1. The remarkable parallels between the North East Atlantic and Arctic regions.
- Author
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Foulger, Gillian R., Nikishin, Anatoly M., Aleshina, Ksenia F., and Rodina, Elizaveta A.
- Subjects
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CONTINENTAL crust , *OCEANIC crust , *IGNEOUS provinces , *OCEAN bottom , *CONTINENTAL shelf - Abstract
Geological understanding of the NE Atlantic and Arctic regions has increased greatly over the last two decades, revealing remarkable similarities. Continental extension in both regions onset during pausing or cessation of adjacent orogenies – the Verkhoyansk-Chukotka and Alpine orogenies – which relaxed compressional stresses and permitted extension. Severe extension accompanied by high-volume magmatism did not onset abruptly but was the culmination of long-term, regional tectonic and magmatic unrest. It was complex and piecemeal, with extension and volcanism occurring along multiple axes simultaneously, a process still ongoing in Iceland today. Large Igneous Province emplacement did not drive breakup but occurred as a consequence of continental extension. The High Arctic Large Igneous Province did not progress to breakup. As a result, much of the Arctic Ocean is floored by hyper-extended continental crust overlain by seaward-dipping reflectors. This crust resembles the passive margins of the NE Atlantic. The Alpha-Mendeleev Rise in the Arctic Ocean is a double-sided passive margin underlain by hyper-extended continental crust draped with seaward-dipping reflectors. A similar structure has been proposed for the Greenland-Iceland-Faroe Ridge. If correct, present-day volcanism in Iceland is building SDRs today. Up to ∼50% of the NE Atlantic Ocean oceanward of the continental shelves is likely underlain by at least some continental crust. For the Arctic Ocean this figure is ∼80%. Similar structures are found elsewhere, including the Madagascar Channel, the NW Indian Ocean, and the South Atlantic. These new ideas suggest promising directions of future study including assessing the true extent of continental crust in the oceans globally. • Orogenic stress relaxation allowed the NE Atlantic and Arctic Oceans to open. • LIP magmatism did not drive breakup but was a consequence of extension. • ∼80% the Arctic Ocean and ∼ 50% of the NE Atlantic Ocean contains hybrid crust. • The Arctic Alpha-Mendeleev Rise is a continental, double-sided passive margin. • The Greenland-Iceland-Faroe Ridge is underlain by hybrid crust. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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