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Petrified wood specimens found at Maya archaeological sites are presumed to have been used during ceremonial fire-drilling. The source of this fossil wood has been an enigma, because in modern times no fossil wood localities were known to occur in Guatemala. In 2019, field work led to the discovery of two locations where silicified wood is abundant. Physical properties and microscopic characteristics of the fossil wood from the two sites have distinctive differences, suggesting that the geologic source of material used by the Classic Maya for cultural purposes can be recognized.

International audience; Six specimens of the fossil wood Xenoxylon meisteri were discovered in the Upper Jurassic Morrison Formation of central Montana and are described herein. The discovery represents the first confirmed occurrence of the species X. meisteri in North America. In addition, we review all occurrences of petrified wood attributed to Xenoxylon from North America. Early to Late Jurassic X. phyllocladoides specimens of Greenland are accepted. Previously reported occurrences of Xenoxylon from the Lower Jurassic Navajo Sandstone of Utah, Xenoxylon morrisonense Medlyn and X. moorei Tidwell from the Upper Jurassic Morrison Formation of Utah, and fossil woods reported from the Lower Cretaceous Cloverly (Wyoming) and McMurray Sandstone (Alberta, Canada) formations have secondary xylem characteristics incongruous with the genus and are discounted. The remaining accepted specimens are Cretaceous in age from the Canadian Arctic (Valanginian) and the North Slope of Alaska (Albian and Maastrichtian). Thus, these new Montana specimens of Xenoxylon are the earliest and southernmost occurrences of the genus in continental North America. Global distribution and paleoecology strongly imply Xenoxylon was constrained to cool/wet climates. Thus, these lower latitude North American occurrences corroborate other proxies indicating a cooler wetter climate, at least locally/briefly, in the northern portion of the Upper Jurassic Morrison foreland basin.

Petrified wood is important evidence of forest type and past climate. Studies from mainly the Neogene of Turkey described many fossil woods, and revealed valuable information about the paleoenvironment structure and climate. This is the first occurrence of plant macrofossils belonging to the Middle Miocene Climate Optimum, a crucial period in Earth's history, found in Turkey. The purpose of the present study is to investigate, for the first time, the Middle Eocene Climate Optimum of Turkey through the first identification of two paleoxylotomical findings of Lutetian age from Central-North Turkey. After working on the thin wood sections, a new fossil genus of Lauraceae, Actinodaphnoxylon gen. nov. was described with a type species of Actinodaphnoxylon zileensis sp. nov. Another coniferous specimen was described as Pinuxylon cf. P. tarnocziense. These species indicate the presence of warm, humid rainforest and lower mountain forest 40–41 million years ago in the middle Black Sea region (Tokat-Zile) of North-Central Turkey.

Aunque solamente el 11.5% del área de Antioquia tiene afloramientos de rocas sedimentarias, la revisión bibliográfica y elaboración de un mapa digital de las localidades fosilíferas (27), permite concluir que esta región tiene un gran potencial paleontológico. Los datos muestran que las ocurrencias fósiles antioqueñas datan desde el período Ordovícico (~ 485.4 a ~443.8 Ma) hasta el Cuaternario (~ 2.6 Ma al Presente). Además, se encuentran macro-fósiles pertenecientes a diferentes phyla (i.e. Arthropoda, Chordata, Hemichordata, Echinodermata, Mollusca y Trachaeophyta). La paleofauna más antigua está conformada por graptolites y trilobites en metasedimentos del Paleozoico, mientras que moluscos marinos y equinodermos conforman las principales localidades fosilíferas del período Cretácico. La paleoflora (i.e. hojas fósiles y xilópalos) de la zona está asociada a la Formación Amagá (Oligoceno - Mioceno). Finalmente, fósiles de vertebrados terrestres (i.e. mastodontes y equinos) se encuentran en depósitos Cuaternarios. Even though only 11.5% of Antioquia's area has outcrops of sedimentary rocks, a review of the literature and the development of a digital map of fossil localities (27), allows us to conclude that the region has a great palaeontological potential. The data show that Antioquia's fossil occurrences date from Ordovician (~ 485.4 to ~ 443.8Ma) to Quaternary (~ 2.6Ma to the Present). Moreover, there are macro-fossils belonging to different phyla (i.e. Chordata, Echinodermata, Hemichordata, Mollusca and Trachaeophyta). The oldest paleofauna in the area, consists of graptolites and trilobites recorded in Paleozoic metasedimentary rocks, whereas marine mollusks and echinoderms compose the major fossil assemblages of the Cretaceous. The paleoflora (i.e. fossil leaves and petrified wood) in the area is associated with to the Amagá Formation (Oligocene - Miocene). Finally, fossils of terrestrial vertebrates (i.e. mastodons and horses) are recorded in Quaternary deposits.

The Early Cretaceous Jehol Biota, one of the most important Mesozoic lagerstatten in East Asia, is especially well-known for occurrences of fossil feathered dinosaurs and early angiosperms. However, the terrestrial biodiversity, especially the fossil wood record, is poorly known. In this study, several structurally preserved coniferous wood specimens from the Lower Cretaceous Yixian Formation are investigated, based on collections from the Heichengzi Basin in Beipiao of western Liaoning, Northeast China. Four species referred to four genera of fossil wood are described, including Taxodioxylon heichengziense sp. nov., Thujoxylon beipiaoense sp. nov., Sciadopityoxylon liaoningense Ding and Protocedroxylon shengjinbeigouense sp. nov. These new records enlarge the fossil wood diversity of the Yixian Formation up to 10 species in 9 genera, and provide further insights into the forest vegetation composition of the Early Cretaceous Jehol Biota. Systematic analysis of the floral constitution indicates that the petrified forests of the Yixian Formation are dominated by conifers, represented by Araucariaceae, Podocarpaceae, Sciadopityaceae, Pinaceae and Cupressaceae in the western Liaoning region. Palaeoclimatical analysis of the fossil wood assemblage implies that the western Liaoning region was dominated by a cool temperate, wet and seasonal climate with variable interannual water supply in the western Liaoning region during the Early Cretaceous.

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.

Plant fossils from the volcano-clastic marine deposits of the Coniacian Hidden Lake Formation of James Ross Island in Antarctica are described based on their macromorphology. Stratigraphic positions of fossiliferous horizons and details of the lithostratigraphic situation of the middle part of the Hidden Lake Formation are published for the first time. The flora consists primarily of leaf impressions and petrified wood. There are also small amounts of mesofossils, dispersed cuticles and charcoalified wood. The megafossils typically occur fragmented, underpinning their allochtonous origin. The plants are described in systematical order. This contribution in contrast to earlier observations reports a high diversity of pteridophytes (11 taxa) and conifers (6 taxa). Angiosperms representing families Nothofagaceae, Atherospermataceae, probably Lauraceae and Sterculiaceae are the most abundant and common plant groups of the flora (12 taxa). The presence of the tropical fern family Marattiaceae and rarity of the genus Nothofagus are of interest, arguing for the prevalence of a warm temperate to tropical humid climate during the Coniacian in this part of Antarctica.

This study reports the first successful statistical ‘crossdating’ among many ring width time series from petrified wood, thus providing a replicable continuous annual resolution window into tree growth and environmental influences during the middle Miocene. The petrified samples, of the genus Quercus, originated at the Stinking Water (SW) locality in Oregon, a Miocene-aged exposure associated with the Columbia River Basalts. 40AR/39AR dating on pillow basalt from the locality yielded a weighted Plateau Age of 13.79 ± 0.09 Ma placing the death of the trees at the end of the Langhian Stage of the Middle Miocene (15.97 ± 0.05 to 13.65 ± 0.05 Ma), during the middle Miocene Climate Transition (MMCT). Ring width time series from 26 radii, 17 different trees, show significant intercorrelation. A Modified Coexistence Approach was applied to determine the likely climate range when the SW trees were growing. The modified approach included regression of site-mean ring width time series statistic values on estimated soil moisture for the site locations, using site-mean data from 126 modern Quercus sites from across the United States. Identification of highly significant linearities indicated strong relationships between ring width intercorrelation and soil moisture and ring width variability and soil moisture. Comparison of individual modern site-mean statistical values with values calculated for the SW locality suggests a mesic growing environment for the SW Quercus, with moderate temperatures. Geographic placement of modern Quercus sites with site-mean statistics similar to the SW values indicates a modern analogue in the eastern United States. Modern distributions of mesic species in the genera present at the SW locality suggest similarities with the central and southern Appalachian Mountains and the Ozark/Ouachita Mountains, indicating a mean annual temperature range of ≅ 10 °C to ≅ 15 °C and a mean annual precipitation range of ≅ 750 mm to ≅ 1200 mm when the SW Quercus were growing.

The Qaidam Basin with the most complete Cenozoic sedimentary preservation in northern Qinghai-Tibet Plateau is a key area for studying uplift and environmental change of the plateau. Three types of woods, Ulmus (Ulmaceae), Leguminosae (?) (angiosperm) and Cupressaceae (gymnosperm) were recognized from the large-scale preservation of fossil woods in late Miocene Shang Youshashan Formation in northern Qaidam Basin on the Qinghai-Tibet Plateau. Both investigations of their Nearest Living Relatives (NLRs) and previous grassland mammal evidences suggest that there have been temperate deciduous broad-leaved forest and needle-leaved forest with grass in northern Qaidam Basin during the late Miocene in contrast to the desert vegetation found there nowadays. The presence of the ancient forest steppe further implies that the southern part of the plateau used to be adequately low, so that the Indian and East Asian monsoons could approach the northern area and to accommodate the vegetation in late Miocene.

A small number of pre-Columbian black lithic carvings are known to have been found at archaeological sites across the Caribbean, as well as in parts of neighbouring mainland South America. The identity of the material used to create these artefacts is often unknown, but suggestions include lignite, wood, petrified wood, manja(c)k, jet (or ‘jet-like’ materials) and hardened asphalt. These identifications are often historical and lacking any scientific basis, and as such can be unreliable. However, identification of the material has the potential to inform on the source of the carving and thereby pre-Columbian trade routes within the circum-Caribbean region. Four analytical techniques (reflectance microscopy, FTIR, Py-GC/MS, x-ray fluorescence) were applied to samples taken from two carvings found on St Vincent and five comparative materials. Both artefacts were found to be most likely to be carved from cannel coal, indicating that they originated in South American (where cannel coal is found extensively in locations in Colombia and Venezuela), as the material is not found within the Caribbean region.

The occurrence and formation of silicified wood from five late Paleozoic basins in Central Europe was investigated. Fossil wood from diverse geological settings was studied using field observations, taphonomic determinations as well as mineralogical analyses (polarizing microscopy, cathodoluminescence (CL) microscopy and spectroscopy). The results indicate that silicification is either a monophase or multiphase process under varying physico-chemical conditions. In particular, CL studies revealed complex processes of silica accumulation and crystallization. The CL characteristics of quartz phases in silicified wood can mostly be related to blue (390 and 440 nm), yellow (580 nm), and red (650 nm) emission bands, which may appear in different combinations and varying intensity ratios. Yellow CL is typical for initial silicification, reflecting quick precipitation under oxygen-deficient conditions caused by initial decay of the organic material. Blue CL is predominantly of secondary origin, resulting from replacement of precursor phases by a secondary hydrothermal quartz generation or subsequent silicification of wood. The red CL can be related to a lattice defect (non-bridging oxygen hole center&mdash, NBOHC).

The Lower Cretaceous Guantou Formation is known as an important horizon for the Cretaceous petrified woods in southern China. Though abundant Cretaceous wood remains have been found in this formation, only one species has been recognized. A new coniferous wood, Brachyoxylon zhejiangense sp. nov. is described from the Lower Cretaceous Guantou Formation in Xinchang of Zhejiang Province, southeastern China. Anatomically, the new species is characterized by obscure annual rings, mixed type of radial pitting, araucarioid cross-field pits and uniseriate xylem rays. The finding of Brachyoxylon zhejiangense sp. nov. represents the first well-defined record of Brachyoxylon in southeastern China, and enriches the diversity of the Early Cretaceous petrified wood in southern China. Additionally, the new finding sheds new light on further understanding the floral composition, especially the forest vegetation type of the southern phytoprovince in the late Early Cretaceous. Diverse compressed leaf fossils of Cheirolepidiaceae have been described from the Guantou Formation in the fossil locality of the present petrified wood. The co-occurrence of Brachyoxylon zhejiangense sp. nov. and those cheirolepidiaceous leaf fossils provide additional evidences to support that Brachyoxylon may be systematically related to the Cheirolepidiaceae.

The best-known and most-studied petrified wood specimens are those that are mineralized with polymorphs of silica: opal-A, opal-C, chalcedony, and quartz. Less familiar are fossil woods preserved with non-silica minerals. This report reviews discoveries of woods mineralized with calcium carbonate, calcium phosphate, various iron and copper minerals, manganese oxide, fluorite, barite, natrolite, and smectite clay. Regardless of composition, the processes of mineralization involve the same factors: availability of dissolved elements, pH, Eh, and burial temperature. Permeability of the wood and anatomical features also plays important roles in determining mineralization. When precipitation occurs in several episodes, fossil wood may have complex mineralogy.

Diverse and rich fossil wood records have been documented from the Mesozoic of Liaoning Province, NE China. The Tiaojishan Formation (mainly distributed in Beipiao, Chaoyang, Fuxin and Jianchang regions) is one of the most significant horizons for the Jurassic petrified wood in Liaoning Province. Previously, wood fossils of this formation were mainly reported in Beipiao and Chaoyang regions, whereas fossil wood record was merely known in Jianchang region. Here we describe new fossil wood specimens from the Tiaojishan Formation in Jianchang County, western Liaoning. Two fossil wood taxa, i.e., Protaxodioxylon jianchangense Tian et Wang sp. nov. and Xenoxylon peidense Zheng et Zhang were recognized on the basis of anatomical features. These fossil wood records add new data for understanding the fossil wood diversity, floral composition and palaeoclimate of the Tiaojishan Formation. The occurrence of Xenoxylon and Protaxodioxylon implies a cool temperate, wet and seasonal climate condition with interannual variations during the Middle to Late Jurassic transition in western Liaoning region.

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.

A silicified wood, Welkoetoxylon multiseriatum, gen. et sp. nov., is described from the late Early Eocene Green River Formation of southwestern Wyoming. The combination of features observed in W. multiseriatum, including latex tubes (laticifers) in the rays and abundant sheath cells, indicates affinities with the Moraceae. This is the first report of fossil moraceous wood from the Eocene of the western interior of the U.S.A. and it provides reliable evidence for the Paleogene occurrence of Moraceae in this region. The indistinct growth rings of this fossil indicate this tree did not experience a distinct dormant season.

Monishar pathorer bon (Monisha and the Stone Forest) is an illustrated, Bengali-language story aimed at children aged 11–17 that uses a place-based approach to teach the principles of stratigraphic geology and global change. It is the first such book to be published in Bengali, the sixth most widely spoken language globally, and thus marks a significant contribution in geoscience education. The story concerns a curious village girl's quest to find a natural explanation for gatchpathor (petrified wood), which is common throughout much of Bengal. In doing so, she discovers a science-based explanation for a phenomenon locally explained supernaturally. Production and free distribution of 4,000 copies of the book involved collaborations between scientists, artists, and others concerned with enhancing educational and social opportunity in rural communities, and with geological societies in India, the U.S., and the UK. Outreach programs involved two female university honors students from the University ...

Site Form, Site 28BU133, for Joint Base McGuire-Dix-Lakehurst.

The palaeontological collection of Chemnitz has been a constantly growing, developing and limitless source of knowledge on the relation of Earth’s history and the development of life on Earth, for over three centuries. Initially founded by science interested citizens on a voluntary basis, only with the premise to enable public access to collections and scientific information, it has developed and has been structuralized based on professional geoscientific considerations. Today, the collection is preserved, extended by selected purchases, diversely used and it serves as a foundation for globally linked up scientific research, as well as for interdisciplinary exhibitions and diverse educational programmes and activities. The essence of the collection documents the evolution and preservation of terrestrial ecosystems with a special emphasis on volcanic environments and petrified wood.

The Naturkunde-Museum Coburg was founded in 1844 by Duke Ernst II of Sachsen-Coburg and Gotha and Prince Consort Albert as ‘Herzogliches Naturaliencabinet’. The present museum building has 4800 m2 of usable floor space, with 2200 m2 for exhibitions, including 13 halls with the following fields: geology, animals of Central Europe and North America, archaeology, ethnology, and museums history. The paleontological collections comprise hundreds of thousands of fossils. About a third of the fossils are from the Jurassic, most of them from the Franconian and Swabian Albs. This is followed by the Triassic (a quarter) with specimens from the wider surroundings of Coburg. The Palaeozoic as well as Cretaceous and Cenozoic are only minor collection parts with 10% each. Important collections are those of Duke Franz Friedrich Anton (1750–1806), including Triassic fish (Semionotus), and petrified wood (Dadoxylon) from the Keuper Group of Coburg and the Reinecke collection (1818) with the type material of Leioceras opalinum etc.

The Bruneau Woodpile site has long been popular among fossil collectors; however, the deposit has received scant attention from scientists. Our research reveals that the fossilized wood was deposited ca. 6.85 Ma, within the Chalk Hills Formation, and was mineralized with carbonate-fluorapatite. The diverse assemblage of conifers and hardwoods is representative of the warm temperate forests that flourished in southwest Idaho, USA during the late Miocene. Limb and trunk fragments preserved in a single thin sandstone bed appear to represent woody debris that was transported by streams. One possible explanation is that wood, pumice, and sandy volcaniclastic sediment arrived separately as a result of ordinary stream action, and later were combined into a single assemblage during a subsequent high-energy sedimentation event. We favor an alternate hypothesis: a catastrophic event (e.g., a windstorm) damaged trees on slopes bordering the ancient lake. Branches and small trunk fragments were carried by wind and rain into local streams and ponds where they became waterlogged. After a delay that allowed pumice and wood to become saturated, storm water transported these materials, along with finer volcaniclastic sediment, into a lake. The resulting density current produced a fining-upward sedimentary cycle where wood was preserved in the lowest, coarsest stratum.

An extensive fossil forest discovered in 2010 on private property in central Colorado, USA, has not previously been described in scientific literature. Horizontal partial logs originated as fluvially transported driftwood. A preliminary study of petrified wood specimens reveals evidence of a complex mineralization sequence that involved multiple episodes of mineral deposition, combined with diagenetic transformation of silica minerals. Specimens from two logs have opalized cell walls. However, minerals filling the cell interiors of these specimens vary. Vessel lumina are filled with chalcedony or crystalline quartz; tracheid lumina may contain opal or chalcedony. Specimens from 5 other logs contain quartz/chalcedony, but relict textures suggest cell walls were originally mineralized with opal that was later converted to microcrystalline silica. Pyrite, calcite, and iron oxides were observed as minor constituents in some specimens, providing additional evidence that fossilization occurred in multiple stages, with temporal and spatial variations in physical and chemical conditions causing episodic precipitation of various minerals within the buried wood. Trace element analyses suggest that Fe is the main source of fossil wood color.

petrified wood resembling modern wood of Terminalia(Combretaceae) is described from the Oligocene of the CairoPetrified Forest, Egypt. On the bases of xylotomicalhomologies, the fossil wood is attributed to Terminalioxylonedwardsii. A summary is given on Terminalioxylon andCombretaceae, with inferences on palaeoclimate.

We report on the distribution and character of fossil charcoal found in the Lower Cretaceous Guantou Formation in the Xinchang Petrified Wood National Geopark, eastern South China. All charcoal fragments studied so far exhibit well-preserved anatomical features of Araucarioxylon, consistent with the taxonomic classification assigned to this geopark's widely known silicified tree trunks. Homogenized cell walls and high vitrinite reflectance values of charcoal particles, and the synchronous presence of tuffaceous deposits within the associated sequence, suggest that charcoal in the Xinchang Geopark may have mainly formed under conditions of complete exclusion of air by entombment in hot pyroclastic flows. Scattered charcoal fragments in several sandstone beds overlying the lahar sediments and locally high concentrations of fragments on channel-scoured surfaces are consistent with postformation reworking and transport of charcoal material. Zircon U–Pb SHRIMP dating of the volcanic interbeds of the G...

Fossil wood is the naturally preserved remain of the secondary xylem of plants that lived before the Holocene epoch. Typically, fossil wood is preserved as coalified or petrified and rarely as mummified tissue. The process of fossilization is very complex and it is still unknown why in the same fossil record, wood can be found in different fossilisation forms. In 2007, a fossil forest was found in the Bukkabrany open-pit coal mine in Hungary. The non-petrified forest is estimated to be 7 million years old (Miocene epoch) and its trees were found standing in an upright position. This fossil assemblage is exceptionally rare because wood has been preserved as soft waterlogged tissue. This study aimed to investigate this remarkable way of fossil wood preservation, by examining its chemistry with C-13 CPMAS NMR and its morphology with light and electron microscopy. For comparison reasons, a petrified wood trunk from the Oligocene epoch (30 Myr) found in 2001 at Porrentruy region in Switzerland and two fresh wood samples of the modern equivalents of the Miocene sample were also examined. The results obtained showed that the outstanding preservation state of the Miocene fossil is not owed to petrification or coalification. Mummification is a potential mechanism that could explain Bukkabrany trunks' condition, however this fossilisation process is not well studied and therefore this hypothesis needs to be further investigated. Copyright (c) 2014 John Wiley & Sons, Ltd.

Trees on the side directly exposed to sunlight generally grow faster than on the opposite side, a phenomenon termed plant phototropism. There are in situ vertical trunks of silicified wood in the Xiadelongwan area of Yanqing County, north Beijing, where the first National Geologic Park of Petrified Wood of China has been built since 2002. A few trunks have well-preserved growth rings. One petrified stump from the formation shows a positive phototropism direction of SW230°. As compared with the modern normal growth stumps in Beijing plain area, which have a positive phototropism direction of SW210 ° ± 5°, the evidence of wood phototropism supports the conclusion of previous palaeomagnetic studies that the North China Plate has rotated clockwise since the Late Jurassic. The known petrified wood stumps in the Yanshan-Liaoning area are mainly found from the strata of 165–136 Ma, which corresponds to the main stage of the Yanshanian Movement.

Fire scars are well known to fire ecologists and dendrochronologists worldwide, and are used in dating fires and reconstructing the fire histories of modern forests. Evidence of fires in ancient forests, such as fossil charcoal (fusain), is well known to paleontologists and has been reported in geologic formations dating back to the Late Devonian. We describe what we conclude is a fire scar on a fossil tree trunk from the Late Triassic Chinle Formation of southeastern Utah (~ 200–225 Ma). The external features of the prehistoric scar match those of modern fire scars better than those of scars created by other kinds of wounding events. The fossil specimen also exhibits a number of changes in wood anatomy similar to those reported in modern fire-scarred trees, including a band of very small tracheids that indicate growth suppression immediately associated with the scarring event; an area with a tangential row of probable traumatic resin ducts; and a significant increase in tracheid size following the scarring event that indicates a growth release. No fire scar resembling those in modern trees has previously been described in petrified wood as far as we can determine. The presence of a fire scar not only provides further evidence of ancient fires, but also shows that at least some individual trees survived them, indicating that fire could have been an ecological and evolutionary force in forests at least as early as the Late Triassic.

The research on chemical composition and microstructure of petrified wood has scarcely been reported in China and abroad, and the study about micro-mechanical characteristics has not been carried out. In this paper, the domestic and foreign research progress was summarized at the same time, and the crystal orientation in the cell wall of Pinus tabulaeformis petrified wood was measured according to the method of wood’s MFA using x-ray diffraction techniques, while micro-mechanical characteristics were further studied using nanoindentation. The results showed that silica crystals in petrified wood cell wall were arranged from 22.19 to 25.98 ° in accordance with the micro fibril angle. The micro-mechanical characteristics of silica crystals in different locations inside the petrified wood were different; the modulus and hardness of silica crystals in the lumen region were 89.86 and 9.33 GPa, but 63.07 and 5.20 GPa in the cell wall region. The difference of hardness and modulus of two parts regional were 44.34 and 27.30 %, respectively; this result was supported by A. Kuczumow’s study, which showed the variability of the secondary electron signal of Si could be even over 30 %, the easiest way to explain it was by claiming that the porosity is much increased.

Over 1900 petrified wood specimens were collected from six localities spanning the Eocene to Miocene along a northeast transect parallel to the dip of the Payne Cliffs Formation and Western Cascades Group in southwestern Oregon. This study also presents new 40Ar/39Ar plateau age data for Cenozoic deposits in southern Oregon. Lower to Middle Eocene deposits yielded 305 specimens of petrified wood from sandstones and conglomerates of the basal part of the Payne Cliffs Formation with only 6% of dicotyledons exhibiting distinct growth rings and none having ring porous or semi-ring porous wood. Middle Eocene exposures just stratigraphically above the first locality produced 278 specimens from the lower to the middle part of the Payne Cliffs Formation, with 66% of the dicotyledons exhibiting distinct growth rings. Two specimens of Palmoxylon were also collected from sediments at this locality. An Upper Eocene exposure produced 792 petrified wood specimens from volcaniclastic sediments with 88% of the dicotyledons exhibiting distinct growth rings. Sediments at this locality also produced one specimen of Cibotium oregonensis (Oregon tree fern) and several specimens of Palmoxylon. Middle Oligocene deposits yielded 218 petrified wood specimens from volcaniclastic sediments of the middle part of the Western Cascades Group with 97% of the dicotyledons exhibiting distinct growth rings. An Upper Oligocene exposure yielded 254 specimens from volcaniclastic sediments of the upper part of the Western Cascades Group with all dicotyledons exhibiting distinct growth rings and 59% having ring porous or semi-ring porous wood. Further, this study establishes a 40Ar/39Ar plateau age date of 24.09 ± 0.24 Ma from plagioclase crystals in a tuffaceous sandy to pebbly siltstone at this locality. Finally, Lower Miocene rocks yielded 101 specimens, including 20 dicotyledons, of which 70% were ring porous or semi-ring porous, with most specimens consisting of gymnosperms. The increase over time in the percentages of dicotyledon specimens with distinct growth rings and with ring porous and semi-ring porous wood from this study suggests an overall climatic shift from tropical (Early Eocene) to cool temperate (Early Miocene) in southwestern Oregon. These results are consistent with a similar climatic shift evidenced by paleoecological reconstructions for the Eocene to Miocene of the John Day Fossil Beds in central Oregon.

Data available from a detailed mineralogical investigation of the Petrified Forest of Lesbos and its host pyroclastic rocks [1] are summarized and a link is provided to the full data at https://data.mendeley.com/datasets/dxwfd32zms/1. Samples were taken from petrified wood, fresh and devitrified tuffs, and from epithermal veins and epithermally altered tuffs. Backscattered electron (BSE) images were made by scanning electron microscope (SEM) from polished thin sections of 16 samples to show textural relationships between minerals. Minerals were identified by energy dispersive spectroscopy (EDS). Further chemical analysis by electron microprobe (EMP) were made of trace elements in the petrified wood and of Mn-oxide minerals. Polymorphs of silica were investigated by Raman spectroscopy. SEM X-Ray maps were made of selected sites with manganese oxide minerals. In this contribution, the general character of each analyzed sample is summarized and a brief inventory of available data is presented, with specific reference to features in the on-line data. The significance of these data for the origin of the petrification of the wood and the epithermal veining of the host pyroclastic rocks is provided in “Nature of the hydrothermal alteration of the Miocene Sigri Petrified Forest and host pyroclastic rocks, Lesbos, Greece” [1] https://doi.org/10.1016/j.jvolgeores.2018.11.018. The data will be of comparative value to those investigating petrification of wood, devitrification of tuffs, and epithermal Mn-Fe mineralization in other areas. Keywords: Opaline silica, Manganese oxides, Raman spectroscopy, Mineral composition, Tuff, Silicified wood

This work is comprised of anatomical study of fossil wood collected from Chnji formation (72°22'E, 32°41'N) of Miocene age exposed at Chinji National Reservoir. The material consists of a single piece of petrified wood dark brown in colour. The three dimensional sections were prepared by ground thin section technique. Microscopic examination of the characters was compared with modern and fossil wood and found comparable with the family Leguminosae. The closest resemblance of our fossil wood is with the wood of Ougenia. This fossil wood shows close resemblance in respect of vessels, fibers, parenchyma and xylem rays character. Therefore it is considered as new species and it is named Ougenioxylon chienjiensis sp. nov. The specific epithet refers to Chinji formation to which fossil wood belongs.

In fossil specimens, measurements of the natural isotopic ratio (129)I/I may provide a method to estimate the age of sample. The motivation for measuring the isotopic composition ((129)I/I) of petrified wood samples collected from Austria was to check this feasibility. Alkaline fusion together with anion exchange was used to extract iodine from the sample. Typical sample size for this study was 10-90 g. An atomic ratio as low as 10(-14) was determined using accelerator mass spectrometry (AMS). Uranium concentrations measured by instrumental neutron activation analysis (INAA) and α-spectrometry were found to be less than 3 mg kg(-1), therefore the contribution from fissiogenic (129)I was small and an estimation of ages was based on the decrease of the initial ratio (due to decay of the cosmogenic (129)I in a closed system) after subtraction of the fissiogenic (129)I. The value of the prenuclear ratio is crucial for the use of the (129)I system for dating purposes in the terrestrial environment. From the preanthropogenic (initial) ratio of 1.5 × 10(-12) of the hydrosphere and the results of the present study for the samples from Altenburg (1.05 × 10(-12)) and Fuerwald (6.16 × 10(-13)), respective ages of 8 ± 2.2 and 20.2 ± 2.2 million years were derived. Since samples were collected from a stratum deposited in the Upper Oligocene/Ergerien period (~25-30 million years ago), it can be concluded that these isotopic ratios do not show ages but an elapsed time since fossil wood was isolated from mineral rich water. Paleontological investigation shows that samples from Altenburg had mixed characteristics of old and modern Tertiary plants, thus an origin from a younger stratum re-sedimented with Oligocene cannot be excluded. However, the sample from Drasenhofen reflects that the (129)I/I system might not always be suitable for the dating of petrified wood sample due to fixation of anthropogenic (129)I into surface fractures.

Transitions in petrified wood samples from several Thailand–Myanmar sites included opal-A to opal-CT, opal-A to metastable β -crystobalite and reordered opal-CT → quartz. The moganite in the samples indicates a potential volcanic silica source for the wood petrifactions. Silica phase transitions evident under SEM include opal-A → opal-CT, opal-A → cuboid quartz (pseudocubic) and opal-CT → quartz. Certain stages of silica transformation and transition processes seem to overlap. Such overlapping results when lepisphere blades transform to the high crystallinity of prismatic quartz through a solid-state mechanism. The results provide some insights into the petrified wood genesis in the region. Thermal inputs into the silicification process may have pre-dated final burial of woods in flood deposits.

La familia Fabaceae se encuentra entre las mejores representadas en el registro fósil del Cenozoico de Argentina y en particular de la Formación Ituzaingó. En el presente trabajo se describen cuatro tipos de leños permineralizados por silicificación y con caracteres afines a esta familia, Menendoxylon vasallensis Lutz, Anadenantheroxylon villaurquicense Brea, Aceñolaza y Zucol emend., Prosopisinoxylon americanum sp. nov. y Gleditsioxylon paramorphoides sp. nov. Se aportan dos nuevas especies fósiles y se enmienda la diagnosis de Anadenantheroxylon villaurquicense. Los ejemplares fueron hallados en los sedimentos fluviales de la Formación Ituzaingó (Plioceno–Pleistoceno), Entre Ríos, Argentina, y sólo han preservado la anatomía del xilema secundario. Se relacionan algunos caracteres anatómicos con la presencia de un clima seco y de estacionalidad. A partir de las características paleogeográficas y paleoecológicas de distribución de los géneros actuales más afines, se propone que, probablemente durante el lapso de tiempo que abarca esta formación, prosperó un ambiente heterogéneo caracterizado por presentar elementos arbóreos vinculados al Chaco, a bosques húmedos o riparios y, en particular, a los Bosques Secos Estacionales Neotropicales (BSEN). La presencia de los fósiles estudiados en la Formación Ituzaingó (Plioceno–Pleistoceno) en el extremo más austral de la Cuenca del Paraná, muestra una rica flora vinculada a los BSEN mucho más al sur de su distribución actual, avalando la hipótesis de que tuvieron una extensión mayor en el continente sudamericano durante el Cenozoico tardío. The family Fabaceae is among the best represented in the fossil record of the Cenozoic of Argentina and in particular of the Ituzaingó Formation. This paper describes four types of permineralized by silicification woods related to this family, Menendoxylon vasallensis Lutz, Anadenantheroxylon villaurquicense Brea, Aceñolaza y Zucol emend., Prosopisinoxylon americanum sp. nov. and Gleditsioxylon paramorphoides sp. nov. Two new fossil species were recognized and the diagnosis of Anadenantheroxylon villaurquicense was amended. The specimens were found in the Ituzaingó Formation (Pliocene–Pleistocene), Entre Rios, Argentina, and have only preserved the anatomy of secondary xylem. Some anatomical features were related with the presence of a seasonal and dry climate. From paleogeographic and paleoecological features of distribution of most related extant genera, it is proposed that during the Pliocene–Pleistocene developed a heterogeneous environment characterized by having arboreal elements linked to Chaco, riparian and component of Seasonally Dry Tropical Forests (SDTF). The presence of the studied fossil wood in the Ituzaingó Formation (Pliocene–Pleis- tocene) in the Paraná Basin shows a rich flora linked to SDTF southermost of its current distribution, supporting the hypothesis that had a greater extent in South American continent during the late Cenozoic. Fil: Franco, María Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina; Fil: Brea, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina; Universidad Autónoma de Entre Ríos; Argentina

This document includes the site forms for Joint Base McGuire-Dix-Lakehurst as well as associated maps, references, and artifact descriptions and drawings. It also includes an addendum to site form Bu526.

Three typical plant taxa from the fossil assemblage of the 290-million-year-old Chemnitz Petrified Forest (Zeisigwald Tuff Horizon, Leukersdorf Formation) were studied with regard to the microstructure of the petrifactions: samples of the tree fern Psaronius sp., the seed fern Medullosa stellata, and the gymnosperm Dadoxylon sp. The plant’s tissues are anatomically preserved by silica exhibiting different crystalline order and by other mineralisations. Specimens were studied by means of electron backscatter imaging and electron backscatter diffraction in a scanning electron microscope. The cell walls were largely preserved by quartz crystals, the cell lumina by cryptocrystalline silica. The former organisation and chemical composition of the vascular tissue are mirrored by varying grain formation and grain size. Results are discussed in terms of extant xylem cell wall organisation showing highly hydrophilic cellulose and hemicellulose cross-linked by hydrophobic lignin. The effect of polar and non-polar wood components on the precipitation of silica from aqueous solution and on the formation of crystals is convincing, and the reported results provide a better understanding of how silica replaced organic matter during the petrifaction process.

Ichnological studies in sedimentary rock formations of Kachchh Basin commenced in the late 1970s, despite an allusion to a 'fossil burrow' in 1872. Numerous research articles have since been published. Most of them merely record trace fossils from sporadic sites, with an unwarranted plethora of new ichnotaxa, mainly due to lack of total comprehension of ichnotaxonomic norms. Though of late, a few articles concerning definite environmental/stratigraphic issues have become available, it is now time to introspect our work vis-a-vis advancements made by fellow ichnologists. Recognising the potential of trace fossils, novel applications with emphasis on organism behaviour and substrate nature are being discovered, pertaining to various problems prompting a reorientation in our perception. Here, we attempt such an exercise in our observations on Diplocraterion -rich horizons from three localities viz., Gamdau, Khari Nadi north of Bhuj City, and near Dahisara on Bhuj- Mandvi road. They occur in the Bhuj Formation, which otherwise is sparsely fossiliferous. The strata under consideration are thoroughly bioturbated with monogeneric ichnofauna, overlying and underlying beds being barren or sparse in traces. These beds represent colonization windows, in turn linked to changes in hydrodynamic regime. While the monogeneric ichnocoenoses suggest opportunistic taxa (r-selected) typical of inhospitable conditions to most life forms; such assemblages characteristically reflecting brackish conditions, where salinity fluctuations are inherent. Prevailing sedimentary structures, presence of colonization events by opportunistic ichnospecies, changing hydrodynamic conditions, preservation of petrified wood and foliages, and stark absence of animal remains advocate transitional ecological setting such as prevalent in a deltaic set-up.

Fossil forests have world-wide distribution, commonly preserving mineralized wood that displays vivid hues and complex color patterns. However, the origin of petrified color has received little scientific attention. Color of silicified wood may be influenced by the presence of relict organic matter, but the most significant contribution comes from trace metals. This study reports quantitative analysis of trace metals in 35 silicified wood samples, determined using LA-ICP-MS spectrometry. The most important of these metals is Fe, which can produce a rainbow of hues depending on its abundance and oxidation state. Cr is the dominant colorant for bright green fossil wood from Arizona, USA and Zimbabwe, Africa. Complex color patterns result from the progressive nature of the fossilization process, which causes wood to have varying degrees of permeability during successive episodes of permineralization. These processes include simple diffusion, chromatographic separation, infiltration of groundwater along fractures and void spaces, and oxidation/reduction.

The 1895 discovery of a petrified tree near Clover Creek in south-central Idaho, USA, attracted worldwide attention and resulted in the naming of a new species of ancient oak, Quercinium pliocaenicum Schuster. For more than a century, the discovery has largely been forgotten, even though specimens reside in reputable museums. Reinvestigation of the locality in 2014/2015 resulted in newly-collected specimens and a wealth of new data. Optical microscopy confirms the cellular anatomy used for the original taxonomic study. X-ray diffraction, scanning electron microscopy, energy-dispersive electron spectroscopy, Raman spectroscopy and cathodoluminescence microscopy reveal details of the mineralization, showing the presence of opal-CT as the primary component, with chalcedony as a lesser constituent. This mineralogy suggests petrifaction occurred in at least two stages, beginning with opalization of cellular tissue, leaving open vessels that became filled with chalcedony during a later mineralization episode. Clover Creek oak represents relict flora growing in a wetter climate before the uplift of the Cascade Range created a rain shadow that caused profound desertification of the inland Pacific Northwest.

Eleven fossil woods belonging to seven families are described from a petrified wood forest of Mizoram. This fossil assemblage is derived from sediments belonging to the Tipam Group considered to be Late Miocene–Early Pliocene in age. The modern counterparts of the identified taxa are: Gluta L., Mangifera L. (Anacardiaceae), Bursera Jacq. ex L. (Burseraceae), Terminalia L. (Combretaceae), Shorea Roxb. (Dipterocarpaceae), Cynometra Linn., Dalbergia L. f., Millettia Wight et Arn.–Pongamia Vent, Ormosia Jacks. (Fabaceae), Artocarpus Forst. (Moraceae) and Madhuca Gmelin. (Sapotaceae). The genus Dalbergia is described for the first time from India. The modern environmental tolerances of the above taxa indicate the existence of a tropical warm and humid climate in Mizoram during the depositional period. The reconstructed climate data using Coexistence Approach (CoA) based on palaeoflora database of Mosbrugger and Utescher, along with other published data sets indicates an MAT (mean annual temperature) of 26.1–27.7 °C, a mean temperature of the warmest month (WMT) of 25.4–28.1 °C, a mean temperature of the coldest month (CMT) of 25.6–26 °C, and a mean annual precipitation (MAP) of 3180–3263 mm. These climatic interpretations are congruent with the data obtained from the anatomical features of all the fossil taxa. As all the fossil taxa possess diffuse porous wood, they further indicate a tropical climate with little seasonality. The majority of the taxa in the fossil assemblage generally have large vessels and simple perforation plates which indicate high precipitation. The present study provides vital evidence of floral exchange or migration between India and southeast Asia.