Gold has been a major economic asset for Suriname for more than a century. The long history of gold mining, concentrated in large parts of a greenstone belt in the northeast of the country, began with small-scale artisanal extraction activities and has recently seen the development of major open-pit operations. Despite the range of mining activities, Suriname's gold deposits and occurrences are under-explored from a scientific point of view. Primary gold mineralisations in the greenstone belt occur in multiple forms, and although their origin is commonly related to the Palaeoproterozoic Trans-Amazonian orogeny, the controls of ore formation in specific cases often remain obscure. This contribution presents an abridged overview of currently available information on the geological setting and characteristics for some of the main deposits where gold is extracted. In view of the consistent link between gold metallogeny and granitoid–greenstone belts in the northern Guiana Shield, the mineralised settings in Suriname are discussed in a regional context.

The positive impact that natural fractures can have on geothermal heat production from low-permeability reservoirs has become increasingly recognised and proven by subsurface case studies. In this study, we assess the potential impact of natural fractures on heat extraction from the tight Lower Buntsandstein Subgroup targeted by the recently drilled NLW-GT-01 well (West Netherlands Basin (WNB)). We integrate: (1) reservoir property characterisation using petrophysical analysis and geostatistical inversion, (2) image-log and core interpretation, (3) large-scale seismic fault extraction and characterisation, (4) Discrete Fracture Network (DFN) modelling and permeability upscaling, and (5) fluid-flow and temperature modelling. First, the results of the petrophysical analysis and geostatistical inversion indicate that the Volpriehausen has almost no intrinsic porosity or permeability in the rock volume surrounding the NLW-GT-01 well. The Detfurth and Hardegsen sandstones show better reservoir properties. Second, the image-log interpretation shows predominately NW–SE-orientated fractures, which are hydraulically conductive and show log-normal and negative-power-law behaviour for their length and aperture, respectively. Third, the faults extracted from the seismic data have four different orientations: NW–SE, N–S, NE–SW and E–W, with faults in proximity to the NLW-GT-01 having a similar strike to the observed fractures. Fourth, inspection of the reservoir-scale 2D DFNs, upscaled permeability models and fluid-flow/temperature simulations indicates that these potentially open natural fractures significantly enhance the effective permeability and heat production of the normally tight reservoir volume. However, our modelling results also show that when the natural fractures are closed, production values are negligible. Furthermore, because active well tests were not performed prior to the abandonment of the Triassic formations targeted by the NLW-GT-01, no conclusive data exist on whether the observed natural fractures are connected and hydraulically conductive under subsurface conditions. Therefore, based on the presented findings and remaining uncertainties, we propose that measures which can test the potential of fracture-enhanced permeability under subsurface conditions should become standard procedure in projects targeting deep and potentially fractured geothermal reservoirs.

In this study, seismic stratigraphic criteria have been used to characterise the evolution of the Southern North Sea (SNS) shelf-delta system that progressively filled the Southern North Sea basin during Plio-Pleistocene times. Based on the prograding and down-stepping architecture of the shelf-delta sequence it is inferred that deposition occurred during a time of high sediment supply and overall sea-level lowering. During this time the delta slopes failed several times, creating at least 30 internally coherent Mass Transport Deposits (MTDs) mainly grouped in common areas, affecting the same clinoform set and partially sharing the basal shear surface (groups of MTDs). The most important features of the studied MTDs are 1) the dominance of brittle deformation; 2) the small amount of material removal from the headwall domain (lack of completely depleted areas above the basal shear surface); and 3) the lack of an emergent toe domain above the un-failed sediment located basinward, although proper confining geometries for the MTD are not detected. Therefore, the studied MTDs can neither be classified as frontally confined nor as frontally emergent but they are a new intermediate type of submarine landslides which has not been described before. These characteristics suggest that the mass movement ceased relatively soon after initiation of failure. Incisions on top of the MTDs suggest the presence of erosive flows. These flows were probably generated due to a concentration of the drainage in the negative morphology the failure event left behind in the upper sector of the slope. The stronger progradational character of the reflections on top of MTDs confirms a concentration of drainage after the erosional phase too.

The interplay between high sediment supply and constant or even decreasing accommodation space (caused by constant or decreasing sea-level) is supposed to be the main precondition for slope instability for most of the MTDs in this study area. Slope failures themselves can also be considered a preconditioning factor by the creation of local very high sedimentation rates (see groups of MTDs). Salt-induced seismicity and storm waves' effect superimposed on high frequency sea level fall are considered the most important triggering factors.

In the Netherlands North Sea area, the Chalk Group has thus far been subdivided into the Cenomanian Texel Formation, the Turonian to Maastrichtian Ommelanden Formation and the Danian Ekofisk Formation. This paper describes the attempt to arrive at a more detailed lithostratigraphic subdivision for this area, particularly of the Ommelanden Formation. To this end, a seismic stratigraphic analysis was carried out on a regional 2D and 3D seismic dataset. The Chalk Group was subdivided into eleven seismic stratigraphic sequences, named CK1 through CK11, based on the mapping and correlation of unconformities. The identified seismic sequence boundaries were used as the main chronostratigraphic markers in the Chalk Group interval. The seismic dataset was subsequently expanded with well log data of 45 boreholes. These were tied to the seismic dataset by constructing a synthetic seismogram for each borehole, after which the seismic sequence boundaries were noted and correlated on the logs. Finally, micropaleonthological data available in 15 boreholes were used to date the seismic sequences. The sequences were interpreted to be of Cenomanian (CK1), Turonian (CK2), Coniacian (CK3), Santonian (CK4), Early Campanian (CK5; CK6), Middle to Late Campanian (CK7), Early Maastrichtian (CK8; CK9), Late Maastrichtian (CK10) and Danian (CK11) age. The seismic units recognised in this study were compared with formal lithostratigraphic units defined in the Chalk Group in the surrounding North Sea sectors. Based on this comparison, a revision of the formal lithostratigraphic scheme, recognising Tor Formation and Herring Formation equivalents, is suggested for the Netherlands North Sea area.

Preliminary stable oxygen isotope data are presented from the southern North Sea Basin successions, ranging from the Lutetian to Rupelian. Analyses were performed on fish otoliths, nuculid bivalves and benthic foraminifera and are presented as bulk δ18O values relative to a well established regional sequence stratigraphic framework. The most significant positive shift in δ18O values clearly falls at the top of the regionally recognised Bassevelde 3 sequence, which base corresponds to the Eocene-Oligocene GSSP boundary. The here documented δ18O shift is closely associated with the base of the traditional Rupelian unit-stratotype and is tentatively correlated to the globally recognised Oi-1 event.

In recent years, a range of operculate sixth abdominal tergite types of pylochelid and parapylochelid hermit crabs (Anomura, Paguroidea) have been recorded from Upper Jurassic (Oxfordian and Kimmeridgian) strata in southern Poland and southern Germany. Here we add two new genera (Parapylochelitergites, Paguritergites) and four new late Early Cretaceous species (Parapylochelitergites pustulosus, Pylochelitergites alatus, Pylochelitergites rugosus and Paguritergites yvonnecooleae) from Navarra, northern Spain. In the reefal limestones at Koskobilo quarry near Alsasua, of late Albian age, the number of sixth abdominal paguroid tergite taxa approximates that of paguroid carapace types. Thus, linking fossil paguroid carapaces to tergites can now be attempted. Assemblages of symmetrical hermit crabs (parapylochelids and pylochelids) in reefal settings appear to have changed drastically from the late Albian onwards, with asymmetrical forms (Diogenidae, Paguridae) becoming predominant.

The Mema is a semi-arid region in central Mali with a rich archaeologicalheritage indicating the former existence of large urban settlements. Thearchaeological data suggest millennia of occupation history of the Mémapreceding relatively sudden abandonment by the 14th or 15th century AD.Population numbers have remained low since then and today’s human presencein the area is sparse and largely mobile. Geomorphologically, the Méma canbe characterized as a graben hosting various generations of aeolianlandforms and (presently mostly dry) interdunal channels and lakes, linkedto the neighbouring Inland Niger Delta floodplain. Given this setting, andthe variability of the Sahelian climate, climatic contributions to theregion’s sudden abandonment are likely. A geomorphological survey of theregion, and interpretation of the observed geomorphological record in termsof climatic history, aimed at providing a basis for understanding theintensive occupation and subsequent abandonment of the Méma. The results ofthis study underscore dramatic Holocene climatic variability, leading to theregion’s present geomorphological diversity, but also suggest thatneotectonic movements constitute an important additional cause of regionaldesiccation. Both may have encouraged prehistoric people to abandon the Mémaafter a long period of occupation.

The occurrence of felt earthquakes due to gas production in Groningen has initiated numerous studies and model attempts to understand and quantify induced seismicity in this region. The whole bandwidth of available models spans the range from fully deterministic models to purely empirical and stochastic models. In this article, we summarise the most important model approaches, describing their main achievements and limitations. In addition, we discuss remaining open questions and potential future directions of development.

Modelling of surface and shallow subsurface data is getting more and more advanced and is demonstrated mostly for onshore (hydro)geological applications. Three-dimensional (3D) modelling techniques are used increasingly, and now include voxel modelling that often employs stochastic or probabilistic methods to assess model uncertainty. This paper presents an adapted methodological workflow for the 3D modelling of offshore sand deposits and aims at demonstrating the improvement of the estimations of lithological properties after incorporation of more geological layers in the modelling process. Importantly, this process is driven by new geological insight from the combined interpretation of seismic and borehole data. Applying 3D modelling techniques is challenging given that offshore environments may be heavily reworked through time, often leading to thin and discontinuous deposits. Since voxel and stochastic modelling allow in-depth analyses of a multitude of properties (and their associated uncertainties) that define a lithological layer, they are ideal for use in an aggregate resource exploitation context. The voxel model is now the backbone of a decision support system for long-term sand extraction on the Belgian Continental Shelf.

The late Maastrichtian to Late Paleocene seismostratigraphic record of the Roer Valley Graben provides new data on the timing and dynamics of stress changes related to the intra-plate deformation of northwestern Europe. During the deposition of late Maastrichtian to middle Danian limestones, no severe tectonic movements occurred in the southern part of the Roer Valley Graben. Around the late Danian, a known fundamental change in the European intra-plate stress field initiated an increase in subsidence of the southern part of the Roer Valley Graben. Subsidence along the graben border zone enabled relatively thick accumulations of the latest Danian to mid-Selandian siliciclastics in the intra-graben zone. Subsidence was not bounded by large offsets along faults, but rather by flexuring within and along the borders of the Roer Valley Graben. The intensity of these dynamics diminished after the middle Selandian. Most likely due to inherited intra-basinal structural differences, the northern and southern part of the Roer Valley Graben experienced distinctly different late Maastrichtian to Late Paleocene tectonics.

This paper presents the method applied to history-match the Groningen field dynamic model to conventional data (pressure data and water influx data) and to subsidence data, which is a novelty. Modelled subsidence is matched to subsidence data based on a simplified geomechanical model, which was built into the dynamic simulator.

A two-tier method was used to first achieve a match on a field-wide scale using field-average history-match quantifiers, which was then further improved at a regional/well level using regional history-match quantifiers. The history match was assisted by a space-filling experimental design. The resulting model has a field-average match to pressure data of ±2.17bar with a measurement uncertainty of ±0.4bar, to water influx data of ±2m with a measurement uncertainty of ±0.5m, and to subsidence data of ±4cm with a measurement uncertainty of ±1cm.

The output from this model is used as input for compaction, subsidence and production forecasts feeding into the hazard and risk assessment completed by NAM for the Groningen Winningsplan 2016.

The coversands along the Peel Boundary Fault in the Netherlands were investigated by a luminescence dating approach combining Infrared Optically Stimulated Luminescence (IRSL) and Thermoluminescence (TL) methods. At the Neer trench, ten samples were collected and investigated in order to set up an independent chronological framework for the deposition history of the fluvio-aeolian and aeolian sediments and hence the timing of Late Weichselian and Holocene earthquake events. Five sedimentary units could be distinguished by this chronological approach. The oldest fluvio-aeolian unit yielded a mean deposition age of 35.9±0.4 ka and is designated to correlate with the Middle Weichselian. An IRSL age estimate of 20.1 ±2.9 ka was determined for the sediment that most likely represents the Older Coversands I, and a mean luminescence age of 15.1±1.2 ka for deposits just below the Beuningen gravel bed. The aeolian sediment from above the Beuningen horizon yielded an IRSL age estimate of 9.4±1.0 ka. The youngest deposits from the colluvial wedge yielded <6.9±0.7 ka BP, and so an earthquake event was likely to occur during the Middle or Late Holocene, as evidenced by the luminescence age estimates.

Remains of Late Cretaceous birds are rare, which is especially true for Europe and the type area of the Maastrichtian Stage (southeast Netherlands, northeast Belgium) in particular. In the present paper, we record new remains (isolated tarsometatarsus and radius) that document the presence of both enantiornithine and ornithurine birds in the Maastrichtian area. These fossils, although fragmentary, are important in view of their stratigraphic age: all bird remains discovered to date in the Maastricht area are amongst the youngest ’non-modern’ avians known, originating from strata deposited less than 500,000 years prior to the end of the Cretaceous Period.

The results from analyses of botanical remains (pollen, wood, charcoal, seeds) from several archaeological features excavated in Kluizen (northern Belgium) are presented. The region was largely uninhabited until the Iron Age and Roman period when a rural settlement was established, resulting in small-scale woodland clearance. The site was subsequently abandoned from c. AD 270 till the High Middle Ages. The results of the archaeological and archaeobotanical analyses provide information on changes in land use and resulting dynamics of woodland cover and composition between c.600 BC and AD 1200, with a spatial and temporal resolution unrivalled in northern Belgium. Especially the long period of woodland regeneration following abandonment of the site around AD 270, covering the Late Roman and Early Medieval period, could be reconstructed in detail. Abandoned fields were first covered with pioneer woodland (Salix, Corylus and Betula), then Quercus-dominated secondary forest and finally a late-successional forest with Fagus sylvatica, Carpinus betulus and Ilex aquifolium, an evolution that took over 300 years. The results also indicate that the observed increase of Fagus during the Early Middle Ages, which was never an important element in the woodland vegetation in northern Belgium before, was related to climatic changes rather than anthropogenic factors.

This study provides an overview of existing palynological and chronological data of the northern Meuse valley which have been collected over recent decades. The palynological data were used to make a vegetation reconstruction in time and space for the Lateglacial and early Holocene. The vegetation development is strongly influenced by the rapid climate changes that occurred during this time period. It is shown that the biostratigraphy can be used to provide better age estimates for the abandoned channel fills, which have been dated in most cases using conventional bulk 14C dates. Furthermore, the combination with a geomorphological reconstruction based on AHN (actual height model of the Netherlands) lidar data has been used to evaluate the interactions between fluvial terrace formation and vegetation development. It appears that, although the vegetation development is comparable to the general vegetation development in the Netherlands, slight differences occur, in particular of the vegetation composition, presumably linked to the dynamic geomorphological activity in the Meuse valley. Finally, the spatial distribution of sites may give indications for the migration routes of pine (Pinus) and poplar (Populus) during this period of rapid vegetation development over the Last Glacial–Interglacial Transition.

The original distribution pattern of Middle-Palaeolithic artefacts may be affected by tectonic movement, sedimentation and periglacial processes. This is e.g. the case in the coversand area of Limburg and Eastern Brabant (NL), where the occurrence of numerous finds in a SW-NE trending zone across the Roer Valley Graben is considered enigmatic. In order to elucidate the processes affecting the spatial distribution and the chance of recovery of such artefacts, we investigated a site in Nederweert. At this site, several Middle-Palaeolithic artefacts had been recovered earlier from unexpectedly shallow depths. A test pit profile and grain size analyses revealed that the shallow sediments at this site have been affected by intense, multi-phase cryoturbation, which has deformed the sand and loam layers and partially mixed them thoroughly. As a result, optically stimulated luminescence dating of these sediments yielded widely scattered single-aliquot equivalent dose distributions. Using a Finite Mixture Model (FMM), it was estimated that cryoturbation caused mixing of sediments deposited between 12 and 50 ka with sediment grains deposited between 60-150 ka. The latter material is probably the original context of the Middle-Paleolithic artefacts. Apparently, cryoturbation and potentially other periglacial processes have transported artefacts closer to the surface. Based on these results, we suggest that the occurrence of Middle-Palaeolithic artefacts is caused by (1) the tectonically-induced spatial distribution of layers of this age and (2) periglacial processes having caused migration of artefacts towards the surface. Although periglacial processes may facilitate finding Middle Palaeolithic artefacts, they may severely disturb the original context to such an extent that Middle Palaeolithic sites can no longer be identified. The results of this study form a basis for improving the Indicative Map of Archaeological Values that is used to predict the presence of archaeological sites. The insights gained are also relevant to other areas where Middle-Palaeolithic sites are affected by periglacial processes.

In southern Belgium (Mons Basin and Tournai region) and northern France (area between Lille, Valenciennes and Maubeuge), condensed sequences have been referred to as ‘tourtias’ since the start of the nineteenth century. These levels correspond to a succession of trangressive systems tracts and generally appear as dark green, glauconitic and microconglomeratic facies. They are distributed all along the base of the more important transgressive systems tracts of the Cenomanian and basal Turonian from the Boulonnais (northwest France) to the Mons Basin (southern Belgium), through the Artois and Douaisis. Their age can now be determined more accurately by identification of their ammonite content, as housed in museums such as the Institut royal des Sciences naturelles de Belgique (IRScNB, Brussels) and the Musée d'Histoire naturelle de Lille (MHNL). Here material from the IRScNB collections is described, illustrated and discussed; specimens contained in the MHNL collections were described in a previous paper.

Since 2003 extensive archaeological research has been conducted in Amsterdam, the Netherlands, connected with the initial phase of the new underground system (Noord/Zuidlijn). Research has mainly focused on two locations, Damrak and Rokin, in the centre of Medieval Amsterdam. Both sites are situated around the (former) River Amstel, which is of vital importance for the origin and development of the city of Amsterdam. Information on the Holocene evolution of the river, however, is relatively sparse. This project has provided new evidence combining archaeological and geological data, and allowed the reconstruction of six consecutive landscape phases associated with the development of the River Amstel. The course of the present-day Amstel is the result of a complex interaction of processes that started with an early prehistoric tidal gully within the Wormer Member of the Naaldwijk Formation, including Late Neolithic (2400–2000 BC) occupation debris in its fill that was subsequently eroded. Next, this system developed into a later prehistoric Amstel river course that was part of the Angstel–Vecht–Oer-IJ system (1020–350 BC), meandering through a peat-dominated landscape. Later on the processes included intensive reclamation of land, drainage and canalisation, although the Amstel was also strongly influenced by natural storm tides. After intense land reclamation, starting around 1200 AD, the meandering Amstel from Nes to Kalverstraat, which was originally 150 m wide, became the rather straight 20–50 m wide tamed, canalised river of today.

The morpho-genetic evolution of the upper Aller valley (Weser basin, North Germany) was reconstructed using geological and géomorphologie data integrated within a numerical process model framework (FLUVER-2). The current relief was shaped by Pre-Elsterian fluvial processes, Elsterian and Saalian ice sheets, followed by Weichselian fluvial processes. Structural analysis based on subsurface data and morphological interpretations were used to reconstruct uplift/subsidence rates. A detailed analysis led to the hypothesis that we are dealing with either a NNW-SSE or a WSW-ENE oriented compression leading to uplift in the upper Aller valley. It is also hypothesised that the NNW-SSE compression might have caused strike-slip deformation leading to differential block movement and tilt. Two different uplift rate scenarios were reconstructed and used as a variable parameter in numerical modelling scenarios simulating the Late Quaternary longitudinal dynamics of the Aller. Each different scenario was run for 150.000 years and calibrated to the actual setting. The resulting model settings were consequently evaluated for their plausibility and validity. Subsequently, regional semi-3D simulations of valley development were made to test the two tectonic stress hypotheses. Differential tectonic uplift and regional tilt seems to have played an important role in shaping the current valley morphology in the upper Aller. Unfortunately, due to the uncertainties involved, we were unable to discriminate between the two postulated tectonic stress scenarios.

Fossil remains of fishes found in Rhaetian (Late Triassic, c.208.5–201.3 Ma) sediments collected from a subrosion pipe in the Winterswijk quarry are described. The fauna shows great similarity to material known from the British Triassic of the Penarth Group and from other localities in Northwestern Europe. Both chondrichthyan and osteichthyan teeth and scales are present. Most abundant are the sharks Lissodus minimus and Rhomphaiodon minor and the actinopterygians Gyrolepis albertii, Saurichthys longidens and Birgeria acuminata. Isolated teeth of the latter two taxa were known under the name Severnichthys acuminatus, but the genus Severnichthys is here considered a nomen dubium; it should be suppressed in order to make the taxonomy less complicated.