Advanced

Structures and PT determination of the Caledonian metamorphism of the lower part of the Planetfjella Group in the area around Mosseldalen, northern Ny Friesland, Svalbard

Friberg, Magnus (1994) In Dissertations in Geology at Lund University
Department of Geology
Abstract
The archipelago of Svalbard is a key area for understanding the
North Atlantic Caledonides. The pre-Devonian rocks of Svalbard are
an assemblage of different terranes, probably juxtaposed by
transpression during the Caledonidian orogenesis. Svalbard's
Eastern Terrane consists of a thick (c. 18 km) succession, of
Paleoproterozoic to Ordavician age, referred to as the Hecla Hoek
sequence, and is divided into three parts; Lower, Middle and Upper.
Within the upper part of the Lower Hecla Hoek lies the Planetfjella
Group. It is interprented to be sequence of marine sediments,
including turbidites. In northern Ny Friesland, in the area of
Mosseldalen, the contacts between the Planetfjella Group and the
underlying Harkerbreen and... (More)
The archipelago of Svalbard is a key area for understanding the
North Atlantic Caledonides. The pre-Devonian rocks of Svalbard are
an assemblage of different terranes, probably juxtaposed by
transpression during the Caledonidian orogenesis. Svalbard's
Eastern Terrane consists of a thick (c. 18 km) succession, of
Paleoproterozoic to Ordavician age, referred to as the Hecla Hoek
sequence, and is divided into three parts; Lower, Middle and Upper.
Within the upper part of the Lower Hecla Hoek lies the Planetfjella
Group. It is interprented to be sequence of marine sediments,
including turbidites. In northern Ny Friesland, in the area of
Mosseldalen, the contacts between the Planetfjella Group and the
underlying Harkerbreen and overlying Veteranen Groups are
tectonic. The importance of these faults has been disputed.
The pressure and temperature of metamorphism of impure pelites
from near the base of the Planetfjella Group, have been calculated
to 575-700°C and 8-11 kbar, using the Hodges and Spear (1982)
garnet-biotite thermometer and the Hodges and Crowley (1985)
geobarometer. These results are supported by petrographic studies.
The Planetfjella Group (c. 4km thick) has been described to be
overlain by c. 8 km of younger strata of Neoproterozoic and Early
Paleozoic age. At the time of metamorphism (c. 420 Ma) the
analysed specimens should therefore have been at a maximum of c.
12km depth. The P-T data presented here indicate that this
succession is not adequate to account for the metamorphism; about
another 10 km are needed.
The rocks overlying the Planetfjella Group in the northern Ny
Friesland, are not metamorphosed above lowermost greenschist
facies, which corresponds to a stratigraphic overburden that cannot
have exceeded 15km. This implies that at least 5km is missing
between the base of the Planetfjella Group and the overlying
Veteranen Group. The thinning is thought to be partly concentrated
to a 100 m wide zone at the top of the Planetfjella Group, but also
to be distributed within the latter. (Less)
Please use this url to cite or link to this publication:
author
Friberg, Magnus
supervisor
organization
year
type
H1 - Master's Degree (One Year)
subject
keywords
Mosseldalen, Planetfjella Group, metamorphism, Caledonides, geography, PT determination, structures, geology, Ny Friesland, Svalbard
publication/series
Dissertations in Geology at Lund University
report number
59
language
English
additional info
David Gee, Uppsala universitet.
id
2370075
date added to LUP
2012-03-09 10:44:16
date last changed
2013-03-26 14:22:54
@misc{2370075,
  abstract     = {The archipelago of Svalbard is a key area for understanding the
North Atlantic Caledonides. The pre-Devonian rocks of Svalbard are
an assemblage of different terranes, probably juxtaposed by
transpression during the Caledonidian orogenesis. Svalbard's
Eastern Terrane consists of a thick (c. 18 km) succession, of
Paleoproterozoic to Ordavician age, referred to as the Hecla Hoek
sequence, and is divided into three parts; Lower, Middle and Upper.
Within the upper part of the Lower Hecla Hoek lies the Planetfjella
Group. It is interprented to be sequence of marine sediments,
including turbidites. In northern Ny Friesland, in the area of
Mosseldalen, the contacts between the Planetfjella Group and the
underlying Harkerbreen and overlying Veteranen Groups are
tectonic. The importance of these faults has been disputed.
The pressure and temperature of metamorphism of impure pelites
from near the base of the Planetfjella Group, have been calculated
to 575-700°C and 8-11 kbar, using the Hodges and Spear (1982)
garnet-biotite thermometer and the Hodges and Crowley (1985)
geobarometer. These results are supported by petrographic studies.
The Planetfjella Group (c. 4km thick) has been described to be
overlain by c. 8 km of younger strata of Neoproterozoic and Early
Paleozoic age. At the time of metamorphism (c. 420 Ma) the
analysed specimens should therefore have been at a maximum of c.
12km depth. The P-T data presented here indicate that this
succession is not adequate to account for the metamorphism; about
another 10 km are needed.
The rocks overlying the Planetfjella Group in the northern Ny
Friesland, are not metamorphosed above lowermost greenschist
facies, which corresponds to a stratigraphic overburden that cannot
have exceeded 15km. This implies that at least 5km is missing
between the base of the Planetfjella Group and the overlying
Veteranen Group. The thinning is thought to be partly concentrated
to a 100 m wide zone at the top of the Planetfjella Group, but also
to be distributed within the latter.},
  author       = {Friberg, Magnus},
  keyword      = {Mosseldalen,Planetfjella Group,metamorphism,Caledonides,geography,PT determination,structures,geology,Ny Friesland,Svalbard},
  language     = {eng},
  note         = {Student Paper},
  series       = {Dissertations in Geology at Lund University},
  title        = {Structures and PT determination of the Caledonian metamorphism of the lower part of the Planetfjella Group in the area around Mosseldalen, northern Ny Friesland, Svalbard},
  year         = {1994},
}