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TitleVolcanism at the western termination of the Charlie-Gibbs Fracture Zone, offshore Newfoundland
AuthorDafoe, L T; Keen, C E; Dickie, K
SourceAtlantic Geoscience Society 40th Colloquium and Annual Meeting, program with abstracts; 2014 p. 15
Alt SeriesEarth Sciences Sector, Contribution Series 20130421
PublisherAtlantic Geoscience Society
MeetingAtlantic Geoscience Society Colloquium 2014; Wolfville; CA; February 7-9, 2014
Mediaon-line; digital
File formatpdf
ProvinceEastern offshore region
Subjectsstructural geology; igneous and metamorphic petrology; volcanism; seafloor topography; seabottom topography; seamounts; Charlie-Gibbs Fracture Zone; Mesozoic; Cretaceous
ProgramFrontier basin analysis, Geoscience for New Energy Supply (GNES)
LinksOnline - En ligne
AbstractAlong the rifted northeast Newfoundland margin at the western termination of the Charlie-Gibbs Fracture Zone, we describe a previously unrecognised mid to Late Cretaceous volcanic province developed on thinned continental crust. Using seismic data, we mapped fourteen volcanic seamounts, now buried below more recent sediments. The seamounts rise 0.5 to 1.7 s twt above the surrounding basement, are about 15-20 km wide, possess a conical to flat-topped morphology, and are generally highly magnetic (up to 801 nT). These features are associated with underlying volcanic flows and sills. Based on magnetic modeling of the associated large positive magnetic anomalies, the total thickness of igneous rocks locally reaches 8 km. This magmatic upwelling occurred in the vicinity of the Charlie-Gibbs Fracture Zone and extends approximately 150 km north along the rifted continental margin. The volcanic pr ovince forms the northe rn boundary to the Jura ssic-Early Cretaceous Orphan Basin. At this boundary, deep crustal reflectors abruptly terminate ag ainst the volcanic province, suggesting the presence of a transform margin. Similar terminations of crustal reflectors extend further into Orphan Basin along trends similar to those of pre-rift Appalachian terrane boundaries on the adjacent shelf. This suggests the existence of a pre-existing weak zone in the continental lithosphere within which a le aky transform margin developed, and may have controlled the location of final continental brea kup between the Rockall and North American plates in the Late Cretaceous.
Summary(Plain Language Summary, not published)
Located offshore of Newfoundland, the Orphan Basin is a large frontier area which contains significant Jurassic oil reserves along its southeast edge (Flemish Pass Basin). In this study, we focus on the northern edge of the basin where the Charlie-Gibbs Fracture Zone offsets the margin and meets a weak zone in the continental crust. We have identified significant accumulations of volcanics associated with this region. In addition to the tectonic story, this paper also refines the northern boundary of Orphan Basin which has implications for industry exploration.