The sedimentology and depositional environments of the Bastians Dal and Muslingebjerg formations: evidence for the earliest phases of Jurassic rifting in North-East Greenland
The aim of this study is to elucidate the character of the earliest phases of Jurassic rifting in North-East Greenland. To achieve this, detailed sedimentological analysis and geological mapping were undertaken on the outcrops of central Kuhn Ø (74°53’55’’N,20°20’56”W). In this region the basement i...
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Geological Survey of Denmark and Greenland
2022
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Online Access: | https://doi.org/10.34194/geusb.v49.8311 https://doaj.org/article/e543be2f365349e8bffc9ae470e0b67b |
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ftdoajarticles:oai:doaj.org/article:e543be2f365349e8bffc9ae470e0b67b 2023-05-15T16:03:38+02:00 The sedimentology and depositional environments of the Bastians Dal and Muslingebjerg formations: evidence for the earliest phases of Jurassic rifting in North-East Greenland Steven D. Andrews Henrik Vosgerau Jørgen A. Bojesen-Koefoed 2022-08-01T00:00:00Z https://doi.org/10.34194/geusb.v49.8311 https://doaj.org/article/e543be2f365349e8bffc9ae470e0b67b EN eng Geological Survey of Denmark and Greenland https://geusbulletin.org/index.php/geusb/article/view/8311/14279 https://doaj.org/toc/2597-2154 2597-2154 doi:10.34194/geusb.v49.8311 https://doaj.org/article/e543be2f365349e8bffc9ae470e0b67b GEUS Bulletin, Vol 49, Pp 1-20 (2022) north-east greenland jurassic tectonics coal fluvial Geology QE1-996.5 Geophysics. Cosmic physics QC801-809 article 2022 ftdoajarticles https://doi.org/10.34194/geusb.v49.8311 2022-12-30T19:54:34Z The aim of this study is to elucidate the character of the earliest phases of Jurassic rifting in North-East Greenland. To achieve this, detailed sedimentological analysis and geological mapping were undertaken on the outcrops of central Kuhn Ø (74°53’55’’N,20°20’56”W). In this region the basement is overlain by the fluvial Bastians Dal Formation (Middle Jurassic) which is, in turn, overlain by the coal-bearing Muslingebjerg Formation. A maximum thickness of 140 m is calculated for the Bastians Dal Formation and mapping of stratal geometries demonstrates thinning to both the north and south, confirming that these deposits infill a palaeovalley. Predominantly south-westward palaeocurrent orientations are observed and likely reflect the orientation of the palaeovalley (NE–SW). The overlying Muslingebjerg Formation displays significant lateral variations in thickness as well as facies, thickening from a 5-m-thick coal seam in the north to 50 m in the south. Southern outcrops include two intervals of fine-grained sandstones displaying low-angle and trough cross-bedding some of which contain suggestions of tidal bundling. The arrangement of facies suggests that coal formation occurred in both fluvial- and shallow-marine (tidal?) environments. Coals are similar to those described elsewhere from the Muslingebjerg Formation and display subtle differences consistent with variable degrees of marine influence. Mapping demonstrates the presence of an NE–SW-oriented bounding fault in the south of the region into which the Muslingebjerg Formation thickens. This likely also controlled the orientation of the underlying NE–SW-aligned palaeovalley and is oblique to the proposed overall N–S orientation of faulting related to rifting through the Mid to Late Jurassic. Instead, these alignments resemble those that define pre-Jurassic phases of rifting and may therefore indicate a transitional phase of tectonism. Faulting on a similar alignment can be traced SW, cutting Lindeman Fjord and following the valleys east of the A. P. Olsen ... Article in Journal/Newspaper East Greenland Greenland Kuhn ø Directory of Open Access Journals: DOAJ Articles Greenland Lindeman ENVELOPE(-135.087,-135.087,59.783,59.783) Kuhn Ø ENVELOPE(-20.267,-20.267,74.851,74.851) Lindeman Fjord ENVELOPE(-20.883,-20.883,74.650,74.650) GEUS Bulletin 49 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
north-east greenland jurassic tectonics coal fluvial Geology QE1-996.5 Geophysics. Cosmic physics QC801-809 |
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north-east greenland jurassic tectonics coal fluvial Geology QE1-996.5 Geophysics. Cosmic physics QC801-809 Steven D. Andrews Henrik Vosgerau Jørgen A. Bojesen-Koefoed The sedimentology and depositional environments of the Bastians Dal and Muslingebjerg formations: evidence for the earliest phases of Jurassic rifting in North-East Greenland |
topic_facet |
north-east greenland jurassic tectonics coal fluvial Geology QE1-996.5 Geophysics. Cosmic physics QC801-809 |
description |
The aim of this study is to elucidate the character of the earliest phases of Jurassic rifting in North-East Greenland. To achieve this, detailed sedimentological analysis and geological mapping were undertaken on the outcrops of central Kuhn Ø (74°53’55’’N,20°20’56”W). In this region the basement is overlain by the fluvial Bastians Dal Formation (Middle Jurassic) which is, in turn, overlain by the coal-bearing Muslingebjerg Formation. A maximum thickness of 140 m is calculated for the Bastians Dal Formation and mapping of stratal geometries demonstrates thinning to both the north and south, confirming that these deposits infill a palaeovalley. Predominantly south-westward palaeocurrent orientations are observed and likely reflect the orientation of the palaeovalley (NE–SW). The overlying Muslingebjerg Formation displays significant lateral variations in thickness as well as facies, thickening from a 5-m-thick coal seam in the north to 50 m in the south. Southern outcrops include two intervals of fine-grained sandstones displaying low-angle and trough cross-bedding some of which contain suggestions of tidal bundling. The arrangement of facies suggests that coal formation occurred in both fluvial- and shallow-marine (tidal?) environments. Coals are similar to those described elsewhere from the Muslingebjerg Formation and display subtle differences consistent with variable degrees of marine influence. Mapping demonstrates the presence of an NE–SW-oriented bounding fault in the south of the region into which the Muslingebjerg Formation thickens. This likely also controlled the orientation of the underlying NE–SW-aligned palaeovalley and is oblique to the proposed overall N–S orientation of faulting related to rifting through the Mid to Late Jurassic. Instead, these alignments resemble those that define pre-Jurassic phases of rifting and may therefore indicate a transitional phase of tectonism. Faulting on a similar alignment can be traced SW, cutting Lindeman Fjord and following the valleys east of the A. P. Olsen ... |
format |
Article in Journal/Newspaper |
author |
Steven D. Andrews Henrik Vosgerau Jørgen A. Bojesen-Koefoed |
author_facet |
Steven D. Andrews Henrik Vosgerau Jørgen A. Bojesen-Koefoed |
author_sort |
Steven D. Andrews |
title |
The sedimentology and depositional environments of the Bastians Dal and Muslingebjerg formations: evidence for the earliest phases of Jurassic rifting in North-East Greenland |
title_short |
The sedimentology and depositional environments of the Bastians Dal and Muslingebjerg formations: evidence for the earliest phases of Jurassic rifting in North-East Greenland |
title_full |
The sedimentology and depositional environments of the Bastians Dal and Muslingebjerg formations: evidence for the earliest phases of Jurassic rifting in North-East Greenland |
title_fullStr |
The sedimentology and depositional environments of the Bastians Dal and Muslingebjerg formations: evidence for the earliest phases of Jurassic rifting in North-East Greenland |
title_full_unstemmed |
The sedimentology and depositional environments of the Bastians Dal and Muslingebjerg formations: evidence for the earliest phases of Jurassic rifting in North-East Greenland |
title_sort |
sedimentology and depositional environments of the bastians dal and muslingebjerg formations: evidence for the earliest phases of jurassic rifting in north-east greenland |
publisher |
Geological Survey of Denmark and Greenland |
publishDate |
2022 |
url |
https://doi.org/10.34194/geusb.v49.8311 https://doaj.org/article/e543be2f365349e8bffc9ae470e0b67b |
long_lat |
ENVELOPE(-135.087,-135.087,59.783,59.783) ENVELOPE(-20.267,-20.267,74.851,74.851) ENVELOPE(-20.883,-20.883,74.650,74.650) |
geographic |
Greenland Lindeman Kuhn Ø Lindeman Fjord |
geographic_facet |
Greenland Lindeman Kuhn Ø Lindeman Fjord |
genre |
East Greenland Greenland Kuhn ø |
genre_facet |
East Greenland Greenland Kuhn ø |
op_source |
GEUS Bulletin, Vol 49, Pp 1-20 (2022) |
op_relation |
https://geusbulletin.org/index.php/geusb/article/view/8311/14279 https://doaj.org/toc/2597-2154 2597-2154 doi:10.34194/geusb.v49.8311 https://doaj.org/article/e543be2f365349e8bffc9ae470e0b67b |
op_doi |
https://doi.org/10.34194/geusb.v49.8311 |
container_title |
GEUS Bulletin |
container_volume |
49 |
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1766399337402728448 |