Breakup volcanism and plate tectonics in the NW Atlantic

• Published in: Tectonophysics
• Main Authors: Abdelmalak, M. M., Planke, S., Polteau, S., Hartz, E. H., Faleide, J. I., Tegner, C., Jerram, D. A., Millett, J. M., Myklebust, R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2019
• Subjects: Baffin Bay; Nuussuaq; Baffin; Davis Strait; Labrador Sea; Upernavik
• Online Access: https://oceanrep.geomar.de/id/eprint/47988/; https://oceanrep.geomar.de/id/eprint/47988/1/Abdelmalak.pdf; https://doi.org/10.1016/j.tecto.2018.08.002

Highlights • Determination of the tectonomagmatic evolution of the NW Atlantic • Mapping of the breakup-related magmatism using the vocanostratigraphy concept • Mapping of the magnetic and gravimetric crustal domain patterns and their boundaries using integrated SGM method • Analyses of seabed and onshore samples and field analogues work • New plate tectonic reconstruction for the NW Atlantic Abstract Passive margins are the locus of tectonic and magmatic processes leading to the formation of highly variable along-strike and conjugate margins structures. Using extensive new seismic, gravity, and magnetic datasets, complemented by seabed samples and field work, we investigate the tectonomagmatic evolution of the northwest (NW) Atlantic where breakup-related igneous rocks were emplaced during several Paleogene events associated with lithospheric stretching, continental breakup, and the formation of new oceanic basins. Interpretational methods include integrated seismic-gravity-magnetic (SGM) interpretation and seismic volcanostratigraphy. In addition, seabed and field samples were collected and analyzed to constrain the basin stratigraphy, hydrocarbon potential, and the geochronology and geochemistry of the volcanic sequences. Offshore, 2D seismic data reveal several Seaward Dipping Reflector (SDR) wedges and escarpments in the Labrador Sea, Davis Strait, and Baffin Bay. Onshore, eastward prograding foreset-bedded hyaloclastite delta deposits and overlying horizontal lava successions outcrop on Nuussuaq. These hyaloclastites and lava successions are world class analogues to the Lava Delta and Landward Flows volcanic seismic facies units identified offshore. Our mapping results document an aerial extent of the Paleogene breakup-related volcanics of 0.3 × 106 km2, with an estimated volume of 0.5–0.6 × 106 km3. Basalt samples recovered by dredging the Upernavik Escarpment have late Paleocene to/early Eocene ages, whereas the sedimentary samples provide an excellent seismic tie with the stratigraphy and the geology in ...