Search publications of the members of the Royal Belgian institute of natural Sciences
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Ichtyosaurs from the French Rhaetian indicate a severe turnover across the Triassic-Jurassic boundary
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Integrated bio-chemostratigraphical correlations and climatic evolution across the Danian–Selandian boundary at low latitudes.
- The Global Boundary Stratotype Section and Point for the base of the Selandian Stage is defined in the Zumaia section (Spain) at an abrupt change in lithology (base of Itzurun Formation), which coincides with the onset of a negative carbonate carbon isotope shift. However, this lithological change is not always very well expressed in other sections. In order to document the stratigraphic position of the Danian/Selandian boundary (DSB) on a more global scale, we have investigated three sections across the DSB, the Zumaia reference section (GSSP), the Loubieng section (auxiliary DSB reference section, France) and the Sidi Nasseur section (Tunisia). The Danian/Selandian boundary interval is subdivided and correlated throughout low latitudes, from the Altlantic Bay of Biscay to the Southern Tethys, on the basis of seven calcareous nannofossil and planktonic foraminiferal events (E-events). The base of the Selandian is proved to coincide with the end of the Braarudosphaera acme, which correlates with the lowest consistent occurrence (LCsO) of Lithoptychius aff. bitectus (=Fasciculithus janii sensu Steurbaut and Sztrákos, 2008) (event E4), but which is slightly posterior to the second radiation of the fasciculiths, up to now considered to represent the primary correlation tool of the DSB. A short-term δ13Corg negative excursion, associated with an increase in pCO2 is recorded at the very base of the Selandian. It is interpreted as a short period of global warming (hyperthermal), the duration of which is estimated at ~30 kyr. It is followed in all the three studied sections by a long-term decoupled carbon isotope event, marked by increasing δ13Corg and decreasing δ13Ccarb values. It may reflect a period of climatic cooling of a few 100 kyr, interpreted as a possible precursor of the global cooling event, marking the late Paleocene in the North Atlantic realm. The integration of the biostratigraphic and the isotope data indicates major differences in sedimentation rates during the early Selandian in the studied sections, but there is no evidence of substantial breaks in sedimentation in any of the sections during this interval. The lithological shift at the base of the Selandian points to an abrupt palaeoenvironmental reorganisation, although our integrated bio-chemostratigraphical investigation does not allow for estimating its duration nor the presence of a hiatus at that time.
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Het oudheidkundig bodemonderzoek aan de Sacramentstraat te Tongeren. Eindverslag 1993
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New Archaeozoological Data from the Fayum ‘‘Neolithic’’ with a Critical Assessment of the Evidence for Early Stock Keeping in Egypt
- Faunal evidence from the Fayum Neolithic is often cited in the framework of early stock keeping in Egypt. However, the data suffer from a number of problems. In the present paper, large faunal datasets from new excavations at Kom K and Kom W (4850–4250 BC) are presented. They clearly show that, despite the presence of domesticates, fish predominate in the animal bone assemblages. In this sense, there is continuity with the earlier Holocene occupation from the Fayum, starting ca. 7350 BC. Domesticated plants and animals appear first from approximately 5400 BC. The earliest possible evidence for domesticates in Egypt are the very controversial domesticated cattle from the 9th/8th millennium BC in the Nabta Playa-Bir Kiseiba area. The earliest domesticates found elsewhere in Egypt date to the 6th millennium BC. The numbers of bones are generally extremely low at this point in time and only caprines are present. From the 5th millennium BC, the numbers of sites with domesticates dramatically increase, more species are also involved and they are usually represented by significant quantities of bones. The data from the Fayum reflect this two phase development, with very limited evidence for domesticates in the 6th millennium BC and more abundant and clearer indications in the 5th millennium BC. Any modelling of early food production in Egypt suffers from poor amounts of data, bias due to differential preservation and visibility of sites and archaeological remains, and a lack of direct dates for domesticates. In general, however, the evidence for early stock keeping and accompanying archaeological features shows large regional variation and seems to be mainly dependent on local environmental conditions. The large numbers of fish at Kom K and Kom W reflect the proximity of Lake Qarun.
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Monitoring polycyclic aromatic hydrocarbons in the Northeast Aegean Sea using Posidonia oceanica seagrass and synthetic passive samplers.
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Validation of modelled bottom shear stress under the influence of currents and waves, using long-term measurements.
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Uncertainty of in situ SPM concentration measurements. Abstract, 13th International Conference on Cohesive Sediment Transport Processes, 7 - 11 September 2015, Leuven, Belgium, 2 pp.
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Surface SPM concentration in Taiwan Strait during summer and winter monsoon
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In situ measurements of SPM concentration to evaluate the impact of the disposal of fine grained sediments from maintenance dredging. Abstract, 13th International Conference on Cohesive Sediment Transport Processes, 7-11 September 2015, Leuven, Bel
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INVESTIGATION OF THE DEGRADATION PHENOMENA OF THE LUXEMBOURG SANDSTONE IN THE ROYAL MUSEUM FOR CENTRAL AFRICA (BELGIUM)
- The Royal Museum for Central Africa in Tervuren was built in the beginning of the 20th century. The outer walls and ornamental elements were almost exclusively constructed in massive blocks of Luxembourg sandstone, a stone well suited as building material. Despite the stated good quality, the facades locally suffer from exposure to weathering. Moreover, certain zones show severe damage due to rain water infiltration originating from defects in the water evacuation system which is entirely hidden within the walls. As a consequence, important damage to the sandstone blocks in the form of crack-formation, scaling, spalling and (salt) staining, is noticed. This paper presents the results of an investigation carried out in the framework of the restoration strategy aiming to explain degradation and damage phenomena in relation to the properties and varieties of Luxembourg sandstone. Detailed visual observations with regard to the architectural concept was followed by a sampling plan and a test program. Physical and microscopic analysis allowed to establish the relationship between rock type, colour and weathering effects. The test program consisted of the determination of physical and mineralogical properties, hardness profiles obtained by means of the portable DRMS device (Drilling Resistance Measurement System), ultrasound velocity measurements and the determination of the actual salt contamination. The strengthening effect of a number of consolidation tests, using tetraethoxysilane (TEOS), was also evaluated by means of hardness profiles
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Middle-Holocene alluvial forests and associated fluvial environments: A multi-proxy reconstruction from the lower Scheldt, N Belgium
- Analyses of pollen, plant macrofossils (seeds, fruits, wood and mosses), molluscs, diatoms and vertebrate (mainly fish) remains allowed a detailed reconstruction of a middle-Holocene alluvial forest and its associated hydrological conditions. The use of multiple proxies resulted in a taxonomically more detailed and environmentally more comprehensive understanding of terrestrial as well as aquatic habitats. The results demonstrate possible biases in palaeoecological reconstructions of alluvial and estuarine environments drawn from single proxies. Many locally occurring woody taxa were underrepresented or remained undetected by pollen analyses. Seeds and fruits also proved to be inadequate to detect several locally important taxa, such as Ulmus and Hedera helix. Apparently brackish conditions inferred from diatoms, pollen and other microfossils conflicted strikingly with the evidence from molluscs, fish bones and botanical macroremains which suggest a freshwater environment. Brackish sediment (and the microfossil indicators) is likely to have been deposited during spring tides or storm surges, when estuarine waters penetrated more inland than usual. Despite the reworking and deposition of estuarine and saltmarsh sediment well above the tidal node at such events, local salinity levels largely remained unaffected.
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Damage assessment of ferruginous sandstone by X-ray tomografie - the "Virgin Tower" of Zichem (Belgium)
- The ferruginous sandstone of the Gothic “Virgin Tower” is suffering from a specific biological deterioration process triggered by perforating activities of mason bees. The damage due to these perforations causes extensive loss of material, so that a durable conservation of such degraded stoneblocks becomes questionable. In order to evaluate the conservation possibilities of stoneblocks damaged by perforating mason bees, an investigation of the internal structure by means of X-ray tomography was carried out. This investigation revealed that the cumulative effect of the digging work by multiple generations of mason bees may result in networks of perforations. Bioturbated sandstones were found to be most suitable for attack by mason bees because of morphological and geometrical compatibility between the original layered burrowings by marine organisms and those by the mason bees. As a conclusion, the conservation is not recommended of sandstoneblocks for which the load bearing capacity is endangered by the branched and layered perforations
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Soil Nematodes
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First report of stubby root nematode, Paratrichodorus teres (Nematoda: Trichodoridae) from Iran
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Comparative suceptability of Macrotermes bellicosus and Trinervitermes occidentalis (Isoptera: Termitidae) to entomopathogenic nematodes from Benin
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Morphological and molecular characterisation of Trichodorus golestanensis (Nematoda: Trichodoridae), a new species from Iran.
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Tracking ancient ship routes through the analysis of caulking material from shipwrecks? The case study of two 14th century cogs from Doel (northern Belgium).
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The Late Neolithic Michelsberg culture – just ramparts and ditches? A supraregional comparison of agricultural and environmental data
- The archaeobotanical state of research from sites of the Michelsberg and the Bischheim culture (5th/4th millenium BC) in France, Belgium, southern Netherlands and Germany has been compiled and discussed in the context of archaeological, climatological and biological data. Compared with Bischheim and the Middle Neolithic the farmers of the Michelsberg culture had a reduced crop spectrum with emphasis on cereal growing. It is still under debate, from where the tetraploid wheat has been introduced. Possibly the growing of oil/fibre plants was abandoned by the Michelsberg farmers. Interestingly the same reduced crop spectrum is found somewhat later in the distribution area of the Funnelbeaker culture as well as in the Neolithic sites of Great Britain and Ireland. Climatic causes are not likely for this phenomenon. Instead, zoologial and botanical results point to an agricultural system with more emphasis on stock farming, which might have been based on a cultural decision.
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Plant use and local vegetation patterns during the second half of the Late Pleistocene in southwestern Germany
- In light of recent discoveries of early figurative art in Paleolithic sites of southwestern Germany, gaining an improved understanding of biological, cultural, and social development of these hunter-gatherer populations under past environmental conditions is essential. The analysis of botanical micro- and macrofossils from the Hohle Fels Cave contributes to the limited floral record from this region. These data suggest generally open vegetation, with the presence of wood near Hohle Fels, as indicated by pollen, phytoliths, and evidence from wood charcoal throughout the whole sequence of occupation. The Aurignacian horizons (early Upper Paleolithic, starting around 44,200 calibrated years before present (cal yr BP) correlate with prevailing shrub tundra. Few arboreal pollen in the transitional section from the Aurignacian to the Gravettian horizons (middle Upper Paleolithic, until ca. 32 cal yr BP) supports the model of an interglacial tundra with a mosaic of cold steppe elements and some patches of woody species. In the Gravettian, the macrobotanical and the palynological records indicate colder climatic conditions and a generally reduced presence of wood patches. Few seed remains, mostly of the Asteraceae and Poaceae families suggesting the use of these plants. The collection of bearberry (Arctostaphylos sp.) for specific purposes is indicated by large amounts of bark fragments.
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Offshore windmolens in de Belgische Noordzee
