The Moho Architecture and Its Role for Isostasy—Insights From the Lofoten‐Vesterålen Rifted Margin, Norway

Abstract

Rifted continental margins are complex zones of transition between continental to oceanic lithosphere. They are often formed by multiple episodes of continental rifting, which ultimately result in the breakup of continental lithosphere (Bradley, 2008;Franke, 2013). The structure of rifted continental margins can be very complex and include (a) variations in crustal thickness, including ribbons, horst and graben structures, and hyperextension (e.g., Gernigon et al., 2020;Péron-Pinvidic & Manatschal, 2010); (b) exhumation of mantle lithosphere (Péron-Pinvidic & Manatschal, 2010;Sibuet, 1992); (c) various amounts of volcanic products (e.g., Franke, 2013;Thybo & Artemieva, 2013); and (d) so-called lower crustal bodies, or high velocity/density lower crust (e.g., Gernigon et al., 2004; from now on called high velocity lower crust, or HVLC). HVLC is predominantly observed in wide-angle refraction studies across rifted continental margins, with characteristic P-wave velocities (Vp) of typically ∼7.1-7.6 km/s, and is usually associated with higher-than-normal (crustal) densities. Such HVLC is not confined to continental margins. For example, it can be found in former collision/suture zones, as well as in cratonic crust or in rift zones (e.g., Schulte-Pelkum et al., 2017;Thybo & Artemieva, 2013).