Polyphase magmatism during the formation of the northern East Greenland continental margin.

Franke, D. , Klitzke, P. , Barckhausen, U., Berglar, K., Berndt, Christian , Damm, V. , Dannowski, Anke , Ehrhardt, A. , Engels, M. , Funck, T. , Geissler, W. , Schnabel, M. , Thorwart, Martin and Trinhammer, Per (2019) Polyphase magmatism during the formation of the northern East Greenland continental margin. Open Access Tectonics, 38 (8). pp. 2961-2982. DOI 10.1029/2019TC005552.

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Supplementary data:


New marine geophysical data acquired across the partly ice‐covered northern East Greenland continental margin highlight a complex interaction between tectonic and magmatic events. Breakup‐related lava flows are imaged in reflection seismic data as seaward dipping reflectors (SDRs), which are found to decrease in size both northwards and southwards from a central point at 75° N. We provide evidence that the magnetic anomaly pattern in the shelf area is related to volcanic phases and not to the presence of oceanic crust. The remnant magnetization of the individual lava flows is used to deduce a relative timing of the emplacement of the volcanic wedges. We find that the SDRs have been emplaced over a period of 2‐4 Ma progressively from north to south and from landward to seaward. The new data indicate a major post‐middle Eocene magmatic phase around the landward termination of the West Jan Mayen Fracture Zone. This post‐40 Ma volcanism likely was associated with the progressive separation of the Jan Mayen microcontinent from East Greenland. The break‐up of the Greenland Sea started at several isolated seafloor spreading cells whose location was controlled by rift structures and led to the present‐day segmentation of the margin. The original rift basins were subsequently connected by steady‐state seafloor spreading that propagated southwards, from the Greenland Fracture Zone to the Jan Mayen Fracture Zone.

Key Points

Polyphase Cenozoic volcanic rifting and consecutive emplacement of breakup‐related lava flows units along the northern East Greenland margin
Breakup along restricted margin segments is followed by north to south directed progressive opening of the Greenland Sea
Widespread post‐middle Eocene (< 40 Ma) offshore magmatism, associated with the breakup of the Jan Mayen microcontinent from East Greenland

Document Type: Article
Keywords: NE Greenland, seismic reflection, seaward dipping reflectors, continent‐ocean transition, rifting, Greenland Sea
Research affiliation: HGF-AWI
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Kiel University
Refereed: Yes
Open Access Journal?: No
Publisher: AGU (American Geophysical Union), Wiley
Date Deposited: 05 Aug 2019 06:58
Last Modified: 31 Jan 2022 09:18
URI: https://oceanrep.geomar.de/id/eprint/47342

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