Contrasting stress fields on correlating margins of the South Atlantic

Salomon, Eric; Koehn, Daniel; Passchier, Cees W.; Hackspacher, Peter Christian; Glasmacher, Ulrich A.

doi:10.1016/j.gr.2014.09.006

Cited by 35 publications

(29 citation statements)

References 115 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, the timing of these events is poorly constrained. Moreover, paleostress analysis in NW Namibia suggests that ENE‐WSW and NE‐SW extension prevailed during rifting and Late Cretaceous, respectively, and provides no clear evidence of compression [ Salomon et al, , ]. In the Vaalputs region, inland of the Namaqualand Highlands, normal fault‐slip structures extend into the silicified and kaolinitized weathering profiles of the Dasdap alluvial fan sediments [ Brandt et al, , ] and into the volcanic breccias preserved at the Gamoep melilite pipe (77–54 Ma) [ Phillips et al, ].…”

Section: Discussionmentioning

confidence: 99%

The chronology and tectonic style of landscape evolution along the elevated Atlantic continental margin of South Africa resolved by joint apatite fission track and (U‐Th‐Sm)/He thermochronology

et al. 2016

View full text Add to dashboard Cite

Atlantic-type continental margins have long been considered "passive" tectonic settings throughout the entire postrift phase. Recent studies question the long-term stability of these margins and have shown that postrift uplift and reactivation of preexisting structures may be a common feature of a continental margin's evolution. The Namaqualand sector of the western continental margin of South Africa is characterized by a ubiquitously faulted basement but lacks preservation of younger geological strata to constrain postrift tectonic fault activity. Here we present the first systematic study using joint apatite fission track and apatite (U-Th-Sm)/He thermochronology to achieve a better understanding on the chronology and tectonic style of landscape evolution across this region. Apatite fission track ages range from 58.3 ± 2.6 to 132.2 ± 3.6 Ma, with mean track lengths between 10.9 ± 0.19 and 14.35 ± 0.22 μm, and mean (U-Th-Sm)/He sample ages range from 55.8 ± 31.3 to 120.6 ± 31.4 Ma. Joint inverse modeling of these data reveals two distinct episodes of cooling at approximately 150-130 Ma and 110-90 Ma with limited cooling during the Cenozoic. Estimates of denudation based on these thermal histories predict approximately 1-3 km of denudation coinciding with two major tectonic events. The first event, during the Early Cretaceous, was driven by continental rifting and the development and removal of synrift topography. The second event, during the Late Cretaceous, includes localized reactivation of basement structures as well as regional mantle-driven uplift. Relative tectonic stability prevailed during the Cenozoic, and regional denudation over this time is constrained to be less than 1 km.

show abstract

Section: Discussionmentioning

confidence: 99%

The chronology and tectonic style of landscape evolution along the elevated Atlantic continental margin of South Africa resolved by joint apatite fission track and (U‐Th‐Sm)/He thermochronology

et al. 2016

View full text Add to dashboard Cite

show abstract

“…More recently, Marques et al (2014) and Nogueira et al (2015) showed structural and geophysical data evidencing inversion tectonics in the Mesozoic Araripe and Rio do Peixe basins of NE Brazil respectively, consistent with the stress field imposed by the Andean and Atlantic ridge pushes. Salomon et al (2014), carried out a paleostress study on correlating margins of S/SE Brazil and NW Namibia and concluded that contrasting stress fields affected both margins. While, the NW margin of Namibia was dominated by extension, the SE/S of Brazil was affected by strike-slip faulting with compression oriented NE-SW in the Paleogene and E-W since the Neogene, presumably related to the Nazca-South America plate convergence at those times.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Synorogenic foreland rifts and transtensional basins: A review of Andean imprints on the evolution of the San Jorge Gulf, Salta Group and Taubaté Basins

Gianni

Navarrete

Folguera

2015

Journal of South American Earth Sciences

View full text Add to dashboard Cite

“…The authors of a recent geomorphic analysis of summit surfaces in the Serra do Mar (Aires et al, 2012) proposed that km-scale normal faulting occurred during the Cenozoic. As in Scandinavia, the present-day stress field in much of Southeast Brasil is generally considered slightly compressive (Riccomini et al, 1989;Riccomini & Assumpção, 1999;Salomon et al, 2014). However, landscapes and neotectonic deformation that include components of normal faulting are also well documented (e.g., Riccomini et al, 1989;Riccomini & Assumpção, 1999;Bezerra & Vita-Finzi, 2000;Fortes et al, 2005;Gontijo-Pascutti et al, 2010;Silva & Mello, 2011).…”

Section: The Model Abroadmentioning

confidence: 99%

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

Redfield¹,

Osmundsen²

2015

NJG

View full text Add to dashboard Cite

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...

show abstract

Contrasting stress fields on correlating margins of the South Atlantic

Cited by 35 publications

References 115 publications

The chronology and tectonic style of landscape evolution along the elevated Atlantic continental margin of South Africa resolved by joint apatite fission track and (U‐Th‐Sm)/He thermochronology

The chronology and tectonic style of landscape evolution along the elevated Atlantic continental margin of South Africa resolved by joint apatite fission track and (U‐Th‐Sm)/He thermochronology

Synorogenic foreland rifts and transtensional basins: A review of Andean imprints on the evolution of the San Jorge Gulf, Salta Group and Taubaté Basins

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

Contact Info

Product

Resources

About