Caledonian eclogite-facies metamorphism of Early Proterozoic protoliths from the North-East Greenland Eclogite Province

The area between Grandjean Fjord and Bessel Fjord was the focus in 1988 of regional geological investigations and 1:500000 mapping during the North-East Greenland project (Henriksen, 1989). The greater part of the area forms part of the East Greenland Caledonides and can be divided into three distinct rock groups: infracrustal gneisses and granites of possibie Archaean or early Proterozoic origin; a metasedimentary sequence which has probably suffered both mid-Proterozoic and Caledonian migmatisation and metamorphism; and the late Proterozoic Eleonore Bay Group, a thick sedimentary sequence which has undergone amphibolite facies Caledonian metamorphism in its lower parts and is intruded by Caledonian granites. Aspects of the stratigraphy and sedimentology of the Eleonore Bay Group are described by Sønderholm et al. (1989); only the structures affecting the sequence are described here.

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Eclogites and related high-pressure rocks from North-East Greenland

Rapport Grønlands Geologiske Undersøgelse ◽

10.34194/rapggu.v162.8250 ◽

1994 ◽

Vol 162 ◽

pp. 77-90

Author(s):

J.A Gilotti

Keyword(s):

High Pressure ◽

Northern Limit ◽

Medium Temperature ◽

East Greenland ◽

High Pressure Metamorphism ◽

North East ◽

Gneiss Complex ◽

Facies Metamorphism ◽

Eclogite Facies

Eclogite, gamet clinopyroxenite, gamet websterite and websterite bodies were discovered within the Skærfjorden gneiss complex during recent mapping in North-East Greenland. These eclogitic pods extend from Danmarkshavn (c. 76° 40'N) to the northern limit of the area mapped (78°N), and attest to widespread high-pressure metamorphism. Eclogites with the assemblage omphacite + garnet ± quartz ± futile are common. The protoliths of some of the eclogites were xenoliths within the precursor batholiths to the gneisses. Field relations, regional correlations and preliminary geochronology indicate that the eclogite facies metamorphism is Caledonian. The eclogites formed at minimum pressures between 10-15 kilobars and temperatures between 600–900°C, and hence are the medium-temperature type typically formed in over-thickened crust during continent collision.

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The Archaean Atâ intrusive complex (Atâ tonalite), north-east Disko Bugt, West Greenland

Geological Survey of Denmark and Greenland Bulletin ◽

10.34194/ggub.v181.5118 ◽

1999 ◽

pp. 103-112

Author(s):

Feiko Kalsbeek ◽

Lilian Skjernaa

Keyword(s):

Intrusive Complex ◽

The South ◽

Original Series ◽

Early Proterozoic ◽

West Greenland ◽

North East ◽

The North ◽

Southern Border ◽

Area North ◽

Igneous Layering

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Kalsbeek, F., & Skjernaa, L. (1999). The Archaean Atâ intrusive complex (Atâ tonalite), north-east Disko Bugt, West Greenland. Geology of Greenland Survey Bulletin, 181, 103-112. https://doi.org/10.34194/ggub.v181.5118 _______________ The 2800 Ma Atâ intrusive complex (elsewhere referred to as ‘Atâ granite’ or ‘Atâ tonalite’), which occupies an area of c. 400 km2 in the area north-east of Disko Bugt, was emplaced into grey migmatitic gneisses and supracrustal rocks. At its southern border the Atâ complex is cut by younger granites. The complex is divided by a belt of supracrustal rocks into a western, mainly tonalitic part, and an eastern part consisting mainly of granodiorite and trondhjemite. The ‘eastern complex’ is a classical pluton. It is little deformed in its central part, displaying well-preserved igneous layering and local orbicular textures. Near its intrusive contact with the overlying supracrustal rocks the rocks become foliated, with foliation parallel to the contact. The Atâ intrusive complex has escaped much of the later Archaean and early Proterozoic deformation and metamorphism that characterises the gneisses to the north and to the south; it belongs to the best-preserved Archaean tonalite-trondhjemite-granodiorite intrusions in Greenland.

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Metamorphic pressure-temperature paths of eclogites from The North-East Greenland Caledonides

10.17077/etd.tbxxgcs0 ◽

2016 ◽

Author(s):

Wentao Cao

Keyword(s):

East Greenland ◽

North East ◽

The North

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Geology and timing of dextral strike-slip shear zones in Danmarkshavn, North-East Greenland Caledonides

Geological Magazine ◽

10.1017/s0016756806001968 ◽

2006 ◽

Vol 143 (4) ◽

pp. 431-446 ◽

Cited By ~ 14

Author(s):

C. SARTINI-RIDEOUT ◽

J. A. GILOTTI ◽

W. C. McCLELLAND

Keyword(s):

Deformation Zone ◽

Shear Zones ◽

Amphibolite Facies ◽

Ultrahigh Pressure ◽

High Mass ◽

Weighted Mean ◽

East Greenland ◽

North East ◽

The North ◽

Land Deformation

The North-East Greenland eclogite province is divided into a western, central and eastern block by the sinistral Storstrømmen shear zone in the west and the dextral Germania Land deformation zone in the east. A family of steep, NNW-striking dextral mylonite zones in the Danmarkshavn area are geometrically and kinematically similar to the ductile Germania Land deformation zone, located 25 km to the east. Amphibolite facies deformation at Danmarkshavn is characterized by boudinage of eclogite bodies within quartzofeldspathic host gneisses, pegmatite emplacement into the boudin necks and subsequent deformation of pegmatites parallel to gneissosity, a widespread component of dextral shear within the gneisses, and localization of strain into 10–50 m thick dextral mylonite zones. The gneisses and concordant mylonite zones are cut by a swarm of weakly to undeformed, steeply dipping, E–W-striking pegmatitic dykes. Oscillatory-zoned zircon cores from two boudin neck pegmatites give weighted mean 206Pb/238U sensitive, high mass resolution ion microprobe (SHRIMP) ages of 376 ± 5 Ma and 343 ± 7 Ma. Cathodoluminescence images of these zircons reveal complex additional rims, with ages from ranging from c. 360 to 320 Ma. Oscillatory-zoned, prismatic zircons from two late, cross-cutting pegmatites yield weighted mean 206Pb/238U SHRIMP ages of 343 ± 5 Ma and 332 ± 3 Ma. Zircons from the boudin neck pegmatites record a prolonged growth history, marked by fluid influx, during amphibolite facies metamorphism beginning at c. 375 Ma. The cross-cutting pegmatites show that dextral deformation in the gneisses and ductile mylonite zones had stopped by c. 340 Ma. Ultrahigh-pressure metamorphism in the eastern block at 360 Ma requires that the Greenland Caledonides were in an overall contractional plate tectonic regime. This, combined with 20% steep amphibolite facies lineations in the eclogites, gneisses and mylonites suggests that dextral transpression may have been responsible for a first stage of eclogite exhumation between 370 and 340 Ma.

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Review of `A confined-unconfined aquifer model for subglacial hydrology and its application to the North East Greenland Ice Stream'

10.5194/tc-2017-221-rc1 ◽

2017 ◽

Author(s):

Douglas Brinkerhoff

Keyword(s):

Unconfined Aquifer ◽

East Greenland ◽

North East ◽

The North ◽

Ice Stream

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Petroleum potential of the Upper Jurassic Hareelv Formation, Jameson Land, East Greenland

Geological Survey of Denmark and Greenland Bulletin ◽

10.34194/geusb.v42.4314 ◽

2018 ◽

pp. 85-113 ◽

Cited By ~ 2

Author(s):

Jørgen A. Bojesen-Koefoed ◽

Morten Bjerager ◽

H. Peter Nytoft ◽

Henrik I. Petersen ◽

Stefan Piasecki ◽

...

Keyword(s):

Significant Proportion ◽

Upper Jurassic ◽

Geochemical Data ◽

Eastern Canada ◽

Petroleum Potential ◽

East Greenland ◽

North East ◽

The North ◽

Clay Formation

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.

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Search for Archaean basement in the Caledonian fold belt of North-East Greenland

Rapport Grønlands Geologiske Undersøgelse ◽

10.34194/rapggu.v162.8254 ◽

1994 ◽

Vol 162 ◽

pp. 129-133

Author(s):

A.P Nutman ◽

F Kalsbeek

Keyword(s):

High Grade ◽

Metamorphic Zircon ◽

Fold Belt ◽

Pb Isotope ◽

Zircon Age ◽

East Greenland ◽

Early Proterozoic ◽

North East ◽

History Of ◽

High Grade Metamorphism

SHRIMP U-Pb isotope data on zircon crystals from a gneiss sample near Danmarkshavn, where the presence of Archaean rocks has earlier been documented, show that the rock has undergone a complex history of igneous and metamorphic zircon growth. At least three generations of zircon are present with ages of c. 3000 Ma, c. 2725 Ma and 1967 ±8 Ma (2 α). Apparently the rock was formed from an Archaean protolith which underwent high grade metamorphism during the early Proterozoic. Another sample from the easternmost exposures of the Caledonian basement, collected further north, yielded only early Proterozoic zircons with an age of 1963 ± 6 Ma. Together with a SHRIMP U-Pb zircon age of 1974 ± 17 Ma reported earlier, these results give evidence of a major igneous and metamorphic event in North-East Greenland about 1965 Ma ago.

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Jurassic dinoflagellate cyst stratigraphy of Store Koldewey, North-East Greenland

Geological Survey of Denmark and Greenland Bulletin ◽

10.34194/geusb.v5.4810 ◽

2004 ◽

Vol 5 ◽

pp. 99-112 ◽

Cited By ~ 4

Author(s):

Stefan Piasecki ◽

John H. Callomon ◽

Lars Stemmerik

Keyword(s):

Middle Jurassic ◽

Upper Jurassic ◽

Dinoflagellate Cysts ◽

The South ◽

Important Species ◽

East Greenland ◽

Sequence Stratigraphic ◽

Fine Grained ◽

North East ◽

The North

The Jurassic of Store Koldewey comprises a Middle Jurassic succession towards the south and an Upper Jurassic succession towards the north. Both successions onlap crystalline basement and coarse sediments dominate. Three main lithostratigraphical units are recognised: the Pelion Formation, including the Spath Plateau Member, the Payer Dal Formation and the Bernbjerg Formation. Rich marine macrofaunas include Boreal ammonites and the successions are dated as Late Bathonian – Early Callovian and Late Oxfordian – Early Kimmeridgian on the basis of new collections combined with material in earlier collections. Fine-grained horizons and units have been analysed for dinoflagellate cysts and the stratigraphy of the diverse and well-preserved flora has been integrated with the Boreal ammonite stratigraphy. The dinoflagellate floras correlate with contemporaneous floras from Milne Land, Jameson Land and Hold with Hope farther to the south in East Greenland, and with Peary Land in North Greenland and Svalbard towards the north. The Middle Jurassic flora shows local variations in East Greenland whereas the Upper Jurassic flora gradually changes northwards in East Greenland. A Boreal flora occurs in Peary Land and Svalbard. The characteristic and stratigraphically important species Perisseiasphaeridium pannosum and Oligosphaeridium patulum have their northernmost occurrence on Store Koldewey, whereas Taeniophora iunctispina and Adnatosphaeridium sp. extend as far north as Peary Land. Assemblages of dinoflagellate cysts are used to characterise significant regional flooding events and extensive sequence stratigraphic units.

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