Search

Several fossil woods from Early Cretaceous sediments in Yumen City in northwestern North China Block, China, have been described. They belong to two fossil wood taxa, Piceoxylon yumeniense Zhou, Peng, Deng, Zhang and Yang n. sp. and Protophyllocladoxylon chijinense Zhou, Peng, Deng, Zhang and Yang n. sp. The well-preserved specimens yield secondary xylem with distinct growth rings. Piceoxylon yumeniense exhibits cross-field with taxodioid pits as well as two distinct xylem ray types. The bi- to triseriate rays are characterised by one or two horizontal resin canals with unequal uniseriate ends. Protophyllocladoxylon chijinense Zhou, Peng, Deng, Zhang and Yang n. sp. shows window-like cross-field pits, which are occasionally cupressoid and have uniseriate xylem rays. These fossil wood records improve our understanding of the fossil diversity, floral composition and palaeoclimate of the Xiagou Formation. Palaeoclimatic analysis of the palaeoxylogical assemblage indicates that the northwestern Gansu region predominantly exhibited a warm and wet climate condition, while a brief cooling event may have occurred in the region during the Early Cretaceous.

Bouchal, Johannes Martin/0000-0002-4241-9075; Guner, Huseyin Tuncay/0000-0001-9742-1319 WOS:000478712100017 The early Miocene was a period of major palaeogeographic reorganization in the eastern Mediterranean region, during which time the Anatolian Plateau became subaerial and several intracontinental basins intermittently became connected to the Paratethys and Mediterranean seas. In this paper, we analyse early Miocene vegetation and climate using leaf records, palynological assemblages, and fossil wood at 36 localities from western and central Turkey, most of which have precise age control based on radiometric dating and mammal faunal ages. Using the leaf flora of Giivem (Bes Konak, Kesekoy), Climate Leaf-Analysis Multivariate Program (CLAMP) analyses and Koppen signatures were employed to infer a palaeoclimate typical of modern laurel forest regions. Based on the palynological records, abundance of various pollen-taxa was used as a measure of openness of vegetation and regional presence of major tree taxa. Most pollen floras are dominated by tree pollen (ranging from 85 to 98%) and indicated widespread afforestation. In the pollen diagrams, shifts in dominance from swamp forest elements (Taxodioideae) to well-drained forests (Pinaceae) indicate changes in lake levels or phases of basin development. Such shifts may have been associated with the development of more xeric forest vegetation. Wood anatomical features such as false tree rings further may indicate seasonal climate. Pollen diagrams and macrofossils reflect zonal and azonal broadleaf and needleleaf forest and extrazonal open vegetation. The latter occurred in areas with shallow soils on volcanic rocks or limestone (e.g. cycads, Dracaena), or coastal areas (herb dominance). Taxonomic composition and biogeographic affinities suggest laurel forest as a major forest biome on well-drained soils and ecotones between laurel forest and broadleaf deciduous forest biomes. A comparison with younger floras shows that these are neither more diverse nor more warmth-loving despite an increase in global temperature (Mid-Miocene Climatic Optimum) suggesting bottlenecks during previous (Oligocene) cooler times for warmth-loving taxa. Swedish Research Council (VR)Swedish Research Council; Scientific and Technologicl Research Council of Turkey (TUBITAK), 2219 Post-Doctoral Research Fellowship Program (2017/2)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [1059B191700382] Bob Spicer, Jakub Sakala, and Howard Falcon-Lang provided valuable suggestions to improve the manuscript. We thank the Turkish Ministry of Mining for permission to work at the lignite mines of Can, Soma, Deni, and Tavsanli, and Atay Holding for permission to work in the lignite mine of Sahnall. Financial support from the Swedish Research Council (VR) to TD is acknowledged. HTG was supported by The Scientific and Technologicl Research Council of Turkey (TUBITAK), 2219 Post-Doctoral Research Fellowship Program (2017/2), project no. 1059B191700382.

Fossilized wood belongs to the most exciting, however, rarely studied objects in nature. Several kinds of petrified wood with different combinations of minerals have been studied: apatite – calcite; calcite – pyrite; hematite – gypsum wood; quartz - goethite; goethite – calcite woods, from different countries and estimated as old in the time range of 1.8–306 MA. The samples cover nearly the whole time of tree existence on the Earth. The application of synchrotron radiation for X-ray microdiffraction analysis of petrified wood is presented and compared to elemental (electron microprobe) and molecular (micro Raman) analyses with the use of table-top instruments. The analysis of preserved cells permineralized with two minerals allows tracing both the structure of cell walls and the remains of ancient organic matter. Lignin is most often met among the remains of the primary organic matter and is clearly observed in all kinds of wood, except the apatite-calcite one. The Eh-pH diagrams tailored to each combination of minerals with organic matter allow to estimate the original conditions of mineralization and give the indications for the potential biomimetic synthesis.

The early Miocene Sigri Pyroclastic Formation in western Lesbos Island hosts the famous petrified forest of silicified tree fossils, protected as a UNESCO Geopark. The formation consists primarily of flow tuffs, mud flow deposits and stream conglomerate. Hydrothermal veins rich in silica, iron, and manganese are preferentially developed in major fault zones and along paleosols. The purpose of this study is to understand the nature of the hydrothermal system and its relationship to the preservation of tree fossils. Samples were collected from fresh and altered pyroclastic rocks, hydrothermal veins and petrified wood. Rock mineralogy and chemistry were investigated using a petrographic microscope, scanning electron microscope, electron microprobe, Laser Raman spectroscopy, and X-ray powder diffraction. Early devitrification of volcanic glass in tuffs formed opaline silica and locally resulted in smectite. At the same time, fossil trees were partly replaced by amorphous silica. Epithermal alteration and hydrothermal veins include (1) adularia + silica + kaolinite; (2) jarosite + hematite + amorphous silica; and (3) “Fe-oxide” and/or “Mn-oxide” + amorphous silica. The MnSi mixture and Mn-oxides comprise structurally amorphous romanechite with some more crystalline grains of todorokite, ramsdellite and/or nsutite. The mixtures of Fe-oxides and silica are also largely amorphous and include α-cristobalite. Such mixtures replace parts of the petrified wood including cell walls. The various colors observed from the petrified wood are principally related to the abundance of iron and organic matter. Faulting and complex hydrothermal alteration was related to the emplacement of laccoliths and dykes around 18 Ma, 1–3 Ma after deposition of the Sigri Pyroclastic Formation. The observed types of low temperature epithermal alteration are compared with that produced by different circulating waters in the modern Taupo volcanic zone of New Zealand. Hydrothermal deposition of Fe-oxides and silica played an important role in the preservation of the petrified forest.

Subsurface fluid systems are important for chemical weathering, ore formation and thermal evolution of the crust. Changes in the dynamics and distribution of subsurface fluid flow systems are controlled by changes in global and regional terrestrial climate, tectonics, and elevation. This paper concerns the dating of changes in ancient subsurface hydrologic systems. However, direct dating of water-rock interaction is challenging because of the lack of appropriate materials to date and the more open and complex nature of subsurface flow regimes. Here, we explore the prospects of using U-Pb dating of petrified (silicified) wood as a means of quantifying continental paleo-hydrology. Oxidizing fluids, often of meteoric origin, tend to leach and mobilize U from the country rock, but when such waters contact organic-rich material, U can become reduced and immobilized, resulting in U-rich silicified wood. We present in situ laser ablation ICPMS analyses of U-Pb isotopes and trace elements in petrified wood from the Upper Triassic Chinle Formation (225–208 Myr) in the Petrified Forest National Park in Arizona (USA), allowing us to establish a generalized workflow for making meaningful paleo-hydrologic interpretations of the U-Pb systematics of silicified wood. Wood characterized by brownish colors and preservation of cellular structure have low Fe contents and positive Ce anomalies, indicating silicification in reducing environments and isolation in relatively reduced conditions after silicification, resulting in closed system behavior of U and Pb. Wood characterized by vivid colors (orange, red, etc.) and little to no preservation of cellular structure are much higher in Fe and exhibit negative Ce anomalies, indicating influence by more oxidized fluids. The brownish samples yield U-Pb ages clustered between 250 and 200 Ma with a peak coinciding with the time of deposition (~220 Ma), which indicates that fossilization largely took place almost immediately after deposition and that U-Pb in quartz faithfully retains the time of such fossilization. In contrast, the orangish-reddish-whitish samples yield younger U-Pb ages, defining distinct errorchron ages, which reflect subsequent generations of quartz crystallization. Scatter associated with errorchrons are likely due to local (mm- to cm-scale) U or Pb mobility or variable initial Pb composition. Distinct younger age peaks appear to correlate with the timing of regional unconformities associated with tectonic or epeirogenic uplift. We suggest that uplift and exhumation may initiate the onset of oxidizing fluid systems, resulting in leaching and transport of U from the surroundings, followed by subsequent generations of quartz precipitation. In summary, U-Pb dating of petrified wood or silicified organic material, has high potential for dating paleo-hydrologic events. However, due to complexities in terrestrial hydrologic systems, interpretations of U-Pb systematics must be informed by accompanying geochemical and textural observations.

Conifer remains including petrified wood resembling Sequoia, and leafy shoots and seed cone scales of Glyptostrobus (Cupressaceae s.l.) were found in the late Paleocene Fort Union Formation (Tongue River Member) in the Powder River Basin of Wyoming, northwestern USA. These findings indicate either a wider distribution of both Sequoia and Glyptostrobus in the late Paleocene compared with narrow habitat of modern genera, or possibly that Glyptostrobus-like cones were borne on trees with wood resembling that of Sequoia. The well-preserved wood is assigned to the new species Sequoioxylon carneyvillense sp. n. while the cone fragments and foliage are assigned to Glyptostrobus europaeus (Brongniart) Unger. Wood anatomical features of extant cupressaceous genera including Glyptostrobus, Metasequoia, Sequoia, Sequoiadendron and Taxodium were studied to provide more information for the identification of fossils.

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.

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.

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.

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.

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

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.

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.

Fungal-arthropod-plant interactions are described from the Middle Jurassic Monumento Natural Bosques Petrificados, Santa Cruz, Patagonia, Argentina. Fossils consist of a silicified araucarian log that appears differentially decayed and displays galleries bored in patterns resembling those produced by extant wood-boring beetles. Galleries are filled completely with frass that is reworked into smaller galleries containing spherical to ellipsoidal coprolites. The coprolites are of possible mite origin and contain fungal and plant remains. Fungi are also found growing from the walls of the smaller galleries and from the coprolites. Identifiable fungal propagules include asexual structures typical of extant imperfect fungi. Comparison with modern wood with similar patterns suggests a xilophagous role for the wood borer, whereas the smaller galleries and coprolites likely are products of a smaller xylophagous/fungivorous woodborer. Decay patterns in the silicified woods are like those produced by extant saprotrophic and pathogenic wood-rotting fungi in modern ecosystems. The fungus on the walls of the galleries and on the coprolites most likely was saprotrophic. However, additional indirect and direct interactions (i.e., phorisms) similar to those between conifers, mites, beetles, and fungi in modern ecosystems could be hypothesized. This report provides unique direct fossil evidence of multitrophic fungal-arthropod-plant interactions and suggests the possibility that complex interactions like those in modern conifers might have been in place by at least the Jurassic. These results underscore the importance of fungi as key elements of past ecosystems, acting as drivers of biological cycles and symbionts with a variety of organisms. Fil: García Massini, Juan Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentina Fil: Falaschi, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Paleobotanica; Argentina Fil: Zamuner, Alba Berta. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina

The early Cenozoic Chickaloon Formation is the main coal-bearing sequence in south-central Alaska. Coal and associated plant macrofossils are well exposed in the Eska, Premier, and Jonesville Coal Groups in the Wishbone Hill District. There is a striking variation in the degree and mode of preservation of fossil trees in a vertical sequence through these coal groups. We examined the wood taxonomy, mineralogy, and geochemistry to elucidate potential cause(s) for these differences. The wood anatomy indicates that the wood is all assignable to the Cupressaceae (Taxodiaceae s.str.) and assignable to the form genus Taxodioxylon Hartig emend. Gothan. However, we found no significant variation in the taxonomy of the wood between stratigraphic layers. The wood generally becomes better preserved in the Jonesville Coal Group. Wood from the stratigraphically lower Premier Coal Group exhibits greater plastic deformation and contains less well-preserved wood anatomical features. The wood from the overlying Jonesville Coal Group retains most of its original morphology, but has suffered from brittle fracture. The geochemistry and mineralogy of the wood follow a pattern that corresponds to the degree of preservation. The less well-preserved wood tends to have a higher concentration of iron carbonate minerals (e.g., siderite and ankerite), whereas the better preserved wood contains more calcium carbonate or silica. All evidence points to rapid permineralization of the original wood, although the least well-preserved wood shows evidence of greater organic matter decomposition than the better preserved wood. The wood taxonomy and mode of preservation of wood from the upper part of the Chickaloon Formation is similar to wood from coeval fossil forests that developed at higher (polar) paleolatitudes.

Published records of supposed Triassic bees' nests are based on trace fossils in silicified wood and in sandstone in Upper Triassic strata of the Chinle Group in Petrified Forest National Park, Arizona. A critical, firsthand restudy of these trace fossils indicates that they lack diagnostic features of bees' nests, such as cells with smooth linings and spiral closure caps. Indeed, many of the observations claimed to identify these traces as bees' nests cannot be replicated. Instead, the putative Triassic bees' nests can be classified as: 1. Clavate borings in petrified wood, somewhat similar to Teredolites; these borings preferentially penetrate heart-rot fungus (Polyporites) and are mostly likely larval chambers of wood-boring beetles. 2. Cylindrical, vertical burrows in sandstone assignable to Skolithos; these are almost certainly arthropod produced. The recognition that the Chinle Group trace fossils are not bees' nests eliminates them as evidence that decouples bee origins from the Cretaceous origin of angiosperms. The Triassic trace fossils in silicified wood are also a new and unique record of likely beetle borings in Triassic wood.

The fossil forest in the Camlidere-Celtikci-Gudul region of the province of Ankara in Turkey has a large number of petrified coniferous and oak tree remains. Petrification occurred in volcanic ashes and tuffs with permineralization, and Fe, Mg, Ca and Ni ions played important roles in the substitution of Si for C. However, the petrified wood samples are heterogeneous in colouration, weight, toughness, and durability, despite being obtained from the same source. Those features are very important for end-users because petrified woods, if cut and polished, are used widely as both decorative indoor tiles and gemstone objects, but heterogeneous materials suffer large wastage while they are being worked and used. Chemical analyses, specific gravity measurements, polarizing microscope studies, X-ray diffraction patterns, and scanning electron image evaluations were performed to classify and identify the homogenous material of the petrified woods relating to its physical and mineralogical characteristics. The different characteristics of the petrified wood samples are due to their varying inner structures, which depend on the replacement silica-building phases and their ratios, and silica particle sizes. Thin sections and XRD patterns revealed that petrified woods in the region were silicified by replacement with both chalcedonic quartz components, including chalcedony (length-fast quartz), moganite and orthorhombic -silica (length-slow quartz), and opalline quartz components including opal-CT and opal-C (length-slow quartz). The scanning electron microscope images were shown that the internal structures of the petrified woods consist of mostly submicron-sized (100–800 nm), and partially nano-sized (60–120 nm) silica-building particles. So, the petrified wood samples can be firstly classified into five main-groups based on their colourations and specific gravity values, then, into three sub-groups based on the principal chalcedonic and opalline quartz silica-building phases and related particle sizes, and also weighing, toughness, and durability. In the first group (samples 1, 2, and 3), the crystallinity gradation of the petrified woods can be classified as quasi-coarse crystalline because they include mainly chalcedony and moganite phases with 800–200 nm ranging in particle size. They are heavy, tough, and resistance as a material, as shown by specific gravity values of 2.60, 2.56, and 2.54, respectively. In the second group (sample 4), the crystallinity gradation of the petrified wood can be classified as quasi-fine crystalline because it includes mainly o -silica and moganite phases with 400–100 nm ranging in particle size. It is medium-heavy, semi-tough and quasi-resistance as a material, as shown by a specific gravity value of 2.42. In the third group (sample 5), the crystallinity gradation of the petrified wood can be classified as quasi-nano-crystalline because it includes mainly opal-CT and opal-C phases with 120–60 nm ranging in particle size. The material is slight, brittle, and weak as a material, as shown by a specific gravity value of 2.18. Ultimately, in the petrified wood found in the Camlidere-Celtikci-Gudul region of Ankara province in Turkey, it is revealed that samples 1, 2, and 3 represent flint and chalcedony quartz mineral species, samples 4 and 5 represent chalcedony and opal quartz mineral species.

Fine structure and tissue substitution by minerals were investigated in silicified woods from Madagascar and Indonesia by scanning electron microscopy and X-ray microanalysis. The silicified woods maintained the exterior morphology of once grown trees and showed typical inner structures of conifers. Radial planes of the silicified wood from Madagascar revealed tracheids as a major component of the axial system in the secondary xylem. Tracheids were mainly characterized by numerous bordered pits where a thickening in the middle (torus) was surrounded with the membrane (margo). The torus appeared to contrast with the fibrillar network of the margo. As a component of the axial system in the secondary phloem, sieve elements were found to have many sieve pores that were filled with seemingly crystalline materials. To correlate the colors of the silicified wood from Indonesia with elemental composition, energy-dispersive X-ray spectrometry was employed in this study. Silicon was present as a basic component of the silicified wood. Calcium and iron were detected from red-colored regions, whereas magnesium was found in blue-colored regions. These results suggest that tissues of silicified woods had been substituted by minerals over the past period, while retaining the inherent morphology of the tree species. Scanning electron microscopy and X-ray microanalysis could be applied to unravel structural details and composition of plant fossils in palaeobotany.

Conifer wood types from the Upper Cretaceous Aguja and Javelina Formations and the Paleocene Black Peaks Formation of Big Bend National Park, Texas, are briefly described. The Big Bend conifer woods represent the largest assemblage of late Cretaceous conifer wood thus far described from the western interior of North America, and include samples with characteristics of the Araucariaceae and Cheirolepidiaceae, and Cupressaceae and Podocarpaceae. Cupressaceae/Podocarpaceae types of the Maastrichtian Javelina Formation have, on average, narrower rings than those of the Campanian Aguja Formation, consistent with the drier climate already proposed for the Javelina Formation. Angiosperm wood assemblages differ between the lower shale and upper shale members of the Aguja Formation, the Javelina Formation, and the Black Peaks, so do the conifer assemblages. The Big Bend conifer woods differ from those described from other western interior localities and document more variation in growth ring types than previously recognized for the whole of the northern hemisphere Late Cretaceous. The sizes of some logs and width of their growth rings suggest that some trees might have reached diameters of 1 m in approximately 80 years. Woods of the Cupressaceae/Podocarpaceae type show that the strategy of having juvenile wood with narrower tracheids and less distinct growth rings than in mature wood occurred in the Late Cretaceous. The incidence of compression wood in mature trunk wood is relatively high and may reflect either unstable substrates or frequent storms with high winds.

Special kinds of petrified wood of complex structure were investigated. All the samples were composed of at least two different inorganic substances. The original cell structure was preserved in each case. The remnants of the original biological material were detected in some locations, especially in the cell walls. The complex inorganic structure was superimposed on the remnant organic network. The first inorganic component was located in the lumena (l.) of the cells while another one in the walls (w.) of the cells. The investigated arrangements were as follows: calcite (l.)—goethite–hematite (w.)—wood from Dunarobba, Italy; pyrite (l.)—calcite (w.)—wood from Łukow, Poland; goethite (l.)—silica (w.)—wood from Kwaczala, Poland. The inorganic composition was analysed and spatially located by the use of three spectral methods: electron microprobe, X-ray synchrotron-based microprobe, μ-PIXE microprobe. The accurate mappings presenting 2D distribution of the chemical species were presented for each case. Trace elements were detected and correlated with the distribution of the main elements. In addition, the identification of phases was done by the use of μ-Raman and μ-XRD techniques for selected and representative points. The possible mechanisms of the described arrangements are considered. The potential synthesis of similar structures and their possible applications are suggested.

Descriptions, comparisons and affinities are given for the following Late Eocene–Early Miocene new, to Egypt, records: Palmoxylon compactum Sahni, Palmoxylon geometricum Sahni, Palmoxylon indicum Sahni, Palmoxylon pondicherriense Sahni, Palmoxylon pyriforme Sahni, Palmoxylon rewahense Sahni and Palmoxylon wadiai Sahni. Comments on the geologic ages of the compared Palmoxylon species, Indian Plate migration, palaeogeography and palaeoclimates are given.

The possibilities of examining patterned natural and mineralised biological objects, using X-ray synchrotron facilities, complemented by electron microprobe and optical analysis are reviewed. The objects under investigation include: petrified wood, speleothems, corals, shells of molluscs and remains of belemnites. All those objects have important information embedded in their patterned structure. Using microprobe type devices, one can disentangle the internal structure of the objects and reveal the hidden information. This information can be of great significance to climatic, geological, chronological, and ecological studies and specific examples in each category are shown, taken from our work and compared with the results of other authors where necessary. The added value of the X-ray and electron microprobe measurements in relation to the mass-spectrometric methods is shown for the specific cases. In addition, the results concern materials where organic and even biological material is combined with inorganic matter, like calcite, silica varieties and metal oxides. The investigation of such patterned objects as goethitized wood, composed of goethite, calcite and organic matter should therefore be of interest to materials scientists, synthesizing composite materials.

Three representative samples of petrified wood were investigated: wood from King George Island, Antarctica; wood from Bio-Bio province, middle Chile and wood from Łukow, Poland. Microdiffraction measurements of the Chilean and Łukow wood were made at LURE. Chilean and Antarctic samples were permineralised by silica material, but the share of undefined calcium silicates in construction of some intracellular locations in the latter sample was significant. In contrast, the wood from Łukow was replaced by calcite with a small presence of secondary silica. Linear scans were conducted using the X-ray microfluorescence beamlines in synchrotron devices in Orsay, France and Pohang, South Korea. The results were completed by the measurements of light elements with the use of electron microprobe. The list of major and minor constituents of all samples was established. The occurrence of such medium-Z elements as Fe, Zn, Cu and Ni was common in the samples. The samples of Chilean wood were more enriched in trace elements and minor amounts of As, La, Br and Cl were found in addition to the previously mentioned elements. Correlation of the trace element contents with the ring structure of the wood was detected. The annual ring, tissue and even cell details of the original wood were preserved by silica and calcite minerals and could be studied using the elemental mapping technique. Implications of the recent study for the material science are indicated.

Hundreds of silicified standing stumps have been discovered within a lignitic horizon in the middle of the Tienen Formation near Hoegaarden in northeast Belgium. The anatomical features of the fossil stumps, as those of the numerous silicified secondary xylem remains collected since the last century from this area, demonstrate that they all belong to a single taxodiaceous taxon. The stumps bear characteristics shared by Taxodioxylon gypsaceum and Glyptostroboxylon tenerum, but affinities with the latter appear closer. They are attributed to Glyptostroboxylon sp. Calibration of the sedimentological, stratigraphical and organic carbon isotope data reveals that these taxodiaceous fossil trees developed in a swampy lowland environment most probably during the Initial Eocene Thermal Maximum at ca. 55 Ma.

Since the investigations on petrified wood performed so far have not proved the assumption that the ring structure is coupled to the changes in the crystalline form of silica, attention was paid to other possible reasons. Using small angle X-ray scattering methods we determined the Porod curves and pore size distributions for five different samples of petrified wood, of different origin. We observed clear porosity differences in different samples. In addition, the normal X-ray diffractometric measurements were carried out, which gave a totally uniform image of the crystallographic structure of all the samples. All of them were made of pure α-quartz. The differentiation of rings in dark and bright zones should be put down to the changes in porosity rather than to other factors. The pores seem to be much more concentrated in those ring locations, which correspond to the original dark wood positions in living wood.

Pieces of petrified wood from south-eastern Poland comprising one of the greatest European collections were investigated. The age of Miocene wood was estimated at 50 million years. Taxodioxylon sequoianum Gothan. was recognised as the dominating species among the preserved samples. Silica material, basic for the petrifaction processes, was investigated by synchrotron-based microfluorescence and microdiffraction. Different distribution patterns were determined after careful examination of linear scans and elemental maps: calcium, potassium and titanium were uniformly spread in the silica matrix while the iron content was concentrated in clear inclusions; other detected elements, as Cu, Zn, Cr, As were observed mainly in the form of inclusions. There was no difference in microdiffractograms for silica between the places of original dark and light wood. One could find little difference in diffraction patterns of samples with the elevated content of iron. In general, the diffraction patterns of silica from petrified wood could be associated with quartz patterns from 1998 JCPDS-International Centre for Diffraction Data.

Field investigations of Middle Miocene fluviatile sediments in an open sand pit at Voervadsbro, Denmark suggest that the transformation processes of wood (lignification and petrifaction) depend on the permeability of the sediment. The petrifying agent in the wood is silica, which must have originated from weathering (and/or soil formation) of silicate minerals as the sediments have seen no history of volcanism. Petrographic investigations (by transmitted light microscopy and SEM) and X-ray diffraction have revealed the resultant of the petrifying agent to be quartz with a remarkably high crystallinity considering its age. The radial structures of the cell walls and the rim around the cell lumina-filling indicate that the first precipitation has been on the cell walls. The zonation of the quartz shows that its precipitation proceeded with interruptions, due to local differences in silica supply, seasonal changes and/or ground-water fluctuations.

A permineralized specimen of Prototaxites Dawson collected from the Upper Devonian Cleveland Shale in Cuyahoga County, Ohio, is grayish black, resembling decorticated, petrified wood. Cellulose acetate peels and ground sections show only the medullary region, consisting of wide and narrow, densely crowded tubes, almost all running parallel, and some oblique, to the long axis of the specimen. The tubes are thick-walled, two-layered, with longitudinal furrowa on the inner surface, septate, showing successive branching, some branches anastomosing. Thin-walled septate branched filaments are present in the intertubal spaces and also cover the tubes; small areas of disintegrated tubes are present all over. Structural details of the tube wall observed with SEM, coupled with other characters, when compared with the structurally known species of Prototaxites, warrant a new name for the Cleveland specimen: P. clevelandensis sp. nov.

Outcrops of the upper Fruitland and lower Kirtland formations (Upper Cretaceous) in the Fossil Forest area of northwestern New Mexico, USA, contain abundant organic remains. This fossil accumulation is “typical” of the late Cretaceous of the Western Interior. The vertebrate fauna is characterized by a lack of coprocoenoses or soil accumulations, few bones with evidence of carnivore damage and a paucity of small bones. Macrovertebrate remains are disarticulated and hydrodynamically sorted. Microvertebrate accumulations are all hydrodynamic in origin. Macerated plant material is common in all rocktypes. An extensive fossil forest was preserved as the result of a large flood which drowned a floodplain forest. Invertebrates are mainly restricted to channel-lag deposits. Vertebrate fossils, and to a lesser extent petrified wood, are restricted to a single downcut fluvial complex.

Seventy-five woods of Australian origin have been examined by means of X-ray diffraction, optical and scanning electron microscopy, and differential thermal analysis. The silica is in one or other of the following forms: opal-A, opal-CT, chalcedony, quartz, quartz + chalcedony, opal + chalcedony. More than half of them consist of opal-CT or chalcedony. The results indicate that petrifaction by silica involves penetration of the wood via splits or checks, permeation of cell walls via a reticulated system of micropores, enlargement of the micropore system as cell wall components break down, and continuing deposition of silica ata rate and in a manner consistent with maintaining the dimensional stability of the wood. Deposition of silica in cell lumina and intercellular voids may be sometimes, but not always, a separate and later event. The final stages of lithification involve loss of water and perhaps transformation of one form of silica into another.

Thirteen species of petrified wood have been assigned previously to the genus Paraphyllanthoxylon which was established by Bailey (1924) as representative of the section Phyllanthoideae of the family Euphorbiaceae. Madel (1962) considered the genus Paraphyllanthoxylon representative of only the Glochidion wood group of the section Phyllanthoideae. This necessitates the establishment of a new genus, Phyllanthoideoxylon , for fossil woods which have characteristics in common with several of the other wood groups in the section Phyllanthoideae. The thirteen previously identified species of Paraphyllanthoxylon are reviewed and compared with the characteristics of the genus. Eleven of these species are retained in Paraphyllanthoxylon Bailey (emend. Madel), one ( P. bangalamodense ) is assigned to Phyllanthoideoxylon nov. gen. and one ( P. keriense ) is transferred to Bridelioxylon Ramanujam.

A collection of petrified wood from the Lower Pliocene Ogallala Formation in western Oklahoma was examined. All specimens appear to be of the same taxon and exhibit features of extant Robinia species. To date, four fossil wood species of Robinia have been described. The relationship of Robinioxylon zuriensis Falqui to Robinia is doubtful because of the lack of diagnostic critical features. The remaining three, Robinia alexanderi Webber, Robinia breweri Prakash, Barghoorn and Scott, and Robinioxylon zirkelii (Platen) Muller-Stoll and Madel do show affinity to Robinia and all have been noted as structurally similar to R. pseudoacacia . The Oklahoma woods and these three fossil species show considerable overlap in quantitative features and are identical in qualitative features. Examination of different sections (and specimens) of extant Robinia pseudoacacia wood reveals quantitative and qualitative variation similar to that found amongst the petrified woods. Robinia alexanderi , Webber, R. breweri Prakash, Barghoorn and Scott, R. zirkelii (Platen) Muller-Stoll and Madel, and the Oklahoma specimens are considered to be conspecific as the differences between these fossil wood species are no different from those accounted for by variation within a single living species, R. pseudoacacia .

This investigation identifies the abundant petrified wood found in the basal Diablo Member of the Palm Spring Formation, Anza Borrego Desert State Park. Three families of temperate hardwood trees are recognized from the fossil wood cell structure. The Lauraceae represented by Umbellularia , the Salicaceae with specimens of Populus and Salix , and the Juglandaceae represented by Juglans . A review of the paleontologic and paleomagnetic literature establishes the base of the Diablo Member at approximately 3.8 m.y.B.P. with continued deposition for 1.2 m.y. The unique paleobotanical assemblage found in the Diablo Member together with the floral ecology of present-day equivalents reflects a temperate climate with ocean influence and predominantly winter rainfall in this region during the Lower Pliocene Epoch.

Conglomerate-silt/mudstone successions are of widespread occurrence within Permian riftogenic troughs from mid Europe. Commonly these beds are abundant in volcanic detritus which was partly derived by weathering of volcanic cones, and partly from directly related certain eruptive pulses. The volcanic influence on sedimentation processes in the course of basin evolution decreases. The lowermost units contain abundant ignimbrites and lahars, whereas the overlying strata exhibit a gradual change from debris flow into more stream-dominated fan deposits. The outer-fan depositions built up by silty sediments, locally mixed with air-fall tuffs, contain coal seams. The coal-bearing host rocks may be categorized into four classes: (1) grey siltstones made up of prevalently non-volcanic detritus; (2) grey to black layers consisting of epiclastic and pyroclastic components; (3) silicified coal seams; and (4) brick-red petrified wood. Ore concentrations in these carbonaceous rocks result from the mobilization of elements from parent material containing large quantities of labile constituents. Four modes of strata-bound U concentration may be encountered: (1) U-bearing petrified wood remains; (2) U-bearing coal lenses; (3) U-bearing carbonaceous volcaniclastic conglomerates; and (4) U-bearing carbonaceous fine-grained tuffites (“fish eyes”). These U accumulations are produced during the course of early diagenesis of volcaniclastic material and coal-bearing beds. The reason for the very high prospectivity of these Permian mid-European sediments is the close intertongueing of carbonaceous matter-bearing rocks and volcaniclastic rocks necessary for the U supply (“uraniferous dirty coal”), in basins of rapid subsidence, which causes the bimodality of those clastic deposits.