A detailed study of a concordant Fe-Ti oxide band in the Njords Gletscher Gabbro, Skjoldungen Alkaline Province, SE Greenland

Trygvi B. Árting, Thomas F. Kokfelt, Tod E. Waight, Martin B. Klausen

Publikation: Bidrag til bog/rapport/konferenceproceedingsKonferenceartikel i proceedings

Abstrakt

The gabbroic intrusion at Njord Gletscher in the Skjoldungen region of SE Greenland was visited by GEUS during the 2011 and 2012 field seasons. The intrusion is part of the ca. 2.7 Ga Skjoldungen Alkaline Province (Blichert-Toft et al. 1995; Kolb et al. 2013). The intrusion was initially registered as a diorite based on the preliminary mapping by Nielsen and Ros-ing (1990), who labelled the intrusion “Hermod Vig Diorite 2”, however based on its compo-sition, we propose the name “Njord Gletscher Gabbro” to be more appropriate. The intru-sion is exposed in the western part of the southern slope of the Njord Gletscher valley in the central part of Skjoldungen island, where it outcrops over ca 1 km laterally by 500 m vertically (Fig. 1). The contact relation to the surrounding agmatitic gneiss basement is not clear, but the intrusion itself is partly broken up by later felsic intrusives. The intrusion is essentially a layered mafic intrusion of gabbroic rocks (gabbro and gabbronorite). Three parts of the intrusions were visited and sampled in various detail; in 2011 the lower part during a 1 day hike into the area, in 2012 the middle and upper parts during a 1 hour reco and a half day drop off, respectively. In the lower and middle part of the intrusion semi-massive magnetite rich bands of up to 30 cm thickness were localised and sampled. The highest density of oxide-rich bands occurs in the lower part of the intrusion, where at least three bands with an interspacing of 20-50 m were found within a layered gabbro sequence. No oxide bands were found in the uppermost part of the intrusion, although magnetite oc-curs as mineral throughout the entire intrusion. Concordant oxide-rich bands are also pre-sent in other SAP intrusions, such as the Vend Om Gabbro, and we seek here to investi-gate their significance by presenting mineral chemical data across a single oxide band from the middle section of the Njord Gletscher Gabbro.
OriginalsprogEngelsk
TitelSouth-East Greenland Mineral Endowment Task (SEGMENT): 2014 Workshop Abstract Volume and Status Primo-2014
RedaktørerBo Møller Stensgaard
UdgivelsesstedCopenhagen
ForlagDe Nationale Geologiske Undersøgelser for Danmark og Grønland
Sider13-17
Antal sider5
DOI
StatusUdgivet - 2014
BegivenhedSouth-East Greenland Mineral Endowment Task (SEGMENT) 2014 Workshop - GEUS, Copenhagen, Danmark
Varighed: 27 mar. 201428 mar. 2014

Publikationsserier

NavnDanmarks og Grønlands Geologiske Undersøgelse Rapport
ForlagGEUS
Nummer79
Vol/bind2014

Konference

KonferenceSouth-East Greenland Mineral Endowment Task (SEGMENT) 2014 Workshop
Land/OmrådeDanmark
ByCopenhagen
Periode27/03/1428/03/14

Programområde

  • Programområde 4: Mineralske råstoffer

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