Structural characteristics of the ocean-continent transition along the rifted continental margin, offshore central Labrador

Keen, C. E.; Dickie, K; Dafoe, Lynn T.

doi:10.1016/j.marpetgeo.2017.10.012

Cited by 30 publications

(33 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The NW Atlantic Manuscript under review for Interpretation formed via multiphase, divergent motion between Greenland and North America, resulting in oceanic crust in the Labrador Sea and Baffin Bay but not the Davis Strait (Chalmers and Pulvertaft, 2001;Hosseinpour et al, 2013;Peace et al, 2018b;Jauer et al, 2019). Estimates of breakup timing in the Labrador Sea ( Figure 1) are variable depending on the interpretation of the earliest magnetic anomaly, ranging from approximately 62 to 80 Ma (Roest and Srivastava, 1989;Chalmers and Laursen, 1995;Srivastava and Roest, 1999;Keen et al, 2017).…”

Section: Manuscript Under Review For Interpretationmentioning

confidence: 99%

Conjugate margins — An oversimplification of the complex southern North Atlantic rift and spreading system?

Peace

Welford

2020

Interpretation

View full text Add to dashboard Cite

The prevalence of conjugate margin terminology and studies in the scientific literature is testimony to the contribution that this concept and approach has made to the study of passive margins, and more broadly extensional tectonics. However, when applied to the complex rift, transform, and spreading system of the southern North Atlantic (i.e., the passive margins of Newfoundland, Labrador, Ireland, Iberia, and southern Greenland), it becomes obvious that at these passive continental margin settings, additional geologic phenomena complicate this convenient description. These aspects include (1) the preservation of relatively undeformed continental fragments, (2) formation of transform systems and oblique rifts, (3) triple junctions (with rift and spreading axes), (4) multiple failed rift axes, (5) postbreakup processes such as magmatism, (6) localized subduction, and (7) ambiguity in identification of oceanic isochrons. Comparison of two different published reconstructions of the region indicates the ambiguity in conducting conjugate margin studies. This demonstrates the need for a more pragmatic approach to the study of continental passive margin settings where a greater emphasis is placed on the inclusion of these possibly complicating features in palinspastic reconstructions, plate tectonics, and evolutionary models.

show abstract

Section: Manuscript Under Review For Interpretationmentioning

confidence: 99%

Conjugate margins — An oversimplification of the complex southern North Atlantic rift and spreading system?

Peace

Welford

2020

Interpretation

View full text Add to dashboard Cite

show abstract

“…The asymmetry is interpreted as related to differences between lower-and upper-plate architectures formed during hyperextension. Iberia-Newfoundland after Sutra et al (2013); Labrador-West Greenland after Keen et al (2018); and Porcupine basin after McDermott et al (2014). The hyperextended domain corresponds to the coupled domain defined by Sutra et al (2013). lower plate (Nirrengarten et al, 2016).…”

Section: Asymmetric Rifted Margins: Observations and Conceptsmentioning

confidence: 99%

Thermal Evolution of Asymmetric Hyperextended Magma‐Poor Rift Systems: Results From Numerical Modeling and Pyrenean Field Observations

Lescoutre

Tugend

Brune

et al. 2019

Geochem Geophys Geosyst

View full text Add to dashboard Cite

We investigate the thermal and structural evolution of asymmetric rifted margin using numerical modeling and geological observations derived from the Western Pyrenees. Our numerical model provides a self-consistent physical evolution of the top basement heat flow during asymmetric rifting. The model shows a pronounced thermal asymmetry that is caused by migration of the rift center toward the upper plate. The same process creates a diachronism for the record of maximum heat flow and maximum temperatures (T max ) in basal rift sequences. The Mauléon-Arzacq basin (W-Pyrenees) corresponds to a former mid-Cretaceous asymmetric hyperextended rift basin. New vitrinite reflectance data in addition to existing data sets from this basin reveal an asymmetry in the distribution of peak heat (T max ) with respect to the rift shoulders, where highest values are located at the former upper-to lower-plate transition. This data set from the Arzacq-Mauléon field study confirms for the first time the thermal asymmetry predicted by numerical models. Numerical modeling results also suggest that complexities in synrift thermal architecture could arise when hanging-wall-derived extensional allochthons and related T max become part of the lower plate and are transported away from the upper-to lower-plate transition. This study emphasizes the limitations of the common approach to integrate punctual thermal data from pre-rift to synrift sedimentary sequences in order to describe the rift-related thermal evolution and paleothermal gradients at the scale of a rift basin or a rifted margin.

show abstract

“…Rifting along the central Labrador margin initiated during the Early Cretaceous and breakup occurred in Maastrichtian or Paleocene time (e.g., Oakey and Chalmers, 2012). Wide-angle reflection/refraction data suggest the presence of a domain of exhumed serpentinized mantle (Chian et al, 1995;Keen et al, 1994Keen et al, , 2017. Discontinuous reflectors are visible below the top basement in the domains interpreted by Keen et al (2017) as the zone of exhumed mantle and the proto-oceanic domain (Fig.…”

Section: The Labrador Rifted Marginmentioning

confidence: 99%

The role of serpentinization and magmatism in the formation of decoupling interfaces at magma-poor rifted margins

Gillard

Tugend

Müntener

et al. 2019

Earth-Science Reviews

View full text Add to dashboard Cite

In spite of recent progress in the understanding of magma-poor rifted margins, the processes leading to the formation and evolution of the exhumed mantle domain and its transition toward steady state oceanic crust remain debated. In particular, the parameters controlling the progressive localization of extensional deformation and magmatic processes leading to the formation of an oceanic spreading center are poorly understood. In this paper, we highlight the occurrence of two major decoupling horizons controlling the structural and magmatic evolution of distal magma-poor rifted margins. They are marked by strong seismic reflectors located at about 1 sec TWTT (Upper Reflectors-UR) and 2 sec TWTT (Lower Reflectors-LR) below top basement in domains of exhumed mantle at several magma-poor rifted margins. Both reflection seismic observations and studies on the physical properties of serpentinized mantle suggest that the UR likely results from deformation localized along a rheological interface at about 3 km below top basement, associated with an abrupt change in the mechanical behavior of peridotites once they are serpentinized to ~15%. We suggest that this interface played a major role in successive fault reorganizations during formation of the exhumed mantle domain. The comparison of reflection seismic observations with Alpine field analogues suggests that the LR likely results from an interaction between magmatism, deformation and hydration reactions during final rifting. Based on our results, we suggest that during final rifting the strain distribution is controlled first by hydration and then by magmatic processes in the domain of exhumed mantle.

show abstract

Structural characteristics of the ocean-continent transition along the rifted continental margin, offshore central Labrador

Cited by 30 publications

References 54 publications

Conjugate margins — An oversimplification of the complex southern North Atlantic rift and spreading system?

Conjugate margins — An oversimplification of the complex southern North Atlantic rift and spreading system?

Thermal Evolution of Asymmetric Hyperextended Magma‐Poor Rift Systems: Results From Numerical Modeling and Pyrenean Field Observations

The role of serpentinization and magmatism in the formation of decoupling interfaces at magma-poor rifted margins

Contact Info

Product

Resources

About