Effect of magnetic field on the strange star

We study the effect of a magnetic field on the strage quark matter and apply to strange star. We found that the strange star becomes more compact in presence of strong magnetic field.Comment: 10 pages (LaTex) and 3 postscript figures available on reques

Ostracods, rock facies and magnetic susceptibility of the Hanonet Formation / Trois-Fontaines Formation boundary interval (Early Givetian) at the Mont d’Haurs (Givet, France)

Approximately 870 carapaces, valves and fragments of ostracods were extracted from 26 samples collected in the Hanonet Formation (= Fm) and Trois-Fontaines Fm in a section located along the southwestern rampart of the historically entrenched military camp at the Mont d’Haurs (Givet, France). Forty-eight species belonging to the Eifelian Mega-Assemblage have been identified and three new are proposed: Coryellina? audiarti nov. sp., Cavellina haursensis nov. sp. and Parabolbinella coeni nov. sp. The ostracod assemblages are generally indicative of shallow marine well-oxygenated environments, except at the base of the Trois-Fontaines Fm where ostracods indicative of semi-restricted and even of lagoonal water conditions are reported.The sedimentary record represents a transition from mixed siliciclastic-carbonate open-marine ramp system to restricted carbonate platform with deposition in low-energy peritidal and lagoonal settings frequently affected by subaerial exposition. A general trend follows a shallowing-upward and a relative sea-level decrease from the Hanonet Fm toward the Trois-Fontaines Fm.High-energy characterized the ramp setting and destroyed most of the stromatoporoid and coral buildups, which occur as floatstone and rudstone accumulations forming a thick biostrome. Girvanella and issinellid shoals developed also in this high-energy environment. The low-field magnetic susceptibility (=MS) log plotted against the lithological column reveals four magnetic sequences. The MS log and microfacies are moderately correlated mainly due to the evolution of sedimentary environments from a ramp to a platform. The MS values of the Trois-Fontaines Fm are very low in the biostromal unit whereas restricted lagoonal facies are characterized by the highest values of MS. A high-resolution stratigraphic correlative pattern is proposed here between the Mont d’Haurs section and the 40 km distant Baileux section despite the greater thickness. The MS signal is strongly controlled by minerals of ferromagnetic characteristics with a minor contribution of paramagnetic phases. The lagoonal sediments of the Trois-Fontaines Fm are characterized also by the highest values of normalized viscosity coefficient and a IRM loss. These results confirm the occurrence of a significantly high proportion of ultrafine magnetic grains which may be formed during diagenesis by chemical remanent magnetization processes.The list of the Givetian ostracods figured by Coen (1985) and recently lodged at the Department of Paleontology at the Royal Belgian Institute of Natural Sciences is reported in annex with new inventory numbers

Ostracods, rock facies and magnetic susceptibility of the Trois-Fontaines and Terres d’Haurs Formations (Early Givetian) in the Rancennes quarry at the Mont d’Haurs (Givet, France)

About 1,200 ostracods were extracted from 64 samples collected in the upper part of the Trois-Fontaines Formation (Fm) and in the base of the Terres d’Haurs Fm in the Rancennes quarry located along the western rampart of an historic entrenched military camp at the Mont d’Haurs (southern part of the Dinant Synclinorium, Ardennes Department, France). The ostracod richness and diversity are quite variable, and monospecificity prevails in numerous samples. Forty-nine ostracod species are recognised. In the Trois-Fontaines Fm, environments were lagoonal or semi-restricted, and the level containing numerous Leperditicopid ostracods (Herrmannina) indicative of (brackish?) lagoonal environments is 40 m thick. In the Terres d’Haurs Fm the environment was semi-restricted or more frequently shallow marine but the energy of the environment was apparently never very high. The level rich in Leperditicopida (Herrmannina) in the Trois-Fontaines Fm corresponds remarkably to the highest magnetic susceptibility (MS) value. The Rancennes microfacies point to a tidal flat system with various subenvironments such as restricted intertidal, supratidal and channel deposits. The system was bordered by subtidal open marine deposits where former reefal constructions have been destroyed. Frequent oscillations in this low-gradient shallow platform led to the exposure and modification of marginal ponds, floodplain environments or palustrine areas. No evidence of evaporitic environments or sabkha were encountered. The sedimentary system records the evolution of a shallow restricted carbonate platform (Trois-Fontaines Fm) to a carbonate ramp setting (Terres d’Haurs Fm). The evolution of the platfom to a ramp could be related to the cessation of the active role of a reefal barrier possibly as a response to synsedimentary tectonism and block faulting.The magnetic susceptibility curve established for the Rancennes quarry highlights 26 short-term magnetic evolutions that can be grouped into 10 major long-term magnetic sequences characterized by decreasing, increasing or stable magnetic susceptibility fluctuations. Magnetic susceptibility values range between 3.75 x 10-9 and 2.98 x 10-7 m³/kg. There is a general good correspondence between the microfacies and magnetic susceptibility curves, which are clearly mimetic at the smaller scale (i.e., 5th-order parasequences). The magnetic susceptibility curve could thus be interpreted as sea-level oscillations. A part of the magnetic minerals carrying the MS signal must have a detrital origin. Magnetization and coercivity ratios deduced from hysteresis loops indicate the presence of detrital coarse-grained multi-domain magnetite and authigenic mixtures of fine-grained superparamagnetic and single-domain magnetite. The MS signal of the Rancennes quarry seems to be controlled by the ferrimagnetic fraction (magnetite) with minor paramagnetic contribution (clay minerals and pyrite).The Rancennes quarry completes the stratotype of the Terres d’Haurs Fm because the section exposes the boundary with the Trois-Fontaines Fm unlike the previously proposed stratotype located on the south-eastern flank of the Mont d’Haurs entrenched camp

Ground Deformations Observed for Three Decades (1992-2022) above Old and Deep Coal Mines Reused for Deep Gas Storage Sites (Wallonia, Belgium) Using PS-InSAR Time-Series

peer reviewedThe exploitations of the coal mines in Wallonia (Belgium) were ceased progressively till the year 1984. Groundwater pumping activities were stopped inducing a progressive groundwater rebound affecting different areas with different rates but still visible today with radar interferometry. To mitigate the threats to the environment during the postmining period, flooding and outbreak risks, surface ground deformations and the stability of civil engineering infrastructures in the vicinity of those mined areas need to be monitored. The persistent scatterer radar interferometry technique (PS-InSAR) revealed ground displacements during three decades above the two underground reservoirs (Peronnes to the West and Anderlues to the East) used for gas extraction and storage south of La Louvière city (Wallonia). 236 Interferograms were produced using images acquired by the ESA's satellites (ERS1/2, ENVISAT, and Sentinel-1A). Land surface displacements trends are heterogeneous both in time and space with different behaviours. During ERS1/2 (1992-2002) an uplift is visible in the western part of the Peronnes reservoir while the eastern part is still affected by subsidence while the Anderlues reservoir is affected by global subsidence. During ENVISAT (2003-2010), the uplifting conditions were stronger in the Peronnes reservoir and only the upper right corner is still affected by subsidence while the Anderlues reservoir records still a general subsidence phenomenon. The most recent data from Sentinel-1A revealed a general uplift through the Peronnes reservoir with decreasing LOS velocity towards the north and the south. The Anderlues reservoir is still affected by a subsidence phenomenon, but the LOS velocity values are reduced compared to the previous decades.monitoring LAnd SUbsidence caused by Groundwater exploitation through gEOdetic measurements15. Life on lan

Ground Deformations Related to an Old Drainage Adit in The Abandoned Coal Concession Around Saint-Vaast (Wallonia, Belgium) Analyzed Using PS InSAR and Piezometric Wells Time Serie

peer reviewedmonitoring LAnd SUbsidence caused by Groundwater exploitation through gEOdetic measurements15. Life on lan

Land subsidence as revealed by PS-InSAR observations in the Antwerp area (Belgium): first steps towards the understanding and modelling

PS-InSAR observations using multi-sensor radar data acquired by ERS 1-2, ENVISAT ASAR, and Sentinel-1A satellite sensors operating in C-band, have shown various land subsidence rates in different zones of the Antwerp area along the Scheldt River and in the harbor zone during the 1992 to 2021 period1. The LOS velocity values calculated from different radar datasets collected over Antwerp City Centre are ranged between -0.96 - +1.14 mm/year (ERS 1-2), -2.21 - +1.11 mm/year (ENVISAT), and -3.31 - +3.87 mm/year (Sentinel-1A). Moreover, the LOS velocity values for Antwerp Harbor are -4.38 - +1.02, -4.06 - +1.65, and -9.46 - +3.86 which are more significant than their corresponding ranges in the Antwerp City Centre. Groundwater is intensively pumped from the sandy Vlaanderen Formation (Holocene), Lillo and Poederlee Formations (Pliocene), and Berchem Formation (Miocene). However, in this area, land subsidence can be attributed to four potentially complementary consolidation processes: - natural consolidation of the Holocene estuarine sediments, - additional consolidation in the saturated Holocene estuarine sediments due to the backfill overload (8 m thick embankments) along the harbor docks, - saturated-unsaturated consolidation of the backfill materials, - consolidation of the most compressible layers, probably in the Boom Formation (Paleocene) and in the Asse clay of the Maldegem Formation (Eocene) due to pore pressure decrease induced by groundwater pumping in the different Cenozoic aquifers. Indeed, several of these processes could be added to produce the actual observed land subsidence. Geomechanical and hydrogeological data were being collected in the frame of the BESLSPO BRAIN project: "monitoring LAnd SUbsidence caused by Groundwater exploitation through gEOdetic measurements (LASUGEO)". For consolidation of estuarine sediments induced by the backfill overload, the rapid increase of total stress should be equilibrated by an increase of both water pore pressure and effective stress. This later, inducing land subsidence, will progressively increase as the water overpressure can be dissipated mostly laterally through groundwater flow. A coupled approach including a 3D groundwater flow model and 1D geomechanical models will be needed for a detailed analysis2,3,4. First, local models will probably be needed in specific zones to understand in detail the ongoing consolidation processes. Then a large 3D groundwater flow model will be considered over the Antwerp area including all the complex boundary conditions with the Scheldt River and the harbor docks to provide realistic transient water pressure conditions to numerous 1D geomechanical models in the area.LASUGE

Ostracods and rock facies across the Givetian/Frasnian boundary interval in the Sourd d'Ave section at Ave-et-Auffe (Dinant Synclinorium, Ardenne, Belgium)

Ostracods from the Sourd d'Ave section have been collected in the Moulin Boreux and Fort Hulobiet Members (Fromelennes Fm., Givet Group) and in the Pont d'Avignon Member (Nismes Fm., Frasnes Group). Ostracods collected in the Fromelennes Fm. by Milhau (1983a) and in the Nismes Fm. by Casier (1987a) have been also reviewed. Forty-four ostracod species are identified in the Fromelennes Fm. and 25 in the Nismes Fm. They belong exclusively to the Eifelian Mega-Assemblage, and several assemblages indicative of restricted and shallow marine, sometimes agitated, environments are recognized in the Fromelennes Fm. The great rarity of ostracods in the upper part of this formation provides evidence for less favourable lagoonal conditions probably related to increasing aridity at the end of the Givetian. In the Frasnes Group, assemblages are exclusively open marine and indicative of increasing water depth. The majority of ostracod species recognized in the Givet Group are missing in the base of the Frasnes Group as a consequence of the Frasnes Event. A systematic list of ostracods identified in the Fromelennes Fm. at Sourd d'Ave is published as an annex. Systematic sampling has been carried out in order to establish the sedimentological evolution of the environments and to detail the Givetian-Frasnian (G/F) transition. This allowed recognition of 13 microfacies types that replicate the standard sequence of Preat & Mamet (1989) from open marine shallow subtidal to restricted supratidal near emersion. The Boreux Member and the Fort Hulobiet Member display restricted facies (Amphipora, spongiostromid and algal bafflestones and bindstones, loferites with desiccation lumps) with poorly fossiliferous beds interbedded with higher energy peloidal and sometimes oolitic grainstone facies. Laminite horizons, sometimes with small-sized lateral linked hemispheroid stromatolites are uncommon, and are associated with dolomicrites showing pseudomorphs of evaporite minerals. These evaporitic facies become common in the upper part of the Fort Hulobiet Member suggesting the palaeoclimate became more arid at the G/F transition. Metre-scale cyclicity is pervasive throughout the Givetian part of the section. The boundary between the Givet Group and the Frasnes Group is very distinctive in the field, and is characterized by a transition from restricted evaporative lagoonal facies to open marine interbedded marly shales and nodular limestones. The upper part of the Fort Hulobiet Member consists of interbedded biostromes (semi-restricted stromatoporoid boundstones) followed by Amphipora floatstones, then fossil-poor units and restricted supratidal laminites with well-developed fenestral fabrics. The Frasnian Pont d'Avignon Member contains a rich faunal assemblage (bryozoans brachiopods, molluscs, nautiloids, tentaculitids) suggesting an abrupt drowning from the marginal Givetian carbonate platform into a Frasnian distal ramp or deep basinal environment below or near storm wave base

Post Mining Ground Deformations Transition Related to Coal Mines Closure in the Campine Coal Basin, Belgium, Evidenced by Three Decades of MT-InSAR Data

peer reviewedSpatio-temporal ground-movement measurements and mappings have been carried out in the Campine coalfield in Belgian Limburg since the closure of the mines to document post-mining effects. MT-InSAR measurements are compared to groundwater head changes in the overburden and to height data from the closest GNSS stations. Radar interferometry is used to estimate the extension and the velocity of ground movements. In particular, the MT-InSAR technique has been applied to SAR acquisitions of the satellites ERS-1/2 (1991–2005), ENVISAT (2003–2010), COSMO-SkyMed (2011–2014), and Sentinel-1A (2014–2022). The images were processed and used to highlight a switch from subsidence to uplift conditions in the western part of the coal basin, while the eastern part had already been affected by a rebound since the beginning of the ERS-1/2 acquisitions. Following the closure of the last active colliery of Zolder in 1992 and the subsequent cease of mine-water pumping, a recharge of mine-water aquifers occurred in the western part of the basin. This process provoked the change from subsidence to uplift conditions that was recorded during the ENVISAT period. In the center of the coal-mining area, measured uplift velocities reached a maximum of 18 mm/year during the ENVISAT period, while they subsided at -12 mm/year during the ERS-1/2 period. Mean velocities in the western and eastern parts of the coalfield area have decreased since the last MT-InSAR measurements were performed using Sentinel-1A, while the Zolder coal mine continues to rise at a faster-than-average rate of a maximum of 16 mm/year. The eastern part of the coalfield is still uplifting, while its rate has been reduced from 18 mm/year (ERS-1/2) to 9 mm/year (Sentinel-1A) since the beginning of the radar–satellite observations. Time-series data from the two GNSS stations present in the study area were used for a local comparison with the evolution of ground movements observed by MT-InSAR. Two leveling campaigns (2000, 2013) were also used to make comparisons with the MT-InSAR data. The station’s measurements and the leveling data were in line with the MT-InSAR data. Overall, major ground movements are obviously limited to an extension of the actual underground-mining works and rapidly diminish outside of them

The Urban Geo-climate Footprint approach: Enhancing urban resilience through improved geological conceptualisation

Urban resilience is critical to allow cities to withstand the challenges of the 21st Century. One factor that is often overlooked in such assessments is the role of the subsurface. A novel methodology called the Urban Geo-climate Footprint (UGF) has been developed to classify cities quickly and comprehensively from geological and climatic perspectives. The method operates on the fundamental assumption that cities with similar geologicalgeographical settings will face similar challenges, due to both common geological issues and associated climate impacts. The UGF approach has been applied to 41 European cities in collaboration with 17 Geological Surveys of Europe, the results of the UGF analysis are presented along with a regional classification of the geological resilience indicators. The UGF tool provides a semi-quantitative representation of the pressures driven by geological and climatic complexity for the cities presented, providing for a first time such classification of the urban environment. The advantage of this methodology lies in increasing awareness among non-experts and decision-makers of the interplay between geological settings, climate change pressures, and anthropogenic activities. Furthermore, it facilitates the exchange best practices among city planners to increase resilience, supporting knowledge based decision making to promote actions and policies, that enhance geoscience-informed climate justice