The impact of conjugate margins analysis on play fairway evaluation – an analysis of the hydrocarbon potential of Nova Scotia

Luheshi, Matt; Roberts, D.G.; Nunn, Keith; Makris, J.; Colletta, B.; Wilson, Hamish A.M.; Monnier, Frederic; Rabary, Guillaume; Dubille, M.

doi:10.3997/1365-2397.2011037

Cited by 15 publications

(14 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Based on the detailed discussion of continental stretching presented in section 5.1 and the presence of very thin crust within the COT, we challenge the interpretation of an underplated magmatic body for the OETR‐2009 model produced by GeoPro GmbH (Play Fairway Analysis Atlas, ), which was suggested to be either beneath thinned continental crust or part of the transitional crust (Luheshi et al, ). First, any voluminous volcanic intrusion within or beneath the crust would result in further thickening of the minor distal crustal swell (117–190 km) instead of the modest seaward thickening modeled.…”

Section: Discussionmentioning

confidence: 99%

“…The much smaller OBS spacing on this profile than on the SMART profiles and the high definition of the crystalline basement available from the coincident GXT‐2000 MCS line should allow for extraction of detailed crustal structural information, as was demonstrated by a recent similarly dense wide‐angle profile collected just to the north in the Orphan Basin (Watremez et al, ). Based on a preliminary OETR‐2009 velocity model, Luheshi et al () interpreted an anomalously high velocity crustal body within the COT as underplated material overlain by highly fractured basalt and, in conjunction with a reinterpretation of the SMART profiles, suggested that the magma‐rich domain extends north up to the Newfoundland‐Azores transform fault. This interpretation fundamentally changes our understanding of the tectonic setting of the margin, including the mechanism behind the transition from magmatic to amagmatic rifting.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Continent‐Ocean Transition Across the Northeastern Nova Scotian Margin From a Dense Wide‐Angle Seismic Profile

2018

View full text Add to dashboard Cite

To improve constraints on rifting processes resulting in the formation of the southeastern Canadian margin, we interpret the most detailed regional 2-D velocity model from offshore Nova Scotia constructed using wide-angle OETR-2009 data. This 405-km-long profile was collected with 78 ocean bottom seismometers. The presented data analysis and interpretation are supported by a reflection image from the coincident long streamer GXT-2000 profile. We identify a continental zone where the full-thickness (~30 km), three-layered continental crust beneath the inner shelf thins sharply seaward by a listric fault that forms a 12-km-deep Huron Subbasin beneath a high-velocity carbonate bank (~5.8 km/s), creating a shadow zone above tilted crustal blocks. Depth-dependent and variable initial thinning is evidenced in all three modeled crustal layers, which, nevertheless, pinch out together at their seaward ends. More gradual and regional thinning and a local amagmatic thickening are modeled seaward beneath the slope until 70 km from the shelf break, beyond which a deepwater amagmatic continent-ocean transition shows velocity characteristics not typical of either continental or oceanic crust. The 100-km-wide continent-ocean transition is characterized by a low-velocity (5.3-5.4 km/s), low gradient, <2-km thick upper crust, above a high-velocity (6.3-7.5 km/s), high gradient, <5-km-thick lower crust, which can be interpreted as moderately serpentinized mantle. Underneath this layer is a <5-km-thick low-velocity (7.1-8.0 km/s) partially serpentinized mantle layer. A~5-km-thick oceanic crust is modeled seaward. Our results suggest that amagmatic processes dominated the continental breakup in this area.Subsequent to these previous studies, a dense wide-angle profile OETR-2009

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Continent‐Ocean Transition Across the Northeastern Nova Scotian Margin From a Dense Wide‐Angle Seismic Profile

2018

View full text Add to dashboard Cite

show abstract

“…In this segment the deep crustal structure is constrained by the SMART‐1 and MIRROR‐1 conjugate profiles. Interpretations can be extended using the CONRAD data set on the Moroccan margin [ Holik et al ., ] and the SMART‐2 and OETR lines along the Canadian margin [ Wu et al ., ; Luheshi et al ., ] (Figure ).…”

Section: Discussionmentioning

confidence: 99%

Opening of the central Atlantic Ocean: Implications for geometric rifting and asymmetric initial seafloor spreading after continental breakup

et al. 2017

View full text Add to dashboard Cite

Study of the deep structure of conjugate passive continental margins combined with detailed plate kinematic reconstructions can provide constraints on the mechanisms of rifting and formation of initial oceanic crust. In this study the central Atlantic conjugate margins are compared based on compilation of wide‐angle seismic profiles from NW Africa Nova Scotian and U.S. passive margins. The patterns of volcanism, crustal thickness, geometry, and seismic velocities in the transition zone suggest symmetric rifting followed by asymmetric oceanic crustal accretion. Conjugate profiles in the southern central Atlantic image differences in the continental crustal thickness. While profiles on the eastern U.S. margin are characterized by thick layers of magmatic underplating, no such underplate was imaged along the African continental margin. In the north, two wide‐angle seismic profiles acquired in exactly conjugate positions show that the crustal geometry of the unthinned continental crust and the necking zone are nearly symmetric. A region including seismic velocities too high to be explained by either continental or oceanic crust is imaged along the Canadian side, corresponding on the African side to an oceanic crust with slightly elevated velocities. These might result from asymmetric spreading creating seafloor by faulting the existing lithosphere on the Canadian side and the emplacement of magmatic oceanic crust including pockets of serpentinite on the Moroccan margin. After isochron M25, a large‐scale plate reorganization might then have led to an increase in spreading velocity and the production of thin magmatic crust on both sides.

show abstract

“…The ocean-continent transition zone consists of a 75 km wide body characterized by seismic velocities between 7.2 and 7.6 km/s, which are interpreted to be serpentinized upper mantle material (Funck et al, 2004). The neighboring SMART 1 wide-angle seismic profile constrains very similar continental and oceanic crustal velocities and thicknesses (Luheshi et al, 2012). However, a high velocity body located at the ocean-continent transition zone is interpreted to consist of volcanic underplate, based on S-wave modeling.…”

Section: Comparison With the Conjugate Nova Scotia Marginmentioning

confidence: 99%

Deep crustal structure of the North-West African margin from combined wide-angle and reflection seismic data (MIRROR seismic survey)

et al. 2015

View full text Add to dashboard Cite

International audienceThe structure of the Moroccan and Nova Scotia conjugate rifted margins is of key importance for understanding the Mesozoic break-up and evolution of the northern central Atlantic Ocean basin. Seven combined multichannel reflection (MCS) and wide-angle seismic (OBS) data profiles were acquired along the Atlantic Moroccan margin between the latitudes of 31.5° and 33° N during the MIRROR seismic survey in 2011, in order to image the transition from continental to oceanic crust, to study the variation in crustal structure, and to characterize the crust under the West African Coast Magnetic Anomaly (WACMA).The data were modeled using a forward modeling approach. The final models image crustal thinning from 36 km thickness below the continent to approximately 8 km in the oceanic domain. A 100 km wide zone characterized by rough basement topography and high seismic velocities up to 7.4 km/s in the lower crust is observed westward of the West African Coast Magnetic Anomaly. No basin underlain by continental crust has been imaged in this region, as has been identified north of our study area. Comparison to the conjugate Nova Scotian margin shows a similar continental crustal thickness and layer geometry, and the existence of exhumed and serpentinized upper mantle material on the Canadian side only. The oceanic crustal thickness is lower on the Canadian margin

show abstract

The impact of conjugate margins analysis on play fairway evaluation – an analysis of the hydrocarbon potential of Nova Scotia

Cited by 15 publications

References 2 publications

Continent‐Ocean Transition Across the Northeastern Nova Scotian Margin From a Dense Wide‐Angle Seismic Profile

Continent‐Ocean Transition Across the Northeastern Nova Scotian Margin From a Dense Wide‐Angle Seismic Profile

Opening of the central Atlantic Ocean: Implications for geometric rifting and asymmetric initial seafloor spreading after continental breakup

Deep crustal structure of the North-West African margin from combined wide-angle and reflection seismic data (MIRROR seismic survey)

Contact Info

Product

Resources

About