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TitleWestern Davis Strait, a volcanic transform margin with petroliferous features
AuthorJauer, C D; Oakey, G N; Li, Q
SourceMarine and Petroleum Geology vol. 107, 2019 p. 59-80,
Alt SeriesNatural Resources Canada, Contribution Series 20180146
PublisherElsevier BV
Mediapaper; on-line; digital
File formatpdf (Adobe® Reader®); html
ProvinceNunavut; Northern offshore region
NTS15; 16; 25A; 25H; 25I; 26P; 27A
AreaDavis Strait; Baffin Island
Lat/Long WENS -65.0000 -57.0000 68.5000 60.0000
Subjectsmarine geology; structural geology; tectonics; fossil fuels; geophysics; sedimentary basins; petroleum resources; hydrocarbons; hydrocarbon potential; petroleum occurrence; oil slicks; gas seeps; methane; source rocks; thermal maturation; bedrock geology; basement geology; structural features; fault zones; faults; faults, extension; faults, thrust; faults, transform; grabens; fracture zones; lithology; igneous rocks; volcanic rocks; basalts; intrusive rocks; sedimentary rocks; geophysical interpretations; seismic interpretations; gravity interpretations; gravity anomalies; bouguer gravity; magnetic interpretations; magnetic anomalies; geophysical logging; tectonic setting; tectonic history; magmatism; volcanism; rifting; rifts; plate margins; intrusions; sills; sea floor spreading; oceanic crust; continental crust; structural analyses; core samples; dredge sampling; remote sensing; satellite imagery; radar methods; exploration wells; Paleogene; Eocene; Paleocene; Saglek Basin; Lady Franklin Basin; Ungava Fault Zone; Davis Strait Fault; Tariut Basin; Imaqpik Basin; Aassiat Basin; North Ungava Basin; Kangamiut Basin; Maniitsoq Basin; Nuuk Basin; Gjoa Rise; Davis Strait High; petroleum systems; geological mapping; flood basalts; synthetic aperture radar; Phanerozoic; Cenozoic; Tertiary; Mesozoic; Cretaceous; Paleozoic
Illustrationslocation maps; geoscientific sketch maps; profiles; seismic profiles; stratigraphic charts; geophysical logs; seismograms; cross-sections; schematic representations
ProgramGEM2: Geo-mapping for Energy and Minerals, Baffin Petroleum Systems
Released2019 05 11
AbstractWe present a compilation of the western Davis Strait region offshore southeastern Baffin Island, Nunavut, Canada with new subsurface geological structural details and observations regarding past hydrocarbon occurrences from scientific and commercial exploration.
This consists of seismic mapping with archival data correlated with a filtered marine Bouguer anomaly gravity compilation and magnetic data sets covering northern Saglek Basin, the western part of the Lady Franklin Basin and the Ungava Fault Zone from south of Baffin Bay.
A regional seismic horizon for mapping basin architecture comes from the top of the Paleogene volcanic syn-magmatic zone, where pervasive volcanic flows and intrusions are intermingled with the sedimentary section. The seismic depth map to the top of the regional volcanic seismic horizon shows pre-rift sedimentary basins having maximum depths of approximately 4-5 km flanking the shallower Ungava Fault Zone. Correlation of Bouguer anomaly gravity and magnetic data interpretations with the seismic mapping, indicate that over some areas true crystalline basement is deeper than can be determined by reflection seismic, as the base of the syn-magmatic section is not resolvable for seismic mapping.
Extensive Paleogene mafic intrusives and extrusive basalts dominate the architecture of this volcanic rifted margin as seen by the dominant high amplitude magnetic anomalies associated with many deeper structures. The over 250 km long Davis Strait Fault is recognised as the key structural element of the Ungava Fault Zone (UFZ) and valley complex. The adjoining Davis Strait High maps on seismic as a continuous structure running the length of Davis Strait plunging southwards to a Bouguer gravity high feature that terminates the western end of the extinct Eocene spreading zone south of Davis Strait. This horn shaped structural feature establishes the presence of an accommodation zone with multiple faults and localised thrust faulting as required to fit the complex mechanics for strike-slip motion that occurs along the south end of this transform fault system. The revised marine Bouguer anomaly gravity data set also defines two new, near shore grabens east of Cumberland Sound, the southern Tariut Basin and the northern Imaqpik Basin, each extending over 100 km in length with sediment thicknesses of at least 4 km. These pre-rift basins most likely originate from the Paleozoic based on seafloor dredge and nearby shallow drill cores from previous studies. The hydrocarbon charge of a previously unexplained petroliferous shallow marine drill core that is adjacent the eastern edge of the Tariut Basin is attributed to Paleozoic source rocks that have undergone enhanced thermal maturation from sill intrusion associated with rifting. The Imaqpik Basin shows strong evidence of a hydrocarbon system from the proximity of clustered interpreted sea surface oil slicks, mapped from satellite radar images, and a local zone of anomalously high dissolved methane measured within the water column that originates from the seafloor immediately east of Cape Dyer at the northern limit of that basin. The overlying Cape Dyer flood basalt field extends from limited onshore exposures into the offshore and maps with magnetic data over an area of approximately 13,000 km2. This extrusive feature and it's implicit underlying intrusive components are likely the unconventional heat source for the anomalous enhanced thermal maturation of Paleozoic to Paleogene source rocks in these pre-rift basins that host this previously unrecognised petroleum system.
Summary(Plain Language Summary, not published)
The marine geology of the west side of Davis Strait, offshore Baffin Island, Nunavut, has been sporadically studied over the past 50 years. This desktop synthesis of vintage data that was re examined now shows that there are two new offshore basins present that have potential for petroleum resources. These basins account for satellite and ship observations of naturally occurring oil slicks, formed from oil leaking from the seafloor. This study complements and expands the more extensive work done by Denmark of the eastern side of Davis Strait.