Stefan Bernstein

Greenroc Mining plc

We compile and analyze all available geothermal heat flow measurements collected in and around Greenland into a new database of 419 sites and generate an accompanying spatial map. This database includes 290 sites previously reported by the International Heat Flow Commission (IHFC), for which we now standardize measurement and metadata quality. This...

We compile, analyse and map all available geothermal heat flow measurements collected in and around Greenland into a new database of 419 sites and generate an accompanying spatial map. This database includes 290 sites previously reported by the International Heat Flow Commission (IHFC), for which we now standardize measurement and metadata quality....

Basement highs are large structural features, commonly buried in sedimentary basins (Busby & Azor 2012). They are of interest for natural resources exploration and research because of their ability to influence migration and entrapment of petroleum (Trice 2014) and water, and the deposition of metals (Hitzman 2005; Borg et al. 2012). Three-dimensio...

Crystalline basement fracture networks are known to host economically viable mineral deposits, e.g. orogenic gold, non-magmatic copper and petroleum Reserves (fractured, basement reservoirs in >30 countries). Liverpool Land Basement High presents an ideal natural lab to discern basement fracture network evolutionary processes in 4D. Reconnaissance...

Peridotite bodies with sizes up to 500 x 1000 m are found within Mesoarchaean orthogneisses in the Fiskefjord region of SW Greenland. Here we present field observations, bulk-rock major, trace, and platinum-group element data, and mineral chemistry for some these peridotites. The largest of these (known as Seqi), has previously been mined for indus...

Supplement to: Peridotite enclaves hosted by Mesoarchaean TTG-suite orthogneisses in the Fiskefjord region of southern West Greenland

Supplement to: Peridotite enclaves hosted by Mesoarchaean TTG-suite orthogneisses in the Fiskefjord region of southern West Greenland

Supplement to: Peridotite enclaves hosted by Mesoarchaean TTG-suite orthogneisses in the Fiskefjord region of southern West Greenland

Supplement to: Peridotite enclaves hosted by Mesoarchaean TTG-suite orthogneisses in the Fiskefjord region of southern West Greenland

Supplement to: Peridotite enclaves hosted by Mesoarchaean TTG-suite orthogneisses in the Fiskefjord region of southern West Greenland

Supplement to: Highly depleted cratonic mantle in West Greenland extending into diamond stability field in the Proterozoic

This study presents bulk-rock major, trace, and platinum-group element data, as well as mineral chemistry for peridotites which form large enclaves (up to 500 by 1000 m) within Mesoarchaean orthogneisses of the Akia terrane in the Fiskefjord region, southern West Greenland. The largest peridotite body, known as Seqi, contains highly fosteritic oliv...

Mineralization of rare-earth elements (REEs) has been discovered in the Karrat Isfjord region of West Greenland (~72°N) at Niaqornakavsak on the island of Qeqertarssuaq along the southwestern margin of the Kangigdleq-Íngia Fjord gneiss dome complex. Mineralization occurs within a distinct ~30-m-thick horizon in an amphibolite host rock, which defin...

This study presents electron microprobe data for dunite xenoliths from a lamprophyre dyke located on the island of Qeqertaa, West Greenland. The minimum age of this dyke is Palaeoproterozoic and it experienced amphibolite facies metamorphism and deformation during that era. The samples consist of nearly 200 xenoliths with a size range of 0.5-8 cm....

This study presents electron microprobe data for dunite xenoliths from a lamprophyre dyke located on the island of Qeqertaa, West Greenland. The minimum age of this dyke is Palaeoproterozoic and it experienced amphibolite facies metamorphism and deformation during that era. The samples consist of nearly 200 xenoliths with a size range of 0.5-8 cm....

The Karrat rare earth element (REE) mineralization is located in the Niaqornakavsak (NIAQ) area of Qeqertarssuaq Island in Greenland (~72°N). A mineralized horizon occurs as a single distinct layer (35-40° dip) within an amphibolite host rock of the Qeqertarssuaq Formation: a member of the Paleoproterozoic Karrat Group sequence. Average Yttrium + R...

The 54 Ma. old Skaergaard intrusion ( East Greenland) is a type example for fractionation of basaltic melt along the Fenner Trend. The Triple Group is the upper most 100 m of the Middle Zone and consists of FeTi-oxide rich layered gabbro with three distinct leugabbro layers 2-5 m thick ( L-layers; L1-L3, 2-5m thick) and a less marked layer (L0) c.2...

Computer-controlled scanning electron microscopy (CCSEM) combines the advantages of energy dispersive X-ray spectrometry (EDX) with those of digital image analysis of back-scattered electron (BSE) micrographs. CCSEM analysis of a wide range of geological or non-geological materials has been introduced at the Geological Survey of Denmark and Greenla...

Sixteen 40Ar–39Ar ages are presented for alkaline intrusions to appraise prolonged post-breakup magmatism of the central East Greenland rifted margin, the chronology of rift-to-drift transition, and the asymmetry of magmatic activity in the Northeast Atlantic Igneous Province. The alkaline intrusions mainly crop out in tectonic and magmatic lineame...

For the characterization of sediments, Computer Controlled Scanning Electron Microscopy (CCSEM) is a powerful method in obtaining chemical data on individual mineral grains and modal analysis of the heavy mineral fraction of sediment samples. Here we show how the CCSEM method can be used to evaluate ilmenite ore grade as well as a tool to investiga...

Exploration for diamonds in West Greenland has experienced a major boost within the last decade following the establishment of world-class diamond mines within the nearby Slave Province of the Canadian Arctic. Numerous companies have active programmes of diamond exploration and increasingly larger diamonds have been discovered, notably a 2.392 cara...

Shallow (garnet-free), depleted cratonic mantle, occurring as xenoliths in kimberlites and alkaline basaltic lavas, has a high Mg# (100 × Mg/(Mg + Fe) > 92) and is poor in Al and Ca compared to off-cratonic mantle. Here we compile data for many suites of shallow cratonic mantle xenoliths worldwide, and demonstrate a remarkably small range in their...

Shallow (garnet-free) cratonic mantle, occurring as xenoliths in kimberlites and alkaline basaltic lavas, has high Mg# (100x Mg/(Mg+Fe)>92) and is poor in Al and Ca compared to off-cratonic mantle. Many xenoliths show rhenium-depletion age of > 3 Ga, and are thus representative of depleted mantle peridotite that form an integral part of the stable...

Spot analysis techniques have been used to unravel crystallization processes in a Palaeogene coarse-grained, olivine-bearing, gabbronoritic plug from East Greenland. Whole-rock analyses of the gabbronorite and its chilled margin are identical to within analytical error, yet the gabbronorite is coarse-grained and has large, strongly zoned pyroxene,...

Dunitic xenoliths from late Palaeogene, alkaline basalt flows on Ubekendt Ejland, West Greenland contain olivine with 100×Mg/(Mg+Fe), or Mg#, between 92.0 and 93.7. Orthopyroxene has very low Al2O3 and CaO contents (0.024–1.639 and 0.062–0.275wt%, respectively). Spinel has 100×Cr/(Cr+Al), or Cr#, between 46.98 and 95.67. Clinopyroxene is absent. Th...

Computer Controlled Scanning Electron Microscopy (CCSEM) is used to analyze indivdual mineral fractions in heavy mineral sands. CCSEM is a fully automated particle analysis technique for the determination of physical and chemical properties of a large number of individual particles. CCSEM enables the precise and accurate determination of the modal...

The discovery in 2002 of a gold mineralised quartz-carbon- ate vein at Ubekendt Ejland, central West Greenland, yield- ing 0.6 ppm Au over 0.7 m, led to a reconnaissance sampling project in summer 2003. Most of the accessible quartz-car- bonate veins on the south-east coast of the island (Figs 1, 2) were sampled during boat-supported field work. Ma...

40Ar/39Ar dating has identified a succession of middle Miocene (14-13 Ma) basaltic lavas in East Greenland that overlie Eocene flood basalts that were erupted during continental breakup ca. 56-55 Ma. The long postbreakup magmatic history (∼40 m.y.) of the East Greenland margin precludes a simple relationship between this later igneous activity and...

The northern margin of the Nagssugtoqidian mobile belt in Southeast Greenland exposes a suite of moderately fractionated Fe-rich tholeiitic dykes of Paleo-proterozoic age. The dykes were intruded during extension of the crust prior to the development of the Nagssugtoqidian mobile belt. Although the dykes recrystallized under amphibolite facies cond...

After continental break-up in the presence of the Iceland mantle plume, nephelinite and melilitite lavas were erupted in NE Greenland in the early Eocene. The lavas are interpreted to represent melts derived directly from recycled oceanic lithosphere. High FeOtot (to>16wt.%), MgO and low SiO_2 Al_2O_3 and CaO suggest that they were derived by low d...

Mantle xenoliths from Tertiary alkaline lavas on Ubekendt Ejland, West Greenland contain extremely depleted harzburgites and dunites. The xenoliths have high Mg# (100 * Mg/Mg+Fe) in olivine (92-94) and low modal orthopyroxene (opx) consistent with an origin as restites from high degrees of melting, and are in that respect similar to depleted xenoli...

Seismic reflection and refraction data acquired on four transects spanning the Southeast Greenland rifted margin and Greenland–Iceland Ridge (GIR) provide new constraints on mantle thermal structure and melting processes during continental breakup in the North Atlantic. Maximum igneous crustal thickness varies along the margin from >30 km in the ne...

The Wiedemann Fjord mantle xenoliths from Tertiary basanitic dykes in east Greenland contain extremely depleted spinel harzburgites. The harzburgites are unusual because of their highly forsteritic olivine and low modal orthopyroxene, consistent with an origin as residues of up to 40% melting. Also present are lherzolites with olivine contents as l...

Alkaline ultramafic lavas in north East Greenland were contemporaneous with Tertiary tholeiitic flood basalts in East Greenland. The alkaline lavas are enriched in light rare earth elements (REEs) and Ti and Nb, but depleted in Rb, Ba, K, Th, and P. The flood basalts have trace element profiles similar to those of the alkaline lavas. These features...

Highly alkaline ultrabasic lavas which occur in the remote Nunatak Region of Northeast Greenland between latitudes 73°45′N and 74°25′N are approximately contemporaneous with the better known, voluminous Tertiary tholeiitic plateau basalts of the coastal region (68°N–71°N, 74°N–76°N). Recent reconnaissance mapping extended the known outcrop of the a...

The Noe-Nygaard Intrusion is a 4 × 2.5 km stock composed of layered gabbros and wehrlites within the Precambrian basement of the coastal mountains west of the Kialineq Plutonic Complex. Transgressive relationships to Tertiary mafic dykes and the occurrence of abundant metabasaltic xenoliths signify a Tertiary age for the intrusion. The intrusion is...

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Bernstein, S., & Brooks, C. K. (1998). Mantle xenoliths from Tertiary lavas and dykes on Ubekendt Ejland, West Greenland. Geology of Greenland Survey Bulletin, 180, 152-154. https://doi.org/10.34194/ggub.v...

Mantle peridotite xenoliths from Archean cratons generally have high molar Mg/(Mg + Fe), or Mg#. The best known suites, from the Kapvaal and Siberian cratons, have high modal orthopyroxene (Opx). These high Opx compositions are probably not residues of partial melting. Less well known cratonic xenolith suites from Greenland and North America includ...

Mafic and ultramafic intrusions in East Greenland adjacent to the offshore Greenland–Iceland ridge were emplaced 5–9 My after continental breakup at 55 Ma [1]. Rare earth element (REE) concentrations determined by secondary ion mass spectrometry are reported for cumulus clinopyroxene from these intrusions, and the data are used to estimate REE abun...

The East Greeland Tertiary Igneous Province includes the largest exposed continental flood basalt sequence within the North Atlantic borderlands. More than ten layered gabbro complexes, including the ∼55 Ma Skaergaard intrusion, and a large dolerite sill complex are the plutonic equivalents of flood basalts; both lavas and intrusions have been rega...

A new collection of mantle xenoliths in Tertiary dykes from the Wiedemann Fjord area in Southeast Greenland shows that this part of the central Greenland craton is underlain by highly depleted peridotites. The samples are mostly spinel harzburgites with highly forsteritic olivines (Fo87–94, average Fo92.7). This, together with unusually high modal...

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Dahl-Jensen, T., Holbrook, W. S., Hopper, J. R., Kelemen, P. B., Larsen, H. C., Detrick, R., Bernstein, S., & Kent, G. (1997). Seismic investigation of the East Greenland volcanic rifted margin. Geology of...

The Kruuse Fjord Gabbro Complex is a composite intrusion of layered gabbro and troctolite with subordinate ultramafic rocks and minor trondhjemitic bodies. It was emplaced into Archaean continental crust of East Greenland during early Tertiary rifting of Greenland from Eurasia. The work to date has identified an outer gabbro series and an inner tro...

The Kap Edvard Holm Layered Series forms part of the East Greenland Tertiary Province, and was emplaced at shallow crustal level (at depths corresponding to a pressure of 1–2 kbar) during continental break-up. It consists of two suites: a gabbro suite comprising olivine and oxide gabbros, leucocratic olivine gabbros and anorthosites, and a suite of...

The lower 3000 m basalt stratigraphy on the Faeroe Islands shows strong positive correlation between degree of fractionation and Zr/Y ratio. This is ascribed to the presence of garnet in the cumulus assemblage during fractionation at the base of the continental crust or in the upper lithospheric mantle at 40-50 km depth. Later basaltic magmas fract...

The gabbros of the Tertiary Kap Edvard Holm Layered Series have a stratigraphic thickness of more than 5000m. Field evidence of magma injections is common, which together with the restricted range in mineral chemistry suggests that the magma chamber was frequently replenished by a less fractionated magma. A detailed study of a 600m section (900-150...