• DOI:10.1126/science.1191349
• Corpus ID: 10943308

Dynamical Instability Produces Transform Faults at Mid-Ocean Ridges

@article{Gerya2010DynamicalIP,
  title={Dynamical Instability Produces Transform Faults at Mid-Ocean Ridges},
  author={Taras V. Gerya},
  journal={Science},
  year={2010},
  volume={329},
  pages={1047 - 1050}
}

• T. Gerya
• Published 27 August 2010
• Geology
• Science

Cracking Up Transform faults perpendicular to mid-ocean ridges are some of the most prominently visual features on the sea floor. Because they form slowly over thousands of years, the lack of observational data means their mechanism of formation has remained controversial. Taking a numerical modeling approach, Gerya (p. 1047) suggests that due to asymmetric growth of the plate boundary, sections of the mid-ocean ridge become unstable and eventually rotate 90°. As the ridge continues to grow, the transform faults continue to develop long after their initiation. This mechanism also explains how offsets of these transform faults occur discontinuously as a result of new fractures at the ridge. Transform faults on the sea floor are rotated and stretched sections of the mid-ocean ridge. Transform faults at mid-ocean ridges—one of the most striking, yet enigmatic features of terrestrial plate tectonics—are considered to be the inherited product of preexisting fault structures. Ridge offsets along these faults therefore should remain constant with time. Here, numerical models suggest that transform faults are actively developing and result from dynamical instability of constructive plate boundaries, irrespective of previous structure. Boundary instability from asymmetric plate growth can spontaneously start in alternate directions along successive ridge sections; the resultant curved ridges become transform faults within a few million years. Fracture-related rheological weakening stabilizes ridge-parallel detachment faults. Offsets along the transform faults change continuously with time by asymmetric plate growth and discontinuously by ridge jumps.