Search publications of the members of the Royal Belgian institute of natural Sciences
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Investigating geological processes and their links with geological structures through geomanifestations
- GeoConnect³d introduced the concept of geomanifestations to define 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. Examples include seismicity, gas seeps, local compositional differences in groundwater and springs, thermal anomalies, mineral occurrences, jumps in hydraulic head, overpressured zones and geomorphological features. Geomanifestations are an addition to the structural framework model also being developed in GeoConnect³d, aiming to show where and how processes and structures may be linked. Data on geomanifestations are being collected in three areas: the Roer-to-Rhine area of interest in northwest Europe, and the Mura-Zala Basin and Battonya High within the Pannonian Basin area of interest in Eastern Europe. A first assessment of available data showed that groundwater-related geomanifestations in the form of anomalies in chemical composition (enrichment in elements such as Fe, or hydrocarbon gases and CO2,) or temperature (thermal water springs, geothermal anomaly in wells) are mappable in all areas. These geomanifestations point to special geological features in each area, such as proximity to magmatic reservoirs, presence of deep-rooted faults and considerable differences in the subsurface relief (trough–high system of the basement) among others. These anomalies at times define spatial patterns, which might or not be represented in the structural framework model, thus demonstrating whether they can be explained by the current geological understanding embedded in the structural framework. With this first test, we conclude that data on groundwater-related geomanifestations add to the robustness of the structural framework model. Further investigations with other types of geomanifestations are foreseen. 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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Structural framework: a new way to organise and communicate geological information
- A structural framework is a well-defined concept, being used primarily to add structural understanding to a geological model. Within GeoConnect³d, a new approach is used, i.e. the structural framework concept is modified to become the leading model, in which geological maps and models can be inserted and related to. This structural framework is being developed and implemented for two areas of interest - Roer-to-Rhine in northwest Europe and Pannonian Basin in eastern Europe - and will soon be implemented in two pilot areas, Ireland and Bavaria. The organisation of information is strongly linked to different scales of visualisation, starting from the pan-European view (1:15,000,000) with the possibility to zoom in to the scale of local geological models and maps in these four areas. The GeoConnect³d structural framework reorganises geological information in terms of geological limits and geological units. Limits are defined as broadly planar structures that separate a given geological unit from its neighbouring units, e.g. faults (limits) that define a graben (unit), or an unconformity (limit) that defines a basin (unit). Therefore, the key relationship between these two structural framework elements is that units are defined by limits i.e. all units must be bounded by limits. It is important to note that this relationship is not necessarily mutual: not all limits have to be unit-defining. A first test of the structural framework methodology was carried out in the Netherlands and Belgium for the Roer Valley graben, as the faults in this area were already modelled in a cross-boundary project (H3O-Roer Valley Graben). Displaying different elements according to scale of visualisation coupled with vocabulary information (definition, grouping and semantic relations between elements, etc.) following the SKOS-system proved a powerful tool to display geological information in an understandable way and improve insights in large-scale geological structures crossing national borders. Additionally, links with other GeoERA projects such as HIKE and its fault database are being successfully established. We consider the outcomes of this test promising to fulfil one of the main goals of GeoConnect³d, i.e. preparing and disclosing geological information in an understandable way for stakeholders. We also consider this as the way forward towards pan-European integration and harmonisation of geological information, where the ultimate challenge is to correlate or otherwise link information from different geological domains and of different scales. 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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Naturally CO2-rich water springs in Belgium evidencing complex subsurface interactions
- Numerous naturally CO2-rich mineral water springs, locally called ‘pouhons’, occur in southeast Belgium. These are oversaturated in CO2 (up to 4g/L) and have attracted economic, touristic and scientific interest for centuries. Water sources occur within Palaeozoic rocks of the Rhenohercynian deformation zone, a fold-and-thrust belt at the north of the Variscan orogeny in central Europe. Many occurrences are concentrated in the Cambro-Ordivician Stavelot-Venn massif. A widely accepted model, supported by H-O isotopic signatures, is that sources are primarily fed by meteoric water, which infiltrates through Quaternary sediments, then reaching Lower Palaeozoic rocks to meet the mineral and CO2 source at unknown depth. Different ideas for the origin of CO2 are grouped in two main hypotheses: a) generation by dissolution of carbonate rocks and/or nodules, and b) volcanic degassing related to the neighbouring Eifel area in Germany. These well-known interpretations are mostly based on geochemical studies that are dispersed and poorly accessible. These have now been gathered in the light of new sampling campaigns, allowing to revisit and compare the views of earlier authors. We also for the first time include the geotectonic setting of the region. Carbonate rocks in the region are represented by Lower Carboniferous and Middle Devonian limestones. Depending on the assumed structural evolution for this foreland fold-an-thrust belt, these may occur at >2 km depth below the Stavelot-Venn massif. Carbonate nodules are present in other formations, but their limited volume is unlikely to originate high and long-lived quantities of CO2. Springs enriched in CO2 are also common in the volcanic Eifel area, with presence of mantle CO2 well established. The supposed extension of the Eifel plume would allow for a magmatic CO2 source below the Stavelot-Venn massif from degassing of the plume (>50 km deep), or of an unknown shallower magmatic reservoir. Available stable and noble isotopes point to a mixed carbonate-magmatic origin. If considering the presence of limestones at depth, meteoric water should infiltrate at least 2 km. Known deep-rooted faults are thought to act as preferential groundwater pathways. However, such deep circulation is incompatible with the low temperatures of springs (~10oC), unless the ascent is slow enough to fully dissipate heat prior to resurfacing. Another possibility is that meteoric water does not infiltrate as deep, with CO2 being transported upwards to meet groundwaters at shallower depths. The presence of CO2 surface leaks, locally called ‘mofettes’, could be evidence of such relatively shallow availability of CO2. The evaluation of existing hypotheses highlights complex subsurface processes that involve water infiltration, CO2 assimilation and water resurfacing in southeast Belgium. As such, this review is an important guide for the newly launched sampling campaigns. This work is part of two research projects: GeoConnect³d-GeoERA that has received funding by the European Union’s Horizon 2020 research and innovation programme under grant agreement number 731166, and ROSEAU project, as part of the Walloon program « Doctorat en Entreprise », co-funded by the SPW Région Wallonne of Belgium and the company Bru-Chevron S.A. (Spadel group), under grant number 7984.
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Where and why: using a structural framework to contextualise and improve the understanding of processes leading to mineral occurrences
- The societal development towards climate neutrality and the ambition for economic growth and well-being in Europe rely on mineral raw materials. Mineral occurrences can be seen as manifestations of specific geological processes that happened in the subsurface, or geomanifestations. Locating and better understanding mineral occurrences and deposits in Europe is crucial for future informed decision making on local resourcing. The GeoConnect³d project is developing a multi-scale structural framework in which geological maps and 3D models can be inserted and related to. In our novel approach, the structural framework reorganises geological information in terms of geological limits and geological units. Limits are defined as broadly planar structures that separate a given geological unit from its neighbouring units, e.g. faults (limits) that define a graben (unit), or an unconformity (limit) that defines a basin (unit). Geomanifestation data are then added to the structural framework model aiming to show where and how processes and structures may be linked. This approach was tested in Belgium, where a structural framework was created at different scales, from most detail at 1:250,000 to more generalised at 1:2,000,000. Mineral occurrence data from the Minerals4EU database were used to test the model. As an example, a spatial link between Pb-Zn deposits and structural framework elements is identifiable in the Herve-Vesdre and Landenne areas. Although the deposits are located within the Variscan orogenic front, deposition is post-Variscan and spatially associated with transverse NNW-SSE faults part of the Rhine graben network (Dejonghe, 1998). With a combination of database attributes and SKOS vocabulary, the information of deposition age and time of activity of faults displayed in the structural framework helps to quickly place these deposits in the context of the Lower Rhine embayment. Therefore, the structural framework can translate highly technical scientific knowledge by using an interactive tool that presents information in a more understandable way. We consider the outcomes of this test promising to fulfil one of the main goals of GeoConnect³d: preparing and disclosing geological information in a way it is more useful for stakeholders. We also consider this as the way forward towards pan-European integration and harmonisation of geological information, where the ultimate challenge is to correlate or otherwise link information from different geological domains and of different scales. This will be beneficial for the identification and better geological understanding of European mineral resources. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 731166. Reference: Dejonghe, L., 1998. Zinc-lead deposits in Belgium. Ore Geology Reviews 12, 329-354.
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Brug en toegangspoort tot kasteel
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Interdisciplinary study of horticultural practices in late medieval Brussels
- Over the last decades a series of sites attesting the presence of ancient crop fields and gardens were discovered in the historical center of Brussels. Well aerated crop field and garden soils with a high biological activity, are often not suitable for the preservation of organic plant remains. In most cases, their studies yielded only small quantities of more resistant seeds and fruits. The identification of the cultivated plants relied therefore mainly on phytolith analysis.Recently, a Holocene peat sequence was excavated in the lower part of the city in a quarter that is historically documented as a horticultural area (rue des Boiteux, BR295). Micromorphology showed that the upper layers of the peat sequence were drained during the late Middle Ages and subsequently converted into horticulture. In this poster the potential of studying these contexts will be discussed. Thanks to the prevailing wet conditions of the soil, higher densities of waterlogged macrobotanical remains could be analysed. Remains of divers cultivated plants and garden weeds were found, most probably partly from the local vegetation and local cultivated crops. The archaeobotanical and archaeozoological studies also shed light on manuring practices.
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Untangling a mess of worms: Species delimitations reveal morphological crypsis and variability in Southeast Asian semi-aquatic earthworms (Almidae, Glyphidrilus)
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Re-description of the type species of the genera Ganesella Blanford, 1863 and Globotrochus Haas, 1935; with description of a new Ganesella species from Thailand (Eupulmonata, Camaenidae)
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Abeilles de Belgique et des régions limitrophes (Insecta: Hymenoptera: Apoidea) Famille Halicitidae
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Body distribution of toxic peptides in larvae of a pergid and an argid sawfly species
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NGS-barcodes, haplotype networks combined to external morphology help to identify new species in the mangrove genus Ngirhaphium Evenhuis & Grootaert, 2002 (Diptera: Dolichopodidae: Rhaphiinae) in Southeast Asia
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The phylogeny of the African wood mice (Muridae, Hylomyscus) based on complete mitochondrial genomes and five nuclear genes reveals their evolutionary history and undescribed diversity
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Stratigraphy of an early-middle Miocene sequence near Antwerp in Northern Belgium (Southern North Sea Basin)
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High concentration of long-snouted beaked whales (genus Messapicetus) from the Miocene of Peru
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New discoveries of fossil toothed whales from Peru: our changing perspective of beaked whale and sperm whale evolution
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A new species of the fossil beaked whale Beneziphius (Cetacea, Odontoceti, Ziphiidae) from the ocean floor off Galicia and biostratigraphic reassessment for the age of the type species
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Earliest mysticete from the late Eocene of Peru sheds new light on the origin of baleen whales
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Neogene and Quaternary fossil remains of beaked whales (Cetacea, Odontoceti, Ziphiidae) from deep-sea deposits off Crozet and Kerguelen islands, Southern Ocean
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A relative of the beluga and narwhal (Odontoceti, Monodontidae) from the Early Pliocene of the North Sea
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Tusk-bearing beaked whales from the Miocene of Peru
