Structural inheritance in the North Atlantic

Schiffer, Christian; Doré, A. G.; Foulger, G. R.; Franke, Dieter; Geoffroy, Laurent; Gernigon, Laurent; Holdsworth, B.; Kusznir, Nick; Lundin, Erik; McCaffrey, K. J. W.; Peace, Alexander L.; Petersen, K.; Phillips, Thomas; Stephenson, Randell; Stoker, Martyn S.; Welford, J. Kim

doi:10.1016/j.earscirev.2019.102975

Cited by 87 publications

(62 citation statements)

References 510 publications

(789 reference statements)

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“…Furthermore, the observation that inherited structures strongly influence rift-related fault propagation is in agreement with other natural examples. For example, Phillips et al (2016) and Schiffer et al (2019) report that inherited basement structures had a major influence on the evolution of rifting in offshore Norway and in the North Atlantic, respectively. This influence on rift development has been observed in analog experiments.…”

Section: 1029/2020tc006211mentioning

confidence: 99%

Exploring the Interactions Between Rift Propagation and Inherited Crustal Fabrics Through Experimental Modeling

et al. 2020

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Continental rifting is a geodynamic process that involves the breakup of the crust and may eventually evolve to seafloor spreading. Although it is often assumed to be a product of orthogonal divergence, continental rifting may result from oblique extension, and in several cases, it is related to the rotation of plates or crustal blocks about a vertical axis. This implies the occurrence of rifts with straight but not parallel margins and rift axis-parallel gradients in extension velocity and amount of strain. The effects of rift propagation through the continental crust has only recently started to be addressed, and even less investigated is the interaction between rift propagation and inherited crustal fabrics. We have studied this issue by carrying out a series of analog laboratory experiments. Modeling results suggest that inherited linear discontinuities in the model brittle upper crust that are oriented above a threshold angle (≥45°) from the orthogonal to the rift axis have the ability to interact with rift-related structures. Depending on their orientation, such inherited discontinuities are reactivated as either transfer zones or rift-bounding faults. We compare our models with four natural prototypes in which rift propagation is likely to have occurred (the Trans Mexican Volcanic belt, the Gofa Province, the Gulf of Suez, and the Kenya Rift). For each case study, we show how the kinematics of propagating rifts is comparable to our model results, and we provide insights into how rift-related deformation may interact with inherited crustal fabrics. Plain Language Summary When the continental Earth's crust breaks due to tensional tectonic forces, deep depressions called continental rifts form. Over geological time, these features may ultimately evolve to oceans. This process is often assumed to occur symmetrically, but it has been shown that this is rarely the case. Indeed, continental rifting is often generated by the rotation of tectonic plates, which induces changes in the extension velocity along the length of the rift. In order to understand the evolution of many natural rifts, it is also important to determine how rifting interacts with existing discontinuities in the crust (e.g., faults). This issue has only been recently addressed by laboratory experimental models, in which natural processes are simulated at reduced time and length scales, using appropriate analog materials to replicate the physical properties of natural rocks. We have performed a series of experiments that test this interaction, discovering that preexisting faults can have a strong influence on the formation and evolution of continental rifts. To verify this correlation, we have compared our models with four (Mexico, Ethiopia, Egypt, and Kenya) natural cases, finding that older faults have often influenced the rifting process and the resulting structure.

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Section: 1029/2020tc006211mentioning

confidence: 99%

Exploring the Interactions Between Rift Propagation and Inherited Crustal Fabrics Through Experimental Modeling

et al. 2020

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“…The distribution of inherited basement domains (Figure 1A), established during the Caledonian Orogeny [16,[28][29][30], influenced the development of the entire North Atlantic [31,32], including the Irish Atlantic Margin [14,33]. Due to the reactivation of basement lineaments and crustal sutures during east-west extension affecting the supercontinent Pangaea [34], the Rockall Basin began to develop in the Permian [4,14] (Figure 2).…”

Section: Rockall Basinmentioning

confidence: 99%

The Rockall and the Orphan Basins of the Southern North Atlantic Ocean: Determining Continuous Basins across Conjugate Margins

MacMahon¹,

Welford²,

Sandoval³

et al. 2020

Geosciences

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Reconstructions of the opening of the North Atlantic Ocean generally result in the Orphan Basin, offshore Newfoundland, Canada, lying approximately conjugate to the rift basins on the Irish Atlantic margin at the onset of seafloor spreading toward the end of the Early Cretaceous. Most of these plate reconstructions have involved rigid plates with plate motions based solely on the interpretation of oceanic magnetic anomalies. In particular, these reconstructions often show the Rockall Basin, west of Ireland, forming a continuous Mesozoic basin with the West Orphan Basin, offshore Newfoundland. However, more recent plate reconstructions involving deformable plates have called this conjugate relationship into question. The goal of this study is to investigate the validity of this potentially continuous basin system by reconstructing and restoring present-day seismically-constrained geological models both spatially and temporally back to their original configurations pre-rift. By comparing the reconstructions in terms of sedimentary package thicknesses and crustal thicknesses in 3D, using both rigid and deformable plate reconstructions to orient the reconstructed models, we are able to test different basin connectivity scenarios using a multidisciplinary approach. Our analysis provides subsurface geophysical support for the hypothesis that the Rockall Basin was originally conjugate to and continuous with the East Orphan Basin during Jurassic rifting, later linking to the West Orphan Basin as rifting evolved during the Early Cretaceous. This complex basin evolution example highlights the need for using 3D rifting mechanism models to properly understand the fundamental driving forces during rifting and has significant implications for assessing basin prospectivity across conjugate margin pairs.

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“…Since continental rifts typically rupture previously deformed lithosphere (Wilson, 1966;Dewey and Spall,1975;Buiter and Torsvik, 2014), the distribution of early-phase strain in magma-poor rifts can be complex due to the interaction between faults that exploit or reactivate pre-existing structures, and those that form independently of any pre-existing structure (e.g., Manatschal et al, 2015;Kolawole et al, 2018;Ragon et al, 2019;Schiffer et al, 2019;Phillips et al, 2019a,b;Heilman et al, 2019;Osagiede et al, 2020). Overall, very little is known about the earliest phase of continental extension, and even less of how strain is partitioned along inherited structures; this reflects the fact that the associated structures and related stratigraphic record are typically deeply buried beneath younger (i.e., post-rift or later rift phase) sequences and are thus difficult to image with geophysical data, or are overprinted by later tectonic events (e.g., post-rift plate collision).…”

Section: Introductionmentioning

confidence: 99%

Structural Inheritance Controls Strain Distribution During Early Continental Rifting, Rukwa Rift

Kolawole¹,

Phillips²,

Atekwana³

et al. 2021

Preprint

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Little is known about rift kinematics and strain distribution during the earliest phase of extension due to the deep burial of the pre-rift and earliest rift structures beneath younger, rift-related deposits. Yet, this exact phase of basin development ultimately sets the stage for the location of continental plate divergence and breakup. Here, we investigate the structure and strain distribution in the multiphase Mesozoic-Cenozoic magma-poor Rukwa Rift, East Africa during the earliest phase of extension. We utilize aeromagnetic data that image the Precambrian Chisi Suture Zone (CSZ) and bounding terranes, and interpretations of 2-D seismic reflection data to show that, during the earliest rift phase (Permo-Triassic Karoo): (1) the rift was defined by the Lupa Fault, which exploited colinear basement terrane boundaries, and a prominent intra-basinal fault cluster (329° ±9.6) that trends parallel to and whose location was controlled by the CSZ (326°); (2) extensional strain in the NW section of the rift was accommodated by both the intra-basinal fault cluster and the border fault, where the intra-basinal faulting account for up to 60% of extension; in the SE where the CSZ is absent, strain is primarily focused on the Lupa Fault. The early-rift strain in the Rukwa Rift is thus, not accommodated by distributed faulting as suggested by classic rift models; instead, strain focuses relatively quickly on large faults and intra-basinal fault clusters following pre-existing intra-basement structures; (3) two styles of early-phase strain localization are evident, in which strain is localized onto a narrow discrete zone of basement weakness in the form of a large rift fault (Style-1 localization), and onto a broader discrete zone of basement weakness in the form of a fault cluster (Style-2 localization). We argue that the CSZ and adjacent terrane boundaries represent zones of basement mechanical weakness that controlled the first-order strain distribution and rift development during the earliest phase of extension. The established early-rift structure, modulated by structural inheritance, then persisted through the subsequent phases of rifting. The results of our study, in a young, and relatively well-exposed and data-rich rift, are applicable to understanding the structural evolution of deeper, buried ancient rifts.

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Structural inheritance in the North Atlantic

Cited by 87 publications

References 510 publications

Exploring the Interactions Between Rift Propagation and Inherited Crustal Fabrics Through Experimental Modeling

Exploring the Interactions Between Rift Propagation and Inherited Crustal Fabrics Through Experimental Modeling

The Rockall and the Orphan Basins of the Southern North Atlantic Ocean: Determining Continuous Basins across Conjugate Margins

Structural Inheritance Controls Strain Distribution During Early Continental Rifting, Rukwa Rift

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