Understanding the offshore flood basalt sequence using onshore volcanic facies analogues: an example from the Faroe–Shetland basin

Abstract

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Abstract -Flood basalts in associated volcanic rifted margins, such as the North Atlantic Igneous Province, have a significant component of lavas which are preserved in the present day in an offshore setting. A close inspection of the internal facies architecture of flood basalts onshore provides a framework to interpret the offshore sequences imaged by remote techniques such as reflection seismology. A geological interpretation of the offshore lava sequences in the Faroe-Shetland Basin, using constraints from onshore analogues such as the Faroe Islands, allows for the identification of a series of lava sequences which have characteristic properties so that they can be grouped. These are tabular simple flows, compound-braided flows, and sub-aqueously deposited hyaloclastite facies. The succession of volcanic rocks calculated in this study has a maximum thickness in excess of 6800 m. Down to the top of the sub-volcanic sediments, the offshore volcanic succession has a thickness of about 2700 m where it can be clearly identified across much of the area, with a further 2700 m or more of volcanic rock estimated from the combined gravity and seismic modelling to the north and west of the region. A large palaeo-waterbody is identified on the basis of a hyaloclastite front/apron consisting of a series of clinoforms prograding towards the eastern part of the basin. This body was > 500 m deep, must have been present at the onset of volcanism into this region, and parts of the water body would have been present during the continued stages of volcanism as indicated by the distribution of the hyaloclastite apron.

Basin-scale architecture of deeply emplaced sill complexes: Jameson Land, East Greenland

“…Saunders et al 1997;Hansen et al 2009;Jerram et al 2009;Brooks 2011;Nelson et al 2015). Along East Greenland this opening propagated northwards to the Norwegian-Greenland Sea and led to plate separation occurring during the Eocene (c. 55 Ma), and was accompanied by widespread igneous activity along 2000 km of the conjugate rifted margins (e.g.…”

Pre-breakup magmatism on the Vøring Margin: Insight from new sub-basalt imaging and results from Ocean Drilling Program Hole 642E

“…Berndt et al, 2001). These peculiar volcanic successions display a large variety of seismic facies that are indicative of the style of volcanic emplacement, depositional environment and subsequent mass transport Planke et al, 2000;Brendt et al, 2001;Jerram et al, 2009;Wright et al, 2012;Abdelmalak et al, Submitted). The volcanic sequences emplaced during the onset of the breakup, partially masked seismically the Late Cretaceous-Eocene and older sedimentary strata and continental structures inferred in the outermost part of the Vøring Margin.…”

Dating the onset and nature of the Middle Permian Emeishan large igneous province eruptions in SW China using conodont biostratigraphy and its bearing on mantle plume uplift models

“…It is noteworthy that Jerram et al (2009) have shown significant thicknesses of hyaloclastite in FaroeShetland basin of the NAIP, which also occur onshore in Greenland, pointing to significant parts of the area not having significant uplift, and therefore complicating the simple plume model in the NAIP example. The domal uplift model may become significantly modified resulting in regions of crustal dilation and contraction.…”