Fossil Plant Material Research Articles

Sampling, handling, and preparation of peat cores from bogs: review of recent progress and perspectives for trace element research

Peat bogs are valuable archives of environmental change, including climate history, landscape evolution, and atmospheric deposition of trace elements, fallout radionuclides, and organic contaminants. Maintaining the fidelity of peat samples during collection and handling can be challenging, given that bogs consist mainly of fossil plant materials that typically have a very low density and are easily compressed. The surface layers of bogs, which are dominated by living plants and poorly decomposed fibrous peats, are especially problematic. To extract peat monoliths, we use a Belarus corer for deep layers and a Wardenaar device for surface layers. Both corers are constructed using titanium alloys to improve strength, reduce weight, and minimize the risk of contamination by the trace metals of environmental relevance. In this review, we include detailed drawings of the Belarus corer and photographs of the modifications to the Wardenaar corer. Modifications to the motorized Noernberg corer for frozen peat are described, and a complete set of drawings provided. A summary is given of simple procedures to minimize the risk of metal contamination in the laboratory from slicing and subsampling the peat cores and milling the dried samples.

HERBARIA IN A CHANGING WORLD

Similar to other scientific institutions, herbaria are continually tasked with new questions and challenges. They are an important repository of data, dedicated to the storing, identifying, cataloging, and systematic arrangement of botanical specimen for scientific purposes. Traditionally they have been used to validate geographical distributions of species and have served as a basis for the typification of species’ names within the scope of Linnaean taxonomy. Herbarium specimens are critical in studies on climate change and biodiversity. Recently, in face of global threats, they are considered the source of qualified information for species monitoring. A fundamental resource in biogeographic studies, herbarium surveys have documented ongoing changes in the geographic ranges of species. An extreme example is the existence of a given species only in the form of herbarium sheets, while in nature it is extinct. In recent times, an especially important role of the herbarium materials is delivering information on the extent and timing of plant invasions posed by human intervention. A new trend is the inclusion of fossil plant materials into paleo-herbaria, which is a subset of traditional Herbarium institutions. Another, still growing function, is the use of plant materials deposited in the herbaria as a source for DNA sampling. This practice poses some threats to plant collections and often is limited by the curators. In general, herbaria constitute a scientific and cultural heritage and are a cornerstone institution for plant and environmental sciences. An alarming trend in the closing of herbaria, by cutting of financial support, is being observed in some countries. Alternatively, in many herbaria, the program of the digitizing these important materials has begun. Now is a critical point in time to work toward a worldwide effort and give these plant and museum collections due recognition.

Epidermal features allowing identification of evolutionary lineages in the Ocotea complex (Lauraceae)

Epidermal characters are widely used in identification of fossil plant material, yet they are insufficiently known in many extant taxa. Here, we examined the cuticle and stomatal complex in 85 species of the Ocotea complex by optical and scanning electron microscopy. We defined 19 types of stomatal surface appearance, which were mostly consistent with genera or species groups recognized based on reproductive characteristics. The epidermal features support the conclusion derived from DNA analyses that Ocotea is heterogeneous in its current circumscription. We suggest an evolution of the subsidiary cells in the Ocotea complex species from asymmetric to symmetric, and from relatively wide to narrower shapes of the stomatal complex.

Carbon isotope alteration during the thermal maturation of non-flowering plant species representative of those found within the geological record.

The carbon isotope (δ13 C value) composition of fossil plant material is routinely used as a proxy of past climate and environment change. However, palaeoclimate interpretation requires assumptions about the stability of δ13 C values in plant material during its decomposition and incorporation into sediments. Previous work on modern angiosperm species shows δ13 C changes of several per mille during simulated decomposition experiments. However, no such tests have been undertaken on non-flowering plants, which are found extensively within the geological record. These plants have distinctly different cellulose-to-lignin ratios from those of their angiosperm counterparts, potentially creating hitherto unknown variations in the original to fossil δ13 C signatures. To test the extent of δ13 C change during decomposition we have subjected a number of plants, representing more basal, non-flowering plant lineages (cycads, ferns, horsetails and dawn redwood), to artificial decay using a hydrothermal maturation technique at two temperatures over periods of up to 273hours. Subsamples were extracted every 12-16hours and analysed for their δ13 C and %C values using a Carlo Erba 1500 elemental analyser, and VG TripleTrap and Optima mass spectrometers. The %C values increased for all samples through the maturation process at both temperatures with the largest increases observed within the first 24hours. Decreases in δ13 C values were observed for all plants at 300°C and for two of the species at the lower temperature (200°C). The maximum shift in the δ13 C value related to experimental decomposition was -0.90‰ (horsetail), indicating a preferential loss of 13 C during thermal maturation. The reduction in the δ13 C value potentially suggests a preferential loss of isotopically heavier cellulose in relation to the isotopically lighter lignin component during maturation. The isotopic offset observed here (<0.9‰) means that palaeoclimatic interpretation of δ13 C values from non-flowering plant material within the geological record remains robust, but only where interpretations are based on variations in δ13 C values greater than 1‰. Copyright © 2016 John Wiley & Sons, Ltd.

Evaluating the use of amber in palaeoatmospheric reconstructions: The carbon-isotope variability of modern and Cretaceous conifer resins

Stable carbon-isotope geochemistry of fossilized tree resin (amber) potentially could be a very useful tool to infer the composition of past atmospheres. To test the reliability of amber as a proxy for the atmosphere, we studied the variability of modern resin δ13C at both local and global scales. An amber δ13C curve was then built for the Cretaceous, a period of abundant resin production, and interpreted in light of data from modern resins. Our data show that hardening changes the pristine δ13C value by causing a 13C-depletion in solid resin when compared to fresh liquid–viscous resin, probably due to the loss of 13C-enriched volatiles. Modern resin δ13C values vary as a function of physiological and environmental parameters in ways that are similar to those described for leaves and wood. Resin δ13C varies between plant species and localities, within the same tree and between different plant tissues by up to 6‰, and in general increases with increasing altitudes of the plant-growing site. We show that, as is the case with modern resin, Cretaceous amber δ13C has a high variability, generally higher than that of other fossil material. Despite the high natural variability, amber shows a negative 2.5–3‰ δ13C trend from the middle Early Cretaceous to the Maastrichtian that parallels published terrestrial δ13C records. This trend mirrors changes in the atmospheric δ13C calculated from the δ13C and δ18O of benthic foraminiferal tests, although the magnitude of the shift is larger in plant material than in the atmosphere. Increasing mean annual precipitation and pO2 could have enhanced plant carbon-isotope fractionation during the Late Cretaceous, whereas changing pCO2 levels seem to have had no effect on plant carbon-isotope fractionation. The results of this study suggest that amber is a powerful fossil plant material for palaeoenvironmental and palaeoclimatic reconstructions. Improvement of the resolution of the existing data coupled with more detailed information about botanical source and environmental growing conditions of the fossil plant material will probably allow a more faithful interpretation of amber δ13C records and a wider understanding of the composition of the past atmosphere.

Reaffirming Pinus mundayi as the oldest known pine fossil: REPLY

Reaffirming Pinus mundayi as the oldest known pine fossil: REPLY

The Early Cretaceous megaflora of the Springhill Formation, Patagonia. Paleofloristic and Paleonvironmental inferences

The Springhill Formation (Lower Cretaceous) is considered as one of the most important oil producer units within the Austral Basin in Argentina. However, knowledge regarding this formation's plant community composition is still very scarce. In this work a thorough survey of the outcrops of the Springhill Formation was conducted regarding both geological and palaeobotanical aspects. Abundant fossil plant material was collected at the Estancia El Salitral and Río Correntoso localities in Santa Cruz Province, Argentina, consisting primarily of compressions of leafy shoots with several branching orders, completely to partially preserved fronds, simple to pinnate leaves and fertile scales. Analysis of these materials made it possible to describe 20 new taxa which add to the already known flora of the Springhill Formation; nine of these taxa were found in Estancia El Salitral, and the remaining 11 were found in Río Correntoso. The floristic diversity of the unit has increased through the discovery of the first megafossils of ginkgophytes (Baiera sp. 1 and Baiera? sp. 2), whereas new taxa have been described within the divisions of Pteridophyta, Pteridospermophyta, Cycadophyta and Pinophyta. Analysis of the vegetative and reproductive epidermal structures of the various groups included within this megaflora has been demonstrated to be a valuable tool for the recognition and differentiation of species. Analysis has also made it possible to suggest paleoenvironmental inferences. Finally, the megaflora from the Springhill Formation was compared to other relevant plant assemblages from the Lower Cretaceous of Western Gondwana. The megaflora was determined to be most similar to that of the well-known Patagonian Anfiteatro de Ticó Formation and most different from that of the Brazilian Crato Formation.

Steam oxidation of fossil power plant materials: collaborative research to enable advanced steam power cycles

Research into improved materials systems and associated manufacturing and reliability issues is a major part of initiatives to produce cleaner and cheaper energy systems in the UK and the USA. Under the auspices of a Memorandum of Understanding on Energy R&D, a work programme concerned with steam oxidation has been conducted. The focus was on the generation of definitive information regarding the oxidation behaviour in steam of current and developmental ferritic steels, austenitic steels, and nickel-based alloys required to enable advanced steam power cycles. The results were intended to provide a basis for quantifying the rate of metal loss expected under advanced steam cycle conditions, as well as understanding of the evolution of oxide scale morphologies with time and temperature to identify features that could influence scale exfoliation characteristics. This understanding and acquired data were used to develop and validate models of oxide growth and loss by exfoliation. This paper provides an overview of the activity and highlights a selection of the results coming from the programme.

Carbon sources in suspended particles and surface sediments from the Beaufort Sea revealed by molecular lipid biomarkers and compound-specific isotope analysis

Abstract. Molecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids) and compound-specific isotope analysis of suspended particulate organic matter (SPM) and surface sediments of the Mackenzie Shelf and slope (southeast Beaufort Sea, Arctic Ocean) were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C3 terrestrial plants, bacterial and zooplankton material in the organic matter (OM) of this area. Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C3 terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and &lt;1%, respectively. In marine SPM from the Mackenzie slope, the major contributions were fresh and detrital algal components (&gt;80%), with a minor contribution of fossil and C3 terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C3 terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60–75%), whereas those from the slope contained the highest proportion of fossil (40%) and C3 terrestrial plant material (10%). Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC) found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the sediments accounted for 30–40% of the total carbon in the inner shelf sediments, 17% in the outer shelf and Amundsen Gulf and up to 25% in the slope sediments. These estimates are low compared to other studies conducted 5–20 yr earlier, and they support the increase in primary production during the last decade mainly because of the increase in the number of ice-free days and due to the strength and persistence of winds favouring upwelling.

Steam oxidation of fossil power plant materials: collaborative research to enable advanced steam power cycles

Steam oxidation of fossil power plant materials: collaborative research to enable advanced steam power cycles

Coprolites from the Cretaceous Bearpaw Formation of Saskatchewan

Coprolites from the Beechy Member of the Cretaceous Bearpaw Formation, southern Saskatchewan, presumably deposited by one or more species of mosasaur or large fish/shark, were recovered and analyzed using SEM/EDS. The data reveal the presence of pseudomorphous coccoid bacteria, potential filamentous bacteria, bacterial endospores and filamentous fungi. No recorded fossil plant or bone material could be identified, either within the highly compressed coprolitic mat-flattened full coprolite bolus – of recovered marine sediment encased in a mixed mat of hematite–apatite primary minerals heavily coated with Ca-smectite and nontronite, or the full coprolite bolus. The presence of fossil bacteria with morphological characteristics similar to those of endospores in other environments suggests that only robust microbial forms such as these survive diagenesis, partly with some carbon still intact, the remainder replaced with silica and iron. The data support the view that coprolites can serve as a useful source of information on the ancient microbial world.

Toxicologically important trace elements and organic compounds investigated in size-fractionated urban particulate matter collected near the Prague highway

Urban particulate matter was collected in the most exposed area of Prague, near a busy highway, in order to provide petrographic and chemical characterization useful for health impact assessment in that locality or other applications. Samples were collected from filters of the air conditioning system in two years, 2009 and 2010, and sieved into four grain-size fractions: 0.507–0.119mm, 0.119–0.063mm, <0.063mm and sub-fraction <0.025mm. Methods of destructive and non-destructive analyses were used for the determination of total analyte (As, Cd, Cr, Mn, Ni, Pb, Zn) contents. Labile forms of some toxicologically important analytes were tested in 2M HNO3 extracted solutions. A composition of inorganic and carbonaceous particles of natural and anthropogenic origin and their morphology were studied by optical and electron microscopy. Organic solvent extracts of the samples were analyzed using gas chromatography to compare the organic compound distribution in fractions. Only slight differences between 2009 and 2010years are visible. The relatively high extractable part of most investigated elements confirms mobility and potential availability to organisms. The changes can be recognized in the petrographic and organic composition in samples from both years, which were likely the result of various inputs of source materials. Specific organic marker compounds indicate contribution from fossil fuels, plant materials and bacteria.

Quantification of climate and vegetation from southern African Middle Stone Age sites – an application using Late Pleistocene plant material from Sibudu, South Africa

In southern Africa numerous Middle Stone Age (MSA) sites document important steps in technological and behavioural development leading to significant changes in the lifeways of modern humans. To assess whether these cultural changes and developments may be related to environmental changes we need to ascertain past environments. To do this we apply a new quantitative method, the GIS-based Coexistence Approach (CAGIS), on fossil plant material from the MSA site Sibudu, KwaZulu-Natal, South Africa. Previous qualitative environmental interpretations of the fossil fauna and flora of the site remain ambiguous. Because much of the material is anthropogenically introduced, it is difficult to distinguish between the effects of natural changes in the local vegetation and behavioural changes of the people that inhabited the shelter. CAGIS can be applied to such biased assemblages and seems to be an adequate method to directly quantify palaeoclimate and vegetation parameters at an archaeological site.The CAGIS analysis shows that during the Howiesons Poort (HP) Industry winters were slightly colder and drier than present, whereas during summer, temperatures and precipitation were similar to today. Post-HP winters were drier and colder than present, presumably colder than during the HP. Summer temperatures remained the same, but summer precipitation decreased from the HP to post-HP. Vegetation cover was less than today, may be even less than during the HP. The late MSA was observably warmer than the older periods, especially during winter. At the same time summer precipitation slightly increased and vegetation became more dense, but still remained generally open similar to today's anthropogenic landscape.Generally, climatic changes are most pronouncedly reflected in winter temperature parameters, especially in minimum winter temperatures, and to a lesser extent by changes in summer precipitation. The observed ecological trends seem to be affected mainly by variations through time in winter temperatures. This refinement of interpretation was not discernible using previous methods for analysing the Sibudu data.

Sedimentology, facies architecture and chemostratigraphy of a continental high-latitude Paleocene–Eocene succession—The Chickaloon Formation, Alaska

The Paleocene–Eocene Chickaloon Formation of southern Alaska represents rapid deposition in a floodbasin setting, contains abundant and diverse fossil plant material, and spans the Paleocene–Eocene Thermal Maximum (PETM). Sedimentologic, lithofacies, and chemostratigraphic analyses of exposures of the Chickaloon Formation were conducted in order to provide a contextual framework for this, late Paleocene–early Eocene high-latitude sedimentary succession and to test if hyperthermal conditions are recorded in the unit. At the main study area in the Evan Jones Coal Mine, strata represent an alluvial sequence dominated by floodplain, channel sandstone, crevasse lobe, crevasse channel, and mire deposition. Floodplain environments are represented by medium-gray, commonly nodular and/or carbonate-cemented, shaly siltstone and centimeter-scale thick sheet-sandstone interbeds. Most channel sandstone deposits are interpreted to be crevasse channels and are generally small (2–5 m thick), rarely coarser than medium-grained sandstone, and sand grains are commonly coated with Fe-oxides. Carbonaceous shale and coal are localized and indicate a high-rate of organic carbon accumulation in the area. δ 13C analyses of bulk organic carbon from the succession at the Evan Jones Mine are internally consistent with this interpretation; they yield uniformly negative values that are typical of continental organic matter (− 21.7‰ to − 28.5‰; X̅ = − 25.4‰). Fossil plant material is also very common and includes leaves, wood, seeds, and resins from broad leaf angiosperms, conifers, ferns, and sphenopsids. Considered together, lithologic and paleontologic data suggest that these strata represent a floodbasin environment; the observed crevasse channels probably originate from a main channel located within several kilometers of the depocenter. Ash-fall tuffs punctuate the studied sequence and contain abundant reworked or recycled zircons, indicating that the depocenter was proximal to a volcanic source. Across all of these Chickaloon depositional environments, a significant negative isotopic shift (− 5.8‰) occurs, which we hypothesize to represent a short-lived perturbation associated with a global hyperthermal event.

Bennettitalean leaf cuticle fragments (here Anomozamites and Pterophyllum) can be used interchangeably in stomatal frequency‐based palaeo‐CO2 reconstructions

Abstract: Bennettites are an abundant and frequently well‐preserved component of many Mesozoic fossil floras, often playing an important ecological role in flood plain vegetation communities. During a recent study focusing on stomatal indices of Triassic–Jurassic fossil plants, it became evident that the leaf fragments of two bennettite genera Anomozamites Schimper (1870) emend. Harris (1969) and Pterophyllum Brongniart (1825) display a significant overlap of leaf shape as well as cuticular characters. Owing to the preference of recognition of single taxa (ideally species) for the stomatal method, we use a database of 70 leaf fragments of Anomozamites and Pterophyllum compressions from five isotaphonomic Late Triassic sedimentary beds of Astartekløft in East Greenland to test whether leaf and cuticle fragments of the two genera can be separated using a range of quantitative and qualitative morphological and statistical analyses. None of the observed characters – including stomatal frequencies – could be applied to separate the fragments of the two genera into well‐defined groups. Our results therefore indicate that fragmented material and dispersed cuticles cannot be utilized to distinguish between Anomozamites or Pterophyllum at the genus level, but that instead these cuticle fragments may be used interchangeably as stomatal proxies. Classification of fossil leaves into either of these genera is thus only possible given adequate preservation of macro‐morphology and is not possible based solely on cuticle morphology. We suggest that this large inter‐ and intra‐generic morphological variation in both leaf and cuticle traits within Anomozamites and Pterophyllum may be related to the bennettites’ role as understory plants, experiencing a range of micro‐environmental conditions, perhaps depending mainly on sun exposure. Based on the results obtained in this study, we conclude that Anomozamites and Pterophyllum cuticle fragments can be employed interchangeably in palaeo [CO2] reconstructions based on the stomatal method, thus potentially annexing a plethora of bennettitalean fossil plant material as CO2 proxies, including dispersed cuticles.

Infrared mapping resolves soft tissue preservation in 50 million year-old reptile skin

Non-destructive Fourier Transform InfraRed (FTIR) mapping of Eocene aged fossil reptile skin shows that biological control on the distribution of endogenous organic components within fossilized soft tissue can be resolved. Mapped organic functional units within this approximately 50 Myr old specimen from the Green River Formation (USA) include amide and sulphur compounds. These compounds are most probably derived from the original beta keratin present in the skin because fossil leaf- and other non-skin-derived organic matter from the same geological formation do not show intense amide or thiol absorption bands. Maps and spectra from the fossil are directly comparable to extant reptile skin. Furthermore, infrared results are corroborated by several additional quantitative methods including Synchrotron Rapid Scanning X-Ray Fluorescence (SRS-XRF) and Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS). All results combine to clearly show that the organic compound inventory of the fossil skin is different from the embedding sedimentary matrix and fossil plant material. A new taphonomic model involving ternary complexation between keratin-derived organic molecules, divalent trace metals and silicate surfaces is presented to explain the survival of the observed compounds. X-ray diffraction shows that suitable minerals for complex formation are present. Previously, this study would only have been possible with major destructive sampling. Non-destructive FTIR imaging methods are thus shown to be a valuable tool for understanding the taphonomy of high-fidelity preservation, and furthermore, may provide insight into the biochemistry of extinct organisms.

Histórico da Paleontologia no Museu Nacional

The Museu Nacional founded in 1818, houses important Brazilian and foreign paleoinvertebrate, paleovertebrate and fossil plant material. This paleontological patrimony is the result of not only the first acquisitions during the 19th century, specially those made by the end of it by the Imperial Geological Commission, but also of the 20th century paleontological activities, which mixes the history of the Paleontology in the Museu Nacional with the own history of the institution

Latest Jurassic–earliest Cretaceous age for a fossil flora from the Latady Basin, Antarctic Peninsula

Dating Jurassic terrestrial floras in the Antarctic Peninsula has proved problematic and controversial. Here U–Pb series dating on detrital zircons from a conglomerate interbedded with fossil plant material provide a maximal depositional age of 144 ± 3 Ma for a presumed Jurassic flora. This is the first confirmed latest Jurassic-earliest Cretaceous flora from the Latady Basin, and represents some of the youngest sedimentation in this basin. The presence of terrestrial sedimentation at Cantrill Nunataks suggests emergence of the arc closer to the Latady Basin margin in the south compared to Larsen Basin in the north, probably as a result of the failure of the southern Weddell Sea to undergo rifting.

The occurrence of p-coumaric acid and ferulic acid in fossil plant materials and their use as UV-proxy

The applicability of p-coumaric acid and ferulic acid concentrations or ratios in (sub)fossil plant remnant as UV-B proxies relies on various aspects, which are discussed in this paper and will be illustrated with some experimental data. A newly developed THM-micropyrolysis–gas chromatography–mass spectrometry method was tested on various spores, pollen and other plant remains, which were analysed for the presence of the UV-absorbing compounds p-coumaric acid and ferulic acid. This revealed that these supposed building-blocks of sporopollenin appear to be present in pollen of many plant species but also in moss spores. The development of this micropyrolysis method paved the way for the quantitative analysis of UV-absorbing compounds in case only a small amount of analyte is available, for example for fossil pollen and spores but also other small palynomorphs and plant fossils. The use of this technique will provide a better insight in the plant responses to UV-radiation, the chemistry of pollen and spores, their fossil counterparts and furthermore the means for a further development of a proxy for the reconstruction of past UV-B radiation.

Climatic control on Quaternary fluvial sedimentology of a Fenland Basin river, England

AbstractUnderstanding and interpreting climate response from ancient fluvial deposits requires a combined approach of detailed sedimentological description and interpretation, local climate proxies, and the accurate comparison of these sequences with further independent climate records. Application of these multiple lines of evidence is particularly effective in the Quaternary Period, where higher resolution and more detailed palaeoenvironmental reconstruction are possible. This paper presents results from a Devensian (Weichselian) age sequence in northern Fenland, England, that integrates these approaches. Detailed sedimentological description has identified three fluvial facies associations overlain by a period of ice‐wedge cast formation. Fossil plant and coleopteran material within these sediments have been studied to provide palaeoenvironmental reconstructions for the local landscape, including quantitative temperature estimates using the mutual climatic range method on fossil Coleoptera. In addition, joint application of radiocarbon and optically stimulated luminescence (OSL) dating allows this sequence to be compared with the stacked marine isotope record, although dates do not agree well at the limit of the radiocarbon technique. Sedimentological interpretations, palaeoenvironments and global ice‐volume variations (a proxy for climatic severity) are all in agreement and show clearly how the River Nene responded to subtle changes in climate and vegetation cover during the Devensian (Weichselian) Stage. The level of detail possible in this reconstruction shows the importance of this approach in understanding fluvial response to past climate changes.