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TitleA volcanic province near the western termination of the Charlie-Gibbs Fracture Zone at the rifted margin, offshore northeast Newfoundland
AuthorKeen, C E; Dafoe, L T; Dickie, K
SourceTectonics vol. 33, issue 6, 2014 p. 1133-1153,
Alt SeriesEarth Sciences Sector, Contribution Series 20130368
PublisherAmerican Geophysical Union
Mediapaper; on-line; digital
File formatpdf
ProvinceEastern offshore region
AreaOrphan Basin
Lat/Long WENS-53.0000 -43.0000 54.0000 48.0000
Subjectstectonics; geophysics; tectonic elements; tectonic history; tectonic environments; tectonic interpretations; tectonic evolution; rifting; rifts; fracture zones; magnetic interpretations; Charlie-Gibbs Fracture Zone; Mesozoic; Cretaceous
Illustrationslocation maps; tables; profiles; plots
ProgramFrontier basin analysis, Geoscience for New Energy Supply (GNES)
AbstractA mid-Cretaceous to Late Cretaceous volcanic province, named here the Charlie-Gibbs Volcanic Province, is described near the western termination of the Charlie-Gibbs Fracture Zone, against the rifted continental margin northeast of Newfoundland. We used seismic data to map 14 volcanic seamounts, now buried below younger sediments. They rise 0.7 to 2 s two-way time (twt) above the surrounding basement level and are about 8 - 30 km wide. Some are conical while others are more flat-topped. Underlying igneous units resembling flows and sills are also observed. Based on magnetic modeling of the large positive magnetic anomalies associated with the seamounts, the total thickness of igneous rocks can locally reach about 8 km. This magmatism occurred in the vicinity of the Charlie-Gibbs Fracture Zone and extends about 150 km to the north along the rifted continental margin. The volcanic province also forms the northern boundary of the Jurassic-Early Cretaceous Orphan Basin, along a major transform margin there. Truncation of rift-related structures which extend to deep crustal levels is observed at the transform, along trends similar to those of prerift Appalachian terrane boundaries on the adjacent shelf. This suggests the existence of a preexisting weak zone in the continental lithosphere within which a complex strike-slip fault system developed and may have controlled the location of final continental breakup 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). During opening of the North Atlantic Ocean, this region was subject to several phases of extension which resulted in a wide basin containing shallow marine Jurassic and Cretaceous sediments, and deepwater Cenozoics. 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 which we have called the Charlie-Gibbs Volcanic Province. We describe the nature of the volcanic rocks and their relationship to the complex margin segment which may have formed as part of a leaky-transform. In addition to the tectonic story, this paper also refines the northern boundary of Orphan Basin which has implications for industry exploration.