Crustal structure and origin of the Eggvin Bank west of Jan Mayen, NE Atlantic

Abstract

The Eggvin Bank, located between the Jan Mayen Island and Greenland, is an unusually shallow area containing several submarine volcanic peaks, confined by two transforms on the Northern Kolbeinsey Ridge (NKR). We represent P and S wave velocity models for the Eggvin Bank based on an Ocean Bottom Seismometer profile collected in 2011, showing igneous crustal thickness variations from 8 km to 13 km. A 2–5 km increase is associated with two separate 20–30 km wide segments under the main seamounts. The oceanic crust has three layers: upper crust (L2A: 2.8–4.8 km/s), middle crust (L2B: 5.5–6.5 km/s), and lower crust (L3: 6.7–7.35 km/s). Both the thick layer 2(A/B) and the high ratio of layer 2(A/B) thickness to total crustal thickness indicate that secondary, intraplate magmatism built the seamounts of the Eggvin Bank. The seamount in the north where the crust is thickest has a flat top indicating subaerial exposure but is deeper than those with rounded tops in the south and is therefore probably older. Comparing lower crustal seismic velocity with crustal thickness also indicates that the degree of mantle melting may be higher in the north than in the south. An enriched mantle source presently feeds the NKR magmatism and probably influenced the Eggvin Bank development also at earlier times. To what extent the Eggvin Bank has been influenced by the Iceland plume is uncertain, both an enriched mantle component and elevated mantle temperature may have played a role at different times and locations.

Lithospheric Control on Asthenospheric Flow From the Iceland Plume: 3‐D Density Modeling of the Jan Mayen‐East Greenland Region, NE Atlantic

“…Thus, the observed trends show a substantial deviation in mantle thermal structure compared to the theoretical half-space cooling model. The poor correlation between the basement depth and oceanic ages observed under the NKR domain is on the other hand, most likely related to large crustal thickness variations as mapped in the eastern NKR by Tan et al (2017).…”

“…Previous studies, including (i) the interpretation of reflection seismic data (Blischke et al, 2016;Peron-Pinvidic et al, 2012a, 2012b, (ii) wide-angle refraction seismic data (Breivik, Mjelde, Faleide, Murai, 2012;Hermann & Jokat, 2016;Kandilarov et al, 2012Kandilarov et al, , 2015Klingelhöfer, Géli, & White, 2000;Klingelhöfer, Géli, Matias, et. al., 2000;Kodaira et al, 1997Kodaira et al, , 1998bTan et al, 2017;Voss & Jokat, 2007;Weigel et al, 1995), and (iii) studies of dredged samples (e.g., Elkins et al, 2011Elkins et al, , 2016Haase et al, 2003;Klingelhöfer, Géli, & White, 2000;Mertz et al, 2004;Schilling, 1999), show that the study area is characterized by large variations in terms of crustal structure as well as mantle composition, and mantle melting degree. Table 1 and Figure 1 provide an overview of the data types and sources used to develop a 3-D structural and density model for the crystalline crust and sedimentary cover.…”

“…The Eggvin Bank is a shallow region surrounding the northern Kolbeinsey Ridge segment. A seismic refraction line across the bank approximately 70 km east of the spreading ridge shows large variations in crustal thickness (from 8 to 13 km; Tan et al, ). The seismic velocities indicate that there could be some thermal Iceland plume influence under the northern Eggvin Bank, while the elevated magmatism in the southern Eggvin Bank may be mostly affected by an enriched mantle source (Tan et al, ).…”

Dynamic Topography Development North of Iceland from Subaerial Exposure of the Igneous Logi Ridge, NE Atlantic

“…Thick black lines show the multichannel seismic reflection lines by the Norwegian Petroleum Directorate (Sandstå et al, 2012), while the white lines indicate our own single-channel seismic reflection survey used in the study. White-filled circles show the location of the OBS positions along the Profile 1 (Tan et al, 2017). Yellow solid lines show seismic profiles along the east Greenland margin (Berger & Jokat, 2008).…”

Crustal S-wave velocity structure across the northeastern South China Sea continental margin: implications for lithology and mantle exhumation

“…Two types of S‐wave arrivals, PPS and PSS, can be identified in the radial components. The PPS wave travels initially as a P‐wave and is converted into S‐wave at an interface on the way up, whereas the PSS wave is converted into S‐wave on the way down, often at the seafloor or a sediment‐crust interface (Au and Clowes, ; Tan PC et al, ). The PSS phases are the main S‐wave phases that give direct estimates of V S in the crust.…”