Fossil Plants Research Articles

Provenance, Depositional Environment, and Paleoclimatic Conditions of a Near-Source Fan Delta: A Case Study of the Permian Jiamuhe Formation in the Shawan Sag, Junggar Basin

The science of the provenance, sedimentary system, and distribution of sand bodies is unclear, limiting oil and gas exploration. Here, we combined heavy mineral, rare earth element, petrographic, and outcrop data to shed new light on the provenance, depositional environment, and paleoclimatic conditions of the Permian Jiamuhe Formation. The provenance is characterized by “a main provenance system, and four provenance zones,” and this result could be interpreted from analyses of its seismic reflection, clastic composition, REES, and heavy minerals. A detailed sedimentological study performed in the excellent outcrops, a comprehensive analysis of logging, and the legalistic cores of this formation allowed for the identification of ten lithofacies and three lithofacies associations. Four distributary/underwater channels were observed. Furthermore, the redox and paleoclimatic conditions based on trace elements (Th/U, V/(V + Ni), V/Cr, Cu/Zn, Sr/Ba, and Sr/Cu) suggested a weak reduction in the environment, as well as semi-humid and semi-dry conditions of the Jiamuhe Formation. These conditions are also supported by the mudstone color and plant fossils. The tectonic setting belongs to the acid island arc area based on the trace element discrimination diagram of La-Th-SC and the values of the La, Ce, ΣREE, L/H, La/Yb, and (La/Yb)N criteria. The research results further confirm that there are differences in the mineral compositions in the same provenance area, and they provide a geological basis for the fine sedimentary facies characterization and a favorable zone prediction in this area.

The role of natural gas in setting electricity prices in Europe

The EU energy and climate policy revolves around enhancing energy security and affordability, while reducing the environmental impacts of energy use. The European energy transition has been at the centre of debate following the post-pandemic surge in power prices in 2021 and the energy crisis following the 2022 Russia-Ukraine war. Understanding the extent to which electricity prices depend on fossil fuel prices (specifically natural gas) is key to guiding the future of energy policy in Europe. To this end, we quantify the role of fossil-fuelled vs. low-carbon electricity generation in setting wholesale electricity prices in each EU-27 country plus Great Britain (GB) and Norway during 2015-2021. We apply econometric analysis and use sub/hourly power system data to estimate the marginal share of each electricity generation type. The results show that fossil fuel-based power plants set electricity prices in Europe at approximately 58% of the time (natural gas 39%) while generating only 34% of electricity (natural gas 18%) a year. The energy transition has made natural gas the main electricity price setter in Europe, with gas determining electricity prices for more than 80% of the hours in 2021 in several countries such as Belgium, GB, Greece, Italy, and the Netherlands. Hence, Europe’s electricity markets are highly exposed to the geopolitical risk of gas supply and natural gas price volatility, and the economic risk of currency exchange.

Influence of human impacts on modern pollen assemblages and an assessment of their reliability in reconstructing climate in eastern China

Understanding the relationship between modern pollen, vegetation, and climate is essential for the reconstruction of paleoenvironments and human land use from fossil pollen spectra. In this study, we collected modern pollen data from natural vegetation and human-disturbed vegetation in eastern China. Results reveal that modern pollen assemblages reflect their natural or human-disturbed vegetation, and differ between northern and southern sample sites in eastern China. Natural vegetation communities are dominated by arboreal taxa, mainly Pinus, Castanopsis, Quercus, and Betula. Farmland, which is the dominant type of human-disturbed vegetation, is dominated by herbaceous taxa particularly Cerealia Poaceae (>35 μm), Poaceae, Chenopodiaceae, and Brassicaceae. In eastern China, pollen assemblages of north China are mainly Betula, Artemisia, Chenopodiaceae, Cerealia Poaceae, Brassicaceae, and Ranunculaceae, while pollen assemblages of south China are mainly Castanopsis, Quercus, Poaceae, Cyperaceae, and Euphorbiaceae. Poaceae, Cerealia Poaceae, Brassicaceae, and Chenopodiaceae from human-disturbed vegetation is mainly distributed at low elevations and has a smaller elevational range than natural vegetation. Pollen assemblages from natural vegetation perform better at reconstructing climate than pollen assemblages from human-disturbed vegetation in eastern China. Mean annual precipitation (Pann) is a better predictor than mean temperature of the coldest month (Mtco) and mean temperature of the warmest month (Mtwa). In this study, surface pollen assemblages from human-disturbed vegetation still reflect the characteristics of the local vegetation and can still be used to reconstruct climate. Nonetheless, for more accurate results, pollen assemblages from natural vegetation communities should preferentially be used in reconstructions.

Amine Chemistry of Porous CO2 Adsorbents.

ConspectusAs renewable energy and CO2 utilization technologies progress to make a more significant contribution to global emissions reduction, carbon capture remains a critical component of the mission. Current CO2 capture technologies involve operations at point sources such as fossil fuel-based power plants or source-agnostic like in direct air capture. Each strategy has its own advantages and limitations, but in common, they all employ sorption-based methods with the use of sorbents strongly adhering to CO2. Amine solutions are the most widely used absorbents for industrial operations due to the robust chemical bonds formed between amines and CO2 under both dry and humid conditions, rendering excellent selectivity. Such strong binding, however, causes problematic regeneration. In contrast, purely physisorptive porous materials with high surface areas allow for the confinement of CO2 inside narrow pores/channels and have a lower regeneration energy demand but with decreased selectivity and capacity. The most promising solution would then be the unification of both types of sorbents in one system, which could bring about a practical adsorption-desorption process. In other words, the development of porous solid materials with tunable amine content is necessary to leverage the high contact surface of porous sorbents with the added ability to manipulate amine incorporation toward lower CO2 binding strength.To answer the call to uncover the most feasible amine chemistry in carbon capture, our group has devoted intense effort to the study of amine-based CO2 adsorbents for the past decade. Oriented along practicality, we put forth a principle for the design of our materials to be produced in no more than three synthetic steps with economically viable starting materials. Porous organic polymers with amine functionalities of various substitutions, meaning primary, secondary, and tertiary amines, were synthesized and studied for CO2 adsorption. Direct synthesis proved to be feasibly applicable for secondary and tertiary amine-incorporated porous polymers whereas primary-amine-based sorbents would be conveniently obtained via postsynthetic modifications. Sorbents based on tertiary amines exhibit purely physical adsorption behavior if the nitrogen atoms are placed adjacent to aromatic cores due to the conjugation effect that reduces the electron density of the amine. However, when such conjugation is inhibited, chemisorptive activity is observed. Secondary amine adsorbents, in turn, express a higher binding strength than tertiary amine counterparts, but both types can merit a strengthened binding by the physical impregnation of small-molecule amines. Sorbents with primary-amine tethers can be obtained via postsynthetic transformation of precursor functionalities, and for them, chemical adsorption is mainly at work. We conclude that mixed-amine systems could exhibit unprecedented binding mechanisms, resulting in exceptionally specific interactions that would be useful for the development of highly selective sorbents for CO2.

Implications of CO2 Sourcing on the Life-Cycle Greenhouse Gas Emissions and Costs of Algae Biofuels.

Production of algal biomass and its conversion to biofuels are important technological platforms within the larger umbrella of CO2 capture and utilization. This analysis incorporates a life-cycle assessment (LCA) with respect to global warming potential and techno-economic assessment (TEA) of algae biofuels, focusing on the sourcing and delivery of CO2. This analysis evolves past work in this area to include high-purity biogenic CO2, industrial fossil fuel use, fossil power plants, and direct air capture, and uses a Sherwood plot approach to estimate the CO2 capture energy penalty. We also show that allocation or displacement facilitates a more intuitive distinction between biogenic and fossil sources of carbon. Thus, the LCA better reflects the influence of coproduct handling strategies as compared to previous works. The TEA is also strongly influenced by the CO2 concentration in the flue gas. Currently, when CO2 is sourced from large-point sources, the price of biofuels ($4.5-6.5/GGE) may become comparable to fossil diesel. However, as DAC systems become more economical, they may deliver competitive CO2 sources for biofuels in 2050 with a total cost of <$7/GGE. Based on the net emissions and costs, algae biofuels with CO2 sourced from biogenic sources are consistent with a decarbonized economy as of now, with substantial potential for DAC with decreasing costs.

Characterization of a pyritized fossil pollen cone from Clarkia, Idaho

The Miocene Lake deposit in Clarkia, Idaho is composed of highly fossiliferous silty clays. These rocks were formed in an anoxic and likely toxic deep lacustrine environment which facilitated the fossilization of plant material with a high amount of morphological detail. Many of the plant compression fossils exhibit exceptional preservation, including the preservation of original biomolecules. Pyritized plant specimens are much less common and the details of plant pyritization at this site are not yet fully understood. Pyritized male pollen cones from Taxodium dubium provide an opportunity to explore the processes of pyrite preservation in the Clarkia deposit.One specimen was examined using scanning electron microscopy (SEM) and energy-dispersive x-ray analysis (EDS). The only pyrite textures observed on this specimen were framboids and framboidal microcrystals. Pyrite was found in abundance on the surface of the pollen cones and to a much lesser extent on the surface of the stem. Underneath the pyrite coating, both the cones and stem were carbon-rich, indicating organic preservation. Some pyrite crystals were found in the interior of the stem, but likely originated from the exterior and developed through cracks or tears in the fossil. Pyrite crystals did not form inside the cell walls of the stem. The decaying specimen likely provided a scaffold that could facilitate the formation of pyrite upon the specimen surface. Gypsum crystals found in close association with pyrite likely formed as a product of oxidation after the specimens were taken from the rock.

The marine fossils and paleoecological significance of the Southern edge of South Sumatra Basin in Linggapura Lampung, Indonesia

The South Sumatra Basin is identified as a Paleogene-Neogene sedimentary basin with Mesozoic basements. It is located in the eastern Barisan Mountains, covering Jambi, South Sumatra, and Linggapura (Lampung), Indonesia. Linggapura represents the southernmost part of the South Sumatra Basin. The basin consists of two well-known rock formations, namely the Talangakar and Baturaja Formations. In this study, we investigated these formations through fossil records and paleoecological interpretations. Our investigation was based on measured stratigraphy and fossil observations along the Way Penandingan River in Linggapura, Lampung. We discovered that the bottom of this area consists of Cretaceous granitoid, which forms a nonconformity with the sedimentary rocks in this area. The Talangakar Formation in this region comprises quartzy-grained sandstone and conglomerates containing fossilized remains of terrestrial plants/vegetation. These plant fossils have undergone coalification, with some being silicified. The Batujara Formation in Linggapura is dominated by bioclasts, primarily consisting of Miocene shoreface-lagoonal larger benthic foraminifera, along with other marine and ichnofossils. Based on our findings, we suggest that the paleoecological condition of this area is associated with shoreline transgression during the Oligo-Miocene period. The hotter Miocene climate contributed to a rise in sea levels, resulting in shoreline transgression. Gradually, the area transformed from a terrestrial environment to a highly bioproductive marine environment, at least from the Late Oligocene to the Early Miocene. This study represents an important milestone in better understanding the paleoenvironmental conditions at the edge of the South Sumatra Basin throughout its geological history.

Kungurian (Cisuralian) conifers and environmental changes: a negative δ13C shift in the flora of Tregiovo (Northern Italy)

The Le Fraine fossil locality, near the Tregiovo village (Trento Province, northern Italy) yields two of the best documented Kungurian (early Permian) plant fossil assemblages of eastern palaeoequatorial Pangea. Both plant assemblages (Tregiovo A and B) are dominated by walchian and voltzian conifers but differ in the relative abundance of the major plant groups. Analyses of the δ13C of the bulk organic carbon throughout the entire stratigraphic succession of Tregiovo show a negative trend towards the upper part of the succession. Several conifer taxa are recognized and taxon-specific δ13C analyses of the conifer remains in both plant fossil assemblages shows the same trend in all taxa. This correlation between the negative shift of the bulk organic carbon and the taxon-specific δ13C analysis shows that the negative δ13C shift recorded along the stratigraphic section is not the result of change in relative abundance within the plant assemblages but instead has an external cause, likely the δ13C values of atmospheric CO2. These results agree well with a negative shift observed in other Kungurian continental successions (e.g., China, South Africa, Australia), supporting a global perturbation in the carbon cycle. The negative shift in δ13C could very well record the last deglaciation phases of the Late Paleozoic Ice Age and the rise of the atmospheric pCO2.

Des civilisations du végétal préhistoriques sous les tropiques ?

Did a toolkit made of plants exist in tropical forests during prehistory? If so, what was its impact on lithic technology? In Southeast Asia and Papua New Guinea, the “simplicity” of lithic industries has been interpreted as the reflection of a technical investment in another material: bamboo. The material clues, including traces of wear and residues on lithic artefacts, show that if a perishable material culture did exist, in the Philippines and in New Guinea, the Bamboo Hypothesis must be nuanced and extended to the plant world in the broad sense. Various plants have been exploited, including palm, to carry out activities that go beyond the manufacture of bamboo knives and arrows: splitting of rigid plants, fibre processing, manufacturing of ropes or baskets. If the relationship with the forest is developed on all continents and combines botanical knowledge, anthropogenization of the landscape and hunting of arboreal animals, its impact on lithics toolkits varies. In South America, stone tools become rarer in forest environment and the operating sequences become simpler. On the contrary, lithic industries of Africa and Sri Lanka show great technical know-how and are characterized by great standardization. Living in the rainforest does not necessarily imply abandoning the mineral to focus on plants and the part of cultural choices was large. A prehistoric plant technology is increasingly attested in Southeast Asia and Papua New Guinea thanks to use-wear analyses but remains to be demonstrated in other tropical regions of the world.

Evolutionary history of Castanea sativa in the Caucasus driven by Middle and Late Pleistocene paleoenvironmental changes.

Due to global climate cooling and aridification since the Paleogene, members of the Neogene flora were extirpated from the Northern Hemisphere or were confined to a few refugial areas. For some species, the final reduction/extinction came in the Pleistocene, but some others have survived climatic transformations up to the present. This has occurred in Castanea sativa, a species of high commercial value in Europe and a significant component of the Caucasian forests' biodiversity. In contrast to the European range, neither the historical biogeography nor the population genetic structure of the species in its isolated Caucasian range has been clarified. Here, based on a survey of 21 natural populations from the Caucasus and a single one from Europe, we provide a likely biogeographic reconstruction and genetic diversity details. By applying Bayesian inference, species distribution modelling and fossil pollen data, we estimated (i) the time of the Caucasian-European divergence during the Middle Pleistocene, (ii) the time of divergence among Caucasian lineages and (iii) outlined the glacial refugia for species. The climate changes related to the Early-Middle Pleistocene Transition are proposed as the major drivers of the intraspecific divergence and European-Caucasian disjunction for the species, while the impact of the last glacial cycle was of marginal importance.

Response to Comment on "Dying in the Sun: Direct evidence for elevated UV-B radiation at the end-Permian mass extinction".

Seddon and Zimmermann have raised questions about the evidence for increased UV-B flux across the end-Permian mass extinction (EPME) that was presented in our recent study, specifically regarding the measurement of UV-B-absorbing compound (UAC) levels in fossil pollen. We respond to these points, arguing that the comparison of FTIR spectra of >250 million-year-old Permian fossil pollen with ~700-year-old subfossil pollen is not valid and that negligible nonrandom interference derived from water vapor fluctuations during data generation cannot coincidentally produce a substantial UAC peak during the EPME. Furthermore, we refute the suggestion that the measured aromatic peak at 1600 cm-1 could have been influenced by diagenetic products from other organic constituents of pollen. The most productive route forward will be to generate sporomorph geochemical data from additional Permian-Triassic boundary sections to test the results put forward in our study.

Global site-specific health impacts of fossil energy, steel mills, oil refineries and cement plants

Climate change and particulate matter air pollution present major threats to human well-being by causing impacts on human health. Both are connected to key air pollutants such as carbon dioxide (CO_text {2}), primary fine particulate matter (PM_text {2.5}), sulfur dioxide (SO_text {2}), nitrogen oxides (NO_text {x}) and ammonia (NH_text {3}), which are primarily emitted from energy-intensive industrial sectors. We present the first study to consistently link a broad range of emission measurements for these substances with site-specific technical data, emission models, and atmospheric fate and effect models to quantify health impacts caused by nearly all global fossil power plants, steel mills, oil refineries and cement plants. The resulting health impact patterns differ substantially from far less detailed earlier studies due to the high resolution of included data, highlighting in particular the key role of emission abatement at individual coal-consuming industrial sites in densely populated areas of Asia (Northern and North-Eastern India, Java in Indonesia, Eastern China), Western Europe (Germany, Belgium, Netherlands) as well as in the US. Of greatest health concern are the high SO_text {2} emissions in India, which stand out due to missing flue gas treatment and cause a particularly high share of local health impacts despite a limited number of emission sites. At the same time, the massive infrastructure and export capacity build-up in China in recent years is taking a substantial toll on regional and global health and requires more stringent regulation than in the rest of the world due to unfavorable environmental conditions and high population densities. The current phase-out of highly emitting industries in Europe is found not to have started with sites having the greatest health impacts. Our detailed site-specific emission and impact inventory is able to highlight more effective alternatives and to track future progress.

An overview of Rodinia-Gondwana Supercontinents, India - Asia Collision, emergence of Himalaya and Paleobiogeography of the eastern Tethys in Indian Subcontinent, South Asia

The existence of Rodinia Supercontinent during Meso-Neoproterozoic and its subsequent breakup and reassembly as Gondwana Supercontinent is a widely accepted hypothesis in geological history of the Earth. The breakup of the Rodinia resulted in formation of rift basins and passive continental margins around 650 Ma. Major palaeoclimatic events like Neoproterozoic global glaciation (Snowball Earth) followed by global warming have been recorded from different continents including Indian Lesser Himalaya (Blaini -Krol Cryogenian-Ediacaran Period). The emergence of multicellular Ediacaran life in the Upper Krol Formation is consistent with an increase in the atmospheric oxygen. The base of Ediacaran System in the Lesser Himalaya is established in the cap carbonate, the Blaini Formation overlying the glacial diamictites (Blainian). The pink cap carbonate of the Blaini Formation shows negative δ13C value (-3‰ PDB) and invariably correlate with the Marinoan glacial event. Large continents of Gondwanaland Supercontinent South America, Africa, India, Australia and Antarctica were located over the South Polar region and global equatorial to polar oceanic circulation was blocked and may have been the main cause of glaciation. Paleogeographically Carboniferous–Permian diamictite, coal beds and plant fossil bearing Gondwana outcrops are found in South Sikkim and Arunachal Lesser Himalaya of Northeast India. The Late Paleocene – Middle EoceneTethyan foraminiferal – algal carbonate biofacies are well developed after Late Cretaceous – Paleogene mass extinction event in the eastern Tethys, Meghalaya, east India. These Tethyan benthic orthophragmine foraminiferal –algal limestones were deposited in the passive continental margin setting of a shallow marine carbonate shelf in eastern Tethys and Standard Benthic Zones (SBZ) of the Alpine- Adriatic western Tethys are recorded from Meghalaya. The Cretaceous – Tertiary boundary is well marked in these basins by biotic mass extinction. Late Cretaceous mega ammonoid fossils and Sauropod dinosaur bones are abundantly found in the Maastrichtian Mahadeo Formation. The present δ13C and δ18O isotope data is comparable with the marine values of the limestone The Umlatodoh Limestone contains foraminiferal taxa of early Ilerdian and Middle Eocene (early Lutetian) age. The Indo-Myanmar Orogenic Belt (IMOB) represents the eastern suture of Indian plate and it was formed due to the collision of the Indian plate with the Myanmar plate. The Naga-Manipur ophiolites have been assigned to range in age from Upper Cretaceous to Eocene on the basis of faunal assemblages (radiolarian, planktonic foraminefera) in the olistolithic blocks of pelagic limestone and cherts. Pan Indian Pre and Post India–Asia Collision, emergence of Himalaya and Paleogeography of the Indian Subcontinent has been discussed in South Asia.

Marine inundation history during the last 3000 years at Lake Kogare-ike, a coastal lake on the Pacific coast of central Japan

Sediment cores collected at Lake Kogare-ike, a coastal lake on the Pacific coast of central Japan, record the marine inundation history during the last 3000 years. The sediments consist mainly of organic mud, sand, gravel, inorganic mud, and volcanic ash, and inundation events were recognized as 19 event deposits (E1–E19, from top to bottom) interbedded with the organic mud. Visual observation by naked eyes and X-ray computed tomography (CT) images identified 16 event deposits based on quantitative and qualitative changes in sand contents and changes in the textures and colors of the sediment samples (E1–E3, E5, E6, E8, E9, and E11–E19). The other three event deposits (E4, E7, and E10) were identified only on the CT images as layers with higher radiodensity than the underlying and overlying organic mud layers. The sedimentary features, the spatial bias of the event deposits toward seaward areas, the diatom assemblages, and the frequency of inundation events suggest that 13 (E1–E10 and E12–E14) of the 19 event deposits were formed by tsunamis or extraordinary storms. To constrain the depositional ages of the event deposits, Bayesian age–depth models were constructed based on radiocarbon dating of plant macrofossils and concentrated fossil pollen and the 137Cs profile. The depositional ages of the event deposits indicate that five or possibly six event deposits can be correlated with historical tsunamis along the Nankai Trough: E2, either of E3 or E4, E5, E7, and E9 correspond to the 1707 CE Hoei, the 1605 CE Keicho, the 1498 CE Meio, the 1096 CE Eicho, and the 684 CE Hakuho tsunamis, respectively. E1 was possibly formed by the 1944 CE Showa-Tonankai tsunami, the 1854 Ansei–Tokai tsunami, the 1959 Isewan typhoon, or a combination of two or all three events.

On the timing of megafaunal extinction and associated floristic consequences in Australia through the lens of functional palaeoecology

The timing and cause of megafaunal extinctions are an enduring focus of research interest and debate. Despite the developments in the analysis of coprophilous fungal spores (CFS), the proxy for reconstructing past megaherbivore changes, the environmental consequences of this fauna loss remain understudied. This is partly due to the general obscurity of such a signal in pollen records, as well as limitations in disentangling human and extinction ecological impact, and the lack of spatial information of megafauna changes in site-level sedimentary records. In Australia, the debate centres on the possibility that habitat loss through climate change, vegetation-fire change, human intervention, or a combination of these factors led to the extinction of some large animals during the Late Pleistocene. Pollen and plant isotope studies have also demonstrated that vegetation-fire responses following the Late Pleistocene megafaunal extinctions were characterized by increased vegetation density and fire activity due to reduced grazing/browsing pressure. Here, we use a well-dated marine sedimentary core record from the Murray Darling Basin in southern Australia and apply palynological and functional palaeoecological approaches to reconstruct the Late Pleistocene megafaunal abundance changes, the timing and potential cause of extinction across the basin and investigate if extinction was associated with any signal of trait-based vegetation changes. We infer megafaunal abundance changes from the abundance of CFS and compare this with climatic proxies from the same core. We then link modern observations of fruit, seed and fire response traits of plant genera within the basin to the fossil pollen record to reconstruct palaeo vegetation community traits and determine if extinction was associated with any changes in plant community trait composition. Closely-spaced 14C dates obtained from planktonic foraminifera and δ18O tie points place a major decline in CFS, and thus the timing of extinction, within the basin at ∼43.3 ka. While climate-driven environmental changes largely controlled megafaunal presence, human arrival and frequent landscape burning are considered the most likely primary cause of extinction or, at the very least, megafauna decline in the Murray Darling Basin. We also found that the proposed period of megafaunal decline was also accompanied and followed by a decline in the prevalence of plants with larger seeds and fruits that were likely to have been once dispersed by megaherbivores. Our study supports the idea of a human-driven megafaunal extinction in mainland Australia and that the extinction caused changes in vegetation due to reduced plant dispersal and herbivory. However, high fire activity primarily linked to these vegetation changes was not observed, as humans were already practicing landscape burning before the period of megafaunal extinction and likely continued to do so afterward.

Discovery of water fern megaspore Ghoshispora and new dating for the Upper Cretaceous Yong'ancun Formation in Jiayin, NE China

The Upper Cretaceous Yong'ancun Formation of the Jiayin area, outcropping along the Heilongjiang (Amur) River in China and yielding fossil plants and dinosaurs, has been considered Santonian in age mainly based on palynostratigraphic studies. Until now, there is no document on isotopic dating and guide fossils from this formation, limiting stratigraphic correlation with its equivalents from adjacent basins. This study reports a new age (84.64 ± 0.65 Ma, late Santonian) for the Yong'ancun Formation based on zircon LA-ICP-MS U–Pb dating for the first time from a rhyolitic tuff in the top of the unit. Ghoshispora, a fossil genus of megaspore of water fern is also reported for the first time, co-occurring with other valuable guide fossils such as G. zhaoi and G. triangulata. Based on the presence of Ghoshispora and plant megafossils, the flora of the Yong'ancun Formation is now interpreted to reflect a moist and warm climate, implying that the temperature dropped from high (mid-Cretaceous thermal maximum, KTM) to moderate warm and wetter conditions, at least in the Heilongjiang (Amur) inland region, close to the paleo-Pacific Ocean. The new discovery and dating evidence could provide valuable data for the correlation with the Yaojia Formation of the Songliao Basin, China.

Palynological investigation of an Upper Triassic sequence in Nanjing area, eastern China, with paleoecological implications

The end-Triassic is characterized by a significant biotic crisis in both marine and terrestrial realms. However, terrestrial records in eastern Tethys are relatively limited, especially in eastern China. The Fanjiatang Formation represents the Upper Triassic sequence in southern Jiangsu and Anhui provinces of eastern China, yielding a rich plant and bivalve fossil record. The present study provides the first detailed palynological investigation for the Upper Triassic of Nanjing area, eastern China. Six of twenty processed palynological samples are productive, and more than 70 terrestrial spore and pollen fossil taxa were identified. A palynological assemblage, namely, the Concavisporites–Dictyophyllidites–Kyrtomisporis–Classopollis Assemblage was established, characterized by abundant fern spores, mainly including Concavisporites, Dictyophyllidites and Kyrtomisporis, and much less abundant gymnosperm pollen grains (important taxa include Alisporites, Chasmatosporites, and Classopollis), indicating a Late Triassic Norian–Rhaetian age. In conjunction with previously reported macro-plant data, the palynofloral analysis reveals a vegetation dominated by ferns, with diverse cycadophytes, less abundant lycophytes, bryophytes, equisetales, ginkgophytes and seed ferns, and a few conifers. Paleovegetation and semiquantitative palynological analysis permit a paleoecological interpretation, suggesting a lowland groundcover-dominated vegetation under (sub)tropical warm and humid climate in Nanjing area during this time interval. More detailed palynological and macro-plant data through the whole Upper Triassic in this region are necessary in the future to better reveal the Late Triassic paleoecological settings and variations on land prior to the end-Triassic mass extinction in eastern Tethys.

The potential of renewable electricity in isolated grids: The case of Israel in 2050

Power generation is one of the main resources for emissions of pollutants and greenhouse gases. Thus, emissions can be seriously regulated if the electricity sector could be driven by renewables. Of special interest are cases with an isolated grid such as Israel, with extensive work already carried out in the past on the evaluation of renewable electricity in this country. Yet, it appears that the methods adopted previously were not rigorous enough to reflect the true potential. The current work is an attempt to deal with this challenge by implementing comprehensive input data collection, as well as detailed performance and energy management modeling. The main goal of the current study is to evaluate the energy mix, together with the required storage capacity, that would allow maximum penetration of renewables into the Israeli grid in 2050. The total electric demand in 2050 is evaluated as 183.3 TWh. The resources of interest are fossils, solar energy (both photovoltaics and agrivoltaics), onshore and offshore wind, sea waves, and organic waste. The total installed power from renewables is evaluated as 180.6 GW. The energy storage capacity is mostly relying on the technology of Vehicle to Grid (V2G), and with the help of additional stationary batteries and several pumped hydroelectric plants, the total capacity is estimated as 216 GWh. However, owing to the uncertainty in future storage technologies, larger capacities are considered as well. The performance model (PM) used in the analysis of solar and wind plants is the System Advisor Model (SAM). To match the electric generation and demand, an energy management system (EMS) model was developed. The EMS is controlling the hourly fossil power to maximize the renewable share on an annual basis while ensuring full supply to consumers (no power outage). Economic evaluation is excluded in the current analysis. It was obtained that renewables share between 80.1% and 99.5% may be achieved, depending on the scenario. The annual energy dumping is between 4.9% and 46.1% and the fossil plants’ annual capacity factor is between 0.4% and 13.6%.

Detection of defects initiation in weld joints

Welded joints on various pipelines, especially steam pipelines of fossil power plants, are exposed to high pressure and temperature of steam during operation. The applied stress and temperature together with the chemical composition and microstructure of the material have a major influence on the damage growth in these joints. Growth of defects as a time-dependent event, the sensitivity of the material to damage due to stress temperature and others plays a major role. In the case of steam pipes of fossil power plants, this is mainly creep damage. Early detection of these defects, especially at their initial stage, can help in managing the service life and thereby reducing the costs for operation, both by minimizing unplanned shutdowns as well as by planning any repairs in time. The work is focused on the detection of defect indications, especially creep damage occurring in weld joints and heat-affected areas. The aim is to distinguish manufacturing defects of welded joints from indications of early crack growth by ultrasonic testing. Indications from manufacturing defects may also be detected during testing and, if detected, will be evaluated in the same way as defects that are primarily targeted by the testing techniques. Several different techniques were tested on samples cut from the operated steam pipeline systems and compared with the results of metallographic analyses on selected parts.

Reconstruction of the Late Holocene Environment of Central Yakutia Based on Fossil Invertebrates and Plants from a Buried Lake at the Vilyuy River Valley

We present the first record of Holocene fossil insect assemblages from Central Yakutia. A stratigraphic sequence in the locality within the Vilyuy River valley is a buried oxbow. The late Holocene water body inherited an impervious stratum from the late Pleistocene. The organic layer preserved rich fossil assemblages of macrofossils including insects and other invertebrates, plants, and charcoal. The ancient flora and fauna include species that are common in Yakutia as well as those that are rare and absent in the region. The most abundant finds are leech cocoons and bogbean seeds. The macrofossils of some insects were found along with remains of their host plants. Despite the absence of intensive human land use in the area, traces of fires were recorded. The oxbow represents the environment of a floodplain wetland that developed separately from the ecosystem of the adjacent sand dunes.