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).
重建过去的长期环境变化是古气候研究中的一个重要问题。然而，古气候重建的大多数关键变量不能直接测量，因此重建是基于代理数据的。在这里，我们展示了双壳类贝壳作为环境参数档案的潜力。丹麦和格陵兰地质调查局(GEUS)开发了一种快速可靠的方法，即激光烧蚀-电感耦合等离子体质谱法(LA-ICP-MS)，用于壳材料的化学分析，在这里我们介绍了一些使用该方法的例子。在热带和亚热带水域，珊瑚可以提供长达一个世纪的过去的水化学档案，每年分辨率。温带和北极水域的可比档案将在气候研究中非常有用，因此已经研究了双壳类贝壳是否可以提供这种档案(例如Schoene et al. 2005)。寿命长的物种可以提供长达几百年的年度分辨率，而寿命短、生长迅速的物种可以提供季节性分辨率，在某些情况下可以提供几年的日常分辨率。大多数双壳类是无柄的，壳通常作为化石保存下来。然而，使用双壳类作为代理档案存在许多挑战:(1)许多代理显示物种特有的行为(Seed 1980);(2)只有极少数代理依赖于单一变量(Wefer et al. 1999);(3)生物和个体发育对贝壳碳酸盐中微量元素吸收和稳定同位素分馏的影响在很大程度上是未知的，需要进行经验评估。因此，任何潜在的代理都必须针对每个感兴趣的物种单独校准，然后才能使用。校准代理需要大量的化学分析。这些通常是通过溶液ICP-MS获得的，其中样品制备是耗时和劳动密集型的。因此，LA-ICP-MS的使用在双壳类代理研究中是一个相当大的进步，因为它大大减少了样品制备所需的工作量。同时，该方法需要较少的分析材料，从而提供更好的空间和时间分辨率。基于双壳类碳酸盐岩的代用物可用于当今的环境监测，也可用于化石壳的环境重建。博物馆收藏的贝壳和考古堆中发现的贝壳可以提供历史和史前环境条件的信息(例如Carrell et al. 1987)，化石贝壳可以作为地质时间尺度上的环境参数档案(例如Hendry et al. 2001)。
{"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}
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.
西格陵兰近海侏罗系/白垩系-古近系广泛而深的沉积盆地具有重要的油气勘探潜力。在Disko和Nuussuaq以西的近海地区尤其如此，在那里，多年来一直有油气系统的记录。目前，该地区的地层学知识几乎不存在，因此，从陆上和海上探井进行的模拟研究对于了解Disko-Nuussuaq海上地区可能的储层岩石的分布和质量至关重要。该地区油气勘探的主要风险参数之一是是否存在足够的储集岩。构造地层学方面的考虑表明，可能存在几个易砂地层，但它们的来源和储层质量目前在陆上和海上都知之甚少。因此，丹麦和格陵兰地质调查局(GEUS)启动了沉积物物源研究，包括锆石物源U-Pb测年和整体岩石地球化学分析，为2006年迪斯科西部许可轮做准备(Schersten et al. 2007)。本研究的主要目的是:1。利用先进的锆石物源U-Pb测年技术(激光烧蚀感应耦合等离子体质谱法(LA-ICP-MS))，对Nuussuaq盆地白垩纪-古新世不同砂岩单元的源区和扩散模式进行了表征，并与选定的西格陵兰海上探井的砂岩单元进行了比较(图1、2);参见Frei et al. 2006)。2. 探测沉积物来源随时间可能发生的变化，例如，本地来源与区域来源。锆石作为一种物源工具正受到越来越多的关注，并已被证明是碎屑沉积物来源的有力指示物，是地球最古老物质的示踪剂，也是大陆地壳形成过程的示踪剂(Froude et al. 1983;Williams & Claesson 1987;Dodson et al. 1988;Fedo et al. 2003;Hawkesworth & Kemp 2006)。锆石普遍存在于陆相岩石中，一般认为其在沉积物中的分布代表了烃源岩。虽然存在一些复杂因素，但沉积物锆石U-Pb年龄频率总体上反映了不同源物质的相对比例。如果能够识别出外来成分，这一假设就尤为重要，因为它们的频率将提供对外来流入的估计;对于追踪影响碎屑组成和随后可能的烃储集岩成岩历史的沉积物路径，这一假设也可能至关重要。
{"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}
P. Schiøler, J. Andsbjerg, O. Clausen, G. Dam, K. Dybkjær, L. Hamberg, C. Heilmann-Clausen, E. Johannessen, Lars Kristensen, I. Prince, J. A. Rasmussen
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.
{"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}
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.
{"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}
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.
{"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}
B. M. Stensgaard, M. Keiding, J. Hollis, J. V. Gool, A. Garde
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.
西格陵兰岛的太古代北大西洋克拉通在约1.9 Ga与北部一个不太为人所知的太古代克拉通碰撞，形成了那苏木托起甸造山带。古元古代的变质等级和应变强度通过造山带向北降低，使其北部的太古代成分得以重新改造。本文利用野外填图、航磁资料、锆石年代学和地球化学等方法，对该地区两个太古宙上地壳带Ikamiut和Kangilinaaq进行了研究。这两个带包括石英长石和泥质变质沉积岩、角闪岩和少量钙硅酸盐岩石、斜长岩和超镁铁质岩石。碎屑锆石的PbPb和U-Pb定年和寄主正交性表明沉积时间约为2800 Ma (Kangilinaaq带)和2740 Ma (Ikamiut带)之后;两个带都有新太古代变质边缘的锆石。伊kamiut地区的变质沉积岩和正长岩具有相似的陡稀土特征，且LREE富集较强，这与沉积物的局部衍生和直接沉积在区域正长岩前体上或近端一致。康基利纳克的锆石年龄数据表明，那里的沉积物既有本地来源，也有远端来源。康基利纳克角闪岩地球化学资料显示双峰型、英基性混合烃源岩具有岛弧玄武岩亲缘关系，符合陆架或弧背景。两个带都经历了相似的构造变质史，包括在约2740-2700 Ma的新太古代角闪岩相变质高峰，可能是由于调性和花岗闪长岩岩浆的持续侵位。那苏托祁甸下角闪岩相变质作用与控制现今露头格局的大型f2褶皱和剪切带的发育有关。从观测到的Kangilinaaq带和Ikamiut带的物源差异以及它们共同的后太古代历史来看，它们形成于不同的新太古代环境，分别靠近大陆板块和在大陆板块上，并在沉积后不久融合在一个辐合边缘环境中。
{"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}
J. Ineson, B. Buchardt, S. Lassen, J. A. Rasmussen, P. Schiøler, N. Schovsbo, E. Sheldon, F. Surlyk
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.
{"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}
D. Frei, J. Hollis, A. Gerdes, D. Harlov, Christine Karlsson, P. Vásquez, Ferhard Franz, L. Johansson, C. Knudsen
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).
激光烧蚀电感耦合等离子体质谱法(LA-ICP-MS)于1985年发展起来，第一个商用激光烧蚀系统在20世纪90年代中期推出。从那时起，LA-ICP-MS已成为地球科学中重要的分析工具。最初，地质学家的主要兴趣在于它能够以相对较高的空间分辨率(斑点直径通常为30-100 μm)在非常低的浓度(几ppm及以下)下定量确定许多矿物中各种元素的含量。LA-ICP-MS在快速原位U-Th-Pb地质年代学方面的潜力早在20世纪90年代初至中期就已实现。然而，LA-ICP-MS作为离子微探针技术的低成本替代品，用于高精度和准确的原位U-Th-Pb年龄测定的全部潜力直到激光技术的相对最新进展和磁场ICP-MS (SF-ICPMS)仪器的引入才得以实现。2005年3月，丹麦和格陵兰地质调查局(GEUS)委托了一个新的激光烧蚀磁场电感耦合等离子体质谱(LA-SF-ICP-MS)设备，该设备采用ThermoFinnigan Element2高分辨率磁场ICP-MS和mertek new Wave 213 nm紫外激光烧蚀系统。新的GEUS LA-SF-ICP-MS设备广泛用于丹麦和格陵兰岛的调查研究项目，以及与全球学术界和工业界合作伙伴进行的合作研究和合同项目。在这里，我们从这些正在进行的研究中举出一些例子，这些研究突出了新设备在地质材料的先进地质年代学和微量元素原位微分析中的应用。Hollis等人(2006年，本卷)介绍了基于原位锆石年代学的LASF-ICP-MS在西格陵兰岛南部太古宙地质区域研究中的应用。
{"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}
T. Larsen, T. Dahl-Jensen, P. Voss, T. Jørgensen, S. Gregersen, H. P. Rasmussen
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).
地震地震学是一个迅速发展的领域，在过去的十年中，它提供了丰富的关于区域范围内深部地质结构的新信息，以及关于地球动力学过程的信息。一个重大的飞跃是1990年左右便携式数字宽带(BB)地震仪的发展。在没有任何配置改变的情况下，这些仪器能够记录来自远距离大地震的信号，以及来自本地弱地震的信号。BB地震仪通常覆盖的频率范围从0.0083赫兹到50赫兹，这使得它们对从爆炸的高频信号到大地震后的低频振荡的研究都很有用。格陵兰的第一个地震观测站于1907年在Qeqertarsuaq (GDH)建立，并服务了大约5年(Hjelme 1996)。后来，在伊维图特(1927年)和伊洛科托米特(1928年)建立了地震仪;(图1)。在研制BB地震仪之前，每个台站都配备了一套不同频率灵敏度的地震仪，试图同时覆盖远震和局地地震。现在每个地点只需要一个小仪器。丹麦和格陵兰地质调查局(GEUS)在格陵兰运行着四台永久BB地震仪(图1)，其中两台是与外国机构合作的。除了永久台网外，格陵兰岛目前有13个临时BB地震仪，其中8个由GEUS操作。其中三个临时地震仪站是作为丹麦大陆架项目(Marcussen et al. 2004)的一部分建立的，其余的与研究项目有关。2005年，作为旨在解决北格陵兰极深区域结构的研究项目的一部分，部署了三个临时地震仪:Citronen Fjord站(CFJ，大陆架项目)和Kullorsuaq站(KUL)和Daneborg站(DBG)。
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An integrative and quantitative assessment of the gold potential of the Nuuk region, West Greenland
西格陵兰努克地区黄金潜力的综合定量评估
{"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}
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