Elevated, passive continental margins: Not rift shoulders, but expressions of episodic, post-rift burial and exhumation

Japsen, Peter; Chalmers, James A.; Green, Paul F.; Bonow, Johan M.

doi:10.1016/j.gloplacha.2011.05.004

Cited by 136 publications

(103 citation statements)

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“…This constraint, plus the textural relationships of the fault rocks in the core, suggests multiple periods of relatively slow uplift probably occurred after 72 Ma, potentially throughout the entire Cenozoic. Davidsen et al, 2001;Bøe et al, 2010) Davidsen et al (2001) and Ramberg et al (2006) Japsen et al, 2012b) Davidsen et al (2001), Ramberg et al (2008), Hendriks et al (2010) and Osmundsen et al (2010).…”

Section: Interpretedmentioning

confidence: 98%

Some remarks on the earthquakes of Fennoscandia: A conceptual seismological model drawn from the perspective of hyperextension

Redfield¹,

Osmundsen²

2015

NJG

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To a first order, patterns of Fennoscandia's seismicity reflect the benchmark domain boundaries of its Mesozoic rifted margin. Three distinct belts of earthquakes strike sub-parallel to the generalized line of breakup. The outermost seismic belt (SB1) marks the Taper Break (TB), or the zone of flexural coupling/decoupling between the distal (seaward) and proximal/necking (landward) domains. A coastal belt (SB2) follows the Innermost Limit of Extension, defined as the onset of 39 km-thick crystalline continental crust. An interior belt (SB3) follows the Hinterland Break in Slope, or the landward limit of the Scandinavian rifted margin. Between each belt, large portions of the necking, proximal, and hinterland domains are seismically quiescent. Evaluation of the 'Cumulative Seismic Moment' (CSM w ) per unit area indicates that the release of seismic energy is asymmetric. Although some of Fennoscandia's largest seismic events occur in the dominantly Proterozoic to Archean lithosphere of the eastern craton, 80% of Fennoscandian CSM w maps to the domain boundaries of the western rifted margin. CSM w energy tends to be highest at the TB and decreases system atically towards the continental interior.As proposed by many previous studies, a first-order spatial correlation between Scandinavia's offshore earthquake belt and voluminous, geo logically rapid, sedimentary loading during the Neogene period is evident. However, the presence of thinned, faulted crystalline basement is also a very important factor behind Scandinavia's offshore seismicity. Where the Neogene deposits are at their thickest the underlying crust is dominantly oceanic; CSM w is lower per unit area there than where lesser Plio-Pleistocene loading impacts continental crust that was fully prepared by Mesozoic necking and hyperextension. CSM w data suggest that the 'strength' of the TB and the continental margin's distal domain is significantly less than that of relatively young (ca. 54 Ma) oceanic lithosphere. Our data imply that ridge push does not contribute significantly to Fennoscandia's seismicity. Rather, we find that thin-plate bending stresses stemming from offshore depositional loading conspire with unbuttressed Gravitational Potential Energy (GPE), onshore erosion, and post-glacial isostatic rebound to generate Fennoscandia's earthquakes.We present a conceptual seismological model for Fennoscadia that is consistent with modern hypotheses of extended margin evolution, including post-breakup reactivation by footwall uplift in regions adjacent to sharp crustal taper. Illustrated by simple concepts of elastic thin-plate theory, the model honors our conclusion that Fennoscandian seismicity is principally the product of locally derived stress fields and that far field stress from the oceanic domain is unlikely to penetrate deeply into a hyperextended continental margin. It predicts the locations of the observed seismic belts and seismic gaps with the mathematics of thin-plate bending. It describes how the outer seismic belt will remain localized in the...

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Section: Interpretedmentioning

confidence: 98%

Some remarks on the earthquakes of Fennoscandia: A conceptual seismological model drawn from the perspective of hyperextension

Redfield¹,

Osmundsen²

2015

NJG

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“…Doré & Lundin 1996;Japsen & Chalmers 2000;Lundin & Doré 2002;Ritchie et al 2003;Gomez & Verges 2005;Doré et al 2008;Stoker et al 2010;Tuitt et al 2010;Japsen et al 2012;Yamato et al 2013;Døss-ing et al 2016). Cenozoic compressional domes have been described on the Vøring, Faroe -Shetland and Hatton margins, in the Rockall Basin (for a short summary see Kimbell et al 2016), and in the NE Greenland margin (Price & Whitham 1997;Hamann et al 2005).…”

Section: Subduction In the Pacific And Mediterranean Realms And The mentioning

confidence: 99%

Break-up and seafloor spreading domains in the NE Atlantic

Gaina

Nasuti

Kimbell

et al. 2017

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An updated magnetic anomaly grid of the NE Atlantic and an improved database of magnetic anomaly and fracture zone identifications allow the kinematic history of this region to be revisited. At break-up time, continental rupture occurred parallel to the Mesozoic rift axes in the south, but obliquely to the previous rifting trend in the north, probably due to the proximity of the Iceland plume at 57-54 Ma.The new oceanic lithosphere age grid is based on 30 isochrons (C) from C24n old (53.93 Ma) to C1n old (0.78 Ma), and documents ridge reorganizations in the SE Lofoten Basin, the Jan Mayen Fracture Zone region, in Iceland and offshore Faroe Islands. Updated continent -ocean boundaries, including the Jan Mayen microcontinent, and detailed kinematics of the EocenePresent Greenland-Eurasia relative motions are included in this model.Variations in the subduction regime in the NE Pacific could have caused the sudden northwards motion of Greenland and subsequent Eurekan deformation. These events caused seafloor spreading changes in the neighbouring Labrador Sea and a decrease in spreading rates in the NE Atlantic. Boundaries between major oceanic crustal domains were formed when the European Plate changed its absolute motion direction, probably caused by successive adjustments along its southern boundary.

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“…It is now clear that geological stability is an inexact term in this context. Ocbils on passive margins 'are subject to a variety of sources of stress, mediated through several different processes' (Blenkinsop and Moore 2013; see also Japsen et al 2012). Sandiford's (2007) concept of Australia as a tilting continent affords an example, highlighting why the SWAFR is one of the most earthquake-prone regions of the continent despite being on a passive margin of the Australian Plate.…”

Section: On Defining and Identifying Landscapes And Ocbilsmentioning

confidence: 99%

Biodiversity hotspots and Ocbil theory

Hopper

Silveira

Fiedler³

2015

Plant Soil

161

129

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Background Ocbil theory aims to develop hypotheses explaining the evolution and ecology of, and best conservation practices for, biota on very old, climatically buffered, infertile landscapes (Ocbils). Scope This paper reviews recent multi-disciplinary literature inspired by or reacting to aspects of Ocbil theory and discusses how it can assist conservation in biodiversity hotspots. Conclusions Ocbils occur in at least 12 out of 35 known terrestrial hotspots, but also in other biologically significant sites. Most evidence comes from the Southwest Australian and Greater Cape Floristic Regions, South America's Pantepui, and the Campo Rupestre of Brazil, though predictions of the theory have been corroborated in 22 sites across South America, Western and Eastern Africa, Southern Asia, and Oceania. Most hypotheses have been corroborated, indicating that Ocbil theory has survived largely intact after 6 years of independent scientific critique, quantitative experimentation, and development. The theory also has been extended to allow identification and characterization of OCBISs (old, climatically-buffered, infertile seascapes), and OCFELs (old, climatically-buffered, fertile landscapes). We illustrate that the principles of Ocbil theory are key to conservation of biodiversity at global scale and provide new directions for research that can improve the theoretical and practical contributions of Ocbil theory.

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Elevated, passive continental margins: Not rift shoulders, but expressions of episodic, post-rift burial and exhumation

Cited by 136 publications

References 91 publications

Some remarks on the earthquakes of Fennoscandia: A conceptual seismological model drawn from the perspective of hyperextension

Some remarks on the earthquakes of Fennoscandia: A conceptual seismological model drawn from the perspective of hyperextension

Break-up and seafloor spreading domains in the NE Atlantic

Biodiversity hotspots and Ocbil theory

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