Search publications of the members of the Royal Belgian institute of natural Sciences
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A large meteoritic event over Antarctica ca. 430 ka ago inferred from chondritic spherules from the Sør Rondane Mountains
- Large airbursts, the most frequent hazardous impact events, are estimated to occur orders of magnitude more frequently than crater-forming impacts. However, finding traces of these events is impeded by the difficulty of identifying them in the recent geological record. Here, we describe condensation spherules found on top of Walnumfjellet in the Sør Rondane Mountains, Antarctica. Affinities with similar spherules found in EPICA Dome C and Dome Fuji ice cores suggest that these particles were produced during a single-asteroid impact ca. 430 thousand years (ka) ago. The lack of a confirmed crater on the Antarctic ice sheet and geochemical and 18O-poor oxygen isotope signatures allow us to hypothesize that the impact particles result from a touchdown event, in which a projectile vapor jet interacts with the Antarctic ice sheet. Numerical models support a touchdown scenario. This study has implications for the identification and inventory of large cosmic events on Earth.
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Structural framework as the new fundament for international geoscientific cooperation and policy support
- The transition towards a clean and low carbon energy system in Europe will increasingly rely on the use of the subsurface. Communicating the potential and limitations of subsurface resources and applications remains challenging. This is partly because the subsurface is not part of the world people experience, leaving them without reference frame to understand impacts or consequences. A second element is that the geological context of a specific area is very abstract, three dimensional, and hence difficult to correctly and intuitively disclose using traditional geological maps or models. The GeoConnect³d project is finalising the development and testing of a new type of information system that can be used for various geo-applications, decision-making, and subsurface spatial planning. This is being accomplished through the innovative structural framework model, which reorganises, contextualises, and adds value to geological data. The model is primarily focused on geological limits, or broadly planar structures that separate a given geological unit from its neighbouring units. It also includes geomanifestations, highlighting any distinct local expression of ongoing or past geological processes. These manifestations, or anomalies, often point to specific geologic conditions and therefore can be important sources of information to improve geological understanding of an area and its subsurface (see Van Daele et al., this volume, Rombaut et al., this volume ). Geological information in this model is composed of spatial data at different scales, with a one-to-one link between geometries and their specific attributes (including uncertainties), and of semantic data, categorised conceptually and/or linked using generic SKOS hierarchical schemes. Concepts and geometries are linked by a one-to-many relationship. The combination of these elements subsequently results in a multi-scale, harmonised and robust model. In spite of its sound technical basis, consultation is highly intuitive. The underlying vocabulary is of high scientific standard and linked to INSPIRE and GeoSciML schemes, but can also automatically, both visually and semantically, be simplified to be understood by non-experts. The structural framework-geomanifestations methodology has now been applied to different areas in Europe. The focus on geological limits brings various advantages, such as displaying geological information in an explicit, and therefore more understandable way, and simplifying harmonisation efforts in large-scale geological structures crossing national borders originating from models of different scale and resolution. The link between spatial and semantic data is key in adding conceptual definitions and interpretations to geometries, and provides a very thorough consistency test for present-day regional understanding of geology. As a framework, other geological maps and models can be mapped to it by identifying common limits, such as faults, unconformities, etc, allowing to bring together non-harmonised maps in a meaningful way. The model demonstrates it is possible to gather existing geological data into a harmonised and robust knowledge system. We consider this as the way forward towards pan-European integration and harmonisation of geological information. Moreover, we identify the great potential of the structural framework model as a toolbox to communicate geosciences beyond our specialised community. Making geological information available to all stakeholders involved is an important step to support subsurface spatial planning to move forward towards a clean energy transition. . This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 731166.
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Enhanced rock weathering: the overlooked hydrodynamic trap
- Enhanced rock weathering (ERW) is a technique proposed to remove large amounts of CO2 from the atmosphere (i.e. a negative emission technology) in which finely fragmented silicate rocks such as basalts (ground basalt) are distributed over agricultural or other land plots. The weathering process involves trapping CO2 but will also typically ameliorate soil properties (pH, soil moisture retention, cation exchange capacity, availability of Si), and can therefore be expected to positively affect plant and microbiological activity. This technique has been proposed in different modified forms over the past decades. In its current format, mainly its potential for near global application (e.g. Beerling et al. 2020) is stressed, and its acceptance is helped by the positive reception by e.g. nature organisations that already apply it as a technique for ecological restoration. Two main and largely separated processes result in trapping of CO2. The first is precipitation of carbonates, often as nodules, in the soil. The second is increased CO2 solubility in groundwater and eventually ocean water due to an increase of the pH value, referred to as the pH-trap. Most of the pH-trapping schemes are built on the assumption that CO2 is dissolved in infiltrating and shallow ground water, then discharged into surface water and consecutively transported to the seas and oceans. In that reservoir CO2 is expected to remain dissolved for centuries and possibly up to ten thousands of years, depending on surfacing times of deep oceanic currents. Another pathway that is systematically overlooked is that of groundwater fluxes that recharge deeper groundwater bodies. Depending on the regional geology, a significant fraction of infiltrating water will engage in deeper and long-term migration. For Belgium, the contribution of hydrodynamic trapping, depending on the hydrogeological setting, could be any part of the 15 to 25% of precipitation that infiltrates. Once infiltrating water enters these cycles, it will not come into contact with the atmosphere for possibly fifty thousand years. In this model, the long-term impact of ERW as a climate mitigation measure rests on a good understanding of the larger hydrogeological context, which encompasses infiltration and the deeper aquifers. Deep aquifers, as well as the migration paths towards them, are strictly isolated and residence times are much longer than for oceans. Recharge areas for deeper aquifer systems may therefore become preferential sites for ERW application, becoming an additional evaluation factor for siting ERW locations that is currently based on surface factors alone.
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A New Species of the Genus Thinophilus Wahlberg from the River Banks of the Mekong River in Thailand (Diptera: Dolichopodidae)
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Cross-taxa generalities in the relationship between population abundance and ambient temperatures.
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Carbon and nitrogen isotopic ratios in archaeological and modern Swiss fish as possible markers for diachronic anthropogenic activity in freshwater ecosystems
- The aim of this study is to investigate isotopic variability in archaeological (n=85) and modern (n=29) freshwater fish specimens from Switzerland. Here, carbon (δ13C) and nitrogen (δ15N) stable isotope ratio analysiswas performed on bone collagen samples of pike (Esox lucius), perch (Perca fluviatilis), barbel (Barbus barbus), roach (Rutilus rutilus) and carp (Cyprinus carpio) fromeleven archaeological (11th to 18/19th centuries CE) andmodern sites. The archaeological vs. modern fish data revealed significant isotopic differences for pike, perch and barbel (δ13Cp≤ 0.03; δ15Np≤ 0.008), and provides possible evidence for a temporal change in Swiss aquatic ecosystems from Medieval to modern times. In comparison to archaeological fish (δ13C mean ± SD; −23.3 ± 1.6‰; δ15N mean ± SD; 8.3 ± 1.8‰), the modern fish samples show decreased δ13C and increased δ15N values (δ13C mean± SD; −27.4 ± 2.3‰; δ15N mean± SD; 12.5± 4.1‰) that can be associated with anthropogenic effects: fossil fuel combustion, deforestation and organic waste in the form of sewage and fertilizers. The isotopic signatures of archaeological fish remains indicate a local fishery practice, but also the exploitation of distant fishing grounds and freshwater fish transportation. Furthermore, a diachronic isotopic trend is observed in young perch from sites in Basel, dating between the 12th and 15/16th centuries CE, and the isotopic data from the Rhine freshwater fish (18/19th century CE) suggests that a significant shift in the river's trophic state was possibly caused by organic pollution fromurban and industrial wastewater. This retrospective research illustrates possible natural processes and human activitieswhich can cause differences in fish stable isotope data and highlights the ability to elucidate changes in past bodies of water. Furthermore, this study provides an interpretative framework for additional palaeoenvironmental studies and modern restoration projects focused on freshwater ecosystems.
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Pyrops auratus, a new lanternfly from the Philippines and taxonomic note on Bornean P. gunjii (Satô & Nagai, 1994) (Hemiptera: Fulgoromorpha: Fulgoridae)
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A review on onshore tsunami deposits along the Atlantic coasts.
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Landschaftsentwicklung und Landnutzung im Segbachtal bei Mendig.
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Holocene climate variability of Mesopotamia and its impact on the history of civilisation.
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Syn- and post-eruptive gully formation near the Laacher See volcano
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Experiments on tsunami induced boulder transport – A review
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Mainstreaming of biodiversity into development cooperation
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Presentation Luc et Jean Didier\_EVAMAB Clearing House Mechanism of Bénin
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Cabindachanos dartevellei gen. and sp. nov., a new chanid fish (Ostariophysi, Gonorynchiformes) from the marine Paleocene of Cabinda (Central Africa)
- The osteology of Cabindachanos dartevellei gen. and sp. nov., a fossil fish from the marine Danian or early Selandian deposits of Landana (Cabinda Territory, Central Africa), is here studied in detail. This fish is known by only one partially preserved specimen that shows typical characters. The opercle is greatly hypertrophied. The preopercle has a very broad dorsal limb and a long narrower ventral limb. There is a wide plate-like suprapreopercle. The lower jaw is deep, with a well-marked coronoid process formed by the dentary. The articulation between the quadrate and the mandible is located before the orbit. The first supraneurals are enlarged. These characters indicate that C. dartevellei belongs to the family Chanidae (Teleostei, Gonorynchiformes). Cabindachanos dartevellei differs from all the other known fossil or recent chanid fishes by the gigantic development of its opercle and by the loss of the subopercle. The straight angle formed by the two limbs of the preopercle and the well-developed posterior median crest of the supraoccipital indicate that C. dartevellei belongs to the subfamily Chaninae and the tribe Chanini.
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Tristichopterids (Sarcopterygii, Tetrapodomorpha) from the Upper Devonian tetrapod-bearing locality of Strud (Belgium, upper Famennian), with phylogenetic and paleobiogeographic considerations
- We describe new material of the tristichopterids cf. Langlieria socqueti and cf. Eusthenodon wangsjoi and other unassignable tetrapodomorph remains from the upper Famennian locality of Strud, Belgium. Because of recent improvements in our tristichopterid knowledge, a new phylogenetic analysis is presented in addition to a paleobiogeographic analysis using the Bayesian binary Markov chain Monte Carlo (MCMC) statistical method. The origin of the whole tristichopterid clade is reconstructed with a very likely western European origin. Much of the early tristichopterid history took place in Euramerica. During the Late Devonian, tristichopterids most probably spread from Euramerica into Gondwana. The highly nested tristichopterid clade formed by Cabonnichthys burnsi, Mandageria fairfaxi, E. wangsjoi, Edenopteron keithcrooki, and Hyneria lindae most likely differentiated in Australia. Then dispersal events occurred from Australia to Euramerica with Hyneria lindae (to eastern North America) and E. wangsjoi (to Greenland/western Europe). The latter dispersal events, during the Famennian, are in agreement with the Great Devonian Interchange, which predicts dispersal events between Gondwana and Euramerica at this time.
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First occurrence of fossil vertebrates from the Carboniferous of Colombia
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Rise of the titans: baleen whales became giants earlier than thought
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Diverse and durophagous: Early Carboniferous chondrichthyans from the Scottish Borders
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Microfacies analysis of a middle to upper Frasnian succession at the Lompret quarry (SW Belgium) documenting a transition from the Lion reef to deep marine Neuville and Matagne environments
