Regional distribution of volcanism within the North Atlantic Igneous Province

Abstract

An overview of the distribution of volcanic facies units was compiled over the North Atlantic region. The new maps establish the pattern of volcanism associated with breakup and the initiation of seafloor spreading over the main part of the North Atlantic Igneous Province (NAIP). The maps include new analysis of the Faroe-Shetlands region that allows for a consistent volcanic facies map to be constructed over the entire eastern margin of the North Atlantic for the first time. A key result is that the various conjugate margin segments show a number of asymmetric patterns that are interpreted to result in part from pre-existing crustal and lithospheric structures. The compilation further shows that while the lateral extent of volcanism extends equally far to the south of the Iceland hot spot as it does to the north, the volume of material emplaced to the south is nearly double of that to the north. This suggests that a possible southward deflection of the Iceland mantle plume is a long-lived phenomenon originating during or shortly after impact of the plume.

Characterization of Seaward‐Dipping Reflectors Along the South American Atlantic Margin and Implications for Continental Breakup

“…This increase forms a triangle with the modern hot spot island of Iceland forming the oceanward apex. The updated mapping of the North Atlantic igneous provence in Á Horni et al () shows a broadly similar distribution of SDRs offshore Greenland but reduces the size of the apex and instead defines the area as the Greenland‐Iceland Ridge. These similarities suggest that the area offshore Brazil may also have been a subaerial, Iceland‐like island that formed as part of the Paraná and Etendeka flood basalt provinces, sourced from anomalously hot mantle of the Tristan plume (Campbell, ; O'Connor & Duncan, ; Renne et al, ; White & McKenzie, ).…”

Polyphase Magmatism During the Formation of the Northern East Greenland Continental Margin

“…There is consensus that the regional Late Cretaceous to early Eocene rift episode (Doré et al, 1999;Faleide et al, 2010;Hopper et al, 2014;Skogseid et al, 2000) of the North Atlantic region was accompanied by a significant magmatic event (see Meyer et al, 2007, Horni et al, 2017, and Wilkinson et al, 2016, for reviews). However, it is unclear if all of the magmatic intrusive and extrusives rocks of the North Atlantic large igneous province can be related to this event, as suggested earlier (Eldholm, 1991;Hinz et al, 1987).…”

“…This study focusses on the continental slope Magnetic chrons (left: orange; right: white) are indicated according to Gaina et al (2017) ("o" and "y" stand for "old" and "young" sides of normal (n) magnetized oceanic crust). Onshore igneous outcrops (brown) according to Horni et al (2017) and rift segment boundaries (white dashed lines) according to Tsikalas et al (2005). NAG-TEC magnetic anomaly map (Nasuti & Olesen, 2014).…”

“…Dashed lines show interpreted seafloor spreading anomalies. Onshore igneous outcrops according to Horni et al (2017).…”

“…SDRs at the continent‐ocean boundary represent subaerial to shallow marine lava flows, which were emplaced during the final rifting stage (Eldholm, ; Hinz et al, ). Typically, they have a concave‐down wedge geometry, resulting from sequential loading and subsidence of older flows (e.g., Hinz et al, ; Horni et al, ) and/or from crustal‐scale faulting (e.g., Becker et al, ; Geoffroy et al, ). On several volcanic rifted margins, there are two distinct sets of SDRs: an inner, landward SDR unit, and a second, outer SDR unit (Planke et al, ).…”