Geological Survey of Denmark and Greenland Bulletin最新文献

{"title":"Laser ablation analysis of bivalve shells – archives of environmental information","authors":"M. Kluender, D. Hippler, R. Witbaard, D. Frei","doi":"10.34194/geusb.v15.5052","DOIUrl":"https://doi.org/10.34194/geusb.v15.5052","url":null,"abstract":"Reconstructing past secular environmental variations is an important issue in palaeoclimate research. However, most key variables for palaeoclimate reconstructions cannot be measured directly, and reconstructions are therefore based on proxy data. Here, we demonstrate the potential of bivalve shells as an archive of environmental parameters. The Geo lo gical Survey of Denmark and Greenland (GEUS) has developed a fast and reliable method for chemical analyses of shell material by laser ablation - inductively coupled plasma - mass spectrometry (LA-ICP-MS), and here we present some ex amples of the use of this method. In tropical and subtropical waters, corals can provide century-long archives of past water chemistry with annual resolution. A comparable archive for temperate and Arctic waters would be highly useful in climate research, and therefore it has been examined whether this can be provided by bivalve shells (e.g. Schoene et al. 2005). Long-lived species may provide archives with annual resolution extending over several hundred years, whereas short-lived, fast-growing species can provide archives with a seasonal or in some cases daily resolution over a period of a few years. Most bivalves are sessile, and shells are commonly preserved as fossils. There are, however, a number of challenges related to the use of bivalves as proxy archives: (1) many proxies show species specific behaviour (Seed 1980); (2) only very few proxies are dependent on a single variable (Wefer et al. 1999); and (3) the effects of biology and ontogeny on the uptake of trace elements and stable isotope fractionation in shell carbonate are largely unknown and have to be evaluated empirically. Therefore, any potential proxy must be calibrated individually for each species of interest before it can be used. A large number of chemical analyses are needed to calibrate a proxy. These are commonly obtained by solution ICP-MS, in which sample preparation is time-consuming and labour-intensive. The use of LA-ICP-MS is therefore a considerable advance in bivalve shell proxy research, as it greatly reduces the effort needed for sample preparation. At the same time, the method requires less material for analysis, thus providing better spatial and hence temporal resolution. Proxies based on bivalve shell carbonate can be used in present-day environmental monitoring, and for environmental reconstructions from shells found as fossils. Shells from museum collections and shells found in archaeological middens can give information on historic and prehistoric environmental conditions (e.g. Carrell et al. 1987), and fossil shells can be used as archives of environmental parameters on geological timescales (e.g. Hendry et al. 2001).","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"40 1","pages":"89-92"},"PeriodicalIF":0.0,"publicationDate":"2008-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79295675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Provenance of Cretaceous and Paleocene sandstones in the West Greenland basins based on detrital zircon dating","authors":"A. Schersten, M. Sønderholm","doi":"10.34194/GEUSB.V13.4969","DOIUrl":"https://doi.org/10.34194/GEUSB.V13.4969","url":null,"abstract":"The extensive and very deep ?Jurassic/Cretaceous–Palaeogene sedimentary basins offshore West Greenland have a significant petroleum exploration potential. This is particularly true for the offshore region west of Disko and Nuussuaq where a live petroleum system has been documented for many years. At present, stratigraphic knowledge in this area is almost nonexistent and analogue studies from onshore areas and offshore exploration wells to the south are therefore crucial to understanding the distribution and quality of possible reservoir rocks in the Disko–Nuussuaq offshore area. One of the main risk parameters in petroleum exploration in this region is the presence of an adequate reservoir rock. Tectonostratigraphic considerations suggest that several sand-prone stratigraphic levels are probably present, but their provenance and reservoir quality are at present poorly known both onshore and offshore. A sediment provenance study including zircon provenance U-Pb dating and wholerock geochemical analysis was therefore initiated by the Geological Survey of Denmark and Greenland (GEUS) in preparation for the Disko West Licensing Round 2006 (Schersten et al. 2007). The main aims of this study were to: 1. Characterise the source areas and dispersal patterns for the various sandstone units of Cretaceous–Paleocene age in the Nuussuaq Basin and compare these with sandstone units in selected West Greenland offshore exploration wells (Figs 1, 2), employing advanced zircon provenance U-Pb dating using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS; cf. Frei et al. 2006). 2. Detect possible changes in sediment source with time, e.g. local versus regional sources. Zircon as a provenance tool is receiving increasing attention and has proven to be a powerful indicator of clastic sediment sources, a tracer of the Earth’s oldest materials, and a tracer of continental crust-forming processes (Froude et al. 1983; Williams & Claesson 1987; Dodson et al. 1988; Fedo et al. 2003; Hawkesworth & Kemp 2006). Zircon is common in continental rocks and it is assumed that its distribution in sediments will normally represent the source rocks. Although there are several complications, the sediment zircon U-Pb age frequency should in general terms mirror the relative proportions of different source materials. This assumption is particularly important if exotic components can be identified, as their frequency will provide an estimate of the exotic influx: it may also be essential in tracing sediment paths that affect the detrital compositions and subsequent diagenetic history of possible hydrocarbon reservoir rocks.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"54 3 1","pages":"29-32"},"PeriodicalIF":0.0,"publicationDate":"2007-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81247261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lithostratigraphy of the Palaeogene – Lower Neogene succession of the Danish North Sea","authors":"P. Schiøler, J. Andsbjerg, O. Clausen, G. Dam, K. Dybkjær, L. Hamberg, C. Heilmann-Clausen, E. Johannessen, Lars Kristensen, I. Prince, J. A. Rasmussen","doi":"10.34194/GEUSB.V12.5249","DOIUrl":"https://doi.org/10.34194/GEUSB.V12.5249","url":null,"abstract":"As a result of a lithological, sedimentological and biostratigraphic study of well sections from the Danish sector of the North Sea, including some recently drilled exploration wells on the Ringkobing–Fyn High, the lithostratigraphic framework for the siliciclastic Palaeogene to Lower Neogene sediments of the Danish sector of the North Sea is revised. The sediment package from the top of the Chalk Group to the base of the Nordland Group is subdivided into seven formations containing eleven new members. The existing Vale, Lista, Sele, Fur, Balder, Horda and Lark Formations of previously published lithostratigraphic schemes are adequate for a subdivision of the Danish sector at formation level. Bor is a new sandstone member of the Vale Formation. The Lista Formation is subdivided into three new mudstone members: Vile, Ve and Bue, and three new sandstone members: Tyr, Idun and Rind. Kolga is a new sandstone member of the Sele Formation. Hefring is a new sandstone member of the Horda Formation. Freja and Dufa are two new sandstone members of the Lark Formation. Danish reference sections are established for the formations, and the descriptions of their lithology, biostratigraphy, age and palaeoenvironmental setting are updated.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"64 1","pages":"1-77"},"PeriodicalIF":0.0,"publicationDate":"2007-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78678938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic anomalies and metamorphic boundaries in the southern Nagssugtoqidian orogen, West Greenland","authors":"J. Korstgård, B. M. Stensgaard, T. Rasmussen","doi":"10.34194/GEUSB.V11.4930","DOIUrl":"https://doi.org/10.34194/GEUSB.V11.4930","url":null,"abstract":"Within the southern Nagssugtoqidian orogen in West Greenland metamorphic terrains of both Archaean and Palaeoproterozoic ages occur with metamorphic grade varying from low amphibolite facies to granulite facies. The determination of the relative ages of the different metamorphic terrains is greatly aided by the intrusion of the 2 Ga Kangâmiut dyke swarm along a NNE trend. In Archaean areas dykes cross-cut gneiss structures, and the host gneisses are in amphibolite to granulite facies. Along Itilleq strong shearing in an E–W-oriented zone caused retrogression of surrounding gneisses to low amphibolite facies. Within this Itivdleq shear zone Kangâmiut dykes follow the E–W shear fabrics giving the impression that dykes were reoriented by the shearing. However, the dykes remain largely undeformed and unmetamorphosed, indicating that the shear zone was established prior to dyke emplacement and that the orientation of the dykes here was governed by the shear fabric. Metamorphism and deformation north of Itilleq involve both dykes and host gneisses, and the metamorphic grade is amphibolite facies increasing to granulite facies at the northern boundary of the southern Nagssugtoqidian orogen. Here a zone of strong deformation, the Ikertoq thrust zone, coincides roughly with the amphibolite–granulite facies transition. Total magnetic field intensity anomalies from aeromagnetic data coincide spectacularly with metamorphic boundaries and reflect changes in content of the magnetic minerals at facies transitions. Even the nature of facies transitions is apparent. Static metamorphic boundaries are gradual whereas dynamic boundaries along deformation zones are abrupt.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"83 1","pages":"179-184"},"PeriodicalIF":0.0,"publicationDate":"2006-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89021071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: Structural analysis of the northern Nagssugtoqidian orogen, West Greenland: an example of complex tectonic patterns in reworked high-grade metamorphic terrains","authors":"S. Mazur, S. Piazolo, G. Ian Alsop","doi":"10.34194/GEUSB.V11.4929","DOIUrl":"https://doi.org/10.34194/GEUSB.V11.4929","url":null,"abstract":"Structural analysis of the deeply eroded northern flank of the Palaeoproterozoic Nagssugtoqidian orogen shows marked regional variations in both the orientation and type of fabrics, as is characteristic of Precambrian high-grade terrains subjected to polyphase deformation. Here we investigate the relationship between strain, metamorphic grade, and the resulting structural patterns. The study area south of Aasiaat in West Greenland consists of amphiboliteto granulite-grade Archaean orthogneisses and relatively thin supracrustal units. The regional foliation displays a WSW–ENE to SW–NE strike associated with steep to moderate dips towards the WNW or SSE. Lineation trends are WSW–ENE and generally plunge gently towards the WSW. Mesoscopic fold hinges are usually colinear with the regional lineation. A systematic change in the plunge of lineations occurs across the south-western part of the study area. Towards the south, the lineation plunge progressively increases, despite the generally uniform strike of foliation. This southward increase of lineation pitch is typically associated with the transition from L > S or L = S shape fabrics in rocks characterised by a low pitch, to S > L or S fabrics in the zone of moderate to high pitch. The structural patterns point to subdivision of the study area into a southern domain mostly characterised by S or S > L shape fabrics and a moderate to high angle of lineation pitch, and a northern domain showing L > S or L = S fabrics and low angles of lineation pitch. This subdivision corresponds well with the map scale boundary between granulite facies rocks in the south and amphibolite facies rocks farther north. The observed structural pattern may be explained by two alternative tectonic models: (1) northward indentation of the previously cooled granulite block into the rheologically weaker amphibolite domain, and (2) strain partitioning within a mid-crustal transpression zone. In model 2 the northern domain represents a localised zone dominated by strike-slip kinematics, whereas the southern domain shows evidence of mostly coaxial shortening. Recent geochronology supports the indentator model in spite of limited available data. Despite the details and structural complexities of the two tectonic models, the granulite and amphibolite facies domains seem to form autochthonous segments of a crustal section linked by a transitional zone that was only reactivated and reworked during indentation or transpression. The Nagssugtoqidian compression was effectively transferred across this zone towards the northern amphibolite domain that suffered penetrative deformation during the Palaeoproterozoic event. The N–S shortening was accommodated through folding, indentation and/or strike-slip displacements, rather than by thrusting and folding as seen south of the study area.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"35 1","pages":"163-178"},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86600471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: Evolution of Neoarchaean supracrustal belts at the northern margin of the North Atlantic Craton, West Greenland","authors":"B. M. Stensgaard, M. Keiding, J. Hollis, J. V. Gool, A. Garde","doi":"10.34194/geusb.v11.4914","DOIUrl":"https://doi.org/10.34194/geusb.v11.4914","url":null,"abstract":"The Archaean North Atlantic Craton of West Greenland collided at c. 1.9 Ga with a lesser-known Archaean craton to the north, to form the Nagssugtoqidian orogen. The Palaeoproterozoic metamorphic grade and strain intensity decrease northward through the orogen, allowing investigation of the reworked Archaean components in its northern part. Two Archaean supracrustal belts in this region – the Ikamiut and Kangilinaaq belts – are investigated here using field mapping, aeromagnetic data, zircon geochronology, and geochemistry. Both belts comprise quartzo-feldspathic and pelitic metasedimentary rocks, amphibolite, and minor calc-silicate rocks, anorthosite and ultramafic rocks. PbPb and U-Pb dating of detrital zircons and host orthogneisses suggest deposition at c. 2800 Ma (Kangilinaaq belt) and after 2740 Ma (Ikamiut belt); both belts have zircons with Neoarchaean metamorphic rims. Metasedimentary rocks and orthogneisses at Ikamiut share similar steep REE signatures with strong LREE enrichment, consistent with local derivation of the sediment and deposition directly onto or proximal to the regional orthogneiss precursors. Zircon age data from Kangilinaaq indicate both local and distal sources for the sediment there. Geochemical data for Kangilinaaq amphibolites indicate bimodal, mixed felsic–mafic source rocks with island-arc basaltic affinities, consistent with a shelf or arc setting. Both belts experienced a similar tectono-metamorphic history involving Neoarchaean amphibolite facies peak metamorphism at c. 2740–2700 Ma, possibly due to continued emplacement of tonalitic and granodioritic magmas. Nagssugtoqidian lower amphibolite facies metamorphism at c. 1850 Ma was associated with development of the large-scale F 2 folds and shear zones that control the present outcrop pattern. The observed differences in the sources of the Kangilinaaq and Ikamiut belts and their shared post-Archaean history suggest they were formed in different Neoarchaean environments proximal to and on a continental plate, and were amalgamated in a convergent margin setting shortly after their deposition.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"34 1","pages":"9-32"},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84821935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stratigraphy and palaeoceanography of upper Maastrichtian chalks, southern Danish Central Graben","authors":"J. Ineson, B. Buchardt, S. Lassen, J. A. Rasmussen, P. Schiøler, N. Schovsbo, E. Sheldon, F. Surlyk","doi":"10.34194/GEUSB.V10.4870","DOIUrl":"https://doi.org/10.34194/GEUSB.V10.4870","url":null,"abstract":"reservoirs in the Danish sector of the North Sea and have been intensively studied, yet their lithological uniformity can frustrate attempts to develop a high-resolution stratigraphic subdivision and a genetic understanding of the factors controlling production and sedimentation of the pelagic carbonate ooze. Recent research into these topics, supported by the Danish Energy Authority, was carried out by the Geological Survey of Denmark and Greenland (GEUS) in collaboration with the Geological Institute, University of Copenhagen by means of a multidisciplinary study involving quantitative/semiquantitative palynology, micropalaeontology (nannofossils, foraminifers) and isotope geochemistry, integrated with detailed sedimentology. Two key wells were selected, the M-10X well from the Dan Field and the E-5X well from the Tyra SE Field (Fig. 1), based on the extensive core coverage in these wells and on their position in the southern part of the Danish Central Graben where evidence of large-scale resedimentation (and consequent stratigraphic complexity) is uncommon within the Maastrichtian section. In focusing on such a pelagic carbonate system, the ultimate aim is a holistic understanding of the marine system including temperature variation, nutrient supply and distribution, salinity, watermass layering, circulation and oxygen distribution. All these factors influence organic productivity and thus the accumulation of biogenic sediment. This study concentrated on a number of palaeoceanographic signals that can be derived from the sedimentary record, summarised in Fig. 2. Planktonic organisms, both phytoplankton (e.g. coccolithophores, some dinoflagellates) and zooplankton (e.g. foraminifers) provide a record of conditions in the upper watermasses, largely within the photic zone, while bottom conditions are indicated by epifaunal/infaunal organisms (e.g. benthic foraminifers) and bioturbation, and by the sedimentological evidence of depositional processes at the sea floor. On a larger scale, the input of terrestrial organic material relative to the marine component can provide an indirect measure of shoreline migration and thus relative sea-level change, a factor that is also reflected in the δ13C isotopic composition of the seawater, as recorded by the biogenic carbonate ooze.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"156 1","pages":"9-12"},"PeriodicalIF":0.0,"publicationDate":"2006-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76801429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advanced in situ geochronological and trace element microanalysis by laser ablation techniques","authors":"D. Frei, J. Hollis, A. Gerdes, D. Harlov, Christine Karlsson, P. Vásquez, Ferhard Franz, L. Johansson, C. Knudsen","doi":"10.34194/GEUSB.V10.4884","DOIUrl":"https://doi.org/10.34194/GEUSB.V10.4884","url":null,"abstract":"Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was developed in 1985 and the first commercial laser ablation systems were introduced in the mid 1990s. Since then, LA-ICP-MS has become an important analytical tool in the earth sciences. Initially, the main interest for geologists was in its ability to quantitatively determine the contents of a wide range of elements in many minerals at very low concentrations (a few ppm and below) with relatively high spatial resolution (spot diameters of typically 30–100 μm). The potential of LA-ICP-MS for rapid in situ U–Th–Pb geochronology was already realised in the early to mid 1990s. However, the full potential of LA-ICP-MS as the low-cost alternative to ion-microprobe techniques for highly precise and accurate in situ U–Th–Pb age dating was not realised until the relatively recent advances in laser technologies and the introduction of magnetic sectorfield ICP-MS (SF-ICPMS) instruments. In March 2005, the Geological Survey of Denmark and Greenland (GEUS) commissioned a new laser ablation magnetic sectorfield inductively coupled plasma mass spectrometry (LA-SF-ICP-MS) facility employing a ThermoFinnigan Element2 high resolution magnetic sectorfield ICP-MS and a Merchantek New Wave 213 nm UV laser ablation system. The new GEUS LA-SF-ICP-MS facility is widely used on Survey research projects in Denmark and Greenland, as well as in collaborative research and contract projects conducted with partners from academia and industry worldwide. Here, we present examples from some of the these ongoing studies that highlight the application of the new facility for advanced geochronological and trace element in situ microanalysis of geomaterials. The application of LASF-ICP-MS based in situ zircon geochronology to regional studies addressing the Archaean geology of southern West Greenland is presented by Hollis et al. (2006, this volume).","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"5 1","pages":"25-28"},"PeriodicalIF":0.0,"publicationDate":"2006-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82247421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Review of Survey Activities 2005: Earthquake seismology in Greenland – improved data with multiple applications","authors":"T. Larsen, T. Dahl-Jensen, P. Voss, T. Jørgensen, S. Gregersen, H. P. Rasmussen","doi":"10.34194/geusb.v10.4910","DOIUrl":"https://doi.org/10.34194/geusb.v10.4910","url":null,"abstract":"Earthquake seismology is a rapidly evolving field that has provided a wealth of new information about deep geological structures on a regional scale over the last decade as well as information about dynamic processes in the Earth. A major leap forward was the development of portable digital broad band (BB) seismographs around 1990. Without any changes in configuration, these are able to record the signals from large distant earthquakes, as well as the signals from weak local events. BB seismographs typically cover a frequency range from 0.0083 Hz to 50 Hz, making them useful for studies ranging from the high frequency signals from explosions to the very low frequency oscillations following major earthquakes. The first seismological observatory in Greenland was established in 1907 in Qeqertarsuaq (GDH) and was in service for about five years (Hjelme 1996). Later, seismographs were established in Ivittut (1927) and Illoqqortoormiut (1928; SCO), and the network has been regularly upgraded and expanded ever since (Fig. 1). Prior to the development of BB seismographs, each station was equipped with a set of seismographs with different frequency sensitivities in an attempt to cover both distant and local earthquakes. Now just one small instrument is needed at each location. The Geological Survey of Denmark and Greenland (GEUS) operates four permanent BB seismographs in Greenland (Fig. 1), two of them in collaboration with foreign institutions. In addition to the permanent network, there are currently 13 temporary BB seismographs active in Greenland, of which eight are operated by GEUS. Three of the temporary seismograph stations were established as part of the Danish Continental Shelf Project (Marcussen et al. 2004), and the remainder in connection with research projects. Three temporary seismographs were deployed during 2005 as part of a research project aiming to resolve very deep regional structures in North Greenland: the Citronen Fjord station (CFJ, Continental Shelf Project), and the stations in Kullorsuaq (KUL) and Daneborg (DBG).","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"109 1","pages":"57-60"},"PeriodicalIF":0.0,"publicationDate":"2006-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81078507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An integrative and quantitative assessment of the gold potential of the Nuuk region, West Greenland","authors":"B. M. Stensgaard, T. Rasmussen, A. Steenfelt","doi":"10.34194/GEUSB.V10.4902","DOIUrl":"https://doi.org/10.34194/GEUSB.V10.4902","url":null,"abstract":"An integrative and quantitative assessment of the gold potential of the Nuuk region, West Greenland","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"34 1","pages":"37-40"},"PeriodicalIF":0.0,"publicationDate":"2006-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80315076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}