463-469－ The structure of volcanic margins some problematics from the North-Atlantic Labrador–Baffin system.pdf

Marine and Petroleum Geology 18 -2001) 463±469
ate/marpetgeo
The structure of volcanic margins: some problematics from the
North-Atlantic/ Labrador±Baf®n system
Laurent Geoffroy*
Laboratoire de GeÂologie, Ecole Normale SupeÂrieure, 24, rue Lhomond 75005 Paris, France
Received 2 May 2000; accepted 30 June 2000
1. Introduction Finally, it is also necessary to consider the question of the
along-strike tectonic/magmatic segmentation of volcanic
Volcanic margins are `passive' margins associated with margins. Does this segmentation exist and could it indicate
the intrusion and extrusion of large volumes of magma -. an active small-scale diapiric mechanism in the mantle
Eldholm, Skogseid, Planke, & Gladozenko, 1995). As during break-up?
clearly shown in the North-Atlantic/Labrador±Baf®n Following is a short and critical review of the current
system -), this magmatism occurred both prior to and ideas concerning each of these points, along with some
during plate break-up and early oceanic spreading -. new ideas or hypotheses, many based on recent onshore
Eldholm, 1991; Tegner et al., 1998). Volcanism predating data from volcanic margins of the North-Atlantic/Labrador±
break-up formed ¯ood basalts covering large areas, up to Baf®n break-up system.
106 km2. Volcanism coeval with plate break-up is concen-
trated at the continent±ocean boundary, notably