Fossil Trunks Research Articles

Filicales y Bennettitales del Cretácico Inferior de Carazuelo, provincia de Soria, España

Silicified woods of the fern Tempskya riojana Barale and Viera and the Bennettitales Cycadeoidea barbarae Crisafulli nov. sp., found together with undetermined conifer woods, from the NW of Carazuelo, province Soria, are described. This site is located south of the so-called San Saturio fault which runs parallel to Road N-234. The fossil trunks are included in the “Conglomerados poligénicos, areniscas y arcillas” fluviatile sediments, dated as Paleogene. The original source of these fossils could be Tera and/or Oncala Groups, both Early Cretaceous in age and outcropping close by at Fuentetecha, Fuensaúco and North of Soria. Similar plant fossil findings from this region are reported and some mistakes in the geological mapping are analyzed. The Tempskya specimens were histologically poorly preserved, but had enough anatomical characters to be undoubtedly assigned to Tempskya riojana. The new species Cycadeoidea barbarae is described, with fairly well preserved cellular structure, viz., pith, vascular cylinder, cortex, foliar/branch traces, as well as strobili surrounded by foliar scales and apical seminal cones. An important and new aspect of the new species is that it includes morphologically and anatomically preserved both fructifications and vegetative parts, whereas these are usually find separated by other species of Bennettitales.

The Late Triassic Schilderia Adamanica and Woodworthia Arizonica Trees of the Petrified Forest National Park, Arizona, Usa

Two fossil tree species, both with unusual characteristics, occur in the Upper Triassic of the Petrified Forest National Park, Arizona, USA and adjacent areas. The first, Schilderia adamanica, has a highly idiosyncratic secondary xylem structure which contains normal uniseriate and broad complex multiseriate ‘herring‐bone’ rays. The trunk cross‐section of the secondary xylem may be either of a normal pycnoxylic type with a central pith and rays radiating from that or it may consist of appressed ‘xylem masses’ with rays curving towards one another at their extremities. The second, Woodworthia arizonica, has narrow, horizontal vascular traces traversing the entire radial width of the secondary xylem. By analogy with extant tree species, these traces would have terminated on preventitious buds deeply embedded in the bark which, in the case of these fossil trunks, have failed to be silicified. Such buds have the capacity to develop into epicormic shoots when the crown foliage of the tree is damaged. A further specimen of W. arizonica is recorded for the first time from the Permian of southern Brazil. Reconstruction drawings of both trees are produced.

Mineralization processes in some samples from the fossil forest of Dunarobba (Umbria, Central Italy)

Two isolated twigs (samples A and B) from the site of the fossil forest of Dunarobba (Central Italy) were examined to assess both the degree of degradation of the organic fraction and the composition of the inorganic component. Sample A, although showing the presence of minute crystals, is mineralised only to little larger extent with respect to the trunks of the fossil forest and exhibits a wood composition almost comparable to that of the fossil forest. Main minerals are silica, calcite, chloroapatite, chloromagnesite, and clays. Residual terpenes perfectly match, as either components or proportions, those found in the fossil forest trunks. Sample B is much more mineralised and physical parts are hard (sample BII, 84% mineralisation) along with others that are quite loose (sample BI, 62% mineralisation). Goethite constitutes the major mineral in both parts. Calcite, on the contrary, is higher in BII than in BI. In agreement with the literature, goethite is present in the interstitial spaces of the cell walls whereas calcite is found in the cell lumina. The wood components are limited to lignin and terpenes; being absent cellulose or other polysaccharides. BI contains the same types of terpenes present in the fossil trunks, whereas only diterpenes have been found in BII. The samples B contain, with respect to either sample A or fossil trunks, a lower content of fully or partly aromatic sesquiterpenes and diterpenes. This fact is probably due to the oxidative environment of iron deposition. The difference in the mineralogical structures exhibited by the two samples must be searched in the different environmental conditions under which the samples were maintained. In particular, an essential role must have been played by water sources much richer in soluble salts and more differentiated than the current spring waters of the region.

A scanning electron microscopy (SEM) study of sediments from Lake Cristol, southern French Alps, with special reference to the identification of Pinus cembra and other Alpine Pinus species based on SEM pollen morphology

The scanning electron microscopy (SEM) pollen morphology of the major Alpine Pinus species was established, then the sediment cores from Lake Cristol (2248 m a.s.l.), southern French Alps, were palynologically studied with the help of SEM. SEM was used in order to distinguish Pinus cembra pollen grains from other Alpine Pinus species with higher reliability, and served to reconstruct the Holocene vegetation history near the site with more accuracy. Recent pollen grains of P. cembra, P. sylvestris, and P. uncinata were examined by SEM in an attempt to establish the diagnostic characteristics of P. cembra pollen. The cappa exine surface of P. cembra is smooth to slightly rugulate, whereas that of the other two species is verrucate to rugulate and deeply sculptured. This difference in ornamentation is so significant that it is possible to identify the fossil pollen grains of P. cembra with SEM. Pollen analyses were carried out on the cores from Lake Cristol using both light microscopy (LM) and SEM. Then both the macro remains in the cores and the fossil trunks in the lake were 14C dated. Pollen curves of P. cembra obtained with LM and SEM showed considerably different trends. SEM results explained the age distribution of the fossil trunks better than LM results, showing the higher reliability of P. cembra identification by SEM. The arrival of the species to the site is estimated around 5600 yr BP (late Atlantic). Its abrupt disappearance is probably correlated with the deforestation around Roman times. Between those two epochs (from late Atlantic to early Subatlantic), fluctuation of P. cembra in the vegetation around the site is represented by its curve in the pollen diagram and the age distribution of the fossil trunks. Comparison of the local history of P. cembra with other nearby studied sites implies the SE to NW migration of the species during its settlement into the Alpine region.

A new Bennettitalean trunk with unilacunar five‐trace nodal structure from the Upper Cretaceous of Hokkaido, Japan

A new species of Bucklandia is described based on a permineralized fossil trunk that was obtained from sediments of Upper Cretaceous age from Hokkaido, Japan. The quality of preservation is exquisite, and anatomical and morphological features are preserved at the cellular level. The specimen is clearly bennettitalean because of the cycadeoidean-type arrangement of vascular bundles in the petiole. However, this specimen is unique among previously described progymnosperms and gymnosperms in possessing a unilacunar five-trace type of nodal structure. The fossil thus contributes to a more complete understanding of the variation of nodal structure in bennettitalean trunks.

The conservation of a fossil tree trunk

A waterlogged non-mineralized fossil tree trunk from a Miocene lignite stratum (c. 20 million years old) had to be stabilized against shrinkage, cracking and exfoliation on drying. Stabilization experiments, and light and electron microscopic examinations of treated samples, showed that impregnation with a low molecular weight polyethylene glycol (PEG) not only prevented any macroscopic damage but also preserved the extraordinary wealth of ultrastructural details in this fossilizing wood. Accordingly, the trunk was treated with 25% PEG 300, and the conservation turned out to be a complete success.

Nota sobre a ocorrência de uma floresta petrificada de idade permiana em Teresina, Piauí

The Pedra de Fogo Formation, of Permian age, which is situated within the Parnaiba Basin, is well know for its content of fossil trunks, principally of the Genus Psaronius. However, in recent years, other genera have been found with some frequency. The occurrence of 33 permineralised fossil trunks, preserved in growth position on the right hand margin of the poti River, in the city of Teresina, Piaui, is reported here. This paper details the area of occurrence of the fossil trunks and describes briefly the characteristics of the sedimentary facies, which suggest a transitional (marine-continental) depositional environment. One wood specimen, belonging to a new genus and a new species (Teresinoxylon euzebioi Mussa) is described; it shows close affinity with the Cycadoxyleae. A probable Lower Middle Permian age can be assigned to the specimens from this important and rare fossiliferous site and it is requested here that the authorities act promptly to ensure its preservation.

A Fossil Wood of Dipterocarpaceae from Pliocene Deposit in the West Region of Java Island, Indonesia

Fossil woods in Java Island have been excavated and sold for outdoor ornaments or indoor decoration purposes since 30years ago. These fossils are in danger of being drained out without known identities, composition and history. This studywas aimed to find out the botanical identity and geographical aspect of a newly recovered silicified fossil wood from Bantenarea in the west region of Java Island. The fossil trunk 28 m in length and 105 cm in diameter was buried in a tuffaceoussandstone layer. The age of the stratum was thought to be Lower Pliocene. A small sample was cut from the outer part ofthe log and then ground to obtain thin section for anatomical observation. The main anatomical features of the fossil woodare as follows: wood diffuse porous; vessel almost exclusively solitary, vascicentric tracheid present; axial intercellular canalpresent, distributed in long tangential rows; fibers with distinctly bordered pit. These features show affinities of the fossilwood to the extant wood Dryobalanops of the family Dipterocarpaceae, regardless of the fact that this genus is no longer exists living in the natural forest of the present day Java Island. 2004 Jurusan Biologi FMIPA UNS SurakartaKeywords: fossil wood, Dipterocarpaceae, Dryobalanoxylon, Pliocene, Java Island

Microbiological processes of silicification of the fossil trunks found in Liassic manganese ore

Microbiological processes of silicification of the fossil trunks found in Liassic manganese ore

On Fossil Plants from the Devonian Rocks of Canada

I n 1843–44, Sir W. E. Logan ascertained, and published in his Report* for the latter year, the occurrence of a series of beds of Devonian age in the Peninsula of Gaspé, Lower Canada, containing fossil plants, apparently of terrestrial origin, and some of them evidently in situ . Nothing was done toward the precise determination and description of these remains until 1856, when Sir William kindly permitted the writer of this paper to examine his collection, and to describe before the American Association for the Advancement of Science the most interesting specimen contained in it—a fossil trunk exhibiting a very remarkable and previously undescribed coniferous structure†. The other specimens in the collection were so fragmentary or obscure, that it was not deemed expedient to attempt their description before studying them (as all fossil plants should, when practicable, be studied) in the rocks in which they occur. With this view I visited Gaspé in the past summer, and examined the localities indicated on the plans and sections of the Geological Survey. The facts and specimens thus obtained will probably be fully described and illustrated in one of the forthcoming Decades of Canadian Fossils; and in the meantime I propose to notice some of the species observed, which appear to be of especial interest in the present state of our general knowledge of the Devonian flora. Before proceeding to these descriptions, it may be necessary to state that the deposit in which the fossils occur consists of sandstone and shale, of various colours