Recently drilled geothermal boreholes in Mol, northern Belgium, provide new information on the Lower Carboniferous carbonates in the Campine–Brabant Basin. Because of low primary porosity, fractures in these limestones and dolostones are of major importance for reservoir permeability. The Fullbore Formation MicroImager (FMI) log of the MOL-GT-01 borehole enabled interpretation of bed boundaries and fractures in the subsurface. Relationships between the frequency of these fractures and bed thickness, lithology variations and the presence of faults were explored. The results show that thick beds contain relatively few fractures and thin beds relatively many. Except for lower values in shaly intervals, the fracture frequency (number per metre) is largely independent of lithology. Zones with substantial changes in the structural dip (called a cusp) and/or azimuth of bed boundaries were identified. The clearest cusp is present at a depth of 3284 m. Since the presence of a normal fault is most likely regarding the local and regional geology, this cusp likely resembles a fault-tip fold of a WSW-ward dipping normal fault with an inclination of at least 54°. It is uncertain whether the borehole crossed the fault itself or only a monocline on top of it. Fracture frequency is increased in the vicinity of the interpreted possible faults. Up to a vertical distance of c.45 m from the faults, the mean fracture frequency is higher than in a non-faulted zone with similar lithology. However, frequency differences between these faulted and non-faulted zones are mostly insignificant, so no clear damage zones are present.

For more than 120 years since the name Caprovis savinii was founded on the basis of a bovid horn core from the ‘Forest Bed’ at Overstrand (Norfolk, UK), only one other find has been assigned to this species. Recently, two horn cores and one horn core fragment of the species have been discovered at two sand and gravel sorting centres in the Netherlands. The bone-bearing sediments are exposed on the North Sea floor, just off the coast of Great Yarmouth (Norfolk, UK). By comparing fossil and extant taxa, a classification within the bovid tribe Antilopini is proposed. Based on the accompanying fauna from the specific dredging area and the litho- and chronostratigraphy at Overstrand, C. savinii is placed within the Early Pleistocene.

Numerous archaeological investigations have been performed along the river Meuse in the Netherlands’ southeastern province of Limburg as part of the major ‘Maaswerken’ infrastructural project. To improve flood risk management and navigability, and for the purpose of gravel production and nature development, several areas of land covering a total of almost 2000 ha are being excavated to a great depth. In anticipation of this, archaeological research was performed for the purposes of recording and documenting archaeological remains in the most important areas and locations. From 1998 to 2015 the Cultural Heritage Agency of the Netherlands (Amersfoort) was in charge of the investigations, and acted as adviser to national public works agency Rijkswaterstaat.

The archaeological research connected with the Maaswerken project differed from regular, site-based investigations in terms of the landscape archaeology perspective on which it was based. The research themes and principles associated with this perspective were published in several documents, including a scientific policy plan published in 2004, and presented in further detail in area programmes and project briefs. The policy plan assigned each project area to one of five value assessment categories, based on the intactness of the landscape and the archaeological potential for addressing the research questions. In areas of high landscape intactness and great archaeological potential (category 1) the Agency selected zones to be surveyed and assessed, and for archaeological excavation. Though most of the fieldwork, including specialist analysis, was performed in these zones, other category project areas have also been the subject of archaeological fieldwork, including borehole surveys, site-oriented research and watching briefs, but on a more incidental basis. Observations were also made in the river Meuse itself and in the river's winter bed.

The archaeological investigations resulted in a large number of standard reports of desk studies and fieldwork, including reports of specialist analyses. A considerable proportion of these refer to the large-scale investigations at Borgharen and Itteren to the north of Maastricht, and at Lomm and Well–Aijen to the north of Venlo. The results of the investigations suggest the archaeological record here is rich and varied, with a time depth of c. 11,500 years, and traces of occupation and land use ranging from the Early Mesolithic (Well–Aijen, Borgharen) to the Second World War (Lomm).

This paper reflects on almost 20 years of archaeological research in the project areas of the Maaswerken and on the principles and methods used in the field research. The common thread is the results of landscape and archaeological studies and the relationship between them. Examples are used to illustrate results that can be regarded as important from a national perspective, and in terms of archaeological heritage management.

In the Netherlands, mineral extraction by means of dredging or quarrying meets with considerable societal resistance. Land surface lowering prior to large land reconstruction projects may raise fewer objections. We have calculated the potential yields of sand and gravel from land surface lowering embedded in planned building and construction projects, and in nature, farmland and recreation area development. Our primary data sets were a compilation of spatial plans for the period 1995 – 2005 and about 95,000 borehole descriptions. Even if embedded consistently, land surface lowering would contribute modestly (up to 5.4 Mio m3/a) to the filling sand provision (annual demand 45 – 50 Mio m3/a).

During the 2007 ‘Kor en Bot’ collecting trip across the Oosterschelde (province of Zeeland, southwest Netherlands), on board trawler cutter ZZ10, a stem fragment of a fossil isocrinid was recognised amongst the contents of the nets pulled on deck. This specimen is here interpreted to be of Early Jurassic age and assignable to the genus Isocrinus. However, because only internodals are preserved in this pluricolumnal, specific identification cannot be but approximate (Isocrinus (Chladocrinus) cf. tuberculatus). In the absence of any outcrop of Jurassic deposits in Zeeland and adjacent Dutch and Belgian territory, the most likely explanation is that this crinoid represents erratic material transported by precursors of the present-day River Maas (Meuse). Between the Langres Plateau and Sedan (northeast France), this river cuts through several occurrences of Lower Jurassic strata from which the present isocrinid might have originated. A less likely explanation is that it stems from boulders used for coastal reinforcement or from a Roman limestone votive altarpiece put up at the temple complex for the goddess Nehalennia, formerly present at Colijnsplaat, near Domburg (Noord-Beveland, Zeeland). Transportation from either northwest France or the southern or eastern United Kingdom, where there are coastal exposures of Jurassic strata, via the North Sea, is another option which, however, is also considered less feasible in view of the good state of preservation of the crinoid.

A micropalaeontological analysis (foraminifera, ostracoda and bolboforma) has been undertaken for the interval between 299.7 and 201.5m of the Maaseik borehole. This interval includes marine glauconitic sands, which are generally not or not strongly decalcified. Independent from each other, the observed taxa of the different microfossil groups indicate a Late (range down to Middle) Miocene age for the interval. On the base of the biozonations of the various microfossil groups, some correlations can be presented with Late Miocene deposits of other areas in Belgium (Antwerp and Campine area), and of other places in NW Europe.

A method for designing efficient sampling schemes for reconnaissance surveys of contaminated bed sediments in water courses is presented. The method can be used in networks of water courses, for instance to estimate the total volume of bed sediment of a defined quality class. The water courses must be digitised as arcs in a Geographical Information System.

The method comprises six steps: (1) stratifying the water courses; (2) choosing a variogram; (3) calculating the parameters of the variance model; (4) choosing a compositing scheme; (5) choosing the values for the cost-model parameters; and (6) optimising the sampling scheme. The method is demonstrated with a survey of the main water courses in the reclaimed areas of Oostelijk Flevoland and Zuidelijk Flevoland.

A new genus and species of euphaneropid, Ciderius cooperi, is recorded from the Lower Silurian Fish Bed Formation of the Midland Valley of Scotland on the basis of articulated material. Euphaneropids constitute an enigmatic group which is known from Devonian deposits in Scotland and Canada. The new find adds to our understanding of this group, in particular with regard to the morphology of some common anatomical elements. The paired head stains are here shown to contain clefts which can be interpreted as optic fissures, indicating that these are the remains of eyes. The anterior head stain is reconstructed and demonstrated to be a barrel-shaped object of an uncertain nature. Paired mineralisations situated in the posterior part of the cranial region appear to represent remains of the parachordals, while fossilised blood vessels might be preserved in the form of black lines which mark a greatly elongated branchial region, similar to euphaneropids. Serially repetitive rows of short horizontal stripes on the posterior half of the body are unique for the new taxo, but their interpretation is problematic.

Two notions, Ocean Space and the Anthropocene, are discussed. The first is occasionally used in legal and governance literature, and in the media. The Anthropocene, however, is widely applied in the global change research community and the media. The notion of ocean space stands for a holistic, system science approach combined with 4D thinking from the ocean, and the processes within it, towards the land. Ocean space is in fact a social-ecological concept that deals with sustainability challenges which are the consequence of the complex interactions between humans and the marine environment on all scales. Ocean space is, on a human scale, impressively large. On a planetary scale, however, it is insignificant, although it has been an ancient feature of the Earth for the last four billion years or so. Yet, ocean space is a critical player in the Earth System; it is central to climate regulation, the hydrological and carbon cycles and nutrient flows, it balances levels of atmospheric gases, it is a source of raw materials vital for medical and other uses, and a sink for anthropogenic pollutants. The notion also encompasses issues such as exploration, adventure, science, resources, conservation, sustainability, etc., and should be an innovative and attractive outreach instrument for the media. Finally, it marks the fundamental change in ocean exploration in the twenty-first century in which ocean-observing systems, and fleets of robots, are routinely and continuously providing quality controlled data and information on the present and future states of ocean space. Advocates of the notion of the Anthropocene argue that this new epoch in geological time, commenced with the British industrial revolution. To date, the Anthropocene has already been subdivided into three stages. The first of these coincides with the beginning of the British industrial revolution around 1800. This transition quickly transformed a society which used natural energy sources into one that uses fossil fuels. The present high-energy society of more than seven billion people mostly with highly improved living standards and birth rates, and a global economy, is the consequence. The downside of this development comprises intensive resource and land use as well as large-scale pollution of the (marine) environment. The first stage of the Anthropocene ended abruptly after the Second World War when a new technology push occurred, leading to the second stage: ‘the Great Acceleration’ (1945-2015) followed by the third: ‘Stewards of the Earth’. Here it is concluded that the notion of the Anthropocene reflects a hierarchical or individualistic perspective, often leading to a ‘business as usual’ management style, and ‘humanises’ the geological time scale. The use of this notion is not supported. However, it is already very popular in the media. This again might lead to overestimating the role of humans in nature, and might facilitate an even more destructive attitude towards it, through the application of geo-engineering. The latter could be opening another Pandora's box. Instead we should move to a more sustainable future in which human activities are better fine tuned to the environment that we are part of. In this respect, transition management is an interesting new paradigm.

Staatsolie Maatschappij Suriname N.V., together with the gold mining industry, has gradually become a major contributor to the Surinamese economy since the decline of the alumina industry. In the last 35 years, about 110MMbbls (million barrels) of crude oil have been produced. Staatsolie is now in the early stages of fulfilling its VISION 2030, which is not only aimed at increased exploration and production but also at power generation, further diversification and regional expansion. The basis for achieving these goals is accelerated on- and offshore exploration, followed by growth in production. The offshore region remains a frontier area, with only a few wells drilled. Current production is about 17,000bopd (barrels of oil per day). Between 2007 and 2014, Staatsolie has spent about US$120 million on exploration. An integrated study for the Suriname–Guyana Basin carried out by Staatsolie in 2009 demonstrated the upside potential of this basin from a source rock potential perspective, which has been proven by both the Liza-1 oil discovery offshore of Guyana in 2015 and the Zaedyus-1 oil discovery offshore of French Guiana in 2011.

Staatsolie is now focusing its efforts on the near-shore area, where it recently concluded a five-well drilling programme, following a 3-D seismic survey. In the deep offshore area, international oil companies (IOCs) are actively pursuing the next discovery in the Atlantic Margin, partly driven by the conjugate-margin theory geologically linking South America and West Africa.

Staatsolie is also attempting to increase recovery from the most mature and largest oilfield, the Tambaredjo Field, through Enhanced Oil Recovery (EOR) technologies of which polymer flooding is deemed the most suitable, with estimated potential incremental recovery of up to 12%.

Staatsolie recognises the role of a highly skilled and motivated workforce and therefore continues investing in its people through internal as well as external training. Thirty-five years after it was founded by Mr Eddy Jharap, a geologist by training and the first Managing Director of the company, it can be stated that Staatsolie has taken its place in Surinamese society as a significant contributor to the economy, a preferred employer, a nucleus for industrial spin-off and an example for other companies.

For the first time, geomorphology and archaeology are combined for a 165 km long stretch of the Meuse river, resulting in a geomorphogenetic map (GKM) and a series of archaeological predictive maps (AVM). The maps cover the central part the Meuse valley, located in the province of Limburg between Mook in the north and Eijsden in the south. The area consists of fluvial and aeolian landforms of the Holocene Meuse floodplain and Younger Dryas aged terraces along it, spanning a period of approximately 15,000 years of landscape genesis and human habitation. The GKM more clearly discriminates between map units of Younger Dryas and early Holocene age than in previous mappings of the Meuse valley. The AVM series provide predictive information on the location of sites for four distinct consecutive archaeological periods and four main cultural themes. The maps contribute to a better understanding of landscape processes (fluvial and aeolian geomorphology and the impact of man on river behaviour), and the possibilities for human habitation and land use in prehistoric and historic times.

The presence of Halisaurus (Squamata, Mosasauridae) in the uppermost Cretaceous of the Maastrichtian type area, suggested by Lingham-Soliar (1996) on the strength of two partial vertebrae, is questioned. The anatomy of these elements suggests that they pertain not to Halisaurus, but more probably to Plioplatecarpus marshi Dollo, 1882.

Hydraulic fracturing is a long-established method of stimulating a well to improve the inflow or outflow potential. Hydraulic fracturing is the most successful stimulation method used by the oil and gas industry, and is also used for water injection and production wells around the world, even for drinking-water wells. Hydraulic fracturing creates a crack in the earth that is then filled with a highly conductive material (proppant). This fracture has a large inflow area compared to an unstimulated wellbore and provides a high-permeability path for the fluid to flow in or out of the reservoir.

Hydraulic fracturing has a long history of being used in hot dry rock (HDR) geothermal applications since the 1980s (Murphy & Fehler, 1986). In those often very tight reservoirs, the aim is to create fracture networks that generate the reservoir flow capacity. In high-permeability formations, fracturing can potentially double the productivity of a well. In low-permeability formations, well performance can be increased by a factor of 5–10 in most cases.

In this paper, we focus on two different scenarios of geothermal stimulation. The first is for permeable, porous formations where the heat exchange happens through the perfect contact between the fluid and the porous reservoir. Stimulation may then be necessary to create a small fracture if the pressure drop near the well is too large due to insufficient reservoir permeability. The other scenario is a formation at great depth, where the formation permeability is so extremely small that very long propped fractures would be needed to obtain sufficient flow or even where the porous system does not provide sufficient heat exchange but the heat exchange has to be facilitated by an artificial or stimulated fracture network: a so-called Enhanced Geothermal System.

For porous, permeable formations we will present examples of fracture treatments that can increase the flow rate so that the economics of the project is improved. In some formations, stimulation is then a contingency in case of poorer than expected reservoir quality. A worst-case well with a large skin value of 20 can perform with stimulation like a base-case unstimulated well. In other formations, stimulation will be integral to well design in order to optimise the project performance. For those cases the Coefficient of Performance can be improved from 7 to 25 with the aid of stimulation.

In Ultra-Deep Geothermal (UDG) recovery, the targets are reservoirs below 4000 m, because industrial heat demand requires a minimum temperature of 120°C up to 250°C. For an economic business case, the rate over a period of 15 to 25 years should be from 150 to 450 m3 h−1, depending on the boundary conditions.

Shallower reservoirs in the Netherlands often show very high permeability, but at great depth the target layers could have very low permeability (Veldkamp et al., 2018). Several stimulation methods can be used, of which hydraulic fracture stimulation with water (proppantless) is the primary candidate. Other stimulation methods are propped fracturing in sandstone, acid fracturing in carbonates and thermal stimulation.

For a geological play that is attractive for UDG in the Netherlands, the most likely stimulation method is with water fracturing, because propped fracturing would require a huge amount of proppant that is very costly. Based on analogues and conceptual designs, the expected flow rate is estimated under selected boundary conditions.

The article tries to answer the question of the origin and structural development of the deformation of the pre-Permian units southwest of Bremen. An interpretetion of a 3D-seismic survey was made to resolve the structural style of the Upper Carboniferous with the aim to get some clues for the Variscan deformation of the Variscan foreland. The area is suitable for the evaluation because of the existence of a 3D-seismic survey. Moreover, the depth of the Zechstein at. 4500 m is not to deep for imaging deeper reflections and there is not a severe distortion of the reflection pattern by later tectonic developments. Because of the 3D insight into the complex and deep seated structures, other 2D-seismic investigations which image similar parts can be better understood and interpretation errors can be avoided. It is concluded that only 3D-seismic measurements can resolve the complex structural devolopment at this site.

The Netherlands is in the midst of an energy transition with hydrocarbon production gradually declining, whereas the role of sustainable energy technologies is on the rise. One of these technologies is geothermal energy production from porous reservoirs at 1.5–3 km depth. As the number of geothermal projects increases, there is a growing concern that felt and/or damaging induced seismic events could occur as a result of geothermal operations. Over the last two decades, such events have occurred in the Netherlands due to gas production, notably in the Groningen gas field. However, the occurrence of felt events is limited to hydrocarbon fields in certain regions or reservoirs. Understanding where and for which plays these events are observed helps to estimate seismogenic potential for geothermal operations and other sustainable subsurface activities. Here, we summarise and review the main similarities and differences in terms of geological and geomechanical characteristics between the hydrocarbon and geothermal plays in the Netherlands, and we consider the differences in pressure and temperature changes. By doing so, we provide better insights into the factors that could play a role for fault reactivation and induced seismicity, and how these differ for hydrocarbon production and geothermal operations in the Netherlands. The review shows that geological characteristics for most geothermal target reservoirs are similar to those of hydrocarbon, albeit geothermal projects so far target higher porosity rocks than hydrocarbon reservoirs. On the other hand, pressure and temperature changes are very different, with significant depletion for hydrocarbon fields vs significant cooling around geothermal injection wells. The different operations result not only in different expected stress change magnitudes but also in a distinct spatio-temporal stress build-up on faults, which has implications for seismogenic potential and monitoring of these different operations.

The origin of a peculiar type of silicified limestone with nodular flints used in parish churches at Sluizen and Vreren, south of Tongeren (province of Limburg, Belgium), has now been elucidated by the discovery of the same rock type in its natural setting, namely the silicified top of the Cretaceous which underlies Clay-with-flints (‘flint eluvium’) and Oligocene sands in a disused quarry at Elst, municipality of Riemst (Limburg, Belgium). Co-operation between professional geologists and amateur palaeontologists has allowed to characterise this rock type, here referred to as ‘Elst tauw’, both petrographically and palaeontologically. The rich echinoid fauna has also been assessed, on the basis of a comparison with assemblages from the Clay-with-flints at Halembaye (Haccourt/Lixhe, province of Liège, Belgium) and at Zichen-Eben Emael in the Hesbaye region. P.J. Felder's ecozones, based on bioclast assemblages, substantiated by analyses of petrographical biofacies features of the original calcarenite, has allowed lithostratigraphic correlation of the ‘Elst tauw’ with the ‘Roosburg block’, which is a variety of ‘Maastricht stone’. Both methods indicate that the ‘Elst tauw’ developed in beds that can be assigned to the condensed Valkenburg-Schiepersberg interval of the lower Maastricht Formation. Petrographical analysis has shown the ‘Elst tauw’ to be quite distinctive; in addition, its natural occurrence at the Elst quarry matches the building stone records in rock type. The latter stem from the same small area, situated southwest of Maastricht. The major steps in its diagenetic history could be reconstructed, starting with pervasive pyritisation of the calcareous allochems, followed by silicification of the grains and pore spaces (different silica cements that became partially recrystallised), completed by oxidation of pyrite with transformation into limonite and, finally, dissolution of the non-pyritised or partially pyritised skeletal allochems creating a mouldic porosity. Silicification probably was achieved prior to the Oligocene. This particular mode of formation has generated a discussion on the proper use of the vernacular term ‘tauw’, a term used in a different sense by the industry, stratigraphers and students of building stones.

The chemical and mineralogical composition of rattlestones found near the main Dutch rivers has been studied by Mössbauer spectroscopy, INAA and XRD. Rattlestones are concretions of iron, formed in an environment of lateral iron accumulation, under the influence of periodical oxidation, around a fine core of ferruginous sediments, mainly clay and sand. The core has shrunk and detached itself from the mantle around it. 57Fe Mössbauer spectroscopy was applied to identify the iron oxides, among which goethite is predominant. The goethite crystallinity was investigated by measuring its magnetic properties and its crystallinity, which is poorest at the outer side of the stone. The latter is confirmed by the broadening of the different X-ray reflections. In addition, illite and vermiculite were identified by XRD; these clay minerals were found mainly in the core.

The elemental composition was determined by INAA. The iron content in the mantle is about 50% by weight and gradually decreases outwards, while the core contains 2–15% Fe by weight. Differences between rattlestones from the Middle Pleistocene East of the Meuse river and those from the Late Pleistocene North of it are the absence of lepidocrocite and a richer mineralogy in the former.

It is concluded that the rattlestones are formed around a fine clayey core. Groundwater supplied the iron and other (trace) elements for the genesis. It is unlikely that rattlestones are the result of oxidation of siderite.

Onshore Maastrichtian strata in the United Kingdom are limited to a few small, isolated blocks of chalk floating within glacial sediments on the Norfolk coast. Isolated outcrops of Campanian and Maastrichtian chalks used to be available around Norwich but the majority of these exposures are now badly degraded. Offshore, in the North Sea Basin, there are complete chalk successions that range throughout the Upper Cretaceous and Lower Cenozoic. There is a limited succession of Maastrichtian chalks exposed on the north coast of Northern Ireland below the Cenozoic flood basalts. In the Western Approaches Basin, Maastrichtian and Danian chalks are known from exploration wells and core samples. West of the United Kingdom a number of DSDP/ODP boreholes have penetrated the Upper Cretaceous succession.

Beginning in the Cenomanian, in southeast England, the whole of the Upper Cretaceous is within the chalk facies, possibly one of the longest intervals of relatively stable environment in the geological record. The Foraminiferida of the chalk have been studied for more than a hundred years and therefore the fauna is exceptionally well known and fully documented. Fifty years ago, the benthonic Foraminiferida were identified as having the potential to provide a viable zonation of the chalk facies and we now have precise, cross-basinal correlation using these taxa.

The planktonic fauna is restricted by both palaeolatitude and water depth. The latter appears to be the most influential as the faunas from onshore are more limited than those recorded from the deeper waters of the North Sea Basin and the Atlantic Margin. Even with this restricted fauna, however, it is still possible to develop a general correlation with the standard Tethyan zonation based on planktonic taxa.