Yesterday, our paper on rift migration and formation of asymmetric continental margins was published in Nature Communications. Using high resolution forward numerical models we investigate the influence of extension velocities on the evolution of continental rifts to passive margins. We find a strong correlation between margin width, asymmetry and extension velocity, illustrated by the conjugate South Atlantic passive margins. Our models can explain the highly asymmetric and hyperextended passive continental margins, further, we propose that large amounts of crustal material during the rift migration phase are transferred from one side of the rift to the other, challenging conventional ideas about passive margin formation. This means that large parts of the outer margins off West Africa could actually be composed of crustal material originating from the conjugate Brazilian margin.
(a–e) Fault kinematics of the model. Active faults are shown in red and inactive faults in black. Brittle faults are indicated with solid lines, ductile shear zones with dashed lines. The wide margin is formed through rift migration and sequentially active faulting towards the future ocean. Hence, thick undisturbed pre-salt sediments pre-dating break-up are predicted by our model to be deposited in the landward part of the margin (d,e). The final crustal structure of the model reproduces the strong asymmetry (f) of the conjugate Campos Basin–Angola margins (modified after ref. 5). Note that the geosection is drawn without vertical exaggeration at the same scale as the model (scale bar in the lower right corner is 50 km long). Vertical scale is in seconds two-way travel time (TWT). Source: Brune, Heine, Perez-Gussinye & Sobolev, Nature Communications (http://www.nature.com/ncomms/2014/140606/ncomms5014/full/ncomms5014.html), licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License (http://creativecommons.org/licenses/by-nc-nd/3.0/).
The GFZ Potsdam has also issued a press release related to this [in German].
Citation: Sascha Brune, Christian Heine, Marta Pérez-Gussinyé & Stephan V. Sobolev, 2014, “Rift migration explains continental margin asymmetry and crustal hyper-extension”, Nature Communications, 5, doi: 10.1038/ncomms5014. The paper is openly accessible, licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
Update 1 (2014-06-11):
Nature Comms’ Article metrics are a pretty cool indicator for immediate online impact (and I believe future citations). By now a few of the standard science news outlets have picked up the press releases (changing by the minute. Here’s a static (and human) collection of the news around the article (including some of the Altmetric links):
- CienciaPlus.es: La separación de América del Sur y África creó márgenes asimétricos
- ScienceDaily
- BeforeItsNews:
- EurekaAlert: Asymmetric continental margins and the slow birth of an ocean
TectonicWaters 