Seamounts and oceanic igneous features in the NE Atlantic: a link between plate motions and mantle dynamics

Abstract

A new regional compilation of seamount-like oceanic igneous features (SOIFs) in the NE Atlantic points to three distinct oceanic areas of abundant seamount clusters. Seamounts on oceanic crust dated 54-50 Ma are formed on smooth oceanic basement, which resulted from high spreading rates and magmatic productivity enhanced by higher than usual mantle plume activity. Late Eocene-Early Miocene SOIF clusters are located close to newly formed tectonic features on rough oceanic crust in the Irminger, Iceland and Norway basins, reflecting an unstable tectonic regime prone to local readjustments of mid-ocean ridge and fracture zone segments accompanied by extra igneous activity. A SOIF population observed on Mid-Miocene-Present rough oceanic basement in the Greenland and Lofoten basins, and on conjugate Kolbeinsey Ridge flanks, coincides with an increase in spreading rate and magmatic productivity. We suggest that both tectonic/kinematic and magmatic triggers produced Mid-Miocene-Present SOIFs, but the Early Miocene westwards ridge relocation may have played a role in delaying SOIF formation south of the Jan Mayen Fracture Zone. We conclude that Iceland plume episodic activity combined with regional changes in relative plate motion led to local mid-ocean ridge readjustments, which enhanced the likelihood of seamount formation.

Break-up and seafloor spreading domains in the NE Atlantic

“…Apart from irregular oceanic crust architecture, plume-ridge interactions led to plate boundary relocations (as outlined by Gaina et al 2009), the formation of the JMMC and asymmetrical seafloor spreading (Figs 4 & 7), and may explain the formation of other features observed within the oceanic domain, such as the elongated volcanic Trail Ø complex ( Fig. 1) ) and seamount-like oceanic igneous features (SOIFs: see Gaina et al 2016).…”

Publisher’s Note

“…The Labrador Sea -Baffin Bay system (here referred to as the NW Atlantic as in Abdelmalak et al, 2018) separated Greenland and North America (Vogt and Avery, 1974;Srivastava, 1978;Torsvik et al, 2002;Hosseinpour et al, 2013;Peace et al, 2016;Welford et al, 2018). Subsequently, the NE Atlantic began to open, separating Greenland and Europe (Talwani and Eldholm, 1977;Skogseid et al, 2000;Lundin and Doré, 2005b;Le Breton et al, 2012;Gaina et al, 2009;Gernigon et al, 2015;Gaina et al, 2017a;Gaina et al, 2017b;Schiffer et al, 2018;Foulger et al this volume). A complex junction exists between these branches to the north of the Charlie-Gibbs Fracture Zone (CGFZ) (Gaina et al, 2009) (Fig.…”

Regional distribution of volcanism within the North Atlantic Igneous Province

“…Except for the GIFRC, which is described separately, assessment polygons are constructed for each margin segment based on the mapped inner SDRs and magnetic Chron C23n.2no (51.826 Ma; (Ogg 2012;Gaina et al 2016)). The polygons constructed are shown in Figure 6.…”

“…Weigel et al 1995;Voss et al 2009). However, the oceanic crust is associated with the second breakup event (see age grids and magnetic spreading anomalies of Gaina et al (2016)). Onshore, tholeiitic lavas have been dated to 56-53 Ma and are thus clearly related to the first breakup event and separation of the eastern Jan Mayen microcontinent from the Møre margin.…”