Explanatory notes to the Geological map of Greenland, 1:500 000, Humboldt Gletscher, Sheet 6

2004 ◽  
pp. 1-48
Author(s):  
Peter R. Dawes
Keyword(s):  
Coarse Grained ◽  
Mobile Belt ◽  
Nares Strait ◽  
General Terms ◽  
Mineral Occurrence ◽  
North Eastern ◽  
Copper Gold ◽  
High Grade Metamorphism ◽  
Geological Map ◽  
Map Series

NOTE: This Map Description was published in a former series of GEUS Bulletin. Please use the original series name when citing this series, for example: Dawes, P. R. (2004). Explanatory notes to the Geological map of Greenland, 1:500 000, Humboldt Gletscher, Sheet 6. Geological Survey of Denmark and Greenland Map Series 1, 48 pp. + map. https://doi.org/10.34194/geusm.v1.4615  _______________ These explanatory notes cover the map region bounded by latitudes 78°N and 81°N and longitudes 56°W and 74°W, with geology shown on the land areas between Nares Strait - the seaway between Greenland and Ellesmere Island, Canada - and the Inland Ice. The bedrock geology is composed of Precambrian and Lower Palaeozoic provinces that continue across Nares Strait into Canada. Map units and mineral occurrences are described in general terms and are proceeded by sections on physical environment, logistics, data sources and geoscientific research. The notes are aimed at the practical user and a guide for further reading. The bedrock is composed of three provinces separated by unconformities, each representing a hiatus of c. 500 Ma during which basic dykes were emplaced. The Palaeoproterozoic Inglefield mobile belt, forming the crystalline shield, is an E-W-trending belt of deposition and orogeny characterised by polyphase magmatism, deformation and high-grade metamorphism. Clastic deposition, with magmatism at c. 1985 Ma, are the oldest events recorded, followed by the accumulation of the Etah Group (carbonate, pelitic and psammitic sediments with supposedly coeval mafic and ultramafic rocks) between 1980 and 1950 Ma ago. These rocks were intruded 1950 to 1915 Ma ago by the Etah meta-igneous complex, that records polyphase plutonism (intermediate to felsic, with some basic and magnetite-rich rocks), followed by deformation and partial melting producing granites 1785 to 1740 Ma ago. The Mesoproterozoic Thule Basin, defined by the unmetamorphosed and little deformed Thule Supergroup, records sedimentation and basaltic volcanism at least as old as 1270 Ma. The faulted, north-eastern basin margin shown on the map preserves the passage from the basinal sequence to a relatively thin platform succession invaded by basic sills. The Palaeozoic Franklinian Basin is represented by a homoclinal Cambrian to Silurian shelf carbonate succession and a major Silurian reef complex, with coeval siliciclastic slope deposits. The map region includes the classical area for Franklinian stratigraphy, now composed of 29 formations and four groups - Ryder Gletscher, Morris Bugt, Washington Land and Peary Land Groups. The only younger units preserved in the map region are widespread Quaternary deposits, an isolated outcrop of coarse-grained fluvial deposits (Bjørnehiet Formation) and non-carbonised wood erratics of Neogene age. Five mineral occurrence types are shown on the map: in lithologies of the Inglefield mobile belt, sulphide-graphite rust zones, a magnetite deposit and copper-gold mineralisation and in the Franklinian Basin, commercially drilled, zinc-lead-silver and zinc-lead-barium mineralisations. The basic ingredients of a petroleum model exist in the Franklinian Basin but prospectivity is low.

scholarly journals Explanatory notes to the Geological map of Greenland, 1:500 000, Humboldt Gletscher, Sheet 6

2004 ◽  
pp. 1-48 ◽  
Author(s):  
Peter R. Dawes
Keyword(s):  
Coarse Grained ◽  
Mobile Belt ◽  
Nares Strait ◽  
General Terms ◽  
Mineral Occurrence ◽  
North Eastern ◽  
Copper Gold ◽  
High Grade Metamorphism ◽  
Geological Map ◽  
Map Series

Dawes, P.R. 2004: Explanatory notes to the Geological map of Greenland, 1:500 000, Humboldt Gletscher, Sheet 6. Geological Survey of Denmark and Greenland Map Series 1, 48 pp. + map. These explanatory notes cover the map region bounded by latitudes 78°N and 81°N and longitudes 56°W and 74°W, with geology shown on the land areas between Nares Strait - the seaway between Greenland and Ellesmere Island, Canada - and the Inland Ice. The bedrock geology is composed of Precambrian and Lower Palaeozoic provinces that continue across Nares Strait into Canada. Map units and mineral occurrences are described in general terms and are proceeded by sections on physical environment, logistics, data sources and geoscientific research. The notes are aimed at the practical user and a guide for further reading.The bedrock is composed of three provinces separated by unconformities, each representing a hiatus of c. 500 Ma during which basic dykes were emplaced. The Palaeoproterozoic Inglefield mobile belt, forming the crystalline shield, is an E-W-trending belt of deposition and orogeny characterised by polyphase magmatism, deformation and high-grade metamorphism. Clastic deposition, with magmatism at c. 1985 Ma, are the oldest events recorded, followed by the accumulation of the Etah Group (carbonate, pelitic and psammitic sediments with supposedly coeval mafic and ultramafic rocks) between 1980 and 1950 Ma ago. These rocks were intruded 1950 to 1915 Ma ago by the Etah meta-igneous complex, that records polyphase plutonism (intermediate to felsic, with some basic and magnetite-rich rocks), followed by deformation and partial melting producing granites 1785 to 1740 Ma ago. The Mesoproterozoic Thule Basin, defined by the unmetamorphosed and little deformed Thule Supergroup, records sedimentation and basaltic volcanism at least as old as 1270 Ma. The faulted, north-eastern basin margin shown on the map preserves the passage from the basinal sequence to a relatively thin platform succession invaded by basic sills. The Palaeozoic Franklinian Basin is represented by a homoclinal Cambrian to Silurian shelf carbonate succession and a major Silurian reef complex, with coeval siliciclastic slope deposits. The map region includes the classical area for Franklinian stratigraphy, now composed of 29 formations and four groups - Ryder Gletscher, Morris Bugt, Washington Land and Peary Land Groups.The only younger units preserved in the map region are widespread Quaternary deposits, an isolated outcrop of coarse-grained fluvial deposits (Bjørnehiet Formation) and non-carbonised wood erratics of Neogene age.Five mineral occurrence types are shown on the map: in lithologies of the Inglefield mobile belt, sulphide-graphite rust zones, a magnetite deposit and copper-gold mineralisation and in the Franklinian Basin, commercially drilled, zinc-lead-silver and zinc-lead-barium mineralisations. The basic ingredients of a petroleum model exist in the Franklinian Basin but prospectivity is low.

scholarly journals Reconnaissance dating of Archaean rocks from South-East Greenland

1986 ◽  
Vol 130 ◽  
pp. 90-95
Author(s):  
J.C Escher ◽  
F Kalsbeek ◽  
O Larsen ◽  
T.F.D Nielsen ◽  
P.N Taylor
Keyword(s):  
Mobile Belt ◽  
East Greenland ◽  
Geological Map ◽  
Map Series ◽  
Major Project ◽  
Age Determinations

A major project of geological investigations in South-East Greenland is planned for 1986 and 1987 with the aim of producing sheet 14 of the 1:500000 geological map series covering Greenland. The northern part of the map sheet is occupied by the Nagssugtoqidian mobile belt, and the southern part consists mainly of Archaean rocks. Because of difficulties of access, the Archaean part of the area is poorly known. Geological reconnaissance has been carried out by Bridgwater & Gormsen (1969), and, as a preparation for the 1986 and 1987 expeditions, by Escher & Nielsen (1982, 1983) and Nielsen & Escher (1985). This report presents reconnaissance Rb-Sr and Pb-Pb whole-rock age determinations from the Archaean part of the map sheet.

scholarly journals The Skjoldungen map sheet: completion of the 1:500 000 geological mapping of South-East Greenland

1991 ◽  
Vol 152 ◽  
pp. 30-31
Author(s):  
J.C Escher
Keyword(s):  
Geological Mapping ◽  
The Other ◽  
Geological Survey ◽  
East Greenland ◽  
Metamorphic Development ◽  
Geological Map ◽  
Map Series

The publication of the 1:500 000 Skjoldungen map sheet (Escher, 1990; Fig. 1) marks the completion of the Geological Survey of Greenland's (GGU's) reconnaissance mapping activities in South-East Greenland. A descriptive text to the map is under preparation. All of South-East Greenland between Kap Farvel (59° 00´N) and Mesters Vig (72° 00´N) is now covered by sheets of the 1:500 000 geological map series of Greenland. Five sheets in the series (nos 5,6,9, 10 and 11) remain to be published (Fig. 1); the Thule map sheet (sheet 5) will be printed in the course of 1991, and sheet 10 is under compilation. The presentation of the Skjoldungen map is somewhat different from that of the other 1:500 000 maps inthe series. In addition to traditional lithological information, an effort has been made to show the tectonic/metamorphic development of the region during the Archaean and Proterozoic.

scholarly journals The geology of the north-eastern corner of Greenland - photogeological studies and 1993 field work

1994 ◽  
Vol 161 ◽  
pp. 21-33
Author(s):  
H.F Jepsen ◽  
J.C Escher ◽  
J.D Friderichsen ◽  
A.K Higgins
Keyword(s):  
Field Work ◽  
Tectonic Activity ◽  
Mobile Belt ◽  
North East ◽  
The North ◽  
Upper Proterozoic ◽  
North Eastern ◽  
Field Season ◽  
Upper Boundary ◽  
Middle Proterozoic

Late Archaean and Early Proterozoic crust-forming events in North-East and eastern North Greenland were succeeded by Middle Proterozoic sedimentation and volcanic activity; Late Proterozoic through Tertiary sedimentation was interrupted by several periods of tectonic activity, including the Caledonian orogeny in East Greenland and the Mesozoic deformation of the Wandel Hav mobile belt. Photogeological studies helped pinpoint areas of special interest which were investigated during the short 1993 field season. Insights gained during field work include: the nature of the crystalline basement terrain in the Caledonian fold belt, redefinition of the upper boundary of the Upper Proterozoic Rivieradal sandstones, revision of Caledonian nappe terminology, and the northern extension of the Caledonian Storstrømmen shear zone.

scholarly journals Mineralogy of Zirconium in Iron-Oxides: A Micron- to Nanoscale Study of Hematite Ore from Peculiar Knob, South Australia

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 244 ◽  
Author(s):  
Keyser ◽  
Ciobanu ◽  
Cook ◽  
Feltus ◽  
Johnson ◽  
...  
Keyword(s):  
South Australia ◽  
Coarse Grained ◽  
Iron Deposit ◽  
High Grade ◽  
Microscopy Imaging ◽  
Grade Metamorphism ◽  
Icp Ms ◽  
High Grade Metamorphism ◽  
Hematite Ore

Zirconium is an element of considerable petrogenetic significance but is rarely found in hematite at concentrations higher than a few parts-per-million (ppm). Coarse-grained hematite ore from the metamorphosed Peculiar Knob iron deposit, South Australia, contains anomalous concentrations of Zr and has been investigated using microanalytical techniques that can bridge the micron- to nanoscales to understand the distribution of Zr in the ore. Hematite displays textures attributable to annealing under conditions of high-grade metamorphism, deformation twins (r~85˚ to hematite elongation), relict magnetite and fields of sub-micron-wide inclusions of baddeleyite as conjugate needles with orientation at ~110˚/70˚. Skeletal and granoblastic zircon, containing only a few ppm U, are both present interstitial to hematite. Using laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) spot analysis and mapping, the concentration of Zr in hematite is determined to be ~260 ppm on average (up to 680 ppm). The Zr content is, however, directly attributable to nm-scale inclusions of baddeleyite pervasively distributed throughout the hematite rather than Zr in solid solution. Distinction between nm-scale inclusions and lattice-bound trace element substitutions cannot be made from LA-ICP-MS data alone and requires nanoscale characterization. Scandium-rich (up to 0.18 wt. % Sc2O3) cores in zircon are documented by microprobe analysis and mapping. Using high-angle annular dark field scanning transmission electron microscopy imaging (HAADF-STEM) and energy-dispersive spectrometry STEM mapping of foils prepared in-situ by focused ion beam methods, we identify [011]baddeleyite epitaxially intergrown with [22.1]hematite. Lattice vectors at 84–86˚ underpinning the epitaxial intergrowth orientation correspond to directions of r-twins but not to the orientation of the needles, which display a ~15˚ misfit. This is attributable to directions of trellis exsolutions in a precursor titanomagnetite. U–Pb dating of zircon gives a 206Pb/238U weighted mean age of 1741 ± 49 Ma (sensitive high-resolution ion microprobe U–Pb method). Based on the findings presented here, detrital titanomagnetite from erosion of mafic rocks is considered the most likely source for Zr, Ti, Cr and Sc. Whether such detrital horizons accumulated in a basin with chemical precipitation of Fe-minerals (banded iron formation) is debatable, but such Fe-rich sediments clearly included detrital horizons. Martitization during the diagenesis-supergene enrichment cycle was followed by high-grade metamorphism during the ~1.73–1.69 Ga Kimban Orogeny during which martite recrystallized as granoblastic hematite. Later interaction with hydrothermal fluids associated with ~1.6 Ga Hiltaba-granitoids led to W, Sn and Sb enrichment in the hematite. By reconstructing the evolution of the massive orebody at Peculiar Knob, we show how application of complimentary advanced microanalytical techniques, in-situ and on the same material but at different scales, provides critical constraints on ore-forming processes.

British Antarctic Survey geological map series

Polar Record ◽  
1980 ◽  
Vol 20 (125) ◽  
pp. 167-169
Author(s):  
Janet W. Thomson
Keyword(s):  
British Antarctic Survey ◽  
Geological Map ◽  
Map Series

scholarly journals Gabbronorite from Jijal Complex, Kamila Amphibolite Belt and Chilas Complex, Northern Pakistan: Implications for Arc Genesis

2020 ◽  
Vol 11 (3) ◽  
pp. 70-78
Author(s):  
Saffi Ur Rehman ◽  
Muhammad Arif
Keyword(s):  
Minor Component ◽  
Coarse Grained ◽  
Northern Pakistan ◽  
Modal Composition ◽  
Mineral Phases ◽  
North Eastern ◽  
Lowermost Part ◽  
Garnet Granulite ◽  
A Minor ◽  
North Eastern Part

Rocks of gabbronoritic composition occur in three principal tectono-stratigraphic units forming the lower andmiddle parts of the Kohistan Island arc (KIA). These include the Jijal complex (JC), the Kamila Amphibolite belt (KAB)and the Chilas complex (CHC). The Jijal complex constitutes the lowermost part and hence is regarded as the root zoneof KIA. Its north-eastern part adjacent to KAB contains gabbronorite as a minor component in the form of small irregularpatches and layers within garnet granulite. The JC gabbronorite is sub-equigranular, medium to coarse grained, largelymassive and consists of variable amounts of plagioclase (53-71 %), orthopyroxene (14-27 %) and clinopyroxene (11-19%) as essential constituents and accessory to minor amounts of amphibole (1-9 %), opaque ore (1-6 %) and orthoclase(1-4 %). The occurrence and distribution of biotite, epidote, chlorite, clay, sericite, muscovite, quartz and actinolite inthe studied samples suggest their formation through alteration and/ or reaction between pre-existing minerals. In manycases, these minerals are disposed such that a variety of simple and complex corona structures are produced. The principalpetrographic features (modal composition, optical properties of the major mineral phases, exsolution in pyroxenes,products of alteration and reactions and the resulting corona textures) of the JC gabbronorite are broadly similar togabbronorites from both the KAB and CHC. Although the observed similarities could reflect identical physico-chemicalconditions during subsolidus or metamorphic re-equilibration, the possibility of a genetic relationship amonggabbronorites from all the three tectono-magmatic units of the KIA (i.e. the JC, KAB and CHC) cannot be ruled out.

The Dalradian rocks of the Lecht, NE Scotland: stratigraphy, faulting, geochemistry and mineralisation

1989 ◽  
Vol 80 (2) ◽  
pp. 143-157 ◽  
Author(s):  
K. Nicholson ◽  
R. Anderton
Keyword(s):  
Factor Analysis ◽  
Field Data ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Geochemical Data ◽  
Red Sandstone ◽  
North Eastern ◽  
Scatter Plots ◽  
Geological Map ◽  
Air Photo

ABSTRACTAir photo interpretation and geochemistry have been used to supplement sparse field data in compiling a reconnaissance geological map of the area around the Lecht. Upper Appin and lower Argyll Group rocks are exposed, the best marker horizons being correlatives of the Appin and Jura Quartzites. Scatter plots, Q mode factor analysis and Pearson correlation coefficients of geochemical data were successfully used in the correlation of the pelite and limestone outcrops. The presence of major recumbent folds is inferred. The area is cut by numerous minor faults which are thought to be related to a major transcurrent fault, the probable north-eastern continuation of the Loch Tay fault, which was active in Lower Old Red Sandstone times.The Lecht manganiferous ironstone is a seepage-bog ore type deposit derived by weathering of the local Dalradian sequence. Despite intensive leaching, this sequence still shows anomalously high levels of several elements, particularly Mn, Ba and Zn. In addition, stratiform sphalerite and manganiferous garnet are present in Blair Atholl Subgroup limestone and pelite horizons, respectively. Mineralogical and geochemical evidence suggests the presence of Zn–Pb–(Ag)–(?Au) exhalative mineralisation within the upper Appin Group Dalradian of the region, of which the Lecht represents the distal manganiferous expression.

Geology of the Bunger Hills area, Antarctica: implications for Gondwana correlations

1993 ◽  
Vol 5 (1) ◽  
pp. 85-102 ◽  
Author(s):  
John W. Sheraton ◽  
Robert J. Tingey ◽  
Lance P. Black ◽  
Robin L. Oliver
Keyword(s):  
Granulite Facies ◽  
Mobile Belt ◽  
High Grade ◽  
Yilgarn Craton ◽  
Zone Formation ◽  
Zircon Age ◽  
Peak Metamorphism ◽  
High Grade Metamorphism ◽  
Subsequent Deformation ◽  
Hills Area

The Bunger Hills area of the East Antarctic Shield consists of granulite-facies felsic orthogneiss, with subordinate paragneiss and mafic granulite. The igneous precursors of granodioritic orthogneiss were emplaced 1500-1700 Ma ago, and late Archaean (2640 Ma) tonalitic orthogneiss occurs in the nearby Obruchev Hills. Peak metamorphism (M1) (at about 750-800°C and 5-6kb) occurred 1190 ±15 Ma ago (U-Pb zircon age), and was accompanied by the first of three ductile deformations (D1). Emplacement of voluminous, mainly mantle-derived plutonic rocks, ranging from gabbro, through quartz monzogabbro and quartz monzodiorite, to granite, followed between 1170 (during D3) and 1150 Ma. Intrusion of abundant dolerite dykes of four chemically distinct suites at about 1140 Ma was associated with shear zone formation, indicating at least limited uplift; all subsequent deformation was of brittle-ductile type. Alkaline mafic dykes were emplaced 500 Ma ago. Marked geochronological similarities with the Albany Mobile Belt of Western Australia suggest that high-grade metamorphism occurred during collision between the Archaean Yilgarn Craton of Australia and the East Antarctic Shield about 1200 Ma ago.

scholarly journals Landsat-8, Advanced Spaceborne Thermal Emission and Reflection Radiometer, and WorldView-3 Multispectral Satellite Imagery for Prospecting Copper-Gold Mineralization in the Northeastern Inglefield Mobile Belt (IMB), Northwest Greenland

2019 ◽  
Vol 11 (20) ◽  
pp. 2430 ◽  
Author(s):  
Pour ◽  
Park ◽  
Park ◽  
Hong ◽  
Muslim ◽  
...  
Keyword(s):  
Hydrothermal Alteration ◽  
Satellite Imagery ◽  
Thermal Emission ◽  
Gold Mineralization ◽  
High Arctic ◽  
Mobile Belt ◽  
Landsat 8 ◽  
Free Region ◽  
Copper Gold ◽  
Ace Algorithm

Several regions in the High Arctic still lingered poorly explored for a variety of mineralization types because of harsh climate environments and remoteness. Inglefield Land is an ice-free region in northwest Greenland that contains copper-gold mineralization associated with hydrothermal alteration mineral assemblages. In this study, Landsat-8, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), and WorldView-3 multispectral remote sensing data were used for hydrothermal alteration mapping and mineral prospecting in the Inglefield Land at regional, local, and district scales. Directed principal components analysis (DPCA) technique was applied to map iron oxide/hydroxide, Al/Fe-OH, Mg-Fe-OH minerals, silicification (Si-OH), and SiO2 mineral groups using specialized band ratios of the multispectral datasets. For extracting reference spectra directly from the Landsat-8, ASTER, and WorldView-3 (WV-3) images to generate fraction images of end-member minerals, the automated spectral hourglass (ASH) approach was implemented. Linear spectral unmixing (LSU) algorithm was thereafter used to produce a mineral map of fractional images. Furthermore, adaptive coherence estimator (ACE) algorithm was applied to visible and near-infrared and shortwave infrared (VINR + SWIR) bands of ASTER using laboratory reflectance spectra extracted from the USGS spectral library for verifying the presence of mineral spectral signatures. Results indicate that the boundaries between the Franklinian sedimentary successions and the Etah metamorphic and meta-igneous complex, the orthogneiss in the northeastern part of the Cu-Au mineralization belt adjacent to Dallas Bugt, and the southern part of the Cu-Au mineralization belt nearby Marshall Bugt show high content of iron oxides/hydroxides and Si-OH/SiO2 mineral groups, which warrant high potential for Cu-Au prospecting. A high spatial distribution of hematite/jarosite, chalcedony/opal, and chlorite/epidote/biotite were identified with the documented Cu-Au occurrences in central and southwestern sectors of the Cu-Au mineralization belt. The calculation of confusion matrix and Kappa Coefficient proved appropriate overall accuracy and good rate of agreement for alteration mineral mapping. This investigation accomplished the application of multispectral/multi-sensor satellite imagery as a valuable and economical tool for reconnaissance stages of systematic mineral exploration projects in remote and inaccessible metallogenic provinces around the world, particularly in the High Arctic regions.

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