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Inproceedings Reference Board games as scientific communication tools for black-box methodologies: the principles of the geo-techno-economic PSS III simulator translated into an interactive educational game
Located in Library / RBINS Staff Publications 2016
Article Reference Genesis of the vein-type tungsten mineralization at Nyakabingo (Rwanda) in the Karagwe–Ankole belt, Central Africa
The vein-type tungsten deposit at Nyakabingo in the central Tungsten belt of Rwanda is located in the eastern flank of the complex Bumbogo anticlinal structure. The host rock is composed of alternating sequences of sandstones, quartzites, and black pyritiferous metapelitic rocks. Two types of W-mineralized quartz veins have been observed: bedding-parallel and quartz veins that are at high angle to the bedding, which are termed crosscutting veins. Both vein types have been interpreted to have been formed in a late stage of a compressional deformation event. Both vein types are associated with small alteration zones, comprising silicification, tourmalinization, and muscovitization. Dating of muscovite crystals at the border of the veins resulted in a maximum age of 992.4 ± 1.5 Ma. This age is within error similar to the ages obtained for the specialized G4 granites (i.e., 986 ± 10 Ma). The W-bearing minerals formed during two different phases. The first phase is characterized by scheelite and massive wolframite, while the second phase is formed by ferberite pseudomorphs after scheelite. These minerals occur late in the evolution of the massive quartz veins, sometimes even in fractures that crosscut the veins. The ore minerals precipitated from a H2O–CO2–CH4–N2–NaCl–(KCl) fluid with low to moderate salinity (0.6–13.8 eq. wt% NaCl), and minimal trapping temperatures between 247 and 344 °C. The quartz veins have been crosscut by sulfide-rich veins. Based on the similar setting, mineralogy, stable isotope, and fluid composition, it is considered that both types of W-mineralized quartz veins formed during the same mineralizing event. Given the overlap in age between the G4 granites and the mineralized quartz veins, and the typical association of the W deposits in Rwanda, but also worldwide, with granite intrusions, W originated from the geochemically specialized G4 granites. Intense water–rock interaction and mixing with metamorphic fluids largely overprinted the original magmatic-hydrothermal signature.
Located in Library / RBINS Staff Publications 2016
Inproceedings Reference The map of the Brabant Massif for offshore Belgium
The cartographic boundary of the Brabant Massif in the northwest is the North Sea, which is an observational limit. Nevertheless the Lower Palaeozoic rocks continue as part of a larger unit, referred to as the Anglo-Brabant Deformation Belt. Maps of the Brabant Massif largely rely on borehole data. The latest map of the Brabant Massif (Piessens et al., 2005) uses structural concepts and direct information, rather than geophysical information. Nevertheless, an aeromagnetic survey and gravimetric data corroborate the large scale distribution of the units. This map is extrapolated to the off-shore territory of Belgium. Direct information from drillings is not available for the off-shore region, and it is therefore not possible to draw this map at the same stratigraphic resolution. The formations are therefore grouped into Cambrian, Ordovician and Silurian units. Magnetic susceptibility is high for the Cambrian, which allows tracing their continuation from on-shore to off-shore. The formations at subcrop level along the central axis of the Brabant Massif are on-shore Cambrian in age, but young in a WNW direction. Also the magnetic pattern becomes less intense, likely corresponding to an increasing depth of the more magnetic lower Cambrian units. This trend continues off-shore, indicating that the Cambrian units disappears at subcrop level. Superimposed on this general trend an aeromagnetic anomaly about 15 km off-shore of Ostend marks the probable local reappearance of the Tubize Formation. A secondary and less continuous Cambrian axis passes near Diksmuide. A second isolated off-shore aeromagnetic anomaly, indicative of the Cambrian unit, lies along the trace of this secondary axis. The gravimetric map shows a low gravimetric anomaly of which the circular shape suggests a genetic link with the chain of gravimetric lows that underlie the southern part of the on-shore part of the Brabant Massif. The higher densities in the northern part of the off-shore territory confirm, in continuation of the on-shore formation boundaries, the presence of the Silurian unit. The validity of the inferred distribution of the stratigraphic units was verified with the structural 3D concept that was developed for the on-shore part of the Brabant Massif, concluding that the inferred distribution of the geological units is in agreement with the structural model derived on-shore. It for example explains the positions of the two magnetic anomalies relative to each another. A central element in the structural model is the Asquempont Detachment System of which a limited number of possible traces is possible.
Located in Library / RBINS Staff Publications 2016
Inproceedings Reference Beyond the current limits of Raman Spectroscopy: controlling fluorescence in solid bitumen with low thermal maturity
Raman spectroscopy is an interesting tool to assess the thermal maturity of solid organic matter. For carbonaceous material with moderate to high maturities, several studies have found good correlations between Raman spectral parameters and thermal maturity, expressed as vitrinite reflectance (VR) or bitumen reflectance (BR). However, at low maturities a large part of the Raman peaks is lost under an intense background radiation, caused by fluorescence. This fluorescence problem mainly occurs at 0.4-1.0% VR (the oil window), and makes it difficult to recognize the original spectrum. In this study, Raman parameters that have been put forward in literature were tested on a low maturity, solid bitumen sample of approximately 0.61% BR. The investigated parameters include the peak’s full width at half maximum FWHM, peak position W, peak area A, area ratio AD/AG and intensity ratio ID/IG. Fluorescence in this sample is very high and covers Raman peaks. It was found that during consecutive measurements at a single location (i.e. irradiation with the Raman laser), fluorescence decreases with time and Raman peaks appear. This is in line with Quirico et al. (2005), who observed the same effect at coal measurements. An interesting observation is the behaviour of Raman parameters during ongoing irradiation. The full widths at half maximum do not change at all for every investigated peak in our spectra. Also peak positions remain the same. The peak areas do change with irradiation, and show a decrease with decreasing fluorescence. Comparison of areas under individual peaks and total spectrum area however suggests that A and fluorescence decrease at equal speeds. This is the case for most important Raman peaks at 1370 (D-band), 1600 (G-band) and 3200 cm-1, with correlation coefficients of 0.66, 0.97 and 0.92 respectively. Lastly, the area ratio AD/AG and intensity ratio ID/IG(approximation) show no trend with fluorescence, indicating that the shape of the spectrum remains the same with irradiation. This is a promising result, because it suggests that fluorescence can be controlled without changing spectral parameters. Although not all peak parameters in this study (FWHM and AD/AG) correspond to parameters from literature regarding maturity, the behaviour of the Raman peak parameters in combination with the decreasing fluorescence is an exciting outcome. If further research proves that the original parameters are not altered by irradiation, this will provide an answer to the problem of fluorescence at low maturity samples.
Located in Library / RBINS Staff Publications 2016
Inproceedings Reference Example of natural fracture patterns in Westphalian deposits: occurence and controls
Located in Library / RBINS Staff Publications 2016
Article Reference Contrubution to the knowledge of Afrotropical Rutelinae IV (Coleoptera: Scarabaeoidea: Melolonthidae)
Located in Library / RBINS Staff Publications 2016
Article Reference Description de Patellapis (Chaetalictus- mpalaensis sp.nov. et redescription de P. (C.) virungae Timmerman, 2009 de l'Afrique orientale et centrale (Hymenoptera: Apoidea: Halictidae)
Located in Library / RBINS Staff Publications 2016
Article Reference Updating laternflies biodiversity knowledge in Cambodia (Hemiptera: Fulgoromorpha: Fulgoridae) by optimizing field work surveys with citizen science involvement through Facebook networking and data access in FLOW website
Located in Library / RBINS Staff Publications 2016
Article Reference The new Oriental lanternfly genus £Bhaskaraena gen.nov. with two new species (Hemiptera: Fulgoromorpha: Fulgoridae)
Located in Library / RBINS Staff Publications 2016
Article Reference Predator effects on the feeding and bioirrigation activity of ecosystem-engineered Lanice conchilega reefs
Ecosystem engineers can considerably affect the community composition, abundance and species richness of their environment. This study investigates the existence of positive or negative feedbacks of species that compose the community in intertidal biogenic reefs constructed by the ecosystem engineer Lanice conchilega. This tubeworm creates attractive nursery and feeding grounds for the predatory brown shrimp Crangon crangon, while at the same time is preyed upon by C. crangon. The effect of the predation pressure exerted by C. crangon on the bioirrigation and feeding activity of the tubeworm is up until now unknown and it is hypothesised that these activities are affected by the high densities of C. crangon in the reefs. A mesocosm experiment was set up to investigate the effects of predation pressure on the bioirrigation and feeding activity of L. conchilega in the i) absence; ii) restricted presence; and iii) unrestricted presence of C. crangon. Bioirrigation was quantified by the decrease of an artificially introduced bromide (Br−) tracer, while feeding activity was measured from the incorporation of 13C via stable isotope analysis. The bioirrigation rate of the L. conchilega reef equalled about 30 L·m−2·d−1 andwas not affected by the presence of the predator. The food uptake of the tubewormwas however about three times lower in the unrestricted presence of C. crangon, presumably due to the retraction of the worm's body and tentacles in its tube induced by physical contact with the predator. Notwithstanding the impacted food uptake of L. conchilega, the tubeworm maintains its functional role in the presence of predators in soft-bottom intertidal areas.
Located in Library / RBINS Staff Publications 2016