Basement-cover relationships in the Harkerbreen Group of the northern Ny Friesland Caledonides, Svalbard
Mapping and isotopic work in the Instrumentberget area has shown that a granitic gneiss, previously referred to the Bangenhuk Formation, is unconformably overlain by a younger meta-sedimentary unit with a basal conglomerate horizon, previously included in the Rittervatnet Formation. In this paper it...
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Lunds universitet/Geologiska institutionen
1994
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ftulundlupsp:oai:lup-student-papers.lub.lu.se:2370084 2023-07-30T04:05:57+02:00 Basement-cover relationships in the Harkerbreen Group of the northern Ny Friesland Caledonides, Svalbard Hellman, Fredrik 1994 application/pdf http://lup.lub.lu.se/student-papers/record/2370084 eng eng Lunds universitet/Geologiska institutionen http://lup.lub.lu.se/student-papers/record/2370084 Harkerbreen Group geology geography Ny Friesland Caledonides Svalbard basement-cover relationships Earth and Environmental Sciences H1 1994 ftulundlupsp 2023-07-11T20:07:39Z Mapping and isotopic work in the Instrumentberget area has shown that a granitic gneiss, previously referred to the Bangenhuk Formation, is unconformably overlain by a younger meta-sedimentary unit with a basal conglomerate horizon, previously included in the Rittervatnet Formation. In this paper it is suggested that the granitic gneiss, named the Instrumentberget Granitic Gneiss, occurs at a lower structural level than the Bangenhuk Formation and that this meta-sedimentary unit is the basal part of the Polhem Formation. Isotopic work on zircons from the Instrumentberget Granitic Gneiss and one boulder in the overlying basal conglomerate has shown that some of the conglomerate clasts are derived from the underlying Instrumentberget Granitic Gneiss the latter having a U-Pb zircon age of 1737±43 Ma. Evidence for this is three fold; firstly, the morphology of the zircons in one of the boulders is similar to zircons in the underlying granitic gneiss; secondly, a single U-Pb analysis from one conglomerate boulder falls right on the discordia line of the granitic gneiss; and thirdly, age analyses by the direct Pb-Pb evaporation method on single zircons from the granitic gneiss and the conglomerate boulder agree with the upper intercept age of the U-Pb analysis. A second conglomerate boulder has a quite different zircon morphology to the underlying granitic gneiss and a single U-Pb analysis falls significantly above the discordia line of the granitic gneiss, suggesting an exotic origin. Direct single zircon Pb-Pb evaporation analyses of this second boulder suggests that the Polhem Formation may be younger than 1000 Ma. Other/Unknown Material Ny Friesland Svalbard Lund University Publications Student Papers (LUP-SP) Svalbard Ny Friesland ENVELOPE(16.847,16.847,79.498,79.498) Polhem ENVELOPE(16.045,16.045,79.893,79.893) Bangenhuk ENVELOPE(15.711,15.711,79.877,79.877) Harkerbreen ENVELOPE(17.046,17.046,78.978,78.978) Boulder Falls ENVELOPE(-107.586,-107.586,67.468,67.468) Instrumentberget ENVELOPE(16.176,16.176,79.840,79.840) Rittervatnet ENVELOPE(16.009,16.009,79.801,79.801) |
institution |
Open Polar |
collection |
Lund University Publications Student Papers (LUP-SP) |
op_collection_id |
ftulundlupsp |
language |
English |
topic |
Harkerbreen Group geology geography Ny Friesland Caledonides Svalbard basement-cover relationships Earth and Environmental Sciences |
spellingShingle |
Harkerbreen Group geology geography Ny Friesland Caledonides Svalbard basement-cover relationships Earth and Environmental Sciences Hellman, Fredrik Basement-cover relationships in the Harkerbreen Group of the northern Ny Friesland Caledonides, Svalbard |
topic_facet |
Harkerbreen Group geology geography Ny Friesland Caledonides Svalbard basement-cover relationships Earth and Environmental Sciences |
description |
Mapping and isotopic work in the Instrumentberget area has shown that a granitic gneiss, previously referred to the Bangenhuk Formation, is unconformably overlain by a younger meta-sedimentary unit with a basal conglomerate horizon, previously included in the Rittervatnet Formation. In this paper it is suggested that the granitic gneiss, named the Instrumentberget Granitic Gneiss, occurs at a lower structural level than the Bangenhuk Formation and that this meta-sedimentary unit is the basal part of the Polhem Formation. Isotopic work on zircons from the Instrumentberget Granitic Gneiss and one boulder in the overlying basal conglomerate has shown that some of the conglomerate clasts are derived from the underlying Instrumentberget Granitic Gneiss the latter having a U-Pb zircon age of 1737±43 Ma. Evidence for this is three fold; firstly, the morphology of the zircons in one of the boulders is similar to zircons in the underlying granitic gneiss; secondly, a single U-Pb analysis from one conglomerate boulder falls right on the discordia line of the granitic gneiss; and thirdly, age analyses by the direct Pb-Pb evaporation method on single zircons from the granitic gneiss and the conglomerate boulder agree with the upper intercept age of the U-Pb analysis. A second conglomerate boulder has a quite different zircon morphology to the underlying granitic gneiss and a single U-Pb analysis falls significantly above the discordia line of the granitic gneiss, suggesting an exotic origin. Direct single zircon Pb-Pb evaporation analyses of this second boulder suggests that the Polhem Formation may be younger than 1000 Ma. |
format |
Other/Unknown Material |
author |
Hellman, Fredrik |
author_facet |
Hellman, Fredrik |
author_sort |
Hellman, Fredrik |
title |
Basement-cover relationships in the Harkerbreen Group of the northern Ny Friesland Caledonides, Svalbard |
title_short |
Basement-cover relationships in the Harkerbreen Group of the northern Ny Friesland Caledonides, Svalbard |
title_full |
Basement-cover relationships in the Harkerbreen Group of the northern Ny Friesland Caledonides, Svalbard |
title_fullStr |
Basement-cover relationships in the Harkerbreen Group of the northern Ny Friesland Caledonides, Svalbard |
title_full_unstemmed |
Basement-cover relationships in the Harkerbreen Group of the northern Ny Friesland Caledonides, Svalbard |
title_sort |
basement-cover relationships in the harkerbreen group of the northern ny friesland caledonides, svalbard |
publisher |
Lunds universitet/Geologiska institutionen |
publishDate |
1994 |
url |
http://lup.lub.lu.se/student-papers/record/2370084 |
long_lat |
ENVELOPE(16.847,16.847,79.498,79.498) ENVELOPE(16.045,16.045,79.893,79.893) ENVELOPE(15.711,15.711,79.877,79.877) ENVELOPE(17.046,17.046,78.978,78.978) ENVELOPE(-107.586,-107.586,67.468,67.468) ENVELOPE(16.176,16.176,79.840,79.840) ENVELOPE(16.009,16.009,79.801,79.801) |
geographic |
Svalbard Ny Friesland Polhem Bangenhuk Harkerbreen Boulder Falls Instrumentberget Rittervatnet |
geographic_facet |
Svalbard Ny Friesland Polhem Bangenhuk Harkerbreen Boulder Falls Instrumentberget Rittervatnet |
genre |
Ny Friesland Svalbard |
genre_facet |
Ny Friesland Svalbard |
op_relation |
http://lup.lub.lu.se/student-papers/record/2370084 |
_version_ |
1772818272387858432 |