (Santa Cruz province, Argentina) 596 Vanner
Fossilwood is one of the most common types of plant fossil and often is well-preserved. It was one of the first objects ever observed with a microscope ( Hooke 1665 ). The development of petrographic thin-sections in the XIX th century has allowed researchers to pursue detailed anatomical studies
. 2018 ). Shipworms, bivalve molluscs of the family Teredinidae, are notorious for boring into wood that is immersed in sea water. Conifers are the most abundant and diversified fossilwood in this assemblage, representing around 90% and at least five different taxa. They consist of large logs
section of carbonized wood above and a section of fossilized wood below, both seen through the microscope. In the preceding chapter ( Observ. XVI . Of Charcoal, or burnt Vegetables ) Hooke also compared fossilwood with burnt wood but not with green wood.