M. Bjerager, C. Kjøller, M. Olivarius, D. Olsen, N. Schovsbo
The fully cored Blokelv-1 borehole was drilled through Upper Jurassic strata in the central part of the Jameson Land Basin, central East Greenland. The borehole reached a total depth of 233.8 m with nearly 100% recovery of high-quality core. An extensive analytical programme was undertaken on the core; sedimentological interpretation and reservoir characterisation were based on facies analysis combined with conventional core analysis, bulk geochemistry and spectral gamma and density scanning of the core. The Upper Jurassic Hareelv Formation was deposited in relatively deep water in a slope-to-basin setting where background sedimentation was dominated by suspension settling of organic-rich mud in oxygen-depleted conditions. Low- and high-density gravity-flow sandstone interbeds occur throughout the cored succession. About two-thirds of the high-density turbidite sandstones were remobilised and injected into the surrounding mud-rock. The resulting succession comprises nearly equal amounts of mudstones and sandstones in geometrically complex bodies. Ankerite cementation occurs in 37% of the analysed sandstones in varying amounts from minor to pervasive. Such ankerite-cemented sandstones can be identified by their bulk geochemistry where Ca > 2 wt%, Mg > 1 wt% and C > 1 wt%. The analysed mudstones are rich in Al, Fe, Ti and P and poor in Ca, Mg, Na and Mn. The trace-metal content shows a general increase in the upper part of the core reflecting progressive oxygen depletion at the sea floor. The reservoir properties of the Blokelv-1 sandstones were evaluated by both conventional core analysis and using log-derived porosity and permeability curves. The high-density turbidite beds and injectite bodies are a few centimetres to several metres thick and show large variations in porosity and permeability, in the range of 6–26 % for porosity and 0.05–400 mD for permeability. Individual sandstone units that are 1–7 m thick yield a net vertical reservoir thickness of 40 m with porosities of 15–26% and permeabilities of 1–200 mD. Heterolithic sandstone–mudstone units are generally characterised by poor reservoir quality with porosities of 2–14% and permeabilities of 0.1–0.6 mD.
{"title":"Sedimentology, geochemistry and reservoir properties of Upper Jurassic deep marine sediments (Hareelv Formation) in the Blokelv-1 borehole, Jameson Land Basin, East Greenland","authors":"M. Bjerager, C. Kjøller, M. Olivarius, D. Olsen, N. Schovsbo","doi":"10.34194/geusb.v42.4309","DOIUrl":"https://doi.org/10.34194/geusb.v42.4309","url":null,"abstract":"The fully cored Blokelv-1 borehole was drilled through Upper Jurassic strata in the central part of the Jameson Land Basin, central East Greenland. The borehole reached a total depth of 233.8 m with nearly 100% recovery of high-quality core. An extensive analytical programme was undertaken on the core; sedimentological interpretation and reservoir characterisation were based on facies analysis combined with conventional core analysis, bulk geochemistry and spectral gamma and density scanning of the core. The Upper Jurassic Hareelv Formation was deposited in relatively deep water in a slope-to-basin setting where background sedimentation was dominated by suspension settling of organic-rich mud in oxygen-depleted conditions. Low- and high-density gravity-flow sandstone interbeds occur throughout the cored succession. About two-thirds of the high-density turbidite sandstones were remobilised and injected into the surrounding mud-rock. The resulting succession comprises nearly equal amounts of mudstones and sandstones in geometrically complex bodies. Ankerite cementation occurs in 37% of the analysed sandstones in varying amounts from minor to pervasive. Such ankerite-cemented sandstones can be identified by their bulk geochemistry where Ca > 2 wt%, Mg > 1 wt% and C > 1 wt%. The analysed mudstones are rich in Al, Fe, Ti and P and poor in Ca, Mg, Na and Mn. The trace-metal content shows a general increase in the upper part of the core reflecting progressive oxygen depletion at the sea floor. The reservoir properties of the Blokelv-1 sandstones were evaluated by both conventional core analysis and using log-derived porosity and permeability curves. The high-density turbidite beds and injectite bodies are a few centimetres to several metres thick and show large variations in porosity and permeability, in the range of 6–26 % for porosity and 0.05–400 mD for permeability. Individual sandstone units that are 1–7 m thick yield a net vertical reservoir thickness of 40 m with porosities of 15–26% and permeabilities of 1–200 mD. Heterolithic sandstone–mudstone units are generally characterised by poor reservoir quality with porosities of 2–14% and permeabilities of 0.1–0.6 mD.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"109 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79204504","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 Geological Survey of Denmark and Greenland (GEUS) successfully drilled the fully cored Blokelv-1 borehole in the central part of the Jameson Land Basin in East Greenland, targeting the Upper Jurassic, rich source-rock interval of the Hareelv Formation. The borehole achieved 100% core recovery from 1.72 m to a total depth of 233.8 m; the recovered Hareelv Formation section consists of interlayered black, laminated organic-rich mudstones, massive sandstones and heterolithic sandstone–mudstone intervals of the Katedralen Member, and amalgamated massive sandstones of the Sjællandselv Member. The core is of very high quality and has been subjected to an extensive sampling and analytical programme focused particularly on petroleum geological aspects, as presented in the following eight papers in this volume. This bulletin describes an important, previously poorly documented member of the ‘Kimmeridge Clay’ family of prolific petroleum source rocks in the North Atlantic area.
{"title":"The Upper Jurassic Blokelv-1 cored borehole in Jameson Land, East Greenland – an introduction","authors":"M. Bjerager, S. Piasecki, J. Bojesen‐Koefoed","doi":"10.34194/geusb.v42.4307","DOIUrl":"https://doi.org/10.34194/geusb.v42.4307","url":null,"abstract":"The Geological Survey of Denmark and Greenland (GEUS) successfully drilled the fully cored Blokelv-1 borehole in the central part of the Jameson Land Basin in East Greenland, targeting the Upper Jurassic, rich source-rock interval of the Hareelv Formation. The borehole achieved 100% core recovery from 1.72 m to a total depth of 233.8 m; the recovered Hareelv Formation section consists of interlayered black, laminated organic-rich mudstones, massive sandstones and heterolithic sandstone–mudstone intervals of the Katedralen Member, and amalgamated massive sandstones of the Sjællandselv Member. The core is of very high quality and has been subjected to an extensive sampling and analytical programme focused particularly on petroleum geological aspects, as presented in the following eight papers in this volume. This bulletin describes an important, previously poorly documented member of the ‘Kimmeridge Clay’ family of prolific petroleum source rocks in the North Atlantic area.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90070551","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}
M. Bjerager, P. Alsen, J. Bojesen‐Koefoed, T. Nielsen, S. Piasecki, Anders Pilgaard
Data from the recently drilled, fully cored Blokelv-1 borehole and previous cored boreholes in the Upper Jurassic of Jameson Land, central East Greenland, are integrated with published field studies to address the depositional evolution of the Jameson Land Basin in the Oxfordian–Volgian. In Jameson Land, the succession represents a marine shelf-to-basin transect in a W–SW-dipping half-graben. Laminated organic-rich mudstones were deposited in the central deep parts of the basin and grade up-slope into bioturbated sandy mudstones. Extensive shallow marine – deltaic sand prograded from the western and northern basin margins and formed prominent sandy shelf-edge wedges. Sand-rich density flows initiated by periodic collapse of the shelf edge deposited massive sand bodies on the slope and basin floor; these sands were prone to post-burial remobilisation to form injectite bodies. Basin evolution was controlled both by relative sea-level changes, typically correlatable with regional and global sea-level curves, and by rift tectonics. During periods with high relative sea level, the organicrich muddy facies onlapped the sandy shelf environments; such periods of basinal expansion and onlap are recorded in the lower Oxfordian (Q. mariae Chronozone), the middle–upper Oxfordian (C. tenuiserratum – A. glosense Chronozones) and uppermost Oxfordian – upper Kimmeridgian (A. regulare – A. autissiodorensis Chronozones); the deepening, transgressive trend culminated in the mid-Kimmeridgian (A. eudoxus Chron). Marked progradation of the sandy shelf and associated deposition of gravity-flow sands on the slope and basin floor occurred in the early Oxfordian (C. cordatum Chron), the middle Oxfordian (C. densiplicatum Chron), the late Oxfordian (A. serratum Chron) and the early Volgian (P. elegans Chron). The basin architecture reflects periodic differential subsidence on the W- to SW-dipping fault block. The lower to middle Oxfordian is highly condensed in the east (<10 m) and thickens markedly towards the west (>300 m), reflecting accumulation during rift/fault-controlled block rotation. The upper Oxfordian – Kimmeridgian, in contrast, shows a broadly symmetrical distribution and records uniform regional subsidence.
最近钻探的Blokelv-1井和之前在东格陵兰中部Jameson Land上侏罗统的取心井的数据与已发表的现场研究结果相结合，以解决牛津- volgian Jameson Land盆地的沉积演化问题。在詹姆逊地，该序列代表了一个西-西向倾斜的半地堑中的海相陆架-盆地样带。富有机质层状泥岩沉积于盆地中部深部，并向上坡演化为生物扰动砂质泥岩。广泛的浅海三角洲砂从盆地西部和北部边缘推进，形成了突出的砂架边缘楔。陆架边缘周期性塌陷引发的富砂密度流在斜坡和盆地底部沉积了大量砂体;这些砂易于在埋后再活化形成注入体。盆地演化受相对海平面变化(通常与区域和全球海平面曲线相关)和裂谷构造控制。相对海平面较高时期，富有机质泥质相与砂质陆架环境相叠置;这样的盆地扩张和叠合时期记录在牛津下部(Q. mariae Chronozone)、牛津中上部(C. tenuiserratum - A. glosense Chronozones)和牛津上部-上kimmeridian (A. regulare - A. autissiodorensis Chronozones);深化的海侵趋势在中基默里纪(A. eudoxus Chron)达到顶峰。早牛津世(C. cordatum Chron)、中牛津世(C. densiplicatum Chron)、晚牛津世(A. serratum Chron)和早伏世(P. elegans Chron)发生了明显的砂质陆架进积，并伴有重力流砂在斜坡和盆地底的沉积。盆地构造反映了西向西倾断块的周期性差异沉降。下部至中牛津层在东部高度凝聚(300 m)，反映了裂谷/断层控制的地块旋转过程中的聚集。而上牛津纪—基默里吉纪则呈现出较宽的对称分布，并记录了均匀的区域沉降。
{"title":"Late Jurassic evolution of the Jameson Land Basin, East Greenland – implications of the Blokelv-1 borehole","authors":"M. Bjerager, P. Alsen, J. Bojesen‐Koefoed, T. Nielsen, S. Piasecki, Anders Pilgaard","doi":"10.34194/geusb.v42.4325","DOIUrl":"https://doi.org/10.34194/geusb.v42.4325","url":null,"abstract":"Data from the recently drilled, fully cored Blokelv-1 borehole and previous cored boreholes in the Upper Jurassic of Jameson Land, central East Greenland, are integrated with published field studies to address the depositional evolution of the Jameson Land Basin in the Oxfordian–Volgian. In Jameson Land, the succession represents a marine shelf-to-basin transect in a W–SW-dipping half-graben. Laminated organic-rich mudstones were deposited in the central deep parts of the basin and grade up-slope into bioturbated sandy mudstones. Extensive shallow marine – deltaic sand prograded from the western and northern basin margins and formed prominent sandy shelf-edge wedges. Sand-rich density flows initiated by periodic collapse of the shelf edge deposited massive sand bodies on the slope and basin floor; these sands were prone to post-burial remobilisation to form injectite bodies. Basin evolution was controlled both by relative sea-level changes, typically correlatable with regional and global sea-level curves, and by rift tectonics. During periods with high relative sea level, the organicrich muddy facies onlapped the sandy shelf environments; such periods of basinal expansion and onlap are recorded in the lower Oxfordian (Q. mariae Chronozone), the middle–upper Oxfordian (C. tenuiserratum – A. glosense Chronozones) and uppermost Oxfordian – upper Kimmeridgian (A. regulare – A. autissiodorensis Chronozones); the deepening, transgressive trend culminated in the mid-Kimmeridgian (A. eudoxus Chron). Marked progradation of the sandy shelf and associated deposition of gravity-flow sands on the slope and basin floor occurred in the early Oxfordian (C. cordatum Chron), the middle Oxfordian (C. densiplicatum Chron), the late Oxfordian (A. serratum Chron) and the early Volgian (P. elegans Chron). The basin architecture reflects periodic differential subsidence on the W- to SW-dipping fault block. The lower to middle Oxfordian is highly condensed in the east (<10 m) and thickens markedly towards the west (>300 m), reflecting accumulation during rift/fault-controlled block rotation. The upper Oxfordian – Kimmeridgian, in contrast, shows a broadly symmetrical distribution and records uniform regional subsidence.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75238117","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}
Apatite fission-track analysis (AFTA) data in two Upper Jurassic core samples from the 231 m deep Blokelv-1 borehole, Jameson Land, East Greenland, combined with vitrinite reflectance data and regional AFTA data, define three palaeo-thermal episodes. We interpret localised early Eocene (55– 50 Ma) palaeotemperatures as representing localised early Eocene heating related to intrusive activity whereas we interpret late Eocene (40–35 Ma) and late Miocene (c. 10 Ma) palaeotemperatures as representing deeper burial followed by successive episodes of exhumation. For a palaeogeothermal gradient of 30°C/km and likely palaeo-surface temperatures, the late Eocene palaeotemperatures require that the Upper Jurassic marine section in the borehole was buried below a 2750 m thick cover of Upper Jurassic – Eocene rocks prior to the onset of late Eocene exhumation. As these sediments are now near outcrop at c. 200 m above sea level, they have been uplifted by at least 3 km since maximum burial during post-rift thermal subsidence. The results are consistent with estimates of rock uplift on Milne Land since the late Eocene and with interpretation of Ocean Drilling Program (ODP) data off South-East Greenland suggesting that mid-Cenozoic uplift of the margin triggered the marked influx of coarse clastic turbidites during the late Oligocene above a middle Eocene to upper Oligocene hiatus.
{"title":"Burial and exhumation history of the Jameson Land Basin, East Greenland, estimated from thermochronological data from the Blokelv-1 core","authors":"P. Green, P. Japsen","doi":"10.34194/geusb.v42.4324","DOIUrl":"https://doi.org/10.34194/geusb.v42.4324","url":null,"abstract":"Apatite fission-track analysis (AFTA) data in two Upper Jurassic core samples from the 231 m deep Blokelv-1 borehole, Jameson Land, East Greenland, combined with vitrinite reflectance data and regional AFTA data, define three palaeo-thermal episodes. We interpret localised early Eocene (55– 50 Ma) palaeotemperatures as representing localised early Eocene heating related to intrusive activity whereas we interpret late Eocene (40–35 Ma) and late Miocene (c. 10 Ma) palaeotemperatures as representing deeper burial followed by successive episodes of exhumation. For a palaeogeothermal gradient of 30°C/km and likely palaeo-surface temperatures, the late Eocene palaeotemperatures require that the Upper Jurassic marine section in the borehole was buried below a 2750 m thick cover of Upper Jurassic – Eocene rocks prior to the onset of late Eocene exhumation. As these sediments are now near outcrop at c. 200 m above sea level, they have been uplifted by at least 3 km since maximum burial during post-rift thermal subsidence. The results are consistent with estimates of rock uplift on Milne Land since the late Eocene and with interpretation of Ocean Drilling Program (ODP) data off South-East Greenland suggesting that mid-Cenozoic uplift of the margin triggered the marked influx of coarse clastic turbidites during the late Oligocene above a middle Eocene to upper Oligocene hiatus.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76069219","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. Bojesen‐Koefoed, M. Bjerager, H. Nytoft, H. Petersen, S. Piasecki, Anders Pilgaard
The marine, mudstone-dominated Hareelv Formation (Upper Jurassic) of Jameson Land, East Greenland is a representative of the widespread Kimmeridge Clay Formation equivalents, sensu lato, known from the greater North Atlantic region, western Siberia and basins off eastern Canada. These deposits constitute the most important petroleum source-rock succession of the region. The present study reports petroleum geochemical data from the 233.8 m thick succession penetrated by the fully cored Blokelv-1 borehole, and includes supplementary data from outcrop samples and other boreholes in Jameson Land. The succession consists of basinal mudstone intercalated with a significant proportion of gravity-flow sandstones, both in situ and remobilised as injectites. The mudstones are generally rich in organic carbon with values of TOC reaching nearly 19 wt% and high pyrolysis yields reaching values of S2 up to nearly 43 kg HC/ton. Hydrogen Indices are up to 363. The data presented herein demonstrate that weathering of abundant pyritic sulfur adversely affects the petroleum potential of the kerogen in outcrop samples. The succession is thermally immature to early mature, except where intrusions have locally heated adjacent mudstones. The documentation of rich gas/oil-prone Upper Jurassic successions in Jameson Land is important for the assessment of the regional petroleum potential, including the North-East Greenland continental shelf.
东格陵兰Jameson Land的海相，泥岩为主的Hareelv组(上侏罗统)是广泛存在的Kimmeridge粘土组的代表，在北大西洋地区，西伯利亚西部和加拿大东部的盆地中都有发现。这些沉积构成了该地区最重要的烃源岩演替。本研究报告了由全取心的Blokelv-1钻孔所钻取的233.8 m厚层序的石油地球化学数据，并包括了来自Jameson Land露头样品和其他钻孔的补充数据。该序列由盆地泥岩和相当比例的重力流砂岩组成，既有原位砂岩，也有作为注入物重新活化的砂岩。泥岩普遍富含有机碳，TOC值接近19 wt%，热解率高，S2值接近43 kg HC/t。氢指数高达363。结果表明，大量黄铁矿硫的风化作用对露头样品中干酪根的含油气潜力有不利影响。除侵入体局部加热邻近泥岩外，该演替为热不成熟至早成熟。Jameson Land上侏罗统富油气序列的记录对于评估该区域的石油潜力具有重要意义，包括格陵兰东北大陆架。
{"title":"Petroleum potential of the Upper Jurassic Hareelv Formation, Jameson Land, East Greenland","authors":"J. Bojesen‐Koefoed, M. Bjerager, H. Nytoft, H. Petersen, S. Piasecki, Anders Pilgaard","doi":"10.34194/geusb.v42.4314","DOIUrl":"https://doi.org/10.34194/geusb.v42.4314","url":null,"abstract":"The marine, mudstone-dominated Hareelv Formation (Upper Jurassic) of Jameson Land, East Greenland is a representative of the widespread Kimmeridge Clay Formation equivalents, sensu lato, known from the greater North Atlantic region, western Siberia and basins off eastern Canada. These deposits constitute the most important petroleum source-rock succession of the region. The present study reports petroleum geochemical data from the 233.8 m thick succession penetrated by the fully cored Blokelv-1 borehole, and includes supplementary data from outcrop samples and other boreholes in Jameson Land. The succession consists of basinal mudstone intercalated with a significant proportion of gravity-flow sandstones, both in situ and remobilised as injectites. The mudstones are generally rich in organic carbon with values of TOC reaching nearly 19 wt% and high pyrolysis yields reaching values of S2 up to nearly 43 kg HC/ton. Hydrogen Indices are up to 363. The data presented herein demonstrate that weathering of abundant pyritic sulfur adversely affects the petroleum potential of the kerogen in outcrop samples. The succession is thermally immature to early mature, except where intrusions have locally heated adjacent mudstones. The documentation of rich gas/oil-prone Upper Jurassic successions in Jameson Land is important for the assessment of the regional petroleum potential, including the North-East Greenland continental shelf.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84460196","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 Hareelv Formation in the Blokelv-1 core is biostratigraphically subdivided by means of ammonite and dinoflagellate cyst stratigraphy. The succession ranges from the Oxfordian C. densiplicatum Chronozone to the Volgian P. elegans Chronozone. The mudstones of the Blokelv-1 core are characterised by large amounts of amorphous organic matter. This hampers the preparation and identification of dinoflagellate cysts, which are also commonly degraded and corroded. Ammonites, on the other hand, are common and well-preserved in the core, contrasting with that observed in the equivalent facies and stratigraphic interval at outcrop. Integration of the ammonite and dinoflagellate cyst biostratigraphical data yields a robust chronostratigraphic subdivision of the middle Oxfordian – lowermost Volgian cored section.
{"title":"Biostratigraphy of the Hareelv Formation (Upper Jurassic) in the Blokelv-1 core, Jameson Land, central East Greenland","authors":"P. Alsen, S. Piasecki","doi":"10.34194/geusb.v42.4308","DOIUrl":"https://doi.org/10.34194/geusb.v42.4308","url":null,"abstract":"The Hareelv Formation in the Blokelv-1 core is biostratigraphically subdivided by means of ammonite and dinoflagellate cyst stratigraphy. The succession ranges from the Oxfordian C. densiplicatum Chronozone to the Volgian P. elegans Chronozone. The mudstones of the Blokelv-1 core are characterised by large amounts of amorphous organic matter. This hampers the preparation and identification of dinoflagellate cysts, which are also commonly degraded and corroded. Ammonites, on the other hand, are common and well-preserved in the core, contrasting with that observed in the equivalent facies and stratigraphic interval at outcrop. Integration of the ammonite and dinoflagellate cyst biostratigraphical data yields a robust chronostratigraphic subdivision of the middle Oxfordian – lowermost Volgian cored section.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90152930","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}
M. Olivarius, R. Weibel, N. Schovsbo, D. Olsen, C. Kjøller
Petrographic analysis combined with X-ray diffraction are used to identify the diagenetic changes that have affected the porosity and permeability of gravity-flow sandstones of the Oxfordian–Volgian Hareelv Formation in the cored Blokelv-1 borehole in Jameson Land. Kaolinite replacement of albite grains probably occurred early after deposition and microquartz coatings formed under shallow burial. At deeper burial, illite and quartz formed from kaolinite and K-feldspar. Pervasive ankerite cement formed in the finest grained sandstones and may have formed at the expense of early calcite cement. Quartz overgrowths are volumetrically small, partly due to inhibition by microquartz coatings and partly due to limited residence time during deep burial. The succession reached the maximum burial depth of c. 2.8 km during the late Eocene. Basaltic material was intruded into the sediments during the early Eocene and the enhanced heat flow accelerated diagenesis in the close vicinity of the intrusions, which have thicknesses of up to 2 m. Most of the sandstones have porosities between 14.4 and 25.7% and permeabilities between 0.4 and 411.9 mD; this variation resulted from a combination of microquartz coatings and clay minerals. However, the intrusion-influenced sandstones and the ankerite-cemented sandstones have lower porosity and permeability.
{"title":"Diagenesis of Upper Jurassic sandstones of the Blokelv-1 core in the Jameson Land Basin, East Greenland","authors":"M. Olivarius, R. Weibel, N. Schovsbo, D. Olsen, C. Kjøller","doi":"10.34194/geusb.v42.4310","DOIUrl":"https://doi.org/10.34194/geusb.v42.4310","url":null,"abstract":"Petrographic analysis combined with X-ray diffraction are used to identify the diagenetic changes that have affected the porosity and permeability of gravity-flow sandstones of the Oxfordian–Volgian Hareelv Formation in the cored Blokelv-1 borehole in Jameson Land. Kaolinite replacement of albite grains probably occurred early after deposition and microquartz coatings formed under shallow burial. At deeper burial, illite and quartz formed from kaolinite and K-feldspar. Pervasive ankerite cement formed in the finest grained sandstones and may have formed at the expense of early calcite cement. Quartz overgrowths are volumetrically small, partly due to inhibition by microquartz coatings and partly due to limited residence time during deep burial. The succession reached the maximum burial depth of c. 2.8 km during the late Eocene. Basaltic material was intruded into the sediments during the early Eocene and the enhanced heat flow accelerated diagenesis in the close vicinity of the intrusions, which have thicknesses of up to 2 m. Most of the sandstones have porosities between 14.4 and 25.7% and permeabilities between 0.4 and 411.9 mD; this variation resulted from a combination of microquartz coatings and clay minerals. However, the intrusion-influenced sandstones and the ankerite-cemented sandstones have lower porosity and permeability.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"63 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80725835","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}
M. Olivarius, M. Bjerager, Nynke Keulen, C. Knudsen, T. Kokfelt
Zircon U–Pb geochronology and heavy mineral CCSEM analysis were used to interpret the provenance of Oxfordian–Volgian sandstones of the Hareelv Formation in East Greenland. Six samples were collected from the Blokelv-1 core drilled in southern Jameson Land, and the zircon age distributions and heavy-mineral assemblages are quite uniform. The samples contain a wide spectrum of Archaean to Palaeozoic zircon ages with peak ages at 2.71, 2.49, 1.95, 1.65, 1.49, 1.37, 1.10 and 0.43 Ga when combining all data. The heavy-mineral compositions show derivation from felsic source rocks, some of which were metamorphic. The results reveal that the sediment was derived from the Caledonides, and it is plausible that some or all of the material has experienced several cycles of sedimentation. Devonian and Carboniferous sediments preserved north of the area have zircon age distributions that correspond to those from the Hareelv Formation, and such rocks may have been reworked into the Jameson Land Basin. The provenance signature describes both the gravity-flow sandstones of the Hareelv Formation and the delta-edge sands that are inferred to have fed them. Lithological and provenance contrasts between the sandstones of the Sjællandselv Member and those of the Katedralen Member indicate a shorter transport distance, source to sink, suggestive of proximal topographic rejuvenation in the Volgian.
{"title":"Provenance of basinal sandstones in the Upper Jurassic Hareelv Formation, Jameson Land Basin, East Greenland","authors":"M. Olivarius, M. Bjerager, Nynke Keulen, C. Knudsen, T. Kokfelt","doi":"10.34194/geusb.v42.4317","DOIUrl":"https://doi.org/10.34194/geusb.v42.4317","url":null,"abstract":"Zircon U–Pb geochronology and heavy mineral CCSEM analysis were used to interpret the provenance of Oxfordian–Volgian sandstones of the Hareelv Formation in East Greenland. Six samples were collected from the Blokelv-1 core drilled in southern Jameson Land, and the zircon age distributions and heavy-mineral assemblages are quite uniform. The samples contain a wide spectrum of Archaean to Palaeozoic zircon ages with peak ages at 2.71, 2.49, 1.95, 1.65, 1.49, 1.37, 1.10 and 0.43 Ga when combining all data. The heavy-mineral compositions show derivation from felsic source rocks, some of which were metamorphic. The results reveal that the sediment was derived from the Caledonides, and it is plausible that some or all of the material has experienced several cycles of sedimentation. Devonian and Carboniferous sediments preserved north of the area have zircon age distributions that correspond to those from the Hareelv Formation, and such rocks may have been reworked into the Jameson Land Basin. The provenance signature describes both the gravity-flow sandstones of the Hareelv Formation and the delta-edge sands that are inferred to have fed them. Lithological and provenance contrasts between the sandstones of the Sjællandselv Member and those of the Katedralen Member indicate a shorter transport distance, source to sink, suggestive of proximal topographic rejuvenation in the Volgian.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"49 2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89203250","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}
Lithological mapping using remote sensing depends, in part, on the identification of rock types by their spectral characteristics. Chemical and physical properties of minerals and rocks determine their diagnostic spectral features throughout the electromagnetic spectrum. Shifts in the position and changes in the shape and depth of these features can be explained by variations in chemical composition of minerals. Detection of such variations is vital for discriminating minerals with similar chemical composition. Compared with multispectral image data, airborne or spaceborne hyperspectral imagery offers higher spectral resolution, which makes it possible to estimate the mineral composition of the rocks under study without direct contact. Arctic environments provide challenging ground for geological mapping and mineral exploration. Inaccessibility commonly complicates ground surveys, and the presence of ice, vegetation and rock-encrusting lichens hinders remote sensing surveys. This study addresses the following objectives: 1. Modelling the impact of lichen on the spectra of the rock substrate; 2. Identification of a robust lichen index for the deconvolution of lichen and rock mixtures and 3. Multiscale hyperspectral analysis of lithologies in areas with abundant lichens.
{"title":"Hyperspectral analysis of lithologies in the Arctic in areas with abundant lichen cover","authors":"S. Salehi","doi":"10.34194/geusb.v41.4341","DOIUrl":"https://doi.org/10.34194/geusb.v41.4341","url":null,"abstract":"Lithological mapping using remote sensing depends, in part, on the identification of rock types by their spectral characteristics. Chemical and physical properties of minerals and rocks determine their diagnostic spectral features throughout the electromagnetic spectrum. Shifts in the position and changes in the shape and depth of these features can be explained by variations in chemical composition of minerals. Detection of such variations is vital for discriminating minerals with similar chemical composition. Compared with multispectral image data, airborne or spaceborne hyperspectral imagery offers higher spectral resolution, which makes it possible to estimate the mineral composition of the rocks under study without direct contact. Arctic environments provide challenging ground for geological mapping and mineral exploration. Inaccessibility commonly complicates ground surveys, and the presence of ice, vegetation and rock-encrusting lichens hinders remote sensing surveys. This study addresses the following objectives: 1. Modelling the impact of lichen on the spectra of the rock substrate; 2. Identification of a robust lichen index for the deconvolution of lichen and rock mixtures and 3. Multiscale hyperspectral analysis of lithologies in areas with abundant lichens.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78682541","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. Hallé, N. Karlsson, A. Solgaard, C. S. Andresen
Arctic sea ice has a significant impact on the global radiation budget, oceanic and atmospheric circulation and the stability of the Greenland ice sheet (Vaughan et al. 2013). Prior to the era of aircraft and satellite, information on sea-ice extent relied on observations from ships and people living at the coast. This information is a valuable contribution to better understand the history of sea ice. However, the information exists in a range of formats, e.g., sea-ice extent before the late 1800s is typically reported in the literature as an annual index from a single geographical point or as hand-drawn maps. This makes it difficult to assess and compare data across time and space. The combination of digitised historical maps and single-point data makes the information more accessible and provides a record that can help understand the dynamics and processes of the climate and its interactions with the cryosphere (Chapman & Walsh 1993). In this study, maps of sea-ice extent by Koch (1945) were digitised. We use these maps in combination with sea-ice charts from the Danish Meteorological Institute (DMI) and Koch’s sea-ice index from 1820 to 1939, to map estimated sea-ice extent between Iceland and Greenland going back to 1821. This information has not been included in even the most recent databases of Arctic sea ice (Walsh et al. 2015, 2017). Furthermore, we extract time series of sea-ice extent at a number of locations and investigate the relationship between them. Our observation area is along eastern Greenland, between the southern tip of Greenland at 59°46´N northwards to 77°21´N.
北极海冰对全球辐射收支、海洋和大气环流以及格陵兰冰盖的稳定性有重大影响(Vaughan et al. 2013)。在飞机和卫星时代之前，关于海冰范围的信息依赖于船只和居住在海岸的人的观察。这些信息对更好地了解海冰的历史是一个有价值的贡献。然而，这些信息以多种形式存在，例如，在文献中，19世纪末以前的海冰范围通常以单个地理点的年度索引或手绘地图的形式报告。这使得评估和比较跨时间和空间的数据变得困难。数字化历史地图和单点数据的结合使信息更容易获得，并提供了有助于理解气候的动态和过程及其与冰冻圈的相互作用的记录(Chapman & Walsh 1993)。在这项研究中，科赫(1945)绘制的海冰范围图被数字化。我们将这些地图与丹麦气象研究所(DMI)的海冰图和1820年至1939年的科赫海冰指数结合起来，绘制了冰岛和格陵兰岛之间自1821年以来的海冰范围。这些信息甚至没有包括在最新的北极海冰数据库中(Walsh et al. 2015,2017)。此外，我们提取了一些地点海冰范围的时间序列，并研究了它们之间的关系。我们的观测区域位于格陵兰岛东部，位于格陵兰岛南端北纬59°46′至77°21′之间。
{"title":"Observationally constrained reconstruction of 19th to mid-20th century sea-ice extent off eastern Greenland","authors":"D. Hallé, N. Karlsson, A. Solgaard, C. S. Andresen","doi":"10.34194/geusb.v41.4349","DOIUrl":"https://doi.org/10.34194/geusb.v41.4349","url":null,"abstract":"Arctic sea ice has a significant impact on the global radiation budget, oceanic and atmospheric circulation and the stability of the Greenland ice sheet (Vaughan et al. 2013). Prior to the era of aircraft and satellite, information on sea-ice extent relied on observations from ships and people living at the coast. This information is a valuable contribution to better understand the history of sea ice. However, the information exists in a range of formats, e.g., sea-ice extent before the late 1800s is typically reported in the literature as an annual index from a single geographical point or as hand-drawn maps. This makes it difficult to assess and compare data across time and space. The combination of digitised historical maps and single-point data makes the information more accessible and provides a record that can help understand the dynamics and processes of the climate and its interactions with the cryosphere (Chapman & Walsh 1993). In this study, maps of sea-ice extent by Koch (1945) were digitised. We use these maps in combination with sea-ice charts from the Danish Meteorological Institute (DMI) and Koch’s sea-ice index from 1820 to 1939, to map estimated sea-ice extent between Iceland and Greenland going back to 1821. This information has not been included in even the most recent databases of Arctic sea ice (Walsh et al. 2015, 2017). Furthermore, we extract time series of sea-ice extent at a number of locations and investigate the relationship between them. Our observation area is along eastern Greenland, between the southern tip of Greenland at 59°46´N northwards to 77°21´N.","PeriodicalId":49199,"journal":{"name":"Geological Survey of Denmark and Greenland Bulletin","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83963845","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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