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Basement-cover relationships in the Harkerbreen Group of the northern Ny Friesland Caledonides, Svalbard

Hellman, Fredrik (1994) In Dissertations in Geology at Lund University
Department of Geology
Abstract
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... (More)
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. (Less)
Please use this url to cite or link to this publication:
author
Hellman, Fredrik
supervisor
organization
year
type
H1 - Master's Degree (One Year)
subject
keywords
Harkerbreen Group, geology, geography, Ny Friesland, Caledonides, Svalbard, basement-cover relationships
publication/series
Dissertations in Geology at Lund University
report number
58
language
English
additional info
David Gee, Uppsala universitet.
id
2370084
date added to LUP
2012-08-14 14:15:36
date last changed
2013-03-26 14:25:16
@misc{2370084,
  abstract     = {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.},
  author       = {Hellman, Fredrik},
  keyword      = {Harkerbreen Group,geology,geography,Ny Friesland,Caledonides,Svalbard,basement-cover relationships},
  language     = {eng},
  note         = {Student Paper},
  series       = {Dissertations in Geology at Lund University},
  title        = {Basement-cover relationships in the Harkerbreen Group of the northern Ny Friesland Caledonides, Svalbard},
  year         = {1994},
}